FATIGUE EFFECT ON BIOMECHANICAL PARAMETERS OF TRAIL RUNNING.

none6noINTRODUCTION: Fundamental biomechanical parameters in trail running are step length (SL) and frequency (SR), contact (CT) and flight time (FT), and shock attenuation (SA) (Derrick et al., 1998). SA is considered a significant indicator for injury prevention (Mizrahi et al. 2000) and is influenced by several factors such as fatigue and foot strike pattern (Giandolini et al. 2014). The aim of the present study was to investigate the effect of fatigue on the kinematic parameters of step and SA during downhill trial running. METHODS: Eleven well trained participants (10 men and 2 women, age: 31.5±11.4 years, height: 173.9±5.6 cm, mass: 34.1±6.5 Kg) were enrolled. Four inertial sensors (EXLs3, 200 Hz) were attached to the pelvis, tibia, heel and second metatarsal head of the foot (Giandolini et al., 2014). Data were collected during a 290m downhill running (mean inclination 13°). The task was performed before and after an 18km trail running and filmed by a videocamera (Panasonic HC-V700, 50hz). The self-selected running speed was similar in both pre and post-trial acquisitions. 854 steps were analyzed. For each step, the following parameters were estimated SL, SR, step time (ST), CT, FT, SA, center of mass acceleration (CA), tibial acceleration (TA) and foot strike pattern (Giandolini et al. 2014). RESULTS: Reduced FT (p<0.009) and CA (p