Effects Of Muscle Fatigue On Gait Characteristics Of Adults With Different Physical Activity Levels

Objective:By recording and analyzing the gait of two groups of subjects with different levels of physical activity under the condition of no muscle fatigue and lower limb muscle fatigue,we explored the influence of muscle fatigue on the gait characteristics of adults with different levels of physical activity,and clarified the effect and interaction between muscle fatigue and physical activity levels.Methods:In this study,16 male exercise-free active participants(ACT group)and 16 inactive participants(INACT group)were recruited from the students of Inner Mongolia Normal University.The physical activity level was divided by Baecke Physical Activity Questionnaire.A two-factor mixed experimental design was used to intervene the lower limb muscle fatigue of the subjects.The basic parameters of natural gait and the symmetry index of the lower limb joint range of motion were measured before and after the intervention,and the main effects and interactions of physical activity level factors and muscle fatigue factors were analyzed.Results:(1)There was no significant difference in heart rate between ACT group and INACT group before and after limb muscle fatigue(P >0.05).There was a significant difference in the time to fatigue between the two groups(P < 0.01).There was no significant difference in RPE between the two groups(P > 0.05).(2)There were no significant differences in stride width,stride length,stride frequency and pace between ACT group and INACT group(P > 0.05),and there were no significant differences in hip,knee and ankle joint motion range SI between ACT group and INACT group(P > 0.05).(3)There was no significant difference between the gait speed without muscle fatigue and the gait speed after lower limb muscle fatigue.The step width without muscle fatigue was smaller than that after muscle fatigue(P < 0.01).The step length without muscle fatigue was larger than that after muscle fatigue(P < 0.05).Except for the Si of knee flexion and extension,there was no significant difference in the Si of hip,knee and ankle joints in all directions in the absence of muscle fatigue compared with the lower limb muscle fatigue(P > 0.05).In the absence of muscle fatigue,the range of motion SI of knee flexion and extension was significantly smaller than that of lower limb muscle fatigue(P < 0.01).(4)There was an interaction between the factors of physical activity level and the factors of muscle fatigue for stride frequency.There was no significant difference in the gait frequency between ACT group without muscle fatigue and lower limb muscle fatigue(P > 0.05),but the gait frequency of INACT group without muscle fatigue was greater than that of lower limb muscle fatigue(P < 0.01).For step width,step length and step speed,there was no interaction between physical activity level and muscle fatigue(P >0.05).Conclusion:(1)The natural gait characteristics of active and inactive subjects were similar,and there was no significant difference in the symmetry of lower limb joint movement during walking.(2)Lower extremity muscle fatigue can significantly affect the natural gait characteristics,and its influence on the symmetry of lower extremity joint motion is mainly reflected in knee flexion and extension movement.