Sex differences in quadriceps and inspiratory muscle fatigability following high-intensity cycling

OBJECTIVES

As females have been hypothesized to have more fatigue resistant inspiratory muscles, this study aimed to compare the development of inspiratory and leg muscle fatigue between males and females following high-intensity cycling.

DESIGN

Cross-sectional comparison.

METHODS

17 healthy young males (27 ± 6 years, V̇O_2peak 55 ± 10 ml･min^-1･kg^-1) and females (25 ± 4 years, V̇O_2peak 45 ± 7 ml･min^-1･kg^-1) cycled until exhaustion at 90% of the peak power output achieved during an incremental test. Changes in quadriceps and inspiratory muscle function were assessed via maximal voluntary contractions (MVC) and assessments of contractility via electrical stimulation of the femoral nerve and cervical magnetic stimulation of the phrenic nerves.

RESULTS

Time to exhaustion was similar between sexes (p = 0.270, 95% CI -2.4 - 0.7 min). MVC of the quadriceps was lower after cycling for males (83.9 ± 11.5% vs. 94.0 ± 12.0% of baseline for females, p = 0.018). Reductions in twitch forces were not different between sexes for the quadriceps (p = 0.314, 95% CI -5.5 - 16.6 percent-points) or inspiratory muscles (p = 0.312, 95% CI -4.0 - 2.3 percent-points). Changes in inspiratory muscle twitches were unrelated to the different measures of quadriceps fatigue.

CONCLUSION

Females incur similar peripheral fatigue in the quadriceps and inspiratory muscles compared with men following high-intensity cycling, despite smaller reduction in voluntary force. This small difference alone does not seem sufficient to warrant different training strategies to be recommended for women.

Comparison of efficiency of elastic and non-elastic taping on induced quadriceps fatigue by knee extension exercise

[Purpose] The purpose of this study is to examine the effects of elastic and non-elastic taping on induced quadriceps fatigue by knee extension exercise. [Subjects and Methods] Thirty healthy females were randomly assigned to an elastic tape group (ET, n=10), a non-elastic tape group (NET, n=10), or a no tape group (NT, n=10). Taping groups attached taping on quadriceps femoris. Three groups are conducted knee extension exercise for 10 times and 3 sets during 10 minutes. Knee extension peak torque measured before and after knee extension exercise. One-way analysis of variance was used to assess the statistical significance of knee extension peak torque. [Results] No significant difference in changes in maximum muscle strength per unit weight from before to after the muscle fatigue exercise was found in the ET, NET, or NT groups (12.1 ± 4.2, 11.7 ± 7.1, and 6.7 ± 3.4 N/kg, respectively). [Conclusion] Taping facilitated muscle performance, but it also increased susceptibility to fatigue resulting from greater muscle activation.