The Influence of Running Cadence Manipulation on Acute Cartilage Response in Distance Runners

We examined the influence of running cadence manipulation on femoral cartilage deformation in runners and assessed the association between knee biomechanics and cartilage characteristics. Thirty-one runners (15 females and 16 males) completed a habitual and high cadence (+10%) run 2-7 days apart in a counterbalanced order. Participants underwent ultrasound imaging of their femoral trochlear cartilage before and after running. A force instrumented treadmill with an 8-camera motion capture system obtained the peak knee flexion angle, peak knee extensor moment, peak patellofemoral joint force (PFJF), peak patellofemoral joint stress (PFJS), and cumulative PFJS. A 2 (condition) by 2 (time) ANOVA with repeated measures revealed medial cartilage thickness decreased similarly between conditions after running (1.97 (95% CI: 1.86, 2.09) vs. 1.89 (95% CI: 1.78, 2.01) mm; mean difference = -0.078 (95% CI: -0.130, -0.026) mm, p = 0.005). No main effect of condition or interaction effect was found despite a difference between biomechanics outcomes (all p < 0.001). Higher peak and cumulative PFJS were associated with a greater decrease in medial cartilage thickness following high cadence running (p = 0.011). Higher PFJS was associated with thicker medial, central, and lateral cartilage thickness (all p < 0.05). Increasing running cadence may be a viable intervention to decrease external joint loading while maintaining an internal stimulus to knee cartilage. Cartilage is avascular and relies on mechanical loading to facilitate nutrient diffusion. As such, joint stress during running may be beneficial for cartilage development.