# Effects of the Combined Abdominal Draw-In Maneuver and Manual Resistance on Lumbopelvic Muscle Activity and Anterior Pelvic Tilt During Prone Hip Extension

## TL;DR

Combining the abdominal draw-in maneuver with manual resistance during prone hip extension increases muscle activity and reduces pelvic tilt, improving lumbopelvic stability.

## Contribution

This study is the first to demonstrate the combined effects of ADIM and MR on muscle activity and pelvic tilt during PHE.

## Key findings

- Combined ADIM and MR significantly increased gluteus maximus and internal oblique activity compared to using either method alone.
- The ADIM condition resulted in the lowest erector spinae activity, while the combined condition reduced it further compared to MR alone.
- Anterior pelvic tilt was significantly reduced in both ADIM and combined ADIM-MR conditions compared to MR alone.

## Abstract

This study investigated the effects of applying the abdominal draw-in maneuver (ADIM) and manual resistance (MR), separately and in combination, during prone hip extension (PHE) on muscle activity and anterior pelvic tilt. Twenty-four healthy adult males performed PHE under three randomized conditions: ADIM, MR, and ADIM combined with MR. Electromyography was used to measure gluteus maximus (GM), erector spinae (ES), internal oblique (IO), and hamstring activity, while anterior pelvic tilt angle was assessed using a gyroscopic sensor. Repeated-measures ANOVA revealed significant differences across conditions (p < 0.05). Post hoc analysis showed that GM and IO activity were significantly greater in the ADIM combined with MR condition than in either ADIM or MR alone, with MR also producing higher values than ADIM (p < 0.05). ES activity was lowest in the ADIM condition, while ADIM combined with MR produced lower ES activity than MR (p < 0.05). The GM/ES ratio was highest in ADIM combined with MR compared with the other conditions (p < 0.05). Anterior pelvic tilt angle was significantly smaller in both the ADIM and ADIM combined with MR conditions compared with MR (p < 0.05). These findings suggest that combined ADIM with MR induces strong IO contraction and enhances lumbopelvic stability, leading to substantially increased GM activity.