Activity and functions of the human gluteal muscles in walking, running, sprinting, and climbing.
It has been suggested that the uniquely large gluteus maximus (GMAX) muscles were an important adaptation during hominin evolution based on numerous anatomical differences between humans and extant apes. GMAX electromyographic (EMG) signals have been quantified for numerous individual movements, but not across the range of locomotor gaits and speeds for the same subjects. Thus, comparing relative EMG amplitudes between these activities has not been possible. We assessed the EMG activity of the gluteal muscles during walking, running, sprinting, and climbing. To gain further insight into the function of the gluteal muscles during locomotion, we measured muscle activity during walking and running with external devices that increased or decreased the need to control either forward or backward trunk pitch. We hypothesized that 1) GMAX EMG activity would be greatest during sprinting and climbing and 2) GMAX EMG activity would be modulated in response to altered forward trunk pitch demands during running. We found that GMAX activity in running was greater than walking and similar to climbing. However, the activity during sprinting was much greater than during running. Further, only the inferior portion of the GMAX had a significant change with altered trunk pitch demands, suggesting that the hip extensors have a limited contribution to the control of trunk pitch movements during running. Overall, our data suggest that the large size of the GMAX reflects its multifaceted role during rapid and powerful movements rather than as a specific adaptation for a single submaximal task such as endurance running.
['Bartlett|Jamie L|JL|', 'Sumner|Bonnie|B|', 'Ellis|Richard G|RG|', 'Kram|Rodger|R|']
D000328:Adult D000704:Analysis of Variance D000885:Anthropology, Physical D005075:Biological Evolution D002081:Buttocks D004576:Electromyography D005260:Female D005684:Gait D006801:Humans D008297:Male D018482:Muscle, Skeletal D012420:Running D016138:Walking D055815:Young Adult
gluteus maximus evolution EMG gait