Timing and Relative Intensity of Hip Extensor and Abductor Muscle Action During Level and Stair Ambulation

Abstract

The timing and relative intensity of electromyographic activity of hip abductor and extensor muscles were recorded during free and fast velocity walking and during ascent and descent of stairs. Eleven healthy subjects were tested using fine wire electrodes to record the electromyographic activity. Data were quantified by normalizing all electromyographic activity during gait with electromyographic activity occurring during a sustained maximum isometric effort resisted either manually or with a dynamometer. The results indicated that the hip extensor muscles had different phasic patterns and moments of peak activity. During level walking, the semimembranosus and long head of the biceps femoris muscles displayed the greatest swing phase activity (beginning in mid-swing). The adductor magnus muscle followed with its onset in terminal swing. Both this muscle and the gluteus maximus were the principal hip extensors active during the loading response. For ascending stairs, the lower portion of the gluteus maximus muscle proved to be the main hip extensor during the loading response and mid-stance. The findings also showed that the upper portion of the gluteus maximus muscle functioned more like the gluteus medius muscle than the lower portion of the gluteus maximus muscle during both level and stair walking.

Knee and hip kinetics during normal stair climbing

“…These values are comparable to those presented in Ref. [21]. In Morrison's work there were two distinct force peaks, one after foot strike and one before toe-off.…”

Treatment of an Individual With Piriformis Syndrome Focusing on Hip Muscle Strengthening and Movement Reeducation: A Case Report

“…Apart from being a strong hip extensor and external rotator, the upper half of this muscle also functions as a hip abductor. 22 Given that the gluteus maximus is a primary external rotator of the hip, 26 we feel that improved performance of this muscle served 2 functions: (1) to decrease the demand on the piriformis through agonist activity and (2) to prevent hip motion that would cause increased strain on the piriformis. At discharge, observed improvements in hip strength corresponded to improvements in hip kinematics.…”

Relative importance of gait vs. joint positioning on hip contact forces after total hip replacement

“…Antagonist activity was neglected since it was either not expected or likely to be minimal at the instances of the peak forces. [26][27][28] Furthermore, antagonist muscle activity predictably and linearly increased hip forces, 25 so their inclusion would increase all force values but should not alter correlations between variables.…”