The effects of eversion fatigue on frontal plane joint position sense in the ankle.

CONTEXT There is limited information on fatigue of the evertors on frontal plane joint position sense (JPS). OBJECTIVE To examine the effects of isokinetic concentric-eccentric fatigue of the evertors on frontal plane JPS of the ankle. DESIGN A2 x 4 factorial design. SETTING Research Laboratory. PATIENTS OR OTHER PARTICIPANTS 40 male and female healthy subjects. INTERVENTIONS JPS was tested at 10 degrees and 20 degrees of inversion and 5 degrees and 10 degrees of eversion in a nonfatigued/fatigued condition. After fatigue of evertors was determined on an isokinetic device, post fatigue testing of JPS occurred. MAIN OUTCOME MEASURES JPS absolute error (AE) for inversion and eversion. RESULTS Main effect for condition and angle were significant with pre/post fatigue. There were overestimation of angles postfatigue with AE greater at 20 degrees of inversion (P = .003), followed by 10 degrees of inversion (P < .001), 10 degrees of eversion (P = .005), and 5 degrees of eversion (P = .005). CONCLUSION When the ankle evertors were fatigued, the AE for JPS was significantly higher at all test angles.