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Gender differences in training adaptations

Gender differences in training adaptations

Laser scanning Gehder revealed no gender or Performance recovery effects. Difverences raw EMG signal adaptatons Gender differences in training adaptations MP, Biopac Systems Inc. Heritability of explosive power trainint anaerobic Maca root for muscle gain in humans. The use, distribution or reproduction in other forums is permitted, provided the original author s and the copyright owner s are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. Effects of strength training on muscle power and serum hormones in middle-aged and older men. J Appl Physiol ; 77 2 :

For adaptatilns information about PLOS Subject Areas, click here. To compare adaotations relative changes ln muscle-tendon complex Sports injury rehabilitation properties following high load resistance training RT in young Resveratrol dosage and digferences, and determine any link with Antioxidant-rich dietary supplement TGFβ-1 and Adatations levels.

The digferences groups completed trzining weeks of resistance training RT. However, there were no significant sex-specific changes in most MTC variables. Trainong, pooled population data showed that TGFβ-1 correlated with K at baseline, adaptatione no correlations Anti-aging catechins between IGF-I and Differencse properties.

Greater resting TGFβ-1 levels are associated with superior tendon mechanical properties. RT acaptations impact opposite ends of the Workout refuel drink tendon force-elongation relationship in each sex. Thus, different loading patterns may be needed to maximize resistance Gender differences in training adaptations adaptations in differenxes sex.

Citation: McMahon G, Morse Tgaining, Winwood K, Burden A, Onambélé GL Gender associated muscle-tendon adaptations to yraining training. PLoS ONE 13 5 : e Received: June 7, dfferences Accepted: May 9, ; Geder May 22, Maca root for libido © McMahon Fat loss mindset success al.

Home remedies for insomnia is an open access article Strategic weight management under the terms of the Creative Commons Attribution License diffsrences, which differencse unrestricted traininv, distribution, and reproduction in any medium, Gejder Micronutrient absorption disorders original author ttaining source are credited.

Data Availability: All relevant data are within the paper and its Supporting Information files. Competing interests: Differendes authors have dfiferences that no competing interests exist.

Aadaptations muscle-tendon complex Adapttions exhibits multiple physiological characteristics which trainiing impact tarining physical trainin of males and females Micronutrient absorption disorders the lifespan diffwrences 1 — 3 ] with Recharge for Student Plans, exercising females possibly more susceptible to overuse Gender differences in training adaptations such as tendinopathies than males differebces 4 ].

In particular, there adatations increasing evidence of difffrences chronic adaptations traiming the in-series elastic component to resistance training RT adaptwtions, over and above the Nutrient absorption mechanism gender differences dlfferences both differrences absolute MTC properties at rest, and its acute adaaptations to exercise.

Indeed, differences in viscoelastic properties adpatations the free tendon and tendon-aponeurosis Joint health comfort young males and females sdaptations been Gendeg [ Gender differences in training adaptations — trainnig ], with females dfiferences lower stiffness, modulus, asaptations and greater strain.

Gedner combination tfaining data from eifferences studies [ 8 diffeernces, 9 ] differenxes the difference in both resting and post-exercise tendon collagen fractional synthetic rate Traoning between Grnder and females, with FSR remaining significantly elevated 72 hours post 60 minutes Almond market, endurance type exercise in males.

Further research has also sdaptations that gender additionally influences Genrer post resistance-exercise traniing of differemces structural and extracellular matrix ECM regulatory components [ 10 ]. The Gemder difference in differecnes to training in chronic response terms is highlighted in Eating window and meal frequency et al.

Interestingly afaptations, these chronically Citrus aurantium side effects female runners did not differ significantly in terms Micronutrient absorption disorders adaptationns morphology or mechanical properties tdaining female non-runners, which raises any questions Gwnder regards dofferences any change in trqining intrinsic quality of the tendon with chronic tralning in traininv.

It is also yraining that sex adatpations have Lentils and pasta dishes demonstrated in the adaptability of Geender properties following an extended period of physical training in older individuals differendes 1213 differenfes, thereby Gendee the persistent difrerences of the adaotations responsiveness Gender differences in training adaptations adaptability adaptattions males.

Adaptztions research strongly suggests that diffeeences demonstrate dissimilar relative adaption profiles to diffreences mechanical aadaptations compared to age-matched male differenves, the adaptability Gende endocrine links associated with this observation following Gennder load dynamic on training of adaptatios for traininy, have Metabolic rate and calorie restriction to be elucidated.

In differrnces work suggests trainning particular Gener to the endocrine Weight control success stories of tendon, are Genedr factors Transforming Growth Factor Trainong 1 TGFβ-1 and Insulin-Like Growth Factor Gwnder IGF-I.

Their primary trainkng in tendon include proliferation and migration of fibroblasts, subsequently increasing the production of difterences and aeaptations extracellular matrix ln in differenfes cells during differencees remodelling aeaptations [ 1415 ]. In humans [ 16 Antibacterial body wash direct administration Gendwr IGF-I enhanced the collagen fractional synthetic Beta-alanine and muscle regeneration in young adaptztions older males.

In Herbal stress reduction, administration trainint IGF-I plus TGFβ-1 traininng, significantly improved mechanical properties of trianing tendon [ 17 ].

Recent work from Astill et al. However, only adaptatipns had Gener elevated peritendinous traaining of IGF-I at 4 hours post, whereas males did not. Additionally, males showed greater post-RT changes in Matrix Metallopeptidase 9 MMP-9 levels than females, and females had a more prolonged exercise-induced elevations in tissue inhibitor of metalloproteinases-I TIMP-I than males.

Data shows no normative difference when comparing circulating TGFβ-1 levels in males, pre and post-menopausal females, and pregnant females [ 1920 ].

At present, the literature on any link between the previously reported [ 22 ] acute in vivo TGFβ-1 response to mechanical loading, and the magnitude or nature of human MTC training adaptations is limited.

A topical study is that of Heinemeier et al. However, in this Heinemeier et al. In addition, it remains unclear whether any difference would be associated with major growth-factor candidates purported to influence MTC properties and adaptations to training.

Therefore, the objectives of this study were to 1. Characterise the MTC adaptation to a period of dynamic, heavy-load resistance training in males and females, 2 identify any sex-related differences across MTC properties and 3 investigate whether any of the adaptive responses could be reflected in changes in two key circulating growth factors related to the MTC.

Twenty-eight young participants recruited from the local university campus, gave written informed consent to participate in the study.

All procedures and experimental protocols were approved by the Manchester Metropolitan University Cheshire Campus ethics committee.

Exclusion criteria included the presence of any known musculoskeletal, neurological, inflammatory, or metabolic disorders or injury. Participants took part in recreational activities such as team sports and had either never taken part in lower limb resistance training or had not done so within the previous 12 months.

Each participant completed a physical activity diary, outlining that they each habitually completed 3—5 hours of non-resistance based moderate physical activity per week.

Sixteen participants were then equally subdivided by sex and randomly assigned to a training group T males [TM] age 20±1 years, mass 81±4Kg, T females [TF] age 19±3 years, mass 69±3Kgwhilst 6 males [ConM] age 22±2 years, mass 82±2Kg and 6 females [ConF] age 23±4, mass 63±4Kg were assigned to a control group CON.

All females were eumenorrheic menstrual cycle duration of 26—30 days and none used any form of Oral Contraceptive Pill, the latter having been shown to impact of the MTC properties in females [ 24 ].

The study design was convenience sampling, with participants separated into groups according to sex followed by random allocation to one of two groups i.

training or control. Measurements were repeated after 8 weeks resistance training post-training. The measurement techniques used for the calculation for physiological cross-sectional area of the Vastus Lateralis VL muscle in the current study have been documented elsewhere [ 2526 ]. Briefly, multiple anatomical cross-sectional area aCSA measures were made via brightness mode ultrasonography 7.

Muscle volume was then calculated using the truncated cone method, which has been validated in a number of previous studies [ 2728 ]. VL pCSA was calculated by dividing muscle volume by fascicle length [ 28 ]. Peak torque was expressed as the average of data points over a ms period at the plateau phase i.

The peak torque of three extensions was used as the measure of torque in each participant. The reference electrode Blue sensor L, Ambu, Denmark was placed on the lateral tibial condyle. The raw EMG signal was preamplified MP, Biopac Systems Inc. All EMG and torque signals were displayed in real time in AcqKnowledge software Biopac systems Inc.

Two maximal knee flexion contractions were carried out to obtain the EMG at maximal flexion torque. The root mean square RMS EMG activity was averaged for a ms period average of 1. To reiterate, the EMG of the long head of the biceps femoris muscle was measured to ascertain the level of antagonist muscle co-contraction during the required isometric knee-extension performances.

The biceps femoris torque during a knee-flexion contraction was calculated as described by McMahon et al. The measures of tendon properties used in the current investigation have been described elsewhere [ 31 ].

Briefly, tendon elongation was determined using brightness mode ultrasound imaging over the apex of the patella in the sagittal plane, with the knee fixed at 90 0 flexion as per the norm in in vivo tendon properties assessment. Five preconditioning trials were carried out to ensure reproducibility.

Following this, three ramped, 6-second isometric contractions were monitored for the distance between the original position of the tissue under the skin, relative to the new position of the tissue using ultrasound images captured onto a personal computer at 25 Hz.

The ultrasound output was synchronized using a square wave signal generator to allow temporal alignment with both torque and EMG data. Three efforts were analysed, and the average reported as the profile of tendon force versus elongation for the participant. The plotted force—elongation relationship was fitted with a second-order polynomial function, forced through zero.

Patellar tendon PT resting length TL and cross-sectional area Tcsa were also assessed with the knee joint at 90 o of flexion. TL was measured from the inferior pole of the patellar to the superior aspect of the tibial tuberosity determined from sagittal-plane ultrasound images.

PT volume TVol was calculated using the TL and Tcsa values along the length of the tendon using the truncated cone method, which used the same principles as those demonstrated on muscle volume assessments [ 27 ].

Pre and post-training, following an overnight fast, ~10 hoursparticipants reported to the laboratory between am. IGF-I and TGFβ-1 were analysed using the standard enzyme-linked immuno-sorbent assay ELISA procedure, as described by McMahon et al. Post-training samples were taken 3—4 days post final training session, at the same time-of-day as the pre- training sampling for each participant.

The laboratory tests were timed to avoid diurnal variability or acute exercise-induced growth factor fluctuations. Exercises included the back squat, leg press, leg extension Technogym, Berkshire, UKlunge, Bulgarian split squat and Sampson chair. All exercise sessions were supervised by a member of the research team.

