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

Paul S Sung,Emily Hosmer

doi:10.3390/sym13112115

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.

Highlights

Low back pain (LBP) affects up to 80% of the population, and those who have nonspecific chronic LBP exhibit neural changes that underlie balance deficits, which may be related to postural control [1,2,3]
The altered patterns of limb reaction, swing, and recovery step times might lead to the adoption of compromised dynamic balance strategies from motor deficits in individuals with LBP
The limb preference difference was analyzed between groups for three repeated perturbations. Both groups used the dominant limb for the first step (31/50 = 62% for the control group vs. 17/30 = 57% for the LBP group; Chi-square = 0.22, p = 0.64), the second step (28/50 = 56% for the control group vs. 16/30 = 53% for the LBP group; Chi-square = 0.06, p = 0.81), and the third step (32/50 = 64% for the control group vs. 18/30 = 60% for the LBP group; Chi-square = 0.13, p = 0.72)

Summary

Introduction

Low back pain (LBP) affects up to 80% of the population, and those who have nonspecific chronic LBP exhibit neural changes that underlie balance deficits, which may be related to postural control [1,2,3]. There is a lack of understanding on preferred lower limb reactions to avoid fall injuries as well as recovery step responses to postural adjustments. Individuals with LBP compensate their lower limb reactions to avoid further injuries or pain recurrences. The altered patterns of limb reaction, swing, and recovery step times might lead to the adoption of compromised dynamic balance strategies from motor deficits in individuals with LBP. Little is known about adaptive lower limb control preference when considering swing and recovery step times following repeated trip perturbations

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