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Sex difference in muscular strength in equally-trained men and women

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Sumario: The purposes of the present study were: (1) to determine the magnitude of the sex difference in upper and lower-body strenght in groups of men and women with similar physical activity backgrounds and (2) to determine the extent to which the sex difference in strenght is explained by differences in FFW and FFCSA. By deduction, the portion of the sex difference in strength not acounted for by FFW and FFCSA could be attributed to neuromuscular and/or other factors
... d/wk days per week, DD ACE genotype DD polymor-phism, ID ACE genotype ID polymorphism, II ACE genotype II polymorphism, High high intensity, Low low intensity, Low + mixed low intensity, Moderate moderate intensity, y years Fig. 7 Forest plot of effect sizes with 95% confidence intervals for the effects of resistance training on sex differences in absolute changes in muscle size. d/wk days per week, DD ACE genotype DD polymor-phism, ID ACE genotype ID polymorphism, II ACE genotype II polymorphism, High high intensity, Low low intensity, Low + mixed low intensity, Moderate moderate intensity, y years In general, baseline strength is greater in adult males than females, which is likely due to greater muscle size in males [84,85], rather than a sex difference in the nervous system's ability to drive the muscle voluntarily (i.e., voluntary activation) [86]. Interestingly, the baseline sex difference in upperbody strength is greater than the baseline sex difference in lower-body strength [84,85], which has been attributed to males possessing a greater proportion of their muscle in their upper bodies [87]. ...
... d/wk days per week, DD ACE genotype DD polymor-phism, ID ACE genotype ID polymorphism, II ACE genotype II polymorphism, High high intensity, Low low intensity, Low + mixed low intensity, Moderate moderate intensity, y years In general, baseline strength is greater in adult males than females, which is likely due to greater muscle size in males [84,85], rather than a sex difference in the nervous system's ability to drive the muscle voluntarily (i.e., voluntary activation) [86]. Interestingly, the baseline sex difference in upperbody strength is greater than the baseline sex difference in lower-body strength [84,85], which has been attributed to males possessing a greater proportion of their muscle in their upper bodies [87]. The overall absolute increases in strength seen with RT may be a function of males' larger stature and subsequent larger baseline strength values [84,85]. ...
... Interestingly, the baseline sex difference in upperbody strength is greater than the baseline sex difference in lower-body strength [84,85], which has been attributed to males possessing a greater proportion of their muscle in their upper bodies [87]. The overall absolute increases in strength seen with RT may be a function of males' larger stature and subsequent larger baseline strength values [84,85]. For example, an untrained older male who has a baseline bench press of 45 kg and makes a 20% relative improvement, would see a 9 kg increase in their 1-RM. ...
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Background Reductions in muscle size and strength occur with aging. These changes can be mitigated by participation in resistance training. At present, it is unknown if sex contributes to differences in adaptation to resistance training in older adults. Objective The aim of this systematic review was to determine if sex differences are apparent in adaptations to resistance training in older adults. Design Systematic review with meta-analysis. Data Sources Web of Science; Science Direct; SPORTDiscus; CINAHL; and MEDLINE were searched from inception to June 2020. Eligibility Criteria Studies where males and females older than 50 years of age performed identical resistance training interventions and had outcome measures of muscle strength or size. Results We initially screened 5337 studies. 30 studies (with 41 comparison groups) were included in our review (1410 participants; 651 males, 759 females). Mean study quality was 14.7/29 on a modified Downs and Black checklist, considered moderate quality. Females gained more relative lower-body strength than males (g = − 0.21 [95% CI − 0.33, − 0.10], p = 0.0003) but there were no differences in relative change for upper-body strength (g = − 0.29 [95% CI − 0.62, 0.04], p = 0.08) or relative muscle size (g = 0.10 [95% CI − 0.04, 0.23], p = 0.16). Males gained more absolute upper-body strength (g = 0.48 [95% CI 0.09, 0.88], p = 0.016), absolute lower-body strength (g = 0.33 [95% CI 0.19, 0.47], p < 0.0001), and absolute muscle size (g = 0.45 [95% CI 0.23, 0.66], p < 0.0001). Conclusion Our results indicate that sex differences in adaptations to resistance training are apparent in older adults. However, it is evident that the interpretation of sex-dependent adaptations to resistance training is heavily influenced by the presentation of the results in either an absolute or relative context. Study Registration Open Science Framework (osf.io/afn3y/).
... Women athletes are known to be less strong and powerful than equally trained men [1], muscle strength of women indeed, is typically reported in the range of 40 to 75% of that of men [2]; women are also known to be less powerful than equally trained men. [3]. ...
... On the contrary, higher maximal strength and power adjusted for LBM were detected in the upper body. Some authors suggested that differences in the upper body strength performance may be related to a different muscle mass distribution between males and females rather than to a different neuromuscular function [1]. In the present study, however, differences between genders in maximal strength and power were still significant when adjusting for the thickness of the main muscles involved in each exercise. ...
