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Low-Back Pain and Knee Position-Related Differences on Postural Control Measures During a One-Legged Stance in
Context:
Chronic low-back pain (CLBP) may be associated with changes in postural balance in athletes as poor postural control during sports practice.
Objective:
To compare the postural control of athletes with and without CLBP during 2 one-legged stance tasks and identify the center of pressure (COP) cutoff values to determine the main differences. Designed: A cross-sectional study.
Setting:
Laboratory of functional evaluation and human motor performance.
Participants:
A total of 56 male athletes, 28 with and 28 without CLBP (mean age = 26 y).
Intervention:
The one-legged stance with knee extension and with the knee at 30° flexion tasks were measured and analyzed on a force platform. The participants completed three 30-second trials (30 s of rest between each trial).
Main Outcome Measures:
The COP parameters: the area of COP, mean COP sway velocity in both the anteroposterior and mediolateral directions, and total COP displacement were computed, and a receiver operating characteristics curve analysis was applied to determine the group differences.
Results:
Athletes with CLBP had poorer postural control (P < .01) in both tasks. The 30° knee flexion reported more postural instability than the knee extension for all COP parameters (a large effect size d = 0.80).The knee extension cutoffs identified were >7.1 cm2 for the COP area, >2.6 cm/s for the COP sway velocity in the anterior-posterior direction, and >3.2 cm/s for the mediolateral direction. Whereas, the 30° knee flexion cutoffs were >10.9 cm2 for the COP area, >2.9 cm/s for the COP sway velocity in the anterior-posterior direction, and >4.1 cm/s for the mediolateral direction. Both measures showed enough sensitivity and specificity (ie, area under the curve = 0.88 in and 0.80, respectively) to discriminate both groups.
Conclusions:
The athletes with CLBP had poorer postural control than the healthy athletes and obtained specific cutoff scores from the COP values.
