The effects of two different intermittent fatigue protocols of the leg extensors and flexors between men and women on electromechanical delay, peak torque, and rapid force characteristics.

摘要

The purpose of the present study was to examine the effects of acute neuromuscular fatigue and recovery on maximal and rapid torque characteristics in females and males for the leg extensor and flexor muscle groups. Twenty young female (mean +/- SD: age = 21.25 +/- 1.45 years; height = 155.14 +/- 33.29 cm; mass = 72.26 +/- 11.98 kg) and twenty male (age = 22.05 +/- 3.58 years; height = 176.83 +/- 7.89 cm; mass = 84.94 +/- 17.64 kg) performed maximal voluntary contractions (MVCs) prior to performing a fatigue-inducing bout of submaximal and maximal, intermittent isometric contractions using a .6 duty cycle at 50% of MVC until volitional fatigue. MVCs were then performed again at immediately after 7, 15, and 30 following the completion of the fatigue task. Four-way mixed factorial ANOVA (muscle[leg extensors vs. leg flexors] x intensity [ maximal vs. submaximal] gender [males vs. females] x time phase [Pre vs. Post0 vs. Post7 vs. Post15 vs. Post30]) was used to analyze all maximal, rapid torque and EMD data. The present findings revealed that females had greater overall endurance times compared to males, as well as the knee flexors were more fatigue resistant than the extensors. No differences were observed between genders for EMD, however when collapsed across gender, no recovery was observed for the knee flexors while the extensors were affected at numerous time points (Post0, Post15, Post30). Differences for PT were observed immediately following the fatigue-inducing tasks in which the extensors were more fatigued than the flexors for PT. However, differential recovery patterns were observed for the extensors and flexors, in which the flexors were, affected more (Post7, Post15, Post30) than the extensors. Additionally, females were more fatigued than males throughout recovery (Post7, Post15, Post30). The early rapid torque variable (RTD30) observed faster recovery for males than females for both muscles, while the later rapid torque variable (RTD100) observed significant reductions in force for the leg extensors, and maximal condition specifically. Also, the flexors were affected similarly collapsed across condition.