Construction and validation of a nomogram model for predicting different sites of ankle pain in runners with chronic ankle instability.

This study aimed to establish a risk prediction nomogram model for anterolateral, mediolateral, and posterolateral ankle pain in runners with chronic ankle instability (CAI) and analyse the potential risk factors for pain at different ankle sites. Thirty recreational runners with CAI who reported ankle pain in the anterolateral, mediolateral, or posterolateral regions were recruited for this study. Kinematic, kinetic, and electromyographic data during running were collected using motion capture system, 3-D force platform, and surface electromyography system. These data were used to generate a dynamic nomogram. The results showed that anterolateral ankle pain in runners with CAI may be caused by insufficient gastrocnemius muscle strength (OR 0.85, 95% CI 0.73-0.97), excessive ground reaction force (GRF, OR 2.64, 95% CI 1.25-6.22), and an increased percentage of ankle energy absorption (OR 9.11, 95% CI 1.50-77.79). Mediolateral ankle pain might be contributed by greater ankle inversion angle (OR 1.08, 95% CI 1.01-1.00) and GRF (OR 2.13, 95% CI 1.17-4.31). Moreover, posterolateral ankle pain was predicted by increased ankle adduction angle (OR 1.06, 95% CI 1.00-1.12), increased GRF (OR 2.16, 95% CI 1.07-4.80), and decreased dynamic stability (OR 0.20, 95% CI 0.05-0.68). To prevent ankle pain, runners with CAI should be encouraged to focus on improving the neuroreceptor sensitivity of the gastrocnemius muscles, and retraining their energy absorption patterns.