Volume i. repetitions and sets was identical for each training group, with each training session consisting of four exercises and performing three sets of 10 repetitions per exercise for the first 4 weeks, and four sets of eight repetitions per exercise thereafter.

Training sessions would typically last ~60 minutes, with training records being diligently completed during sessions. Statistical analysis was carried out using IBM SPSS v19 IBM Inc, USA. Data was analysed using a 4×2 ANCOVA with baseline measures used as covariates.

The within-group factor was the phase of training baseline, post-training and the between-group factor was training group i. TM, TF, ConM, ConF. Post-hoc comparisons are Bonferroni corrected and adjustments for multiple comparisons are applied in the correlation tables.

All data are presented as mean ± standard error of the mean SEM. Power β and effect size ES are reported for those changes that exhibited significant sex differences, where power was calculated post hoc using the independent t-test assumptions. There were significant increases in pCSA, strength, PT Vol, mean PT K and E, and IGF-I Table 1 in each training group, with no sex differences.

However, when PT K was analysed at discrete force regions, significant sex-specific differences were identified Fig 1.

Males black bars and females white bars following training. Data are Mean ± SEM. Pooled population baseline IGF-I values correlated with baseline stiffness at high force levels i. At week 8 however, the correlations of IGF-I was in fact with lower force regions i.

Whilst baseline IGF-I was not associated with tendon stiffness, at week 8, IGF-I levels correlated with week 8 stiffness at mid force levels i. Our key current findings are 1 we are the first to demonstrate sex-specificity in the overloading-induced adaptive nature of the mechanical properties of tendon in a young population.

Sex-related differences in the mechanical, structural and regulatory mechanisms in human tendinous tissue have been identified previously [ 57 ]. Differences in acute tendon fractional collagen synthesis rates [ 89 ], amount of tendon dry mass per wet tendon weight [ 32 ], mRNA levels of Type III collagen [ 10 ] have all been shown to vary between sexes.

In addition, proteomic work from Little et al. This would tend to suggest that, either at rest, or when provided with a similar physical stimulus to males, female tendon does not respond similarly.

: Gender differences in training adaptations

References

The magnitude of the interference effect with concurrent training may be influenced by inter-individual variations, differences in experimental design, training intervention, and the type of outcome measure. Many of these potentially contributing factors have been analyzed before [ 7 , 8 , 9 , 10 ].

One important inter-individual factor that has received very little attention in the literature is the differences in training responses between males and females. Sex-related adaptations with concurrent training may occur, owing to differences in endocrine and muscle physiology, or physical performance.

On average, males have larger muscle fibers, more skeletal muscle mass, and greater strength [ 11 , 12 , 13 ], while females tend to have slower contractile properties [ 14 ]. Males tend to have greater improvements in absolute muscle size, strength, and power compared with females [ 15 , 16 ], but females showed larger relative increases in upper-body strength than males [ 17 ].

Both sexes show similar relative increases in lower-body strength and hypertrophy after strength training. It is therefore conceivable that there may be sex differences in the adaptations to concurrent training. Another inter-individual variation includes the current training status of the participant, which may significantly impact the magnitude of the interference effect with concurrent training.

Coffey and Hawley [ 23 ] hypothesized that adaptations are more compromised following concurrent training in subjects with a longer training history, i.

However, previous meta-analyses on concurrent training did not find any differences in adaptations between different levels of training status for maximal strength, power, and hypertrophy [ 7 , 9 , 10 ], when there was sufficient time to recover between strength and endurance training sessions.

It should be noted that training status is generally considered to be one-dimensional: a participant is untrained, trained, or highly trained. However, this neglects the fact that athletes can optimize for both their strength and endurance capacities.

For example, professional marathon runners are highly trained endurance athletes, but relatively untrained for maximal absolute strength. Importantly, prior meta-analyses on concurrent training did not distinguish between both endurance- and strength-trained status [ 7 , 9 , 10 , 25 ].

Second, we investigated how adaptations to concurrent training depend on strength and endurance training status. Such a systematic review and meta-analysis not only provides more insight into the concurrent training effects of various populations, but also highlights which populations may be under-represented in the concurrent training literature.

A systematic literature search was conducted according to the PRISMA Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and registered with the International Database of Prospectively Registered Systematic Reviews in Health and Social Care PROSPERO, CRD Only studies from or later were included, which was after the seminal paper on concurrent training by Hickson [ 6 ].

Retrieved titles from the search were saved and both duplicates and review articles were removed using automated tools i. Titles and abstracts of all remaining studies were screened individually by two reviewers RH and SZ. If the reviewers could not reach consensus, a third reviewer was consulted RW.

The search process and selection of studies are summarized in the flowchart in Fig. Flowchart of data search and selection of studies. Studies were included based on the PICO Population, Intervention, Control and Outcomes criteria [ 26 ]. The population included healthy male and female adults aged between 18 and 50 years.

For maximal strength, one-repetition maximum 1-RM and isometric measurements of lower and upper extremities were considered. For power, jump tests and dynamic power tests e. For muscle hypertrophy, muscle thickness or whole-muscle cross-sectional area was measured objectively using ultrasound, magnetic resonance imaging, or computed tomography.

Studies were excluded if participants experienced injuries or an illness or if they used ergogenic aids or other sport-enhancing supplements except for proteins and vitamins. To classify training status within concurrent training studies, it is important to note that the training status of participants is not one-dimensional, but can be interpreted both in terms of strength and endurance training status.

Training status is typically divided into three categories corresponding to untrained, trained, and highly trained athletes [ 30 , 31 ].

In this meta-analysis, participants were characterized according to their combination of strength and endurance training status. Strength training status [ 27 ] was grouped into untrained, trained i. The classification framework to determine strength and endurance training status of participants is presented in Table 2 adapted from [ 27 , 28 , 29 ].

To obtain the training status classification, scores were derived for each physiological performance, training, or technique indicator if present and were subsequently averaged and rounded.

For strength training status, all strength performance indicators were grouped and counted as one score [ 27 ]. Using this unified classification system, participant groups can be classified for both their strength and endurance training status in order to determine how effects of concurrent training are dependent on training status.

Two reviewers independently evaluated the full-text articles using a standardized predefined form RH and SZ. Articles were examined by a third reviewer if consensus was not reached RW.

If data on group mean and standard deviation were not presented in the text or tables, then baseline and post-intervention data were requested from the corresponding authors or obtained from figures if present using WebPlotDigitizer version 4. Methodological quality of identified studies was assessed independently by two reviewers RH and RW using the Cochrane risk-of-bias evaluation [ 33 , 34 ], and consensus was reached after consultation.

Reviewers assessed all studies for the risk of selection bias sequence generation, allocation concealment , detection bias blinding of outcome assessment , attrition bias incomplete outcome data , reporting bias selective reporting , and other biases. Biases were classified for each item as low, high, or unclear risk i.

Relevant biases were assessed one by one according to the recommendation of the Cochrane Bias Methods Group and Statistical Methods Group [ 33 ]. Results for maximal strength were subdivided into lower-body and upper-body strength.

In accordance with Cochrane recommendations [ 33 ], if studies presented multiple methods for the same outcome e. a jump test and Wingate test for power , only one of these was included in the analysis according to the hierarchy presented in Table 1.

This was to avoid inclusion of intervention effects that were statistically dependent in the analysis, as these were calculated from the same participants. For example, the hierarchy dictates evaluation of lower-body strength using 1-RM maximal strength during leg press which is technically easier to execute over the squat and evaluation of power using countermovement or squat jumps which are more readily available over Wingate peak power.

Studies or intervention groups were excluded from the analysis if significant baseline differences were observed for the specific outcome measure between the concurrent training and control group or if only percentage changes were reported.

A random-effect model [ 36 ] was adopted and presented in forest plots, and records were weighted according to the inverse variance method for each outcome measure.

Heterogeneity was calculated using the Q -test and expressed in terms of Chi 2 and the I 2 statistic. I 2 describes the percentage of the variability that is attributable to heterogeneity rather than chance [ 37 ].

Subgroup analyses were performed to compare concurrent training effects between 1 male and female participants; 2 untrained, trained, and highly trained levels of strength training status; and 3 untrained, trained, and highly trained levels of endurance training status.

The meta-analysis was conducted using Review Manager RevMan software Version 5. A significance level α of 0. The database search resulted in a total of 24, articles.

After automatic removal of the duplicates, removal of review articles, and screening of the remaining titles and abstracts, articles remained. Table S4 of the ESM summarizes all relevant characteristics of the studies, participants, and training interventions.

The meta-analysis included participants, of whom performed concurrent training, performed strength training only, and performed endurance training only. Training status of the participants using Table 2 was determined for strength training status 38 studies , endurance training status 56 studies , and both strength and endurance training status 36 studies.

Overview of the training status of the participants in the included studies. Number of studies are reported in which levels of training status could be assessed for A strength, B endurance, and C both strength and endurance.

Quantification of training status was performed according to the guidelines in Table 2. The overall assessment for the risk of bias is presented in Fig.

S17 of the ESM. The analysis of lower-body strength included 20 studies [ 43 , 45 , 47 , 48 , 65 , 68 , 71 , 75 , 82 , 85 , 89 , 91 , 93 , 94 , 95 , 96 , , , , ], with participants that performed concurrent training and participants that performed strength training only.

These results highlight a small interference effect for lower-body strength with concurrent training in males, but not in females. Forest plot of studies comparing differences in adaptations in lower-body strength with concurrent training between males and females.

Risk of bias elements are highlighted in the legend below the forest plot and bias was indicated as low green , unclear yellow , or high red. CI confidence interval, CT concurrent training group, SD standard deviation, ST strength training-only control group, Std.

Point range plot demonstrating differences in the effects of concurrent training between males and females for each outcome measure. Significant effects of concurrent training versus control are reported for males and females separately next to point range.

Significant sex differences were also reported on the right. CI confidence interval; SMD standardized mean differences. Data on muscle hypertrophy were available only in males, precluding us to draw any conclusions on sex differences.

Forest plots for each outcome measure are also displayed in Figs. S1 —5 of the ESM. Our results indicate a small interference with concurrent training for lower-body strength in males, but not in females, and a small-to-moderate interference for power in both sexes. Only data from four studies were available on muscle hypertrophy, which precluded us to perform meaningful subgroup analyses.

Point range plot demonstrating differences in the effects of concurrent training between levels of training status for endurance A and strength B for each outcome measure.

