Wednesday, October 23, 2013

Pronation is not the primary cause of injury in novice runners: New Study

There is a popular belief moderate foot pronation i.e. the inward roll of the foot during the stance phase of gait can if left uncontrolled increase the risk of injury among novice runners. Hence much focus is placed on controlling middle range motion of the subtalar joint by restricting prontal plane eversion after heel strike with both shoes and shoe inserts. A new Danish study published in the British Journal of Sports Medicine has revealed after a one-year epidemiological observational prospective cohort study of 927 novice runners, pronation may not be the cause of patho mechanics. Participants had their “foot posture” i.e. the degree to which their foot pronates or supinates, measured and classified as “highly supinated” (n=53), “supinated” (n=369), “neutral” (n=1292), “pronated” (n=122) , or “highly pronated ” (n=18), with a foot posture index. The subjects were then asked to commence a running routine, using a “neutral” shoe and to use global positioning system watch to quantify the running distance in every training session. Runners were required to report on any injuries they experienced. For the purpose of the study an injury was defined as “any musculoskeletal complaint of the lower extremity or back caused by running, which restricted the amount of running for at least one week.” The 927 participants ran a total of 326,803 km over the course of the year. .A total of 252 participants sustained a running-related injury. Of these, 63 were bilateral injuries. Compared with a neutral foot posture, no significant body mass index-adjusted cumulative risk differences (RD) were found after 250 km of running for highly supinated feet (RD=11.0% (−10% to 32.1%), p=0.30), supinated feet (RD=−1.4% (−8.4% to 5.5%), p=0.69), pronated feet (RD=−8.1% (−17.6% to 1.3%), p=0.09) and highly pronated feet (RD=9.8% (−19.3% to 38.8%), p=0.51). In addition, the incidence-rate difference/1000 km of running, revealed that pronators had a significantly lower number of injuries/1000 km of running of −0.37 (−0.03 to −0.70), p=0.03 than neutrals. The results of the study show there were no significant injury-risk differences after 250 km of running between a “highly supinated” and a “neutral” foot and pronators had a much lower rate of injury per 1,000 km of running than those with neutral feet. Researchers are still left scratching their heads to know what this actually means but the results do indicate pronating feet in healthy subjects are not necessary a predictor of injury.

Nielsen R O, Buist I, Parner E T, Nohr E A, Sørensen H., Lind M, and Rasmussen S 2013 Foot pronation is not associated with increased injury risk in novice runners wearing a neutral shoe: a 1-year prospective cohort study Br J Sports Med bjsports-2013-092202Published Online First: 13 June 2013 doi:10.1136/bjsports-2013-092202.

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