The Influence of 9-marathons completed in 9 days on injury incidence and selected musculoskeletal tests.

Multi-day running events are increasingly popular, however, research on these events is lacking and fails to consider the dynamic nature of musculoskeletal physiology. Twenty-three athletes completing a 10-day marathon event participated in the study. Proprioception, dynamic balance, knee valgus, and flexibility were assessed the day before the event and after one, five, and nine consecutive marathons. There were significant reductions in these measurements across the event and reductions were more apparent in the nondominant side. Each runner suffered, on average, 4.2 injuries. Runners performed significantly worse in musculoskeletal measurements, particularly on the nondominant side, as the competition progressed. Therefore, athletic trainers should design appropriate between-day recovery strategies during events based on within-event data collection.