Treadmill running is a common method of exercise and to study human locomotion. Research has examined the kinematics and kinetics of overground and treadmill running, but there has been less focus on the levels of muscle activity during treadmill running. We investigated if muscle activity is different while running overground compared to running on a variety of treadmills. A total of 11 healthy individuals ran at 3 speeds (2.6, 3.6, 4.5 m/s) under 4 different running conditions (3 treadmills, overground). The three treadmills included a typical home exercise treadmill, a midsize commercial research treadmill, and a large, instrumented research treadmill. Surface EMG of the tibialis anterior (TA), gastrocnemius medialis (GM), rectus femoris (RF) and biceps femoris (BF) muscles were measured for each running condition. The integrated EMG was computed for each running condition for the stance and swing phase, as well as 100 ms before and after the heel-strike. Friedman analysis revealed significant effects during the stance phase for GM and RF at all speeds, such that muscle activation was lower on the treadmills relative to overground. During the stance phase at faster speeds, the muscle activity was higher for the TA and lower for the BF while running on the different treadmills compared to overground running. Before heel-strike, the TA was significantly less active during treadmill compared to overground running at 2.6 m/s and the RF showed significantly higher activity at 3.6 m/s and 4.5 m/s while running on the different treadmills. Summarizing, differences were mainly observed between the different treadmill conditions relative to overground running. Muscle activation differences between the different treadmill conditions were observed at faster running speeds for RF during the pre-heel-strike phase only. Different types of treadmills with different mechanical properties affects the muscle activity during stance phase as well as in preparation to heel-strike. Additionally, the muscle activity is greater during overground compared to treadmill running during the stance phase for the GM, BF, and RF.

中文翻译：

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不同型号跑步机跑步时下肢肌肉活动比较

跑步机跑步是一种常见的锻炼方法和研究人体运动的方法。研究检查了地上跑步和跑步机跑步的运动学和动力学，但很少关注跑步机跑步期间的肌肉活动水平。我们研究了在地面上跑步时与在各种跑步机上跑步时的肌肉活动是否不同。共有 11 名健康个体在 4 种不同的跑步条件（3 台跑步机、地上）下以 3 种速度（2.6、3.6、4.5 m/s）跑步。这三台跑步机包括典型的家用跑步机、中型商业研究跑步机和大型仪器化研究跑步机。在每种跑步条件下测量胫骨前肌（TA）、腓肠肌内侧肌（GM）、股直肌（RF）和股二头肌（BF）的表面肌电图。计算站立和摆动阶段的每种跑步条件以及脚跟着地前后 100 毫秒的综合肌电图。 Friedman 分析显示，在所有速度下，站立阶段对 GM 和 RF 都有显着影响，因此跑步机上的肌肉激活相对于地面上较低。在较快速度的站立阶段，与地面跑步相比，在不同跑步机上跑步时，TA 的肌肉活动较高，BF 的肌肉活动较低。在脚后跟着地之前，与以 2.6 m/s 的速度跑步相比，在跑步机上跑步时 TA 的活跃度明显较低，而在不同跑步机上跑步时，RF 在 3.6 m/s 和 4.5 m/s 时的活跃度明显较高。总而言之，主要观察到不同跑步机条件相对于地面跑步之间的差异。仅在脚跟触地前阶段，以较快的跑步速度观察到不同跑步机条件之间的肌肉激活差异。不同类型的跑步机具有不同的机械性能，会影响站立阶段以及准备脚跟着地时的肌肉活动。此外，与在站立阶段的跑步机上跑步相比，GM、BF 和 RF 在地面上的肌肉活动更大。