Effects of the Abdominal Draw-In Maneuver with Manual Resistance on Lumbopelvic Muscle Activity and Lateral Pelvic Tilt During Side-Lying Hip Abduction

Background and Objectives: This study aimed to investigate the effects of the abdominal draw-in maneuver (ADIM) and manual resistance (MR), applied independently and with simultaneous application during side-lying hip abduction (SHA). Muscle activation patterns were assessed using the electromyographic activity of the gluteus medius (GM), quadratus lumborum (QL), and internal oblique (IO), along with the GM/QL ratio, and lumbopelvic control was assessed using lateral pelvic tilt (LPT). It was hypothesized that the simultaneous application of ADIM and MR during SHA would influence muscle activation patterns and lumbopelvic control compared to each intervention alone. Materials and Methods: Healthy young male participants (n = 22) performed SHA under three conditions: ADIM alone, MR alone, and ADIM with MR. Surface electromyography was used to measure muscle activity of the GM, QL, and IO. The GM/QL activity ratio and LPT angle were also assessed to evaluate lumbopelvic control. Statistical analysis was performed using repeated-measures ANOVA (p < 0.05). However, the findings may have limited generalizability to other populations. Results: The ADIM with MR condition significantly increased IO activity (p < 0.05, dz = 1.07, 95% CI 54.65, 62.26) and the GM/QL ratio (p < 0.05, dz = 0.87, 95% CI 1.42, 1.73) while reducing QL activity (p < 0.05, dz = −1.04, 95% CI 48.52, 56.24) and lateral pelvic tilt compared to the MR condition (p < 0.05, dz = −1.85, 95% CI 4.88, 6.06). In addition, GM activity was significantly higher in the MR and ADIM with MR conditions than in the ADIM condition (p < 0.05, ηp2 = 0.812). Conclusions: The simultaneous application of ADIM and MR during SHA may enhance IO activation and the GM/QL ratio while reducing compensatory LPT. However, these findings should be interpreted as acute experimental responses, and their clinical applicability remains to be determined.