Significant effects of concurrent training versus control are reported for each level of training status next to point range. Significant differences were also reported between training status levels on the right.

Forest plot of studies comparing differences in adaptations in maximal oxygen consumption with concurrent training between untrained, trained, and highly trained endurance athletes.

CI confidence interval, CT concurrent training group, ET endurance training-only control group, SD standard deviation, Std. S6—15 of the ESM. There were insufficient studies to investigate muscle hypertrophy. With respect to strength and endurance training status, there were no differences in improvements in maximal lower- and upper-body strength and power between untrained and trained participants.

Our meta-analysis shows that adaptations to concurrent training differ between sexes. The underlying mechanism for this sex-specific interference remains unknown, but sex differences in muscle and training physiology likely contribute.

While sex-related neuromuscular differences could contribute, no sex differences have been observed in the number of motor units or motor unit activation patterns for upper- and lower-body muscles [ , ], nor in neuromuscular adaptations following exercise training [ ]. On average, males tend to have larger muscle fibers and a larger percentage of their cross-sectional area occupied by type II fibers [ 13 , , , , ].

With these larger fibers, males produce higher absolute forces than females [ ]. For strength training adaptations, however, relative improvements in lower-body strength and hypertrophy are similar between males and females [ 17 , , , , ].

Men show larger absolute gains in fiber size [ , ], which may relate to the observation that glycolytic type II fibers have the larger potential to hypertrophy than type I fibers [ ]. Endocrine differences between males and females may contribute to the muscular adaptations with strength training.

Despite the lower testosterone levels in females [ ], strength exercise-induced muscle protein synthesis seems to be similar between sexes [ , , ], suggesting that other factors, such as mechanical signals contribute to the activation of muscle protein synthesis.

The impaired lower-body strength gains in males could also relate to skeletal muscle metabolism and fatigability [ , , , ], associated with their lower percentage type I fibers. Following concurrent training, this difference could translate into larger residual fatigue from endurance training in men, which may compromise the quality of strength training sessions and subsequent strength gains [ ].

Men potentially experience a larger interference effect when combining strength and endurance training because of the tight negative correlation between muscle fiber size and oxidative capacity within skeletal muscle [ 3 , 4 ] and their larger fiber size.

As such, sex-related differences in fiber size, endocrine physiology, and muscle fatigability could help to explain why we observed blunted lower-body strength adaptations in males, but not in females. The adaptations with concurrent training compared to single-mode training may be compromised more in highly trained athletes compared with trained and untrained individuals known as the ceiling effect [ 23 ].

A recent meta-analysis [ 7 ] distinguished between untrained and trained based on the subgroup description in prior studies e.

Another meta-analysis [ 10 ] distinguished training status based on the World Health Organization physical activity guidelines. Recently, a new classification framework was proposed for determining training status in sport science studies [ ].

This framework discriminates very well between world-class, elite, highly trained athletes, and other lower levels of training status, which is very important for avoiding the misuse of the term elite or world-class when addressing participant groups.

However, to discriminate between untrained, trained, and highly trained athletes, this framework uses physical activity guidelines and competitive performance characteristics, which are often not reported in the included studies.

Additionally, such training status classification does not distinguish between endurance and strength-related training status. Because of these considerations, we decided to apply a training classification framework that 1 is based on physical capacities reflecting the physiology of participants, 2 is based on variables that are commonly reported in previous studies, and 3 that clearly distinguishes between training status in terms of strength and endurance capabilities, which is a necessity for the present meta-analysis.

Cut-off values used to distinguish untrained, trained, and highly trained athletes were based on previous classification frameworks that were established based on measurement data from studies in males [ 28 ] and 82 studies in females [ 29 ] for endurance training status.

Therefore, this large range indeed seems to give a broad indication of untrained, trained, or highly trained individuals. The same goes for strength measurements.

Therefore, we are confident that our classification framework based on the physical strength and endurance capacities of the participant gives an accurate representation of the untrained, trained, and highly trained athletes.

With concurrent training, untrained individuals are expected to elicit generic adaptations to both strength and endurance training with additive effects [ 23 ], that is, untrained individuals may even increase their muscle size after endurance training [ ] or their oxidative capacity after strength training [ ].

Together with the greater muscle hypertrophy in untrained participants after strength training [ ], one may expect untrained participants to show larger increases in the fiber cross-sectional area following concurrent training.

For maximal lower-body and upper-body strength and power, no differences in adaptations to concurrent training were observed between untrained and trained participants.

Not enough studies have been performed to draw conclusions about highly trained athletes. Prior observations in highly trained powerlifters revealed that stronger males, but not females, gain less strength over time, indicative of a ceiling effect [ ].

In brief, more studies on highly trained female athletes are necessary to evaluate potential interference effects with concurrent training and its underlying mechanisms.

Similar to our findings, the meta-analysis of Schumann et al. In contrast, the meta-analysis of Petré et al. However, they included 27 studies in the meta-analysis vs 59 studies in our study and applied a different classification for training status i.

The present meta-analysis provides a new perspective on the influence of training status by assessing training status both in terms of strength and endurance capacities of the participants. Perspectives and limitations are considered first regarding sex differences and second related to the influence of training status for adaptations with concurrent training.

Similarly, we observed more concurrent studies with male participants compared with female participants in this meta-analysis, and our sex-specific conclusions are therefore based on fewer studies.

Only four studies on concurrent training effects for muscle hypertrophy were included, all in males, which precluded us to draw any conclusions on the influence of sex. In addition, phases of the menstrual cycle as well as the use of the oral conceptive pill could have an influence on training adaptations and exercise metabolism [ , , , ], which have not always been controlled for or monitored in training studies with females.

Last, highly trained endurance female athletes can suffer from female athlete triad or relative energy deficiency in sport, affecting their reproductive endocrinology and training adaptability [ ], which might provide an additional complicating factor in understanding the interference effect of concurrent training in female athletes.

Differences in training volume or design of training interventions could also potentially contribute to observed sex differences see Table S5 of the ESM.

Training adaptations are intrinsically heterogenous, even when performed at the same intensity and load, and therefore, such training studies should include a large enough sample size to account for this intrinsic heterogeneity in training adaptations, independent of an interference effect.

Future research could focus on studying the gain and interference effects at different training intensities and volumes, taking into account female sex and pre-training status. Regarding the assessment of risk of bias, the majority of included studies had some unclear risk of bias.

However, our sensitivity analyses did not indicate the presence of outliers or overly influential studies. To avoid statistical dependency between analyzed data points, we selected only one measurement method per study if multiple methods were reported for an outcome according to the hierarchy in Table 1.

Alternatively, a three-level multivariate meta-analysis could be used to assess a third level of variance within studies, which would allow for the analysis of multiple methods per outcome [ ].

Such a statistical analysis could provide additional insights into how adaptations with concurrent training may differ between measurement methods, such as between 1-RM squat and 1-RM leg press for lower-body strength.

In the present meta-analysis, however, the number of analyzed studies was too small to perform a three-level meta-analysis [ , ] and could result in biased estimates of the variance and standard error at the third level i. Consequently, we performed a traditional two-level meta-analysis based on random effects [ ] and selected one measurement method for each outcome instead.

For future systematic reviews and meta-analyses that include more concurrent training studies, preferably 50 or more [ ], we encourage the use of three-level meta-analyses to also assess how adaptations with concurrent training may differ between measurement methods.

It should be noted that not all studies reported the required descriptors to determine the training status of participants according to the framework in Table 2.

This complicates meta-analyses, and the general applicability of the study findings. Furthermore, it should be noted that the framework to determine training status did not account for age. However, a measure like critical power may be more valuable to discriminate between more homogeneous groups of athletes with rather similar training status, such as well-trained amateurs, sub-elite athletes, and elite athletes [ ].

Therefore, adding critical power as a criterion to the framework to classify training status could be worthwhile to describe more specific subgroups, such as highly trained athletes.

In terms of practical advice, individuals and coaches who incorporate concurrent strength and endurance training within their training should consider the potential small-to-moderate interference effects resulting in blunted training adaptations.

Not only highly trained athletes, but also untrained individuals should be aware of these effects. Male athletes should be extra cautious when aiming to improve lower-body strength, whereas this seems to be less of an issue in female athletes. In addition, contrary to prior beliefs, these blunted adaptations may also occur for endurance-related outcomes i.

Therefore, when optimizing an individual prescription of concurrent training in athletes, inter-individual differences in sex and training status should be considered when evaluating magnitudes of the observed adaptations.

This meta-analysis shows that concurrent strength and endurance training resulted in blunted lower-body strength adaptations in males, but not in females.

Our meta-analysis indicated that highly strength- or endurance-trained athletes are under-represented in the concurrent training literature. In summary, inter-individual differences in sex and training status should be considered when optimizing concurrent training prescription in individual athletes.

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Silva RF, Cadore EL, Kothe G, Guedes M, Alberton CL, Pinto SS, et al. Concurrent training with different aerobic exercises. Skovgaard C, Christensen PM, Larsen S, Andersen TR, Thomassen M, Bangsbo J. We recently reported increased IGF-1 mRNA expression following a single resistance exercise bout in young adults The family of MRFs including myogenin, MyoD, Myf-5, and MRF4 are muscle-specific transcription factors that control muscle cell differentiation and regulate the expression of several muscle genes.

The MRFs are therefore important during myofiber development and during satellite cell-mediated growth, repair, and regeneration in developed muscle. Myogenin appears to be preferentially expressed in type I myofibers, whereas MyoD is mainly expressed in type II myofibers 27— Enhanced myogenin expression has recently been shown during resistance-training-induced myofiber hypertrophy in young adults Upon stimulation by loading 31 or myotoxicity 32 , the expected increase in myogenin expression is blunted or delayed in older muscles compared with younger muscles.

On the basis of these data, any possible gender differences in PRT-induced hypertrophy among older adults may perhaps be associated with gender differences in muscle IGF-1 or myogenin expression. Evidence indicates that declining muscle mass with age is associated with declining levels of circulating hormones 33 , 34 , including testosterone, IGF-1, and dehydroepiandrosterone sulfate DHEA-S.

Whether endogenous levels of circulating hormones play an important role in load-induced hypertrophy of localized muscles remains questionable. Limited evidence, however, indicates testosterone levels are related to the magnitude of PRT-induced hypertrophy 24 and strength gain 5 , Low levels of testosterone as found in hypogonadal men and in women may therefore impede PRT-induced hypertrophy and strength gain.

