Lumbar extensor fatigue and circumferential ankle pressure impair ankle joint motion sense

Fatigue of the lumbar extensor muscles has been associated with a degradation of balance, but the mechanism is not well understood. The ankle plays a major role in upright standing, and loss of proprioceptive acuity at the ankle could contribute to a degradation of balance. Therefore, the first objective of this study was to investigate the effect of lumbar extensor fatigue on ankle proprioceptive acuity. The second objective was to investigate the effect of circumferential ankle pressure (CAP) on ankle proprioceptive acuity to evaluate CAP as a potential intervention to mitigate any loss of proprioceptive acuity at the ankle with lumbar extensor fatigue. To address these objectives, ankle joint motion sense was evaluated with and without CAP, both before and after the lumbar extensors were fatigued. Results showed an impairment in joint motion sense with both fatigue and CAP. These results indicate that lumbar extensor fatigue impairs ankle proprioceptive acuity, which may help explain observed increases in postural sway subsequent to lumbar extensor fatigue.