Effects of ankle-foot orthoses on muscle fatigue of the lower limbs / 中国组织工程研究

ABSTRACT

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.