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The aim of this study was to compare male vs. female athletes in strength and power performance relative to body mass (BM) and lean body mass (LBM) and to investigate the relationships between muscle architecture and strength in both genders. Sixteen men (age = 26.4 ± 5.0 y; body mass = 88.9 ± 16.6 kg; height = 177.6 ± 9.3 cm) and fourteen women (age = 25.1 ± 3.2 y; body mass = 58.1 ± 9.1 kg; height = 161.7 ± 4.8 cm) were tested for body composition and muscle thickness (MT) of vastus lateralis muscle (VT), pectoralis major (PEC), and trapezius (TRAP). In addition, participants were tested for lower body power at countermovement jump (CMJP) and upper-body power at bench press throw (BPT). Participants were also assessed for one repetition maximum (1RM) at bench press (1RMBP), deadlift (1RMDE), and squat (1RMSQ). Significantly greater (p < 0.01) MT of the VL, PEC and TRAP muscles and LBM were detected in men compared to women. Significantly greater (p < 0.05) 1RMBP and BPT adjusted for LBM were detected in men than in women. No significant gender differences after adjusting for LBM were detected for 1RMSQ (p = 0.945); 1RMDE (p = 0.472) and CMJP (p = 0.656). Significantly greater (p < 0.05) results in all performance assessments adjusted for MT of the specific muscles, were detected in males compared to females. Superior performances adjusted for MT and LBM in men compared to women, may be related to gender differences in muscle morphology and LBM distribution, respectively.
... Additionally, women were found to have greater relative force with the BS when compared to the CP exercise. These results are in accordance with previous findings (4,19). ...
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Monteiro ER, Brown AF, Bigio L, Palma A, Dos Santos LG, Cavanaugh MT, Behm DG, Correa Neto VG. Male Relative Muscle Strength Exceeds Females for Bench Press and Back Squat. JEPonline 2016;19(5):79-85. The purpose of this study was to examine gender based strength differences during one repetition maximum (1RM) back squat (BS) and chest press (CP) exercises. Fifteen females (age, 25.3  5.3 yrs; height, 164.9  6.8 cm; weight, 64.7  10.0 kg) and 15 males (age, 28.1  5.3 yrs; height, 178.0  6.6 cm; weight, 85.9  25.5 kg) performed 1RM BS and CP with 4 days rest between each session. Relative strength was calculated as load/fat free mass. Men had higher relative strength in BS (P<0.001) and CP (P<0.001) 1RM tests when compared to females. Females exhibited greater relative strength with BS versus the CP (P<0.001). In conclusion, male relative strength exceeded females for both the upper and lower tests employed in this study.
... The results of sex differences observed in the current study align with previous findings that males are taller and heavier than females, and have greater maximal strength, vertical jump performance, sprinting speed, and endurance characteristics (Bishop et al., 1987;Bale et al., 1992;McMahon et al., 2017;Cardoso de Araújo et al., 2020). In comparison, females are significantly more flexible than males (Bale et al., 1992). ...
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... Accordingly, higher levels of muscle strength and power in the aging athletes are not surprising but seem predominantly due to hypertrophy of remaining fibers as the loss of fiber numbers seems not to be preventable by lifelong PA [153]. The magnitude of differences between sexes in muscular strength is well documented and may almost entirely be explained by the difference in muscle size of equally trained men and women [154], indicating similar muscle quality characteristics for both sexes. The overall muscle mass and power is greater in men than women and the absolute changes in muscle mass following resistance training are also larger in men, but the relative changes in strength and muscle hypertrophy are similar in both sexes [155]. ...
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Summary By means of the ultrasonic photography of the cross-section of the acting muscle bundle, together with the measurement of the muscle strength developed by the subject with maximum effort, the strength per unit area of the muscle was calculated in 245 healthy human subjects, including 119 male and 126 female.The result was summarized as the following:1. The ultrasonic method used in this work was possibly admitted as the best way to calculate the cross-sectional area of the muscle. 2. The arm strength was fairly proportional to the cross-sectional area of the flexor of the upper arm regardless of age and sex. 3. The strength per unit cross-sectional area of flexor of the upper arm was 6.3 kg/cm2 in the average, standard deviation of 0.81 kg/cm2. When cross-sectional area of muscle was measured at extensive position of the forearm the strength per unit area was calculated to be 4.7 kg/cm2 at flexed position of the forearm. 4. As to the individual variation, the strength per unit area was distributed in a range from 4 kg/cm2 to 8 kg/cm2. 5. The strength per unit cross-sectional area was almost the same in male and female regardless of age. In addition to that, there was not found any significant difference in ordinary and trained adult.