# Greater Lumbopelvic Motion Is Associated with Faster Hip Flexion in Soccer Players

## TL;DR

Soccer players with faster hip flexion movements also show greater lumbopelvic motion, suggesting that some trunk movement may be beneficial for speed.

## Contribution

This study reveals a novel association between lumbopelvic motion and faster lower-limb movement in soccer players.

## Key findings

- Greater lumbopelvic rotation and flexion–extension were observed during high-speed hip flexion in both dominant and non-dominant legs.
- High-speed trials showed consistent movement patterns, unlike low-speed trials.
- The findings challenge the assumption that minimizing lumbopelvic motion is optimal for speed.

## Abstract

Faster lower-limb motion is closely related to soccer performance, but the contribution of lumbopelvic motion to achieving it remains unclear. This cross-sectional study aimed to examine whether faster lower-limb motion in soccer players was accompanied by greater lumbopelvic motion. Fifty-one male high school soccer players performed a thigh-raising (hip flexion) task from a standing position at low (approximately 100°/s) and high (approximately 400°/s) speeds. Lumbopelvic motion was measured at the lumbar spinous process (L3). Rotation (LBrot, transverse plane) and flexion–extension (LBf/e, sagittal plane) were derived from the angular velocity. Motions were compared between speeds using the Wilcoxon tests. In the dominant leg, both LBrot (10.2° vs. 8.1°, r = 0.62) and LBf/e (6.4° vs. 5.0°, r = 0.57) were greater at high speed. In the non-dominant leg, both LBrot (11.2° vs. 8.6°, r = 0.49) and LBf/e (6.9° vs. 5.3°, r = 0.62) were also greater at high speed. High-speed trials exhibited consistent movement patterns, whereas low-speed trials did not. These findings suggest that minimizing lumbopelvic motion may not always be optimal for achieving faster lower-limb motion, which may inform coaching and clinical practice regarding the appropriate degree of lumbopelvic motion during lower-limb tasks across movement speeds.