Outdoor effects of running fatigue and training session type on accelerometer-based loading and stability

The current study examined 200 outdoor training runs from 23 recreational runners at predefined durations and intensities. The first and last 10% of each training session were compared for fatigue effects on dynamic loading, stability, and spatio-temporal variables using a single trunk mounted accelerometer and evaluated using generalised estimating equations. Training session type (i.e. long slow duration (LSD) or lactate threshold (LT) training sessions) was added as an additional factor in the model and checked for fatigue interactions. Overall, braking peak accelerations decreased, while mediolateral trunk acceleration waveforms became more variable and less complex with fatigue (p< 0.05), regardless of training session type. Braking peak accelerations and step frequency were higher overall during LT sessions compared to LSD sessions (p< 0.01). These results add to the small body of ecological, biomechanical evidence regarding how runners fatigue during commonly prescribed outdoor training sessions