Foot type and overuse injury in triathletes.

Abnormal foot morphology has been suggested to contribute to overuse injuries in athletes. This study investigated the relationship between foot type and injury incidence in a large sample of competitive triathletes not wearing foot orthoses during a 6-month retrospective analysis and a 10-week prospective cohort study. Foot alignment was measured using the Foot Posture Index and the Valgus Index, and participants were assigned to supinated, pronated, and normal foot-type groups. Overall, 131 triathletes sustained 155 injuries during the study. Generally, foot type was not a major risk factor for injury; however, there was a fourfold increased risk of overuse injury during the competition season in athletes with a supinated foot type. The results of this study show that triathletes with a supinated foot type are more likely to sustain an overuse injury.