The purpose of this study was to examine the effects of 5 days of Creatine (Cr) loading on the electromyographic fatigue threshold (EMGFT) in college-aged women. Fifteen healthy college-aged women (mean ± SD = 22.3 ± 1.7 yrs) volunteered to participate in this double-blind, placebo-controlled study and were randomly placed into either placebo (PL – 10 g of flavored dextrose powder; n = 8) or creatine (Cr – 5 g di-creatine citrate plus 10 g of flavored dextrose powder; n = 7; Creatine Edge, FSI Nutrition) loading groups. Each group ingested one packet 4 times per day (total of 20 g/day) for 5 days. Prior to and following supplementation, each subject performed a discontinuous incremental cycle ergometer test to determine their EMGFT value, using bipolar surface electrodes placed on the longitudinal axis of the right vastus lateralis. Subjects completed a total of four, 60 second work bouts (ranging from 100–350 W). The EMG amplitude was averaged over 10 second intervals and plotted over the 60 second work bout. The resulting slopes from each successive work bouts were used to calculate EMGFT. A two-way ANOVA (group [Cr vs. PL] × time [pre vs. post]) resulted in a significant (p = 0.031) interaction. Furthermore, a dependent samples t-test showed a 14.5% ± 3.5% increase in EMGFT from pre- to post-supplementation with Cr (p = 0.009), but no change for the PL treatment (-2.2 ± 5.8%; p = 0.732). In addition, a significant increase (1.0 ± 0.34 kg; p = 0.049) in weight (kg) was observed in the Cr group but no change for PL (-0.2 kg ± 0.2 kg). These findings suggest that 5 days of Cr loading in women may be an effective strategy for delaying the onset of neuromuscular fatigue during cycle ergometry.
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机译:这项研究的目的是检查5天肌酸(Cr)负荷对大学女性的肌电图疲劳阈值(EMGFT)的影响。 15名健康的大学年龄妇女(平均±SD = 22.3±1.7岁)自愿参加这项双盲,安慰剂对照的研究,并随机放入任一安慰剂中(PL – 10克调味葡萄糖粉; n = 8)或肌酸(Cr – 5 g柠檬酸二肌酸加10 g调味葡萄糖粉; n = 7; Creatine Edge,FSI Nutrition)负荷组。每组每天摄取一包4次(总计20克/天),持续5天。在补充之前和之后,每个受试者都使用放置在右侧股外侧肌纵轴上的双极表面电极进行了不连续的增量循环测功计测试,以确定其EMGFT值。受试者总共完成了四次60次第二次练习(范围为100-350 W)。 EMG振幅在10秒间隔内取平均值,并在60秒工作周期内绘制。来自每个连续工作回合的结果斜率用于计算EMGFT。双向方差分析(组[Cr vs. PL]×时间[pre vs. post])导致显着(p = 0.031)相互作用。此外,相关样本t检验显示,从补充铬到补充铬后,EMGFT增加14.5%±3.5%(p = 0.009),但PL治疗无变化(-2.2±5.8%; p = 0.732) )。此外,Cr组的体重(kg)显着增加(1.0±0.34 kg; p = 0.049),而PL组则无变化(-0.2 kg±0.2 kg)。这些发现表明,女性五天的铬负荷可能是在周期测功期间延迟神经肌肉疲劳发作的有效策略。
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