Context: Fatigue has been shown to disrupt dynamic stability in healthy volunteers. It is not known if wearing prophylactic ankle supports can improve dynamic stability in fatigued athletes.
Objective: To determine the type of ankle brace that may be more effective at providing dynamic stability after a jump-landing task during normal and fatigued conditions.
Design: Two separate repeated-measures analyses of variance with 2 within-subjects factors (condition and time) were performed for each dependent variable.
Setting: Research laboratory.
Patients or other participants: Ten healthy female collegiate volleyball athletes participated (age = 19.5 +/- 1.27 years, height = 179.07 +/- 7.6 cm, mass = 69.86 +/- 5.42 kg).
Intervention(s): Athletes participated in 3 separate testing sessions, applying a different bracing condition at each session: no brace (NB), Swede-O Universal lace-up ankle brace (AB), and Active Ankle brace (AA). Three trials of a jump-landing task were performed under each condition before and after induced functional fatigue. The jump-landing task consisted of a single-leg landing onto a force plate from a height equivalent to 50% of each participant's maximal jump height and from a starting position 70 cm from the center of the force plate.
Main outcome measure(s): Time to stabilization in the anterior-posterior (APTTS) and medial-lateral (MLTTS) directions.
Results: For APTTS, a condition-by-time interaction existed (F(2,18) = 5.55, P = .013). For the AA condition, Tukey post hoc testing revealed faster pretest (2.734 +/- 0.331 seconds) APTTS than posttest (3.817 +/- 0.263 seconds). Post hoc testing also revealed that the AB condition provided faster APTTS (2.492 +/- 0.271 seconds) than AA (3.817 +/- 0.263 seconds) and NB (3.341 +/- 0.339 seconds) conditions during posttesting. No statistically significant findings were associated with MLTTS.
Conclusions: Fatigue increased APTTS for the AA condition. Because the AB condition was more effective than the other 2 conditions during the posttesting, the AB appears to be the best option for providing dynamic stability in the anterior-posterior direction during a landing task.
Keywords: dynamic stability; postural control.