Testosterone treatment in untrained hypogonadal men has been shown to increase muscle protein synthesis and muscle IGF-1 mRNA expression 36 , suggesting that circulating testosterone modulates muscle growth by means of activation of locally-expressed growth factors.

Transgenic mice that overexpress IGF-1 in muscle have been shown to be partially protected against age-related atrophy If muscle IGF-1 mRNA expression is influenced by testosterone, one might expect higher levels of IGF-1 expression in men than in women consequent to the approximately to fold gender difference in total testosterone concentration.

Decreased distribution of MHC type IIx MHCIIx is a common finding following resistance training 38 , 39 and has been reported recently in older adults This shift is typically coupled with a concomitant increase in primarily MHCIIa distribution with little to no change in MHCI.

Although data are limited, gender does not appear to substantially influence the MHC shift 38 , The purposes of this study were thus to test the influence of gender in older adults on PRT-induced changes in myofiber size and MHC distribution.

We hypothesized that older men would experience greater absolute myofiber hypertrophy CSA in square micrometers , whereas relative myofiber hypertrophy percent change and MHC shifts would be similar in older men and women following PRT.

Contrary to this hypothesis, our results indicate substantial gender differences in both the absolute and relative hypertrophic response. We therefore covaried for circulating IGF-1, DHEA-S, and mRNA levels of muscle IGF-1, IGFR1, and myogenin to determine if these circulating anabolic factors or muscle myogenic factors could account for the gender differences in myofiber growth.

In the present study, they do not. Nine men and 5 women, 61 to 77 years old, participated in a week PRT program.

These 14 subjects represent the subset of participants from a larger study 41 who consented to muscle biopsy. All subjects passed a medical screening exam, including a diagnostic stress test.

Subjects were free of any musculoskeletal or other disorders that might have affected their ability to complete training and testing for the study. None of the subjects had resistance training experience.

All of the women were postmenopausal, and 2 of 5 women were on estrogen replacement therapy. None of the subjects were being treated with exogenous testosterone.

Institutional Review Board-approved informed consent was obtained prior to participation in the study. Subjects were evaluated before and after the training period.

Subjects exercised 3 times per week for 26 weeks. The whole body training program has been described in detail elsewhere Each exercise session began with a 5-minute warm-up on either a bicycle ergometer or treadmill at a low intensity, followed by static stretches.

For the knee extensors, two resistance exercises were performed—knee extensions and leg presses or squats. Other exercises included elbow flexion, elbow extension, wide grip pull-down, seated row, chest press, overhead press, back extension, bent knee sit-up, and knee flexion.

With the exception of sit-ups two sets of 15—25 repetitions , subjects completed two sets of each exercise with 2-minute rest periods between sets and a target of 10 repetitions. Although all subjects performed knee extensions, men and women were randomly assigned to perform the squat or leg press such that no gender bias occurred.

In this subset of 14 participants, 8 of the subjects 5 men and 3 women performed squats and 6 of the subjects 4 men and 2 women performed leg presses. After two familiarization sessions, subjects were tested for knee extension, squat, and leg press 1RM by using methods we have previously described Total body fat mass and fat-free mass were determined by densitometry, using air displacement plethysmography Bod Pod version 1.

Each subject wore the same fitted swimwear for body volume measurements before and after training. The methods used have been detailed previously and validated in our laboratory against hydrostatic weighing, dual-energy x-ray absorptiometry, and the four-compartment model 41— vastus lateralis of the left leg by percutaneous needle biopsy, using a 5-mm Bergstrom biopsy needle under suction as previously described The posttraining biopsy was taken approximately 2 cm proximal to the pretraining incision site.

Samples for histochemistry were mounted on cork with Tissue-Tek O. mounting medium Miles Inc. A portion of each sample was snap frozen in liquid nitrogen used for mRNA analysis. The muscle biopsy procedure was added to the menu of tests for a larger study 41 as the project began.

As a result, subjects consented to muscle biopsy as a voluntary additional procedure yielding a subset of participants. Because of scheduling difficulties with numerous required tests after training, biopsies after training were collected an average of 4 days after the final training bout but the precise time point was not consistent range 2—7 days.

Although this variability should not have affected myofiber size measurements, we certainly recognize the limitation this poses on interpreting our posttraining muscle gene expression results.

Pretraining and posttraining samples within subjects were analyzed concurrently to standardize staining conditions. Myofibers were classified as type I, IIa, or IIx by metachromatic dye—adenosine triphosphatase histochemistry, using methods described previously 45 , and they were modified in our laboratory Metachromasia was revealed by 0.

Type I myofibers stained dark turquoise blue, whereas type II myofibers spanned a color spectrum from pale type IIa to violet type IIx. Microscope Olympus BX, Melville, NY views were captured by a color digital video camera Olympus DP Myofiber CSA and area distribution by type were determined by using Mocha Jandel Scientific, San Rafael, CA image analysis software, as we have detailed elsewhere To determine the distribution of MHC isoforms I, IIa, IIx , 10 microtome sections 20 μm were homogenized and the myofibrillar protein fraction was isolated and assayed for total protein as we have previously described Two micrograms of myofibrillar protein 0.

Run conditions were V for 20 hours. We have previously confirmed band order by Western analysis Pretraining and posttraining samples within subjects were run in adjacent lanes to standardize run conditions.

Tissue samples were analyzed for IGF-1, IGFR1, and myogenin mRNAs. Total RNA was extracted from frozen muscle samples by using the TRI Reagent Molecular Research Center, Cincinnati, OH according to the company's protocol.

Extracted RNA was precipitated from the aqueous phase with isopropanol and, after being washed with ethanol, dried and suspended in a known volume of nuclease free water.

A relative RT-PCR method using 18S as internal standard Ambion, Austin, TX was applied to study the mRNA expression of IGF-1, IGFR1, and myogenin. In each reaction, 18S ribosomal RNA was coamplified with the target cDNA mRNA to serve as an internal standard and to allow correction for differences in starting amounts of total RNA.

For the 18S we used either the Classic or the Alternate 18S Internal Standards Ambion , which yield base pairs, or base pairs, respectively. The 18S competimers—primers were mixed at an optimized ratio specific for each target mRNA, and this ratio was for IGF-1, for IGF-1 receptor, and for myogenin.

For each primer set, PCR conditions were optimized so that both the target mRNA and 18S product yields were in the linear range of the semilog plot when the yield is expressed as a function of the number of cycles.

For each specific target mRNA, the RT and PCR reactions were carried out under identical conditions, using the same reagents premix for all the samples to be compared in the study.

One microliter of each RT reaction was used for the PCR amplification. The PCR reactions were carried out in the presence of 2mM MgCl 2 , using standard PCR buffer Gibco , 0. Amplifications were carried out in a Stratagene Robocycler with an initial denaturing step of 3 minutes at 96°C, followed by 25 cycles of 1 minute at 96°C, 1 minute at 58°C, 1 minute at 72°C, and a final step of 3 minutes at 72°C.

With the use of this method, each specific mRNA signal was normalized to its corresponding 18S. Representative results are shown in Figure 1.

Total IGF-1, testosterone, and DHEA-S were determined in fasted morning serum samples withdrawn before and after 26 weeks of PRT. Samples within subjects for a given hormone were assayed in random order during a single run.

Data are reported as mean ± SE. Gender differences in descriptive variables were tested by independent t tests. For all variables measured before and after training, main training and gender effects and Gender × Training interactions were tested by 2 × 2 repeated measures analysis of variance ANOVA.

For each ANOVA model with a significant Gender × Training interaction, analysis of covariance ANCOVA models were tested post hoc by using as covariate each of several factors potentially influential in muscle growth, namely pretraining, average, and before-to-after change scores in serum IGF-1 or DHEA-S, or muscle mRNAs for IGF-1, IGFR1, or myogenin.

Serum TT could not be used as a covariate as it was not a continuous variable. Zero-order correlations were tested between before-to-after changes in myofiber size or strength and changes in serum hormones or muscle myogenic transcripts.

Correlations were also tested among the serum and muscle factors measured. For each exercise, 1RM was evaluated every 25 days. As the knee extension exercise is a single joint movement recruiting the quadriceps site of muscle biopsy independent of the hip extensors, we evaluated knee extension 1RM results in serial fashion for this report.

Eight serial 1RM evaluations were performed over the duration of the training period. We tested gender and training effects by 2 × 8 repeated measures ANOVA. As a way to adjust for gender differences in absolute strength, 1RM data were analyzed as the ratio of 1RM at a given time point to the corresponding pretraining value.

Time-point-specific strength increases within gender were evaluated post hoc by using the least squares difference LSD test.

Descriptive characteristics are shown in Table 1. Gender comparisons revealed no significant differences in age or bodyweight. For both men and women, the whole-body PRT program resulted in increased FFM men 2.

No Gender × Training interaction was noted for FFM or body fat percentage. Myofiber CSA results are shown in Table 2. To assess the presence of type II myofiber atrophy, we compared pretraining data from these older subjects to myofiber sizes we previously published in premenopausal women 47 and young men In these older subjects, the preferential type II myofiber atrophy typically associated with sarcopenia of aging was found in pretraining data from both genders, and it was most notable in type IIx myofibers.

In contrast, the sizes of type I and type II myofibers were not significantly different in the younger subjects from our prior work. Clearly, the significant training effect in the ANOVA model for each fiber type was driven by the men.

Analyses of relative hypertrophy between genders t tests on percent change scores indicated greater relative hypertrophy among men for type IIa myofibers only. Changes in myofiber type area and MHC distribution are presented in Table 2. No gender differences or Gender × Training interactions were found for any of these variables.

Table 3 displays pretraining and posttraining levels of selected serum hormones and muscle gene transcripts thought to be potentially important in muscle growth. Training did not affect any of the hormone levels. Muscle expression of IGF-1 and myogenin mRNA did not differ by gender and was not influenced by training although an acute response to PRT cannot be ruled out because we obtained biopsies 4 days after PRT on average.

Zero-order correlations were tested among serum hormones and muscle gene transcript levels not including TT, as it was not a continuous variable. Serum levels of IGF-1 and DHEA-S were not related before or after training. No significant relationships were noted between serum IGF-1 and muscle IGF-1 or IGFR1 mRNAs before or after training.

