Halder Amitava, Gao Chuansi, Miller Michael
Division of Ergonomics and Aerosol Technology, Department of Design Sciences, Faculty of Engineering, Lund University, P.O. Box 118, 221 00 Lund, Sweden.
Division of Physiotherapy, Department of Health Science, Faculty of Medicine, Lund University, P.O. Box 157, 221 00 Lund, Sweden.
J Sports Med (Hindawi Publ Corp). 2014;2014:520124. doi: 10.1155/2014/520124. Epub 2014 May 4.
The effects of cooling on neuromuscular function and performance during gait are not fully examined. The purpose of this study was to investigate the effects of local cooling for 20 min in cold water at 10°C in a climate chamber also at 10°C on maximal isometric force and electromyographic (EMG) activity of the lower leg muscles. Gait ground reaction forces (GRFs) were also assessed. Sixteen healthy university students participated in the within subject design experimental study. Isometric forces of the tibialis anterior (TA) and the gastrocnemius medialis (GM) were measured using a handheld dynamometer and the EMG was recorded using surface electrodes. Ground reaction forces during gait and the required coefficient of friction (RCOF) were recorded using a force plate. There was a significantly reduced isometric maximum force in the TA muscle (P < 0.001) after cooling. The mean EMG amplitude of GM muscle was increased after cooling (P < 0.003), indicating that fatigue was induced. We found no significant changes in the gait GRFs and RCOF on dry and level surface. These findings may indicate that local moderate cooling 20 min of 10°C cold water, may influence maximal muscle performance without affecting activities at sub-maximal effort.
冷却对步态期间神经肌肉功能和表现的影响尚未得到充分研究。本研究的目的是调查在气候舱中10°C的冷水中进行20分钟局部冷却,对小腿肌肉最大等长肌力和肌电图(EMG)活动的影响。同时也评估了步态地面反作用力(GRF)。16名健康大学生参与了这项受试者内设计的实验研究。使用手持测力计测量胫骨前肌(TA)和腓肠肌内侧头(GM)的等长肌力,并用表面电极记录肌电图。使用测力台记录步态期间的地面反作用力和所需摩擦系数(RCOF)。冷却后TA肌肉的等长最大肌力显著降低(P < 0.001)。冷却后GM肌肉的平均肌电图幅度增加(P < 0.003),表明诱发了疲劳。我们发现在干燥且水平的表面上,步态GRF和RCOF没有显著变化。这些发现可能表明,在10°C冷水中进行20分钟的局部适度冷却,可能会影响最大肌肉表现,而不影响次最大努力时的活动。