Compare postural control in athletes, with and without chronic low back pain (CLBP), during two one-legged stance tasks and identify center of pressure cut-off differences.

Fifty-six male athletes, 28 with and 28 without CLBP (mean age=26 years) performed on a force platform:

– one-legged stance with knee extension;

– one-legged stance with the knee at a 30° flexion, both tasks with eyes open.

Participants completed three 30-s trials (with 30-s of rest between each trial), and the mean across trials was used for subsequent analysis.

Athletes with CLBP had poorer postural control (P<0.01) in both tasks. The 30° knee flexion showed poor postural control in all center of pressure (COP) parameters (mean effect size d=0.80). The cut-offs identified in the knee extension position were:>7.1cm² for COP area,>2.6cm/s for COP sway velocity in the anterior-posterior direction and>3.2cm/s for medio-lateral direction. In the knee flexion position, these variables were related to:>10.9cm² for COP area,>2.9cm/s for COP sway velocity in the anterior-posterior direction and>4.1cm/s for the medio-lateral direction. Both measures showed enough sensitivity and specificity (i.e., area under curve=0.88 in extension and 0.80 in flexion).

Athletes with CLBP had poorer postural control than healthy athletes. Athletes with CLBP obtained specific cut-off scores on COP values for early detection of the effects of low back pain on balance.