OBJECTIVES To compare mechanical and neuromuscular strategies between high- and low-pain subgroups of male athletes with chronic ankle instability (CAI) during single-leg drop landing. DESIGN Cross-sectional study. SETTING Biomechanics laboratory. PARTICIPANTS Eighty-four male Tier 2-3 athletes, stratified into high-pain CAI (n = 28), low-pain CAI (n = 28), and healthy control (n = 28) groups. MAIN OUTCOME MEASURES Lower-limb kinematics, impact loading, joint moments, eccentric work and energy contributions, surface electromyographic root mean square amplitude, and co-contraction index. RESULTS Significant group effects were observed for kinematic outcomes (p ≤ 0.042; ηp2 = 0.075-0.384), joint kinetics and energetics (p ≤ 0.042; ηp2 = 0.075-0.561), and neuromuscular outcomes (p = 0.005-0.017; ηp2 = 0.096-0.124). The high-pain CAI group exhibited lower ankle plantarflexor moment than both comparison groups (both p < 0.001; d = 1.192-1.210), lower ankle eccentric work (p ≤ 0.001; d = 1.030-1.853), lower ankle energy contribution (p ≤ 0.002; d = 0.983-2.133), and greater knee energy contribution (both p < 0.001; d = 1.209-1.818). The low-pain CAI group exhibited less hip flexion and greater ankle plantarflexion at initial contact and greater ankle dorsiflexion range of motion (p ≤ 0.024; d = 0.736-1.398). The high-pain CAI group showed greater tibialis anterior activation than the low-pain group (p = 0.004; d = 0.903) and greater rectus femoris-biceps femoris co-contraction than controls (p = 0.045; d = 0.672). External impact-loading measures did not differ among groups (p = 0.114-0.265; ηp2 = 0.032-0.058). CONCLUSIONS Pain-defined CAI subgroups differed in interjoint load sharing and selected neuromuscular measures despite comparable external impact loading.
Objectives To compare the effects of short-foot exercise (SFE) and toe-curl exercise (TCE) on movement control during single-leg landing in individuals undergoing anterior cruciate ligament reconstruction (ACLR). Design Multicenter exploratory randomized controlled trial. Setting One hospital and two outpatient orthopedic clinics. Participants Thirty-eight individuals who had undergone ACLR and demonstrated dynamic knee valgus during a single-leg landing task. Main outcome measures Participants were randomized to the SFE or TCE group, performed the allocated exercises daily, and received supervised exercise therapy once weekly for 12 weeks. The primary outcome was hip adduction excursion during single-leg landing. Assessments were conducted at baseline, 6 weeks, and 12 weeks and analyzed using mixed models for repeated measures. Results At 6 weeks, hip adduction excursion was lower in the SFE group than in the TCE group, with a between-group difference of −6.30° (95% confidence interval [CI], −9.19 to −3.41; effect size [ES], −1.41). The between-group difference in change from baseline was −6.98° (95% CI, −9.88 to −4.08; ES, −1.57). At 12 weeks, hip adduction excursion remained lower in the SFE group. Conclusions SFE may facilitate earlier improvement in frontal-plane movement control in patients who have undergone ACLR.
