Altered neuromuscular control in individuals with exercise-related leg pain.

PURPOSE

To compare neuromuscular control ofthe lower limb during gait between individuals with and without a history of exercise-related leg pain (ERLP).

METHODS

Fourteen females with a history of ERLP and 14 age-, height-, and weight-matched asymptomatic female controls participated in the study.Electromyographic activity, normalized to maximum voluntary contraction (MVC), from 12 lower limb muscles during walking gait was the primary outcome. Secondary outcomes were three-dimensional kinematics of the lower limb during gait, measurements of static foot posture (arch height and midfoot width in weight bearing and non-weight bearing), and foot mobility (difference in arch height and midfoot width from non-weight bearing to weight bearing and foot mobility magnitude).

RESULTS

Individuals with a history of ERLP demonstrated lower peak activation (13.7% MVC, 95% confidence interval (CI) = 3.2%-24.3% MVC) and lower average activation of gluteus medius (2.3% MVC, 95% CI = 0.3%-4.3% MVC) when compared with controls (P G 0.05). This reduction in gluteus medius activation was moderately determined (57.1%, P = 0.01) by the duration (beta = 0.555) and severity of pain (beta = -0.516). Peak and average activation of lateral gastrocnemius were also lower than controls (20.5% MVC, 95% CI = 0.6%-40.5% MVC and 1.7% MVC, 95% CI = 0.2%-3.1% MVC, respectively) but were not explained by pain duration or severity. No differences in kinematics at the ankle, knee, hip and pelvis, or differences in static foot posture and mobility were observed between groups (P > 0.05).

CONCLUSIONS

This study provides evidence of altered neuromuscular control of gait in females with a history of ERLP. Further work is required to discern the clinical relevance of this finding.