BACKGROUND:At present, there is no relevant systematic research about the effects of ankle-foot orthoses on lower limb muscles. OBJECTIVE:To extract the main features of the surface electromyography signals of the lower limbs from normal people with ankle-foot orthoses and to analyze the effects of the fixed ankle-foot orthoses on lower limb muscle fatigue. METHODS:Each of five male healthy young adults was respectively required to walk with and without special ankle-foot orthoses for three times. (1) Group 1, walking in a nature gait without orthoses. (2) Group 2, walking in a natural gait with ankle-foot orthoses (the ankle center was packaged over 1.0 cm by the orthoses that was recorded 1.0 cm); wearing the same orthoses but 1.0 cm in the ankle was removed and the ankle plastic edge was just through the ankle center to colect the data (recorded as 0 cm); after 1.0 cm was removed again in the ankle, walking in a natural gait (recorded as-1.0 cm). (3) Group 3, wearing 1.5 cm heel-height ankle-foot orthoses and walking in a natural gait; wearing the same orthoses but with 1.0 cm and 2.0 cm heel-height and walking in a natural gait. During walking, surface electromyography signals were colected from the biceps femoris muscle, rectus femoris muscle, tibialis anterior muscle, and gastrocnemius of the lower limbs. RESULTS AND CONCLUSION: (1) Without orthoses, the surface electromyography signals were the weakest. (2) For any muscle, the electrical activity of subjects without orthoses was weaker than that of subjects wearing orthoses at different hardness. (3) For the biceps femoris muscle, the integral electrical value without orthoses was very close to that wearing orthoses with normal heel height. Meanwhile, these two values were lower than that wearing orthoses with abnormal heel height. These findings indicate that the fixed plastic ankle-foot orthoses could cause the fatigue of the biceps femoris muscle, rectus femoris muscle, tibialis anterior muscle, and gastrocnemius; and the orthoses with abnormal heel height can further increase the fatigue of the biceps femoris muscle.%背景：目前尚未见到系统研究踝足矫形器对下肢肌肉影响的文献。目的：提取正常人穿戴固定踝足矫形器时的下肢肌电信号，分析固定踝足矫形器对下肢肌肉疲劳性的影响。方法：选择5名健康男性受试者参加试验，每名受试者分别进行3组试验：①第1组，在不穿戴任何矫形器的情况下以自然步态行走。②第2组，受试者穿戴平跟踝足矫形器以自然步态行走(此时矫形器踝部包裹超过踝中心1 cm，记1.0 cm)，穿戴同一矫形器但在踝部去掉1.0 cm、踝部塑料边缘刚好通过踝中心时采集(记0 cm)，在踝部再去掉1.0 cm后以自然步态行走(记-1.0 cm)。③第3组，受试者穿戴1.5 cm正常跟高踝足矫形器以自然步态行走，穿戴同一矫形器，但跟高分别改为1.0，2.0 cm后以自然步态行走。行走中采用肌电采集仪检测受试者下肢股二头肌、股直肌、胫骨前肌、腓肠肌的表面肌电信号。结果与结论：①正常不穿戴任何矫形器时，4块肌肉的肌电信号是最弱的。②对于任何一块肌肉，正常不穿戴矫形器时所对应肌电值比穿戴不同硬度矫形器时所对应的肌电值要小。③对于股二头肌，正常不穿戴矫形器时所对应的积分肌电值与穿戴正常跟高矫形器时所对应的值很接近，同时这两个值要比穿戴不正常跟高矫形器时所对应的积分肌电值小。表明固定塑料踝足矫形器会引起股二头肌、股直肌、胫骨前肌、腓肠肌的疲劳，当固定塑料踝足矫形器的跟高不合适时会进一步增加股二头肌的疲劳程度。
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