Abstract:

Objective To explore the characteristics of surface electromyography (sEMG) of flat foot in lower extremity muscles when walking flat and stairs.Methods From March to June, 2019, 20 male subjects (10 with normal feet, 10 with flat feet) were recruited to use sEMG system of Noraxon to collect the average amplitude and integral electromyography of sEMG of tibialis anterio (TA), medialis gastrocnemius (MG), lateralis gastrocnemius (LG), rectus femoris (RF) and biceps femoris (BF) during the flat ground walking and the stair walking. Results As ascending stairs, the average amplitudes of TA, RF and BF of flat feet were higher than that of normal feet (|t| > 2.461, P< 0.05); as descending stairs, the average amplitude of MG of flat feet was higher (t = -1.976, P< 0.05), and the average amplitude of BF of flat feet was lower than that of normal feet (t = 2.298, P< 0.05). Compared with ground walking, the average amplitudes of TA, RF and BF of flat feet increased when ascending stairs (|t| > 2.257, P < 0.05), and the average amplitudes of RF and BF increased when descending stairs (| t| > 2.630, P < 0.05). As ascending stairs, the integral electromyography of TA, MG, LG, RF and BF of flat feet was higher than that of normal feet (| t| > 2.492, P < 0.01); as descending stairs, the integral electromyography of MG of flat feet was higher ( t = -5.271, P < 0.05), and the integral electromyography of BF was lower ( t = 2.685, P < 0.05) than that of normal feet. Compared with ground walking, the integral electromyography of TA, MG, LG and BF increased when ascending stairs (| t| > 2.088, P < 0.05), and the integral electromyography of TA, LG and RF decreased when descending stairs ( t > 2.059, P < 0.05). Conclusion The lower extremities muscles of flat foot compensate for the excessive rotation of the joint when walking stairs.

Key words: flat foot, stair walking, lower limbs, surface electromyography