Effects of Abdominal Hollowing During Stair Climbing on the Activations of Local Trunk Stabilizing Muscles: A Cross-Sectional Study

OBJECTIVE: To examine using surface electromyography whether stair climbing with abdominal hollowing (AH) is better at facilitating local trunk muscle activity than stair climbing without AH. METHODS: Twenty healthy men with no history of low back pain participated in the study. Surface electrodes were attached to the multifidus (MF), lumbar erector spinae, thoracic erector spinae, transverse abdominus - internal oblique abdominals (TrA-IO), external oblique abdominals (EO), and the rectus abdominis. Amplitudes of electromyographic signals were measured during stair climbing. Study participants performed maximal voluntary contractions (MVC) for each muscle in various positions to normalize the surface electromyography data. RESULTS: AH during stair climbing resulted in significant increases in normalized MVCs in both MFs and TrA-IOs (p<0.05). Local trunk muscle/global trunk muscle ratios were higher during stair climbing with AH as compared with stair climbing without AH. Especially, right TrA-IO/EO and left TrA-IO/EO were significantly increased (p<0.05). CONCLUSION: Stair climbing with AH activates local trunk stabilizing muscles better than stair climbing without AH. The findings suggest that AH during stair climbing contributes to trunk muscle activation and trunk stabilization.