Labarbera K E, Murphy B G, Laroche D P, Cook S B
Department of Kinesiology, University of New Hampshire, Durham, NH, USA -
J Sports Med Phys Fitness. 2013 Aug;53(4):444-52.
It has been shown that females have greater muscular endurance than males and that this advantage is eliminated when blood flow is restricted. It is unknown if sex differences in dynamic endurance exist during low-load blood flow restricted (BFR) resistance exercise. The purpose of this study was to investigate sex differences in quadriceps femoris fatigability during isotonic knee extension exercise coupled with a blood flow restriction.
Ten males and ten females completed three sets of low-load isotonic knee extension exercises (20% of peak torque) to volitional failure under two conditions: blood flow restricted (BFR) and non-restricted free flow (FF). The number of repetitions, exercise volume, post-exercise strength loss and surface electromyography (EMG) were measured.
Females performed more repetitions than males in the FF (252±37 vs. 112±17 repetitions; P<0.01) and BFR conditions (165±29 vs. 79±8 repetitions; P<0.01). Both sexes performed ~30% fewer repetitions during the BFR condition. MVC torque decreased approximately 37% following both conditions (P<0.01) and EMG activity increased (P<0.05) during the exercise bouts.
Similar fatigue characteristics were evident in FF and BFR conditions for both sexes, and females demonstrated greater endurance, as determined by the number of repetitions completed, in both conditions. It may be beneficial to increase the relative exercise load for females in order to decrease the time under BFR.
研究表明，女性比男性具有更强的肌肉耐力，并且当血流受限的时候，这种优势就会消失。目前尚不清楚在低负荷血流限制（BFR）抗阻运动中是否存在动态耐力的性别差异。本研究的目的是调查等张膝关节伸展运动结合血流限制时股四头肌疲劳性的性别差异。
10名男性和10名女性在两种条件下完成三组低负荷等张膝关节伸展运动（峰值扭矩的20%），直至自主疲劳：血流限制（BFR）和无限制自由血流（FF）。测量重复次数、运动量、运动后力量损失和表面肌电图（EMG）。
在FF（252±37次 vs. 112±17次；P<0.01）和BFR条件下（165±29次 vs. 79±8次；P<0.01），女性的重复次数多于男性。在BFR条件下，两性的重复次数均减少了约30%。两种条件下最大随意收缩（MVC）扭矩均下降约37%（P<0.01），运动期间肌电图活动增加（P<0.05）。
在FF和BFR条件下，两性都表现出相似的疲劳特征，并且根据完成的重复次数确定，女性在两种条件下都表现出更强的耐力。为了减少BFR下的时间，增加女性的相对运动负荷可能是有益的。
