Special Poster Session 51st International Society for the Study of the Lumbar Spine Annual Meeting 2025

INTRODUCTION

People with low back pain (LBP) often display aberrant movement patterns and motor control. Coordination variability (CV) provides information about how body segments move in relation to each other over multiple repetitions. A healthy level of variability provides flexibility when responding to perturbations or navigating challenging movements [1]. People with LBP may display changes to CV where increased variability can be interpreted as “loose control” and decreased as “tight control” of trunk movement [2]. Decreased CV might lead to standardized movements, predisposing individuals to tissue overload. Conversely, increased CV could lead to instability and inefficiency in motor control. Influencing people’s level of CV might be helpful in clinical rehabilitation settings. This study assessed the immediate effects of changing a person’s focus of attention on squat movement CV in people with and without LBP. We hypothesized that focusing on a static cue would decrease CV while a dynamic cue would increase CV. We also hypothesized that the LBP group would respond less consistently to the interventions.

METHODS

21 asymptomatic controls (mean ± SD age: 24.8 ± 12.0 years, mass: 64.3 ± 12.3 kg, height: 1.69 ± 0.1 m) and 7 individuals with chronic/recurrent LBP (age: 36.4 ± 18.0 years, mass: 69.2 ± 10.7 kg, height: 1.69 ± 0.1 m) participated in the study. Marker-based motion capture techniques were used to quantify 3D kinematic data. Participants performed 3x15 body weight squats at a comfortable pace. Set 1 was considered the CV baseline, set 2 involved fixing their gaze on a small static visual cue, and set 3 involved throwing a ball between their left and right hands during the squat movements. A custom MATLAB script was used to calculate joint angles [3] and perform a modified vector coding procedure [1] to extract thorax-pelvis coupling angle variability (CAV).

RESULTS

A 2-way mixed model ANOVA investigated the effects of group (control versus LBP) and trial on CAV. There was no interaction between group and trial for mean CAV, and no main effect of group. The main effect of trial displayed a statistically significant difference (p = .013) in CAV (Figure 1). Post hoc analysis with Bonferroni adjustment revealed a significant (p = .046) increase in CAV for the ball trials (mean ± standard error 17.0° ± 1.0°) compared to the visual cue trials (13.9° ± 0.7°), and a slightly smaller (p = .056) increase compared to the baseline trials (14.1° ± 0.7°).

DISCUSSION

The results indicate that throwing a small ball while performing squats immediately increases thorax-pelvis CV, thus “loosening control”, in people with and without LBP. The effect is less pronounced in the LBP group (Figure 1), but this is partially explained by one participant who demonstrated a large decrease in CAV from baseline to the ball trial (-7.5°). This could be a protective strategy where perturbations, such as throwing a ball, led to a “tighter” control of their movements. The effects of fixing your gaze on a small visual cue appear limited. Modulation of CV could benefit LBP rehabilitation programs.