Journal of Science and Medicine in Sport (2007) 10, 311—319 ORIGINAL PAPER Foot morphology and foot/ankle injury in indoor football Lauren E. Cain a,* , Leslie L. Nicholson b , Roger D. Adams b , Joshua Burns c a Hawkesbury Physiotherapy, 89 The Terrace, Windsor, Sydney, NSW 2756, Australia b School of Physiotherapy, Faculty of Health Sciences, University of Sydney, Australia c Discipline of Paediatrics and Child Health, Faculty of Medicine, The University of Sydney, Australia Accepted 14 July 2006 KEYWORDS Foot morphology; Indoor football; Performance; Injury Summary While the pronated foot is implicated as a risk factor for sports injury in some studies, others suggest that a supinated foot posture increases the risk of overuse lower limb injuries. Athletes in a given sports discipline may tend to have a similar foot morphology, which varies from that observed elsewhere. Further, the foot morphology that is beneficial for performance in a sport may be detrimental with regard to injury. Intra- and inter-rater reliability of the Foot Posture Index (FPI- 6) as a measure of foot morphology was determined (ICC (2,1) 0.88 and 0.69 respec- tively). Thereafter, in a prospective cohort study using the FPI-6, 76 adolescent male indoor football (Futsal) players were measured and followed monthly over one com- petition season. Coach-rated ability and reports of any overuse injuries at the ankle and/or foot over this period were obtained. A significant negative linear relationship was found between the mean FPI-6 scores and coach-rated ability (p = 0.008), with supinated and under-pronated postures related to higher ability level. Overall, 33% of injuries at the ankle and/or foot were classified as overuse. Foot Posture Index scores of less than 2, indicating the supinated and under-pronated feet, were found to be associated with a significant increase in the risk of overuse injury (p = 0.008). The greater rigidity of these foot types may assist adolescent, male, indoor football players to perform at a higher level in their sport. Unfortunately, these players are also more likely to sustain ankle and/or foot overuse injuries. © 2006 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. Introduction The relationship between foot morphology and lower extremity injury is unclear, with both high ∗ Corresponding author. Tel.: + 61 433 980 238. E-mail address: lauren.cain@hotmail.com (L.E. Cain). and low arches reported as making the foot more prone to injury. 1—3 Excessive foot prona- tion has been implicated as a risk factor for injuries in football, 4 netball 5 and in the develop- ment of medial tibial stress syndrome. 6,7 Interest- ingly, supinated foot types have also been found to be associated with increased risk of sustain- 1440-2440/$ — see front matter © 2006 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jsams.2006.07.012