Improved ankle mobility following a 4-week training program affects landing mechanics: a randomized controlled trial

This study examined the effects of a 4-week ankle-mobility intervention on landing mechanics. Twenty participants with restricted ankle dorsiflexion range of motion (DF ROM) were allocated to either a strength training only (n = 9) or a strength training and ankle mobility program (n = 11). Participants performed a weight-bearing lunge test and bilateral drop-landings before and following the intervention. Normalized peak vertical ground reaction force (vGRF), time to peak vGRF and loading rate were calculated, alongside sagittal-plane initial contact angles, peak angles and sagittal-plane joint displacement for the ankle, knee and hip. Frontal-plane projection angles were also calculated. Following the intervention, only the strength and mobility group improved ankle DF ROM (mean difference = 4.1°, effect size (ES) = 1.00, P = 0.002). A one-way analysis of covariance found group effects for ankle joint angle at initial contact (P = 0.045), ankle (P < 0.001) and hip joint angle at peak flexion (P = 0.041), and sagittal-plane ankle (P < 0.001) and hip joint displacement (P = 0.024) during bilateral drop-landings. Post-hoc analysis revealed that the strength and mobility group landed with greater ankle plantar flexion at initial contact (mean difference = 1.4 ± 2.0˚, ES = 0.46) and ankle dorsiflexion at peak flexion (mean difference = 6.3 ± 2.9˚, ES = 0.74) following the intervention, resulting in greater ankle joint displacement (mean difference = 7.7 ± 4.0˚, ES = 1.00). However, the strength training only group landed with increased peak hip flexion (mean difference = 14.4 ± 11.0˚, ES = 0.70) and hip joint displacement (mean difference = 8.0 ± 6.6˚, ES = 0.44) during post-testing. The findings suggest that changes in landing strategies following the performance of a strength training program are specific to whether restrictions in ankle mobility are considered as part of the intervention.