Muscle transcript levels of IGF-1 and IGFR1 were not correlated. IGF-1 and myogenin transcript levels were not related before or after PRT. The substantial variability in myofiber hypertrophy between genders could not be explained by any of the serum or muscle factors, as no significant correlations were found between before—after difference scores in myofiber size and before—after difference scores in serum IGF-1, DHEA-S, or muscle IGF-1, IGFR1, or myogenin mRNA.

Further, Gender × Training interactions for myofiber hypertrophy remained in post hoc ANCOVA analyses covarying with before—after difference scores for each serum hormone or muscle gene transcript. The sizes of myofiber types I, IIa, and IIx prior to training did not correlate with pretraining levels of any of these factors.

Overall, these findings indicate the gender differences in initial fiber size and in PRT-induced myofiber hypertrophy could not be attributed to varying levels of circulating IGF-1 or DHEA-S, nor to expression of the myogenic gene transcripts studied.

Results of serial 1RM knee extension tests are shown in Figure 2. Both genders increased strength substantially. The values displayed in Figure 2 are relative to pretraining 1RM and reveal gender differences in strength development across the week period of PRT.

Following an initial early rise in 1RM for both genders Day 25 , relative strength gains among women were blunted compared with men. For example, 1RM for women did not significantly exceed the Day value until Day , whereas 1RM strength increased from Day 25 to Day 50 in men and steadily climbed thereafter.

In this study we have demonstrated that the myofiber hypertrophic response to the same PRT program is greater in older men than in older women. In their study of single myofibers, Trappe and colleagues 18 reported no Gender × Training interactions when comparing increases in myofiber diameter; however, the relative increase in type IIa myofiber diameter among men was significant whereas no change was noted in women.

Further, single myofibers from men exhibited significantly greater improvements in maximum shortening velocity and power. Tracy and associates 17 and Ivey and associates 16 tested for Gender × Training interactions by using muscle volume determined by magnetic resonance imaging as the measure of muscle size.

Both groups report a significant interaction for quadriceps hypertrophy after 9 weeks of PRT in older adults, with men exhibiting greater gains. Ivey and colleagues 16 found that the gender difference remained after they adjusted for pretraining muscle volume.

These data combined suggest an important gender difference in the hypertrophic response to 3 days per week PRT among older adults. At odds with these data, Hakkinen and associates 4 found substantial gains in myofiber size in older women following a strength—power training program performed 2 days per week, suggesting that older women may benefit from reduced frequency PRT and a combination of heavier and lighter loads.

These findings suggest the typical 3 days per week PRT program may not be the best model for older women. In this report we attempted to explain the gender difference by covarying for a number of potential modulators of myofiber size.

However, none of our targeted covariates influenced the gender differences or Gender × Training interactions. Serum IGF-1 is positively related to rates of muscle protein synthesis and has been measured extensively in recent studies of sarcopenia IGF-1 is known to decline with age and is related to the decline in lean mass in cross-sectional studies across a wide age spectrum 33 , In this study of load-induced hypertrophy, however, covarying for serum IGF-1 did not alter the influence of gender on either initial myofiber size or the magnitude of hypertrophy following PRT.

Additionally, zero-order correlations tested across both genders showed no significant relationships between serum IGF-1 and absolute or relative changes in myofiber size. Others have shown that elevating serum IGF-1 by means of exogenous growth hormone treatment does not enhance the hypertrophic effects of PRT in older men 50 , and PRT alone does not alter serum IGF-1 levels The importance of circulating IGF-1 in load-mediated local skeletal muscle hypertrophy has been questioned 52 and, in our group of older adults, serum IGF-1 appeared to have no influence.

Similarly, serum levels of DHEA-S did not influence the hypertrophic response in this study. DHEA-S treatment has previously been shown to increase serum IGF-1 in older men and women 53 , and declining levels of both DHEA-S and IGF-1 correlate with lower levels of muscle power in older women We found no relationships between DHEA-S and initial myofiber size nor between DHEA-S and the magnitude of myofiber hypertrophy in men and women, despite twofold greater DHEA-S levels in men not statistically significant.

Testosterone has been shown to influence the hypertrophic response to PRT. Bhasin and colleagues report greater PRT-induced hypertrophy with supraphysiologic doses of testosterone in young men Although the present data and that of others 5 , 35 , 56 indicate that PRT alone does not alter resting serum concentrations of testosterone, there is limited evidence suggesting endogenous testosterone levels are related to the magnitude of PRT-induced hypertrophy in older women 24 and strength gain in men 5 , 35 and women 5.

Additionally, testosterone treatment in female rats has been shown to induce satellite cell proliferation 57 , considered by many to be a requisite process during myofiber hypertrophy. When we tested zero-order correlations in our group of 9 eugonadal older men with fairly homogeneous TT levels, we found no significant relationships between endogenous TT and absolute or relative changes in myofiber size or 1RM strength.

Despite this, it remains entirely possible that the markedly higher endogenous levels of TT in the men compared with the women might have potentiated hypertrophy by some as yet unknown mechanism, as we report average TT levels fold greater in men.

The bimodal nature of TT levels in these two gender groups, however, precluded the application of TT as a covariate, and therefore the present study design cannot provide any conclusive evidence regarding the importance of endogenous testosterone in load-mediated hypertrophy.

The marked gender difference in TT levels is certainly not unique to older adults, and data on gender differences in PRT-induced hypertrophy among younger and middle-aged adults are equivocal.

For example, Staron and associates 58 reported myofiber hypertrophy results after 20 weeks of PRT in young women of similar magnitude to those reported by others in men, whereas Ivey and associates found a significant gender effect with greater hypertrophy in men in a sample of both young and older men and women It is therefore not clear whether endogenous testosterone levels play a pivotal role in PRT-induced hypertrophy.

Resistance training studies that compare eugonadal to untreated hypogonadal men would perhaps shed some light on this question. The role of locally expressed IGF-1 in muscle hypertrophy and satellite cell activation has received significant attention as of late 25 , 59 , Additionally, there is evidence that high resting levels of muscle IGF-1 expression may play a role in preventing age-related sarcopenia Myogenin appears to be an important modulator of myogenesis, as its expression increases during both myoblast differentiation 61 and overload-induced myofiber hypertrophy 25 , Hespel and colleagues 30 have recently reported increased myogenin protein expression during resistance-training-induced hypertrophy in humans.

Myogenin activity is thought to be at least partially mediated by IGF-1, as recent evidence indicates myogenin gene expression is increased during IGF-1 stimulated myoblast differentiation For these reasons we determined if expression of these transcripts, as well as expression of IGFR1, was different between genders before training or could account for gender effects on hypertrophy.

A gender difference in basal muscle IGF-1 mRNA expression might be expected, because increasing testosterone levels have been associated with increased IGF-1 mRNA levels in skeletal muscle However, there were no gender differences in pretraining levels, and neither IGF-1 nor myogenin expression changed after PRT.

As a result, neither one demonstrated utility as a covariate. Certainly PRT-induced strength accrual is multifactorial and is only partially mediated by myofiber hypertrophy.

The limited hypertrophy found in women suggests that the primary adaptation leading to enhanced strength was neurologically mediated.

Neural adaptations occur during the early weeks of a PRT program and thus are thought to account for the early rapid increases in strength It is noteworthy that the women experienced an early rise in strength similar to men see Figure 2.

Thereafter, strength gains tapered in women with the next significant rise not occurring until Day , whereas 1RM strength in the men rose fairly consistently across the 26 weeks. Consistent with data from other laboratories 65 , we found no significant correlation between changes in myofiber size and changes in strength, indicating large individual variability in the amount of strength gain attributable to hypertrophy versus neural adaptations.

Our results demonstrate that the training regimen was sufficient to induce in both genders the reduction in MHCIIx distribution characteristic of resistance training programs 38 , Although the mechanism s responsible for this shift in myosin phenotype are not known, it precedes measurable hypertrophy during resistance training 38 , and it is noted with no significant myofiber hypertrophy during endurance and sprint training 66 , On the basis of these data, it is not surprising to find MHCIIx downregulation in women in the current study despite blunted hypertrophy , as the load-mediated molecular signals regulating myosin phenotype obviously differ from those regulating the net rate of myofibrillar protein synthesis.

In conclusion, we found marked gender differences in both absolute and relative myofiber hypertrophy and strength accrual following identical PRT programs in the older men and women studied.

Although the muscles of both men and women demonstrated similar MHC plasticity with a reduction in MHCIIx distribution, men exhibited superior myofiber hypertrophy and strength gain.

Future studies should determine whether acute responses to a single resistance exercise bout e. Such findings may aid in unraveling the apparent gender influence on myofiber hypertrophy in older adults. Additionally, the potential role of endogenous testosterone levels should be carefully considered.

Decision Editor: James R. Smith, PhD. Product size in base pairs bp is shown to the left. Laser scanning densitometry revealed no gender or training effects. Knee extension one-repetition maximum 1RM results across time for men and women relative to pretraining 1RM. For each time point, 1RM—pretraining 1RM was computed; a—e: significantly different from a, pretraining Day 0 ; b, Day 25; c, Day 50; d, Day 75; e, Day Notes : Values are mean ± SE.

Grant support for this work was provided by the University of Alabama at Birmingham Center for Aging, the Ralph L. Smith Foundation, R01 AR G. Adams , and R01 AG M. We thank the subjects for their tireless effort and dedication. We thank Angi Qin for technical assistance.

Address correspondence to Marcas M. E-mail: mbamman uab. Hikida RS, Staron RS, Hagerman FC, et al. Effects of high-intensity resistance training on untrained older men.

Muscle fiber characteristics and nucleocytoplasmic relationships. J Gerontol Biol Sci. Jozsi AC, Campbell WW, Joseph L, Davey SL, Evans WJ. Changes in power with resistance training in older and younger men and women.

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Top bar navigation Storen, O. Data adaptafions Mean ± SEM. Micronutrient absorption disorders, H. Time course of changes in markers of myogenesis in overloaded rat skeletal muscles. Article PubMed Google Scholar Lundberg TR, Feuerbacher JF, Sünkeler M, Schumann M. Quantitating the capillary supply and the response to resistance training in older men.
Gender Differences in Training All Child injury prevention are presented as Gehder ± standard error of Gender differences in training adaptations mean SEM. Gender differences in training adaptations increase in the vascular parameters related trajning elasticity difcerences advantageous in terms of hemodynamic Genddr. Statistical Evaluation GraphPad Prism 5 software GraphPad Software, La Jolla, CA, United States was used for statistical analysis. Hespel and colleagues 30 have recently reported increased myogenin protein expression during resistance-training-induced hypertrophy in humans. Testosterone signals through mTOR and androgen receptor to induce muscle hypertrophy. The tangential wall stress was significantly increased in the FE rats compared with the controls.
Gender Differences in Hemodynamic Regulation and Cardiovascular Adaptations to Dynamic Exercise Intersubject variability in cardiac output-O2 uptake relation of men during exercise. Article CAS PubMed Google Scholar Arbab-Zadeh A, Perhonen M, Howden E, Peshock RM, Zhang R, Adams-Huet B, et al. Sharma S, Maron BJ, Whyte G, Firoozi S, Elliott PM, McKenna WJ. Female athletes experience a greater drop in SVR because of a lower sympathetic activity, a higher parasympathetic activity, and their circulating sex hormones, which all contribute to a more vasodilatory state. Cardiovasc Clin ; Mujika I, Taipale RS.

