No abstract

Male athletes tend to outperform female athletes in several endurance sports. Maximum cardiac output can be estimated by maximal oxygen consumption (V˙O2max), and it has been established that men present V˙O2max values about 20% higher than women. Although sex differences in V˙O2max have already been well studied, few studies have assessed sex differences with regard to muscle oxidative capacity. The aim of this study was to compare aerobic muscle quality, accessed by V˙O2max and adjusted by lower limb lean mass, between male and female amateur triathletes. The study also aimed to compare sex differences according to V˙O2 submaximal values assessed at ventilatory thresholds. A total of 57 participants (23 women and 34 men), who had been training for Olympic-distance triathlon races, underwent body composition evaluation by dual-energy X-ray absorptiometry and performed a cardiorespiratory maximal test on a treadmill. Male athletes had significantly higher V˙O2max, both absolutely and when adjusted to body mass. Conversely, when V˙O2max was adjusted for lean mass, there was no significant difference between sexes. The same was observed at submaximal exercise intensities. In conclusion, differences in V˙O2max adjusted to body mass but not lean mass may explain, at least in part, sex differences in performance in triathlons, marathons, cycling, and other endurance sports.

Performance in endurance sports decreases with aging, which has been primarily attributed to cardiovascular and musculoskeletal aging; however, there is still no clear information on the factors that are most affected by aging. The aim of this study was to compare two groups of runners (< 50 and > 50 years of age) according to their absolute, weight-adjusted maximal oxygen uptake (V̇O2max), lower limb lean mass-adjusted V̇O2max, ventilatory threshold, and respiratory compensation point (RCP). A total of 78 male recreational long-distance runners were divided into Group 1 (38.12 ± 6.87 years) and Group 2 (57.55 ± 6.14 years). Participants were evaluated for body composition, V̇O2max, VT, and RCP. Group 1 showed higher absolute and body mass-adjusted V̇O2max (4.60 ± 0.57 l·min−1 and 61.95 ± 8.25 ml·kg−1·min−1, respectively) than Group 2 (3.77 ± 0.56 l·min−1 and 51.50 ± 10.22 ml·kg−1·min−1, respectively), indicating a significant difference (p < 0.001, d =  − 1.46 and p < 0.001, d =  − 1.16). Correspondingly, Group 1 showed a significantly higher lower limb lean mass–adjusted V̇O2max (251.72 ± 29.60 ml·kgLM−1·min−1) than Group 2 (226.36 ± 43.94 ml·kgLM−1·min−1) (p = 0.008, d =  − 0.71). VT (%V̇O2max) (p = 0.19, d = 0.19) and RCP (%V̇O2max) (p = 0.24, d = 0.22) did not differ between the groups. These findings suggest that both variables that are limited by central or peripheral conditions are negatively affected by aging, but the magnitude of the effect is higher in variables limited by central conditions. These results contribute to our understanding of how aging affects master runners.