Abstract des Autors

This study compares the electromyographic (EMG) peak amplitude changes of gluteus medius (Gmed), vastus medialis (VMO), vastus lateralis (VL) and biceps femoris (BF) during load carrying walking due to the increased load. The percentage of maximum isometric voluntary contractions (%MVIC) of both limbs and 3D kinematic of lower limbs were detected on eighteen resistance-trained men (mean age ± SD, 31 ± 3.4 years) while carrying loads of 25, 50 and 75% of their body mass (BM). The repeated measurement ANOVA was used to evaluate the differences in muscles %MVIC and 3D kinematics at all load conditions. Significant differences were found for Gmed %MVIC (F3,99 = 19.8, p < 0.001). Gmed activity was significantly different between load carrying walking with 25% of BM (mean ± SD, 20 ± 12%MVIC), 50% of BM (32 ± 17%MVIC) and 75% of BM (45 ± 26%MVIC) condition. Differences were found in hip flexion at Gmed EMG peak (F3,96 = 14, p < 0.001), between 25% of BM (18 ± 11°) and 50% of BM (29 ± 7°). No significant differences were found for thigh muscles, when thigh muscle activity did not exceed 30%MVIC even at 75% of BM condition. Load carrying walking is an exercise which activates Gmed more than thigh muscles. This exercise increases the Gmed activity along with increased loads and it should be regarded as a complex Gmed strengthening exercise. This exercise is recommended for strengthening the Gmed with low activation of VL and VMO.