Preferred Limb Reaction, Swing and Recovery Step Times between Subjects with and without Chronic Low Back Pain

Abstract

A compensatory stepping strategy following repeated perturbations may compromise dynamic balance and postural stability. However, there is a lack of study on preferred limb reaction, swing, and step time adjustments. The purpose of this study was to investigate limb reaction, swing, and recovery step times following repeated trip perturbations in individuals with and without non-specific chronic low back pain (LBP). There were 30 subjects with LBP and 50 control subjects who participated in the study. The limb reaction, swing, and recovery step times (s) were measured following treadmill-induced random repeated perturbations (0.12 m/s velocity for 62.5 cm displacement), which caused subjects to move forward for 4.90 s. Both groups demonstrated a significant interaction of repetitions and times (F = 4.39, p = 0.03). Specifically, the recovery step time was significantly shorter in the LBP group during the first trip (t = 2.23, p = 0.03). There was a significant interaction on repetitions and times (F = 6.03, p = 0.02) in the LBP group, and the times were significantly different (F = 45.04, p = 0.001). The initial limb reaction time of the LBP group was significantly correlated with three repeated swing times to avoid falls. The novelty of the first trip tends to enhance a protective strategy implemented by the LBP group. Although limb preference did not demonstrate a significant difference between groups, the LBP group demonstrated shorter recovery step times on their preferred limb initially in order to implement an adaptive strategy to avoid fall injuries following repeated perturbations.

Keywords

• reaction time
• recovery step time
• perturbations
• low back pain
• compensation
• balance