Biomechanical differences between overground and treadmill running in professional runnersa pilot study

Purpose: The aim of this study was to compare the biomechanical parameters of runners during overground and treadmill running, to assess the significance of these differences for treadmill training, and to evaluate their relevance for physiotherapy. Methods: Ten professional runners (mean age of 31.2 ± 6.8 years) were evaluated using a 10-camera Vicon motion capture system and a Phantom V12 high-speed camera. After completing a 200-meter overground run at a self-selected pace, each athlete entered the calibrated capture volume, where their running velocity and kinetic data were recorded. The individual mean velocities were then replicated on a treadmill positioned within the same capture space. Results: Treadmill running altered lower limb biomechanics compared to over-ground running. Median step length was 3% longer and markedly less variable on the treadmill than over-ground ( p < 0.001). The knee-flexion angle differed by surface and side ( p < 0.0001), changes were (1° for left, -2° right) but variability narrowed on the treadmill, while the knee-impact angle remained unchanged. Relative to over-ground running treadmill running reduced the horizontal distance between the center of gravity and foot initial contact; ground-contact time (12%) and heel velocity after toe-off by 19% ( p < 0.0001). Conclusions: Treadmill running alters lower limb biomechanics by reducing ground contact time, heel velocity, and variability in movement patterns. The consistent mechanics observed on the treadmill may support its use in physiotherapy, particularly for hamstring rehabilitation. However, due to limited replication of natural conditions, treadmill training should complement rather than replace overground running.