The effect of foot position on erector spinae and gluteus maximus muscle activation during sit-to-stand performed by chronic stroke patients

[Purpose] The aim of this study was to use surface electromyography (EMG) to investigate the effects of different foot positioning on bilateral erector spinae (ES) and gluteus maximus (GM) activation during sit-to-stand performed by individuals with stroke. [Subjects] Fifteen randomly selected participants with stroke were enrolled in this study. [Methods] All the participants were asked to perform sit-to-stand (STS) using three different strategies: (1) symmetric foot position, (2) unaffected foot placed behind the affected foot position (asymmetric-1), (3) affected foot placed behind the unaffected foot position (asymmetric-2). An EMG system was used to measure ES and GM muscle activities. The strategies were performed in a random order, and the mean values of five measurements were used in the analysis. One-way repeated measure ANOVA was used to determine the statistical significance of differences between the conditions. [Results] The affected ES muscle activity was significantly greater in asymmetric-2 (180.7±73.4) than in symmetrical foot placement (149.8±54.2). In addition, the affected ES, unaffected ES, and affected GM muscle activity were significantly greater in asymmetric-2 (180.7±73.4, 173.5±83.1, 98.3±90.3 respectively) than in asymmetric-1 foot placement (147.3±53.8, 151.2±76.5, 84.9±73.8 respectively). [Conclusion] Our results suggest that it may be more desirable for persons with stroke to place the affected foot behind the unaffected foot when performing STS to increase affected ES and GM muscle activation.