MINIMIZING SHOE-SURFACE FRICTION AT INITIAL CONTACT: A NOVEL APPROACH TO PREVENT LATERAL ANKLE SPRAINS

The lateral ligament complex is the most frequently injured single structure in the body. The purpose of this study was to investigate how minimizing lateral shoe-surface friction could aid in the prevention of lateral ankle sprains. Two initial studies were carried out to examine the effect of reduced lateral friction during two typical but different indoor sports movements. Ankle joint moments were analyzed using an inverse dynamics model and revealed that minimizing lateral shoe-surface friction does not affect performance and ground contact mechanics during typical indoor sports movements. These movements are in general performed with a medial initial contact. Based on these results, a future test protocol is outlined testing the preventative effect of Spraino® Slide when initial contact is carried out with an initially supinated foot position during landing and cutting situations

Lateral edge friction variability in indoor sports shoes

It has previously been speculated that the occurrence and severity of lateral ankle sprain injuries is linked to excessive shoe-surface friction. The purpose of this study was to assess the amount of lateral edge friction in indoor sports shoes, and evaluate the variation from the traditional forefoot traction test. Therefore, we modified the ISO:12387:2019 test for slip resistance and positioned the shoe on its lateral edge while simulating a sideways movement. All tests were conducted on an indoor surface. In general, we found that lateral edge friction on average was 22% lower than forefoot friction (p<0.0001). However, linear regression showed that the forefoot test could only explain 63% of the variation in edge friction, thereby suggesting that a lateral test is needed to adequately inform on lateral edge friction. Future research is planned to determine whether a noticeable change in friction coefficient is also a ‘valuable change’, hence potentially having clinical implications for injury prevention