# Low Back Pain Reduces the Amount of Lumbopelvic Movement During Lower Limb Motion: A Cross-Sectional Study of Soccer Players

## TL;DR

Soccer players with low back pain move their lower back and pelvis less during slow leg movements, possibly to avoid pain, but show no difference during fast movements.

## Contribution

This study reveals how low back pain affects lumbopelvic movement strategies in soccer players during different motion speeds.

## Key findings

- Soccer players with LBP showed reduced total lumbopelvic movement during low-speed tasks.
- LBP players had significantly less rotational movement under low-speed conditions.
- No significant differences in lumbopelvic movement were found during high-speed tasks.

## Abstract

Introduction: Low back pain (LBP) is common among soccer players and may influence lumbopelvic movement strategies. This study aimed to examine the effect of LBP on the amount of lumbopelvic movement during lower limb motion tasks performed at both high and low speeds.

Methods: Ninety-nine high school soccer players from Osaka Metropolitan University, Osaka, Japan, participated in this study. They performed a task in which they raised the dominant leg by flexing the hip and knee joints from a standing position until the hip reached approximately 90 degrees of flexion, under both high (400°/s) and low (100°/s) speed conditions. An inertial measurement unit (IMU) attached to the lumbar spine measured total lumbopelvic movement and movement in three directions (rotation, flexion-extension, and side bending) based on the angular velocity. Participants were classified into the LBP and non-LBP groups based on the self-reported presence of the current LBP. Group differences were analyzed using independent t-tests and Mann-Whitney U tests.

Results: Under low-speed conditions, the LBP group exhibited reduced total lumbopelvic movement (p < 0.02; d = 0.56), particularly for rotation (p < 0.01; d = 0.73). No significant differences were observed under high-speed conditions.

Conclusion: Soccer players with LBP demonstrate reduced lumbopelvic movement, particularly in rotation, under low-speed conditions. This may reflect a motor control strategy to avoid pain by limiting lumbopelvic movement. However, no significant differences were observed under high-speed conditions, possibly because high-velocity tasks require greater lumbopelvic movement, making it difficult to restrict movement even in the presence of pain. Rapid lower limb motions, such as kicking or sprinting, may involve greater lumbopelvic movement. Consequently, training and rehabilitation programs for soccer players with LBP should consider the potential for symptom aggravation under high-speed conditions.