Zhou S, McKenna M J, Lawson D L, Morrison W E, Fairweather I
Department of Physical Education and Recreation, Victoria University of Technology, Melbourne, Australia.
Eur J Appl Physiol Occup Physiol. 1996;72(5-6):410-6. doi: 10.1007/BF00242269.
Electromechanical delay (EMD) of knee extensors in isometric contraction was investigated in six healthy men before and after four periods of 30-s allout sprint cycling exercise, conducted pre and post a 7-week sprint cycling training programme. The EMD was lengthened from 40.4 (SEM 3.46) ms at rest to 63.4 (SEM 7.80) ms after the fatiguing exercise (P < or = 0.05) in the pre-training test. During maximal voluntary contractions (MVC) conducted after the fatiguing exercise, the peak contraction force (Fpeak) and peak rate of force development (RFDpeak) were reduced by 51%-56% and 38%-50%, respectively (both P < or = 0.05). The mechanisms of EMD lengthening during fatigue could have been due to the deterioration in muscle conductive, contractile or elastic properties and require further study. The training programme increased the total work performed during the four periods of sprint exercise (P < or = 0.05). However, no significant training effects were found in the resting or postexercise EMD, Fpeak and RFDpeak during isometric MVC. These unchanged isometric contraction variables but enhanced dynamic performance suggest that isometric tests of muscle are insensitive to the neuromuscular adaptations to sprint training.
在一项为期7周的冲刺骑行训练计划前后，对6名健康男性进行了研究，以调查等长收缩时膝伸肌的机电延迟（EMD）。在训练前测试中，疲劳运动后，EMD从静息时的40.4（标准误3.46）毫秒延长至63.4（标准误7.80）毫秒（P≤0.05）。在疲劳运动后的最大自主收缩（MVC）期间，峰值收缩力（Fpeak）和峰值力量发展速率（RFDpeak）分别降低了51%-56%和38%-50%（均P≤0.05）。疲劳期间EMD延长的机制可能是由于肌肉传导、收缩或弹性特性的恶化，需要进一步研究。训练计划增加了四个冲刺运动阶段的总工作量（P≤0.05）。然而，在等长MVC期间，静息或运动后EMD、Fpeak和RFDpeak未发现显著的训练效果。这些等长收缩变量未改变但动态性能增强表明，肌肉等长测试对冲刺训练的神经肌肉适应性不敏感。