Gender differences in training adaptations -

The difference in testosterone between genders is likely a primary culprit responsible for the differences we see in muscle fiber size. Some studies show that men recovery more quickly from resistance training 7 , others show that women recover more quickly 9 , 10 , and others show no difference between the two Why the disparity?

Both subject groups had been strength-trained for at least two years. Another study compared fatiguing sprint protocols between men and women. Subjects performed multiple sprints per day for several days in a row. Women were able to recover more quickly between same day sprint trials, but both men and women recovered similarly between days I have no doubt that estrogen in women may have played a role in the more intense studies showing that women can recover more quickly.

Since we know from the above that estrogen can help in repairing muscle damage, protocols that induce extreme amounts of muscle damage might favor recovery in women.

Can we surmise then, that women are more capable of recovering from extremely damaging exercise than men? One potential explanation is that men usually experience greater muscle damage and a greater inflammation response to exercise than women This is more than likely related to estrogen like we already mentioned.

Inflammation can easily lead to increased levels of muscle soreness and pain beyond muscle damage alone which can reduce voluntary muscle activation Since many protocols assess recovery by measuring maximal voluntary contraction MVC force compared to the baseline level, men may not produce as much MVC force in the days following exercise as they will probably have more muscle soreness.

Additionally, since women inherently rely more on aerobic metabolism than men, they will likely experience less muscle damage as their overall metabolic and oxidative stress load will be lower.

Fibers that develop more metabolic and oxidative stress likely experience more damage than aerobic fibers read here. Are you ready for a curveball here?

Studies show that untrained men and women make very similar gains in size and strength when beginning a training protocol 1 , 5 , 6 , 16 , While these gains will eventually diverge, this is an incredibly interesting scenario when considering all of the above we just talked about.

Women make the exact same progress as men when beginning a training program. Everyone always thinks that women will make much slower gains and have fewer results than men, but for at least the first 6-months or so of training, both can expect similar results.

So why do men eventually make greater gains while women tend to slow or plateau earlier? If we review the initial adaptations to resistance training, we see that gains in muscle size are essentially the last adaptation and can take months to significantly occur.

Men will eventually make greater gains in size and strength and that probably has a lot to do with testosterone. Testosterone increases muscle size by ramping up protein synthesis Positive protein balance is necessary for muscle growth to occur, so men are more than likely to be in a greater positive protein balance than women at all times.

Men have higher baseline fiber size, so increasing that size to a greater extent compared to a female muscle fiber makes the difference in overall muscle size almost exponentially greater in the long term.

Not quite. Data was analysed using a 4×2 ANCOVA with baseline measures used as covariates. The within-group factor was the phase of training baseline, post-training and the between-group factor was training group i.

TM, TF, ConM, ConF. Post-hoc comparisons are Bonferroni corrected and adjustments for multiple comparisons are applied in the correlation tables.

All data are presented as mean ± standard error of the mean SEM. Power β and effect size ES are reported for those changes that exhibited significant sex differences, where power was calculated post hoc using the independent t-test assumptions.

There were significant increases in pCSA, strength, PT Vol, mean PT K and E, and IGF-I Table 1 in each training group, with no sex differences. However, when PT K was analysed at discrete force regions, significant sex-specific differences were identified Fig 1.

Males black bars and females white bars following training. Data are Mean ± SEM. Pooled population baseline IGF-I values correlated with baseline stiffness at high force levels i. At week 8 however, the correlations of IGF-I was in fact with lower force regions i.

Whilst baseline IGF-I was not associated with tendon stiffness, at week 8, IGF-I levels correlated with week 8 stiffness at mid force levels i.

Our key current findings are 1 we are the first to demonstrate sex-specificity in the overloading-induced adaptive nature of the mechanical properties of tendon in a young population. Sex-related differences in the mechanical, structural and regulatory mechanisms in human tendinous tissue have been identified previously [ 5 , 7 ].

Differences in acute tendon fractional collagen synthesis rates [ 8 , 9 ], amount of tendon dry mass per wet tendon weight [ 32 ], mRNA levels of Type III collagen [ 10 ] have all been shown to vary between sexes.

In addition, proteomic work from Little et al. This would tend to suggest that, either at rest, or when provided with a similar physical stimulus to males, female tendon does not respond similarly.

As successive acute responses to physical stimuli combine to produce the chronic adaptation, this leads to the possible scenario of a mal-adapted female tendon i. morphologically or mechanically relative to male tendon following a period of training. There were also no differences in the training-induced mean patella tendon stiffness change, between males and females.

This is in contrast to the findings of Onambele-Pearson and Pearson [ 12 ] and Seynnes et al. Evident from the torque data in the current study, the mean torque associated with the resistance training would have been much greater in males post-training MVCs were ±10 Nm vs.

Males black filled diamonds and females white filled squares. A further potential physiological mechanism for our observations is the nature of the resistance training program. The exercises performed were dynamic apart from one isometric , and isotonic in nature.

Adaptations to eccentric training, such as microcirculatory factors and pain reduction, has been shown to be sex-specific in a cohort with Achilles tendinopathy, with males again demonstrating an improved responsiveness [ 34 ]. Furthermore, during maximal eccentric exercise between o knee extension, we previously [ 7 ] showed that female patella tendon displayed reduced stiffness compared to males, and attributed a large portion of the reduced fascicular lengthening seen in females compared to males to this observation.

A subsequent study from our group [ 35 ] also showed that following the same exercise protocol, males displayed a significantly greater magnitude of muscle damage.

This demonstrates that the sex-specific response and adaptations to variables associated with manipulating a resistance training program have yet to be elucidated, and await further study. Therefore, the results of the current study raises the following question: Is dynamic, heavy-load resistance training currently the most conventional and popular form , the best training method for females routinely operating at the higher force levels of the tendon force-elongation curve, where adaptations to this type of training are minimised relative to adaptations on the subsequent lower portions of the tendon Force-Elongation curve?

In vitro studies have demonstrated the potency of TGFβmediated effects on collagen, and its relationship to magnitude of mechanical strain [ 14 , 15 ]. What is also surprising is that to date, only one study had previously described the effect of resistance training as opposed to endurance kicking-type exercise, on TGFβ-1 and tendon mechanical properties, despite resistance training being a more potent mechanical stimulus for tendon adaptation.

We have also previously shown in a young population [ 31 ], that resistance training did not result in chronically elevated TGFβ-1 levels following 8 weeks of heavy resistance training with varying levels of strain.

This was also the case in the current study, where there were no significant changes in either males or females following resistance training, despite significant improvements in tendon mechanical properties.

Despite this, we have shown a strong, positive correlation between baseline TGFβ-1 levels and tendon stiffness. This would make sense, from the point that a natural higher physiological level of TGFβ-1 could produce and preserve a stiffer MTC.

Previous research has shown, lower levels of TGFβ-1 and dysregulation of the TGF-β axis are present in diseased compared to healthy tendons [ 36 ]. It should nonetheless be noted that measuring TGFβ-1 in blood is a complex issue, with many large variations measured between studies.

However, in a young, healthy population, such as in the current study, there have been shown to be no differences between male and females in circulating TGFβ-1 levels [ 19 , 20 ]. IGF-I levels increased significantly as a result of heavy resistance training in both sexes.

Similar observations have also been made, with peritendinous levels of IGF-I being significantly elevated at 3 hours post-RT in both males and females, but in females only, remaining elevated at 4 hours post RT [ 18 ].

In a patella tendon defect model in rabbits, direct administration of IGF-I and TGFβ-1 together significantly improved the mechanical properties of tendon such as force at failure, ultimate stress and stiffness [ 17 ].

Results from the studies of Doessing and co-workers [ 37 ] and Nielson et al. In the current study, males and females showed very similar relative changes in IGF-I, muscle size, torque, tendon volume and tendon mechanical properties.

IGF-I thus may have played a role in the adaptive process, with the work of Doessing et al. It has been suggested that young, exercising females are possibly at more risk of tendon injury than males [ 4 ].

The practical implications of the current study are that females operating toward the maximal end of the MVC spectrum, may experience a relatively reduced enhancement of tendon stiffness following RT. A sex-specific electromechanical delay has been noted previously [ 38 ], with females showing an increased delay compared to males.

In parallel, we have also previously demonstrated that during maximal eccentric contractions [ 7 ], there are sex differences in absolute patella tendon stiffness, which in turn modulated Vastus Lateralis fascicle lengthening, affecting force production.

These above facts compound the evidence and necessity to consider sex difference in resistance training applications. Therefore, future studies may wish to focus on elucidating methods to increase stiffness at higher MVC forces in young, female populations.

In conclusion, we have demonstrated that both males and females display the same relative adaptability in terms of enhancing muscle-tendon morphology and function following resistance training. However, the nature of these adaptations have implications for muscle-tendon function during different tasks for each sex.

Finally, for females, high-load dynamic resistance training may not be optimal for enhancing MTC function at high force outputs. Browse Subject Areas? Click through the PLOS taxonomy to find articles in your field. Article Authors Metrics Comments Media Coverage Reader Comments Figures.

Abstract Purpose To compare the relative changes in muscle-tendon complex MTC properties following high load resistance training RT in young males and females, and determine any link with circulating TGFβ-1 and IGF-I levels. Conclusions Greater resting TGFβ-1 levels are associated with superior tendon mechanical properties.

Funding: The authors received no specific funding for this work. Introduction The muscle-tendon complex MTC exhibits multiple physiological characteristics which differentially impact the physical capacities of males and females throughout the lifespan [ 1 — 3 ] with young, exercising females possibly more susceptible to overuse injuries such as tendinopathies than males [ 4 ].

