INFLUENCE OF ANKLE STABILIZERS ON SHOCK ABSORTION AND PERFORMANCE IN RUNNING AND JUMPING.

Abstract

Stabilizing the ankle has been investigated as a method of prevention of ankle sprains.. Several studies have found a significant decrease in ankle injuries with an increased support. In some sports with high risk of ankle injuries like basketball, high top shoes are extensively used to reduce injuries. Nevertheless, in other Sports with also high risk, high top shoes are not so extensively used because they are considered to reduce performance in runniest with rapid lateral movements. Ankle movement is also an important shock absorptions mechanism and limiting this 'movement can lead to higher impacts suffered by the body. For these reasons, performance and shock absorptions on the one hand and, prevention of ankle sprains on the other, seem to be opposite points for the ankle support issue. The aim of this paper is to understand better the effects of ankle support in both shock attenuation and performance of jumps. The influence in performance through a obstacle course has been also investigated. Three subjects participated in the study and two types of shoes were used for the tests. The shoes had exact midsole and sole and the differences between them were only in the upper vamp. First shoe was a high top shoe with firm heel counters designed to obtain a good ankle support. The second one was a low top shoe with no heel counter. Three types of experiments were carried out. The first experiment consisted of series of three maximal jumps in which the shoes were randomized. For this test the jump height was measured. The second test was also a performance test but consisted of a obstacle court and the times were measured by a chronometer. For this test also series of three runs with randomized order of shoes were performed. For the third test two accelerometers were firmly attached to the subject's tibia and forehead. Series of three jumps at 95% of the maximal jump and reach were performed barefoot and randomly wearing the shoes. The subjects landed on their right foot over a force plate. The accelerometers and force plate were sampled at 1000 Hz. Statistical significant differences between shoes were found both in the performance tests and in the shock absorption ones. High top shoes were found to reduce the performance in jumps and obstacle course and to increase impacts that reach the forehead.