Does high-intensity running to fatigue influence lower limb injury risk?

Abstract

Objectives: The aim of this study was to quantify changes in peak bending moments at the distal tibia, peak patellofemoral joint contact forces and peak Achilles tendon forces during a high-intensity run to fatigue at middle-distance speed. Design: Observational study. Methods: 16 high-level runners (7 female) ran on a treadmill at the final speed achieved during a preceding maximum oxygen uptake test until failure (~ 3 min). Three-dimensional kinetics and kinematics were used to derive and compare tibial bending moments, patellofemoral joint contact forces and Achilles tendon forces at the start, 33 %, 67 % and the end of the run. Results: Average running speed was 5.7 (0.4) m·s−1. There was a decrease in peak tibial bending moments (− 6.8 %, p = 0.004) from the start to the end of the run, driven by a decrease in peak bending moments due to muscular forces (− 6.5 %, p = 0.001), whilst there was no difference in peak bending moments due to joint reaction forces. There was an increase in peak patellofemoral joint forces (+ 8.9 %, p = 0.026) from the start to the end of the run, but a decrease in peak Achilles tendon forces (− 9.1 %, p < 0.001). Conclusions: Running at a fixed, high-intensity speed to failure led to reduced tibial bending moments and Achilles tendon forces, and increased patellofemoral joint forces. Thus, the altered neuromechanics of high-intensity running to fatigue may increase patellofemoral joint injury risk, but may not be a mechanism for tibial or Achilles tendon overuse injury development