Effects of hip flexion by sitting posture on trunk muscle activity and balance in healthy adults

Objective: This study compared trunk muscle activity and balance by applying hip joint flexion according to sitting posture tohealthy adultsDesign: Cross-sectional studyMethods: Twenty-four healthy adults (18 men and 6women) were instructed to perform the hip flexion while assuming two typesof posture (erect sitting and slump sitting). EMG (Electromyography) data (% maximum voluntary isometric contraction) were recorded three times from the rectus abdominis, interanl oblique abdominis, external oblique abdominis and erector spine ofparticipant’s both side and the mean values were analyzed. Results: During hip flexion in erect sitting, rectus abdominis, internal oblique abdominis and external oblique muscles showed a statistically significant difference compared to hip flexion in a slump sitting position (p<0.05). In addition, the left and rightdeviation of hip flexion in the erect sitting position was found to be smaller than that of hip flexion in the slump sitting position. Conclusions: In this study, we compared the trunk muscle activity and balance of hip flexion in a standing sitting position and a bent sitting position. However, since only a temporary effect was verified with the cross-sectional study design, it is thought that an experimental study that can verify the long-term effect is needed in the future. Therefore, it is thought that it would be better toanalyze by adding more variables than this study.