Abstract: Objective To establish normal reference range of surface electromyography (sEMG) in related myoelectric activity when maximum isometric voluntary contraction of ankle dorsiflexors and plantarflexors in healthy middle to old people.Methods From September to December, 2015, a total of 110 healthy people aged 41 to 75 years were divided into 41 to 50 years group, 51 to 60 years group and >60 years group according to age. The integral electrical values were measured in each subject by sEMG technique and analysis system under maximum isometric voluntary contraction of ankle dorsiflexors and plantarflexors.Results and Conclusion Under ankle dorsiflexion and plantar flexion movement modes, no significant difference was found in the integral electrical values of tibialis anterior muscle, long peroneal muscle, short tibial muscle and gastrocnemius among different groups (F<4.545, P>0.05). No significant difference was found in the integral electrical values of different sides and different genders (F<7.028, P>0.05). Normal reference range for integral electrical values was established under maximum isometric voluntary contraction of ankle dorsiflexors and plantarflexors in healthy people.

Key words: health, middle-old age, isometric contraction, surface electromyography, integrated electromyogram