The Influence Of Running Intensity On Femoral Cartilage Deformation In Competitive Runners

Competitive compared with recreational runners have higher odds of osteoarthritis (OA) and running related injuries, possibly from different types of running that are associated with high loading rates. PURPOSE: To investigate the influence of running intensity on acute femoral cartilage deformation in competitive runners. METHODS: Twenty-four competitive runners participated (11 females and 13 males; Height = 1.73 ± 0.08 m, Mass = 64.4 ± 9.4 kg, Weekly Running Amount = 78.4 ± 17.6 km, 1500 m Personal Best = 257.1 ± 23.2 s). Competitive runners were currently competing or competed within the last year on an intercollegiate team or at a national/provincial championship level in the 800 m to 10,000 m. Participants underwent two counterbalanced running sessions (continuous and interval) 2-7 days apart. Ultrasound imaging of femoral cartilage was done before and after each running session. The continuous run was 7 km at participants’ self-selected pace (Speed = 12.11 ± 0.7 km/hour). The interval run was 10 x 400 m with 300 m recovery at 85 to 90% of their 1500 m personal best pace (Interval Speed = 18.7 ± 1.6 km/hour; Rest Speed = 11.7 ± 0.7 km/hour). Footwear was instrumented with force sensing insoles to measure the vertical loading rate, peak ground reaction force, and impulse. 2 (time) by 2 (condition) ANOVA with repeated measures evaluated the change in cartilage thickness between conditions after running. Pearson correlation assessed the association between kinetic outcomes and the change in cartilage thickness in each condition. RESULTS: Lateral femoral cartilage demonstrated greater deformation after interval running compared to continuous (p = 0.003). A significant main effect of time was seen in medial femoral cartilage where deformation was similar collapsed across conditions (1.92 (1.82, 2.02) vs. 1.83 (1.73, 1.93) mm; Mean Difference = -0.094 (-0.147, -0.042) mm, p = 0.001). The vertical loading rate, peak ground reaction force, and impulse was not associated with cartilage deformation (all r < 0.32, all p > 0.05). CONCLUSIONS: Interval running may contribute to increased lateral joint stress and greater acute cartilage deformation, which may contribute to the disparity in knee OA between recreational and competitive runners. Moreover, patellofemoral pain symptoms may be worsened by faster interval running. This project received funding from the Natural Science and Engineering Research Council of Canada (RGPIN-2022-04804, PI: DN Pamukoff)