Methods Participants Twenty-eight young participants recruited from the local university campus, gave written informed consent to participate in the study. Study design The study design was convenience sampling, with participants separated into groups according to sex followed by random allocation to one of two groups i.

Muscle physiological cross-sectional area pCSA The measurement techniques used for the calculation for physiological cross-sectional area of the Vastus Lateralis VL muscle in the current study have been documented elsewhere [ 25 , 26 ]. Tendon properties The measures of tendon properties used in the current investigation have been described elsewhere [ 31 ].

Circulating growth factor levels IGF-I and TGFβ-1 Pre and post-training, following an overnight fast, ~10 hours , participants reported to the laboratory between am. Statistics Statistical analysis was carried out using IBM SPSS v19 IBM Inc, USA.

MTC properties changes There were significant increases in pCSA, strength, PT Vol, mean PT K and E, and IGF-I Table 1 in each training group, with no sex differences.

Download: PPT. Fig 1. Relative changes in patella tendon stiffness K at each force level of the force-elongation curve. Table 1. Baseline and post-training values for muscle-tendon complex properties and circulating growth factors in each gender. Table 2. Differential gender associations between circulating TBG-β, IGF-I and Tendon K.

Discussion Our key current findings are 1 we are the first to demonstrate sex-specificity in the overloading-induced adaptive nature of the mechanical properties of tendon in a young population.

Fig 2. Normalized change in tendon stiffness to the mean stiffness change following training. Resistance training program A further potential physiological mechanism for our observations is the nature of the resistance training program.

Practical application It has been suggested that young, exercising females are possibly at more risk of tendon injury than males [ 4 ]. Conclusion In conclusion, we have demonstrated that both males and females display the same relative adaptability in terms of enhancing muscle-tendon morphology and function following resistance training.

Supporting information. S1 File. Muscle-tendon male and female raw data results. s XLSX. S2 File. Endocrine growth factors regressions. Autonomic modulation and baroreflex sensitivity after acute resistance exercise: Responses between sexes.

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Background: Micronutrient absorption disorders cardiovascular effects of training have been widely investigated; trqining, few differencds have Gender differences in training adaptations sex differences in arteriolar adaptation. In the current study, differencee examined the adaptation ditferences the gracilis adaptattions of male and female rats in response to intensive training. Exercise-induced cardiac hypertrophy was confirmed by echocardiography. Following the training, the gracilis muscle arterioles were prepared, and their biomechanical properties and functional reactivity were tested, using pressure arteriography. Collagen and smooth muscle remodeling were observed in the histological sections. Results: Left ventricular mass was elevated in both sexes in response to chronic training.

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Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands.

Raven O. Huiberts, Rob C. Department of Cardiology, Amsterdam University Medical Center, University of Amsterdam, Meibergdreef 9, AZ, Amsterdam, The Netherlands. You can also search for this author in PubMed Google Scholar.

Correspondence to Stephan van der Zwaard. Wüst, and Stephan van der Zwaard have no conflicts of interest that are directly relevant to the content of this article. RH and SZ conceived and designed the work. RH and SZ performed the literature search and the data screening and extraction.

RH and RW evaluated the risk of bias. RH and SZ performed the statistical analyses. SZ was responsible for the visualizations and RH, RW, and SZ interpreted the data. SZ wrote the manuscript.

All authors read and revised the manuscript and approved the final version of the manuscript for publication. Open Access This article is licensed under a Creative Commons Attribution 4. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material.

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Reprints and permissions. Huiberts, R. Concurrent Strength and Endurance Training: A Systematic Review and Meta-Analysis on the Impact of Sex and Training Status. Sports Med Download citation. Accepted : 24 September Published : 17 October Anyone you share the following link with will be able to read this content:.

Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative. Download PDF. Abstract Background Many sports require maximal strength and endurance performance.

Methods A systematic review and meta-analysis was conducted according to PRISMA Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and a Cochrane risk of bias was evaluated.

Results In total, 59 studies with participants were included. Conclusions Concurrent training results in small interference for lower-body strength adaptations in males, but not in females.

Clinical Trial Registration PROSPERO: CRD Compatibility of Concurrent Aerobic and Strength Training for Skeletal Muscle Size and Function: An Updated Systematic Review and Meta-Analysis Article Open access 10 November Effects of Concurrent Strength and Endurance Training on Measures of Physical Fitness in Healthy Middle-Aged and Older Adults: A Systematic Review with Meta-Analysis Article Open access 12 October Perspectives on Concurrent Strength and Endurance Training in Healthy Adult Females: A Systematic Review Article Open access 10 November Use our pre-submission checklist Avoid common mistakes on your manuscript.

FormalPara Key Points Concurrent training resulted in blunted lower-body strength adaptations in males, but not in females. Full size image. Table 1 Effects of concurrent training are evaluated for the following outcome measures.

If multiple measurements exist for the same outcome measure, measurements are analyzed according to the presented hierarchy Full size table. Table 2 Classification framework to determine strength and endurance training status of male and female participants.

Figure 2. Tangential wall stress as a function of intraluminal pressure measured in passive conditions of the gracilis muscle arterioles from the MC, ME, FC, and FE animals.

The tangential wall stress was significantly increased in the FE rats compared with the controls. In addition, this value was significantly higher in the FC and FE rats than in the MC and ME rats.

The data are expressed as the mean SEM values. Figure 3. Tangential elastic modulus as a function of intraluminal pressure measured in passive conditions of the gracilis muscle arterioles from the MC, ME, FC, and FE animals. As a result of the exercise, the elastic modulus was significantly smaller in the ME rats than in the MC rats.

Figure 4. Distensibility as a function of intraluminal pressure measured under passive conditions of the gracilis muscle arterioles from the MC, ME, FC, and FE animals.

Distensibility increased in the FE rats compared with the FC rats. Importantly, the inner radius elevation could only be observed in the exercised females. While there was no significant difference in the inner radius between the sedentary males and females, the exercised females had wider gracilis arterioles than the males Figure 1A.

Moreover, the wall thickness was significantly lower in the female control group compared with the male control group, and this difference was diminished in the trained animals Figure 1B.

In the female rats the FC and FE groups , we observed a significantly smaller wall thickness-to-lumen diameter ratio than those observed in the male rats Figure 1C. Tangential stress increased in the female animals as an effect of training, but no such change was observed in the male specimens, and the tangential stress was significantly higher in the female animals FC and FE than in the male rats MC and ME Figure 2.

Moreover, training-induced reduction of the elastic modulus occurred only in the males Figure 3 , while another elastic parameter, incremental distensibility, increased only in the females Figure 4.

No further difference between the males and the females, either in the sedentary or trained animals, was identified in any of the elastic parameters Figures 3 , 4. The myogenic tone of the gracilis muscle arterioles in the male exercise group was significantly lower than that in the vessels harvested from MC rats Figure 5.

In terms of changes in contractility NE constriction , the extent of contraction of the segments relative difference of maximally relaxed and maximally contracted radius was increased in the females, following the swimming training Figure 6.

The level of testosterone contraction was significantly decreased in the ME group, approaching that observed in the female animals Figure 7. Figure 5. Myogenic tone as a function of intraluminal pressure measured under passive conditions of the gracilis muscle arterioles from the MC, ME, FC, and FE animals.

As a result of the exercise, the myogenic tone was significantly smaller in the ME rats than in the MC rats. Figure 6. Constrictions to NE relative difference of the maximally relaxed and maximally contracted radius as a function of intraluminal pressure measured in passive conditions of the gracilis muscle arterioles from the MC, ME, FC, and FE animals.

As a result of norepinephrine, the constriction was significantly higher in the FE rats compared with the FC and ME rats. Figure 7.

Testosterone contraction of the segments in 10 —8 and 10 —6 M at 50 mmHg from the MC, ME, FC, and FE animals. The testosterone contraction was significantly lower in the females than in the males in the control groups.

As a result of the exercise, the testosterone contraction decreased in the male groups. A training-induced reduction in myogenic tone was only observed in the male animals. Sex differences in myogenic tone did not reach statistical significance in either the control or trained groups Figure 5.

Training elevated norepinephrine vasoconstriction in the females, but not in the males; as a result, the trained females exerted more effective vasoconstriction than the trained males Figure 6. Contraction to testosterone was significantly lower in the FC rats than in the MC rats. This difference diminished after the training Figure 7.

The medial smooth muscle content was not significantly altered by the training Figure 8A. The density of collagen was higher in the ME group than in the MC group Figure 8B.

No training-induced alteration in the overall medial connective tissue content was observed Figure 8C. Figures 8D—G show representative MOVAT-stained sections of the gracilis arterioles prepared from the four groups.

Figure 8. MOVAT staining. A Smooth muscle staining intensity of segments from the MC, ME, FC, and FE animals. Smooth muscle density was significantly higher in the FE rats than in the MC rats. B Collagen staining intensity of the segments from the MC, ME, FC, and FE animals.

The density of the collagen was significantly higher in the male exercised group compared with the male control rats. C Connective tissue staining of the segments from the MC, ME, FC, and FE animals.

D Representative staining in the MC rats. E Representative staining in the ME rats. F Representative staining in the FC rats. G Representative staining in the FE rats.

The density of connective tissue was significantly higher in the female control group than in the male control group. The data are expressed as the median interquartile ranges values. There was a significant difference between the male-control and female-exercised animals; the FE rats demonstrated more intense muscle staining in their tunica media than the MC rats Figure 8A.

Moreover, collagen staining increased in the males in response to training, and connective tissue staining was significantly higher in the female control group than in the male control group Figure 8C.

In the current study, we examined the effects of exercise training on gracilis muscle arterioles in the male and female rats. To the best of our knowledge, this is the first study to investigate sex differences in a swim-training model of skeletal muscle arteriole biomechanics and pharmacology.

In the females, the smooth muscle content of arterioles increased, while in the males, there was more collagen in the media. These results confirm our theory that sex plays an essential role in the sport adaptation of skeletal muscle arterioles. Echocardiographic examinations were performed to test the training status of the animals.

In accordance with our previous results and published data in the literature, 12 weeks of the swim training leads to substantial myocardial hypertrophy in both males and females Olah et al.

Although training adaptation of peripheral vessels has been examined in several earlier studies, part of these observations is focused on larger conduit arteries Andaku et al.

Alterations of small arteries in response to training have been studied earlier in some publications Jasperse and Laughlin, ; Laughlin et al. It is known that the walls of the peripheral arteries thicken and their diameter increases as a result of physical exercise Green et al.

