Biomechanical evaluation of modified track shoes

Abstract

Track and field runners, especially sprinters and mid-distance runners, face many problems due to walking in spike shoes. Due to the fact that track and field spike shoes are designed specifically for running, the runner’s feet remain in an uncomfortable, flexed position when walking between workouts and races. Problems caused by the dangerous foot-positioning include, but are not limited to, the following: back pain, shin splints, bone spurs, blisters, and overall decreased level of running performance. Over time, runners wearing improper footwear for walking may face chronic injuries such as plantar fasciitis, shin splints, Achilles tendinitis, chondromalacia, and iliotibial band syndrome. To address this problem, a modified spike shoe was tested. The modification consists of adding a removable heel to the shoe. The removable heels were attached to the sole after exercise or between races to shoe angle of flexion, so that the foot can be leveled. The modified shoes were tested in terms of health and comfort through the use of two experimental protocols. Nine healthy, resistance-trained participants volunteered to perform walking drills on a treadmill. They walked with regular spikes at 2 mph and 3 mph. Then, they repeated the drill with the redesigned spike shoes. EMG measurements were used to evaluate the participant’s muscle activity, fatigue, and stress during the exercise. The analyzed muscles were the tibialis anterior and the medial gastrocnemius. The statistical tool used for the mathematical interpretation of the data was ANOVA, the hypotheses being tested with the softwares Statistix 9.0. and SAS 9.0 English version. Complementarily, participants were individually asked to rate their discomfort on a scale of 1 to 10, using a body map as a further evaluation of the effects of the removable heel. Results showed a 22 % average decrease in EMG muscle activity from walking without heels to walking with heels in the tibialis