Within one day of baseline testing, BAL will begin a progressive balance training protocol on the involved limb. The balance training program consists of three 20-minute sessions per week for eight weeks. Post-test assessments for BAL will completed within one week of completing the 8-week training interval.

After baseline testing, CON will be instructed to continue their normal daily routine. They will not participate in the balance training intervention.

The balance exercises consist of single limb stances with eyes open and closed, single-leg hops with stabilization, and single-leg hops and reach. Thirty-second breaks will be provided between exercise sets. Progressions for single-leg stance exercises involve longer durations and introduction of unstable surfaces. Progressions for hopping exercises involve longer hopping distances. To progress to the next level, participants must complete a balance training session without any errors. Errors include 1) touching the floor or bracing with the opposite limb, 2) excessive lateral trunk flexion or hip abduction, 3) hands coming off hips (hop tasks) or shoulders (stance tasks), 4) missing the landing target, 5) using the reach leg for a substantial amount of weight bearing.

The Star Excursion Balance Test (SEBT) measured balance performance through a series of lower body reaches in anterior, posterolateral, and posteromedial directions. Participants maintained a single-leg stance on the uninvolved limb while reaching with their non-stance limb for maximal distance along a tape measure fixed to the floor. Participants were required to maintain their hands on their hips and keep their stance limb flat against the floor. As a common practice, there were four practice trials and three test trials for each direction performed. For each SEBT direction, we averaged the three reach scores and normalized them as a percent of the stance leg length, measured from the anterior superior iliac spine to the most distal part of the medial malleoli.

Isometric hip strength was measured via handheld dynamometry for extension, abduction, and external rotation. Participants completed one practice trial and three test trials for each motion in random order. Each trial lasted 5 seconds, with the first 3 seconds gradually increasing force and then the final two seconds exerting maximum force. We averaged the three trials for each hip strength test, multiplied by the length of the moment arm, and divided by body mass to calculate normalized torque (Nm/kg). We measured EXT and ABD moment arms from the greater trochanter to the lateral femoral epicondyle and ER moment arm from the medial tibial plateau to the distal end of the medial malleolus.

We measured lumbopelvic stability with a unilateral hip bridge test. Participants began in a hook-lying position with their arms folded across their chest. Participants completed an initial double-leg bridge to find a neutral alignment of the spine and hips.To start the unilateral hip bridge, participants initiated another bilateral hip bridge, then extended the non-test knee and kept their thighs in parallel. Participants completed a single trial for maximal time (s).