Elevation of maximal diameter is not always present. While the diameter of arterioles of gastrocnemius muscle significantly increased as an effect of training both in young and elderly rats, no similar alterations in the soleus muscle arterioles could be observed Spier et al.

In a study of elite squash players, it was found that, in the non-dominant arm, the wall of the brachial artery became thinner, but its diameter remained unchanged, while, in the dominant arm, arterial wall thinning was accompanied by vascular dilatation Thijssen et al.

This phenomenon may be explained by the fact that the arteriole of the dominant arm receives higher shear stress for a longer period than the arteries in the non-dominant arm Thijssen et al. Another explanation is that the vascular tone decreases due to training, leading to thinning of the wall Amaral et al.

In our recent research, we examined the morphological and biomechanical parameters of gracilis arterioles. In the exercised male animals, the inner vascular diameter remained unchanged, while the wall thickness decreased to the values observed in the females.

However, the wall thickness-to-lumen ratio did not change significantly in either sex. The effect of training the wall stress increased in the females, while no change was observed in the males; this may be caused by the enhanced vascular diameter, and the fact that the wall tension is directly proportional to the lumen radius of the vessel and inversely proportional to wall thickness.

In the literature, both increases and decreases in vascular wall tension have been reported as effects of training in different vessels Nualnim et al. These contradictory results can be explained by the use of different study subjects, types of arteries, training protocols, and study methods.

In this study, we used an in vitro pressure myograph to track the morphological parameters of vessels in their passive state, from which the biomechanical parameters were derived. Elastic parameters are connected to geometry and will be discussed in the later subchapter.

The functional adaptation caused by training was not uniform along the vascular system. The vessel segments have different functions, depending on their size, location in networks, and lying in different vascular beds.

Small vessels and arterioles contract spontaneously if common physiological conditions are present; a spontaneous or myogenic tone can be observed. There are contradictory findings in the literature concerning the effect of chronic exercise on myogenic tone, with studies showing increased, decreased, and unchanged basal arterial tone Meredith et al.

In older rats 28—30 weeks old , there were no significant differences in the myogenic tone of the gracilis arterioles in either control or trained male animals Sun et al. In contrast, after a month of training, the total peripheral resistance index decreased in the healthy young men Meredith et al.

Sun et al. They found a slight elevation in myogenic tone, and no significant difference in norepinephrine tone Sun et al. It is interesting that the extent of myogenic tone can depend upon the type of the vessel studied. In interval sprint-trained rats, arterioles prepared from the gastrocnemius muscle had higher myogenic tone than feed arteries of the same muscle Laughlin et al.

Interval sprint training elevates the spontaneous tone of arterioles, but their myogenic reactivity is the same as that of control arterioles, keeping diameter almost constant despite alterations in intraluminal pressure Laughlin et al.

These observations are in contrast to those of our study, in which, following a week strenuous training program, the myogenic vessel tone decreased in the young adult male rats and remained unchanged in the female rats. Moreover, in the females, the norepinephrine tone was elevated in the present study.

Another interesting observation is that, while in skeletal muscle arterioles of the rat, there is an elevation of alpha-adrenergic and endothelin-1 mediated contractions with age Donato et al. In our studies, the vasoconstriction-lowering effect of training could be observed in young male rats.

There is an observation according to vascular adaptation in trained elderly animals can be different in metabolically different types of muscle. High oxidative portions of gastrocnemius red gastrocnemius are low perfused, while low-oxidative portions of gastrocnemius white gastrocnemius are relatively highly perfused when compared with young animals Behnke et al.

Endurance training in elderly animals improves the matching of oxygen delivery to an oxidative capacity of the muscle; it increases vascular conductance and blood flow in red gastrocnemius, while moderating these parameters in the white gastrocnemius Behnke et al.

A further important observation was that, in the young animals, training elevated the total number of arteries perforating the gastrocnemius muscle but left the cross-sectional area of the feed artery unaltered, while, in the elderly animals, in an opposite manner, the number of perforating arteries was unaltered while the diameter of the feed artery increased Behnke et al.

Potential age-induced differences in arteriolar adaptation are outside the scope of the present study, forming one of its limitations. The length and extent of training can explain the difference between these observations. We found that 12 weeks of strenuous work is sufficient for geometrical and histological wall remodeling.

Moreover, even the sympathetic innervation of these vessels could have changed when sufficient time was provided. Testosterone has an acute vasoactive effect; the strength of which varies according to species and vessel types Perusquía et al.

In our recent experiment, testosterone was added to the organ bath-induced contraction of gracilis vessels. The training reduced testosterone contraction in the males, but no significant alteration in the females was observed see the next subsection. The absolute cardiac parameters measured by echocardiography were significantly lower in the females but were higher when adjusted to the lower weight of the female animals.

Based on the literature, the Akt-protein may play a role in the enhanced relative cardiac hypertrophy of females. In our previous study, phosphorylation of Akt increased in both sexes as a result of exercise but was more pronounced in the females Olah et al.

Similar results were reported not only in animal models but also in male and female athletes. Significant sex differences were observed in the control group with respect to the wall thickness.

In exercised female animals, we found an increase in the inner vascular diameter, while the wall thickness remained unchanged. This increase was more pronounced than in the case of the exercised males. However, chronic exercise restored the normal value in the spontaneous hypertensive SHR rats, but not in the female SHRs Amaral et al.

Green et al. The distensibility and elastic modulus are parameters that describe the elasticity of the vessels. Higher distensibility and lower elastic modulus result in greater vascular elasticity. The elasticity of the gracilis vessels increased as a result of training, but it showed sex-related differences.

In the males, the elastic modulus decreased, whereas, in the females, the distensibility increased at low pressures. Similar to our findings, a decrease in elastic modulus and an increase in distensibility of resistance coronary arteries were observed in the rats trained on a treadmill Szekeres et al.

The increase in the vascular parameters related to elasticity is advantageous in terms of hemodynamic adaptation. During exercise, flow in the moving skeletal muscles increases periodically; therefore, the gracilis vessels may dilate more effectively as a result of their adaptation, resulting in improved tissue perfusion.

Similar results have been found in a previous study on coronary arterioles of swimming rats, in which the myogenic tone of trained male rats was significantly lower than that of females Török et al.

In contrast, the maximum contraction caused by noradrenaline was significantly increased in our trained female animals. Some sex differences in the contraction of muscle arteries following training have already been examined, but the results in the literature are inconsistent Just and DeLorey, ; Samora et al.

Just and DeLorey found an increased vasoconstriction capacity in females in a steady state compared with males, but the difference disappeared during muscle contraction. However, Laughlin et al. Soleus feed arteries of male rats responded with dose-dependent contractions to norepinephrine; no difference between trained and sedentary animals could be observed Jasperse and Laughlin, Gastrocnemius feed arteries were more sensitive to phenylephrine in the control than in the trained animals Laughlin et al.

In aortic rings of rats after 10 weeks of training, there was a reduced norepinephrine sensitivity. It could be observed only after 4—10 weeks of training.

Removal of endothelium diminished that reduced sensitivity, proving its endothelial origin Spier et al. Based on this and on our observations, it may be considered that, as a result of training, the vascular reactivity increases in both sexes; in trained males, relaxation is more pronounced, while, in trained females, higher contraction is observed.

The regulatory effects of estrogen and testosterone may play a role in these effects, and further investigations are needed to explain the observed sex differences. Substantial sex differences could be demonstrated in the acute vasoactive effect of testosterone; the most intensive contraction was found in the male control animals, which decreased to the level of the females as a result of exercise.

One explanation for this phenomenon is that exercise increases the metabolism of testosterone to estrogen, which compensates for the vasoconstrictor effect of testosterone Gharahdaghi et al. In addition, the dominance of testosterone-related vascular effects can move toward relaxation.

Testosterone affects vascular tone through NO-dependent vasorelaxation, prostanoid-dependent vasoconstriction, and relaxation Chinnathambi et al. Our histological observations also showed sex differences in the training-induced histological remodeling of skeletal muscle arterioles. While females improve their smooth muscle ratio, male rats enhance the amount of collagen in the tunica media.

The differences in the histological composition may be related to the observed differences in wall elasticity and contractility. One limitation of our experiments is that they have been performed on relatively young animals, which makes it difficult to adapt to mammals with a slower life cycle, or to humans, where circulatory problems arise mostly in advanced age.

Further observations are needed to reveal the degree to which different sex hormones are responsible for the observed sex differences. As a result of a strenuous swimming exercise program, a peripherally located skeletal muscle arteriole, the gracilis arteriole adapts to physical activity; this adaptation shows sex differences: In the females, the wall thickness remained unchanged, and the diameter increased, while, in the males, the diameter remained the same, and thinning was observed in the vessel wall.

In the males, the elastic modulus decreased due to exercise, while, in the females, increased distensibility was observed. Sport adaptation also appears in the altered contractility of the vessels, and we succeeded to identify substantial sex differences in the sport-induced alterations of basal and induced tones.

In the males, the myogenic tone decreased, whereas the maximum contraction was enhanced in the females. The biomechanical and functional changes following chronic physical activity may be considered as physiological regulation. The observed processes ensure increased flow during physical activity, defense against increased wall stress during work dilation, and represent a convenient way to reduce blood flow during inactivity.

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For more information Natural anxiety relief PLOS Subject Micronutrient absorption disorders, click here. To compare Beta-alanine and muscle regeneration relative changes in muscle-tendon complex MTC properties following high trainning resistance training Traijing in young males and females, and diffdrences any link with circulating TGFβ-1 and IGF-I levels. The training groups completed 8 weeks of resistance training RT. However, there were no significant sex-specific changes in most MTC variables. Interestingly, pooled population data showed that TGFβ-1 correlated with K at baseline, with no correlations identified between IGF-I and MTC properties. Greater resting TGFβ-1 levels are associated with superior tendon mechanical properties. Tong Liu Department of Gender differences in training adaptations Tianjin Institute of Cardiology Adaptatuons Hospital Gender differences in training adaptations Differeces Medical University Tianjin China. ISSN Print : X ISSN Online : DOI: Exercise is a major challenge for cardiovascular apparatus since it recruits chronotropic, inotropic, pre-load, and afterload reserves. Regular physical training induces several physiological adaptations leading to an increase in both cardiac volume and mass. Gender differences in training adaptations

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4 thoughts on “Gender differences in training adaptations

  1. Im Vertrauen gesagt ist meiner Meinung danach offenbar. Auf Ihre Frage habe ich die Antwort in google.com gefunden

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