Hip Abductor Fatigability and Recovery Are Related to the Development of Low Back Pain During Prolonged Standing.

Abstract

A prolonged standing exposure can identify asymptomatic adults who have a higher risk of developing clinical low back pain later in life. Hip abductor cocontraction differences can predict low back pain development during standing exposures. This study's purpose was to determine if hip abductor strength, fatigability, and recovery during prolonged standing were related to standing-induced low back pain. Forty young, asymptomatic adults (50% female) performed two 2-hour standing sessions; a fatiguing hip abductor exercise was performed prior to 1 of the 2 standing sessions. Hip abductor strength and surface electromyography of gluteus medius and tensor fascia latae were measured. Self-reported low back pain differentiated low back pain developing (PD) and nonpain developing (NPD) groups. The PD group hip abductors fatigued before the NPD group, with similar perceived effort and force losses. Mean power frequency decreases with fatigue were similar between pain groups for all muscles measured after the fatiguing exercise. Unlike NPDs, PDs did not recover force losses after 120minutes of standing. Hip abductor fatigability may be related to the development of low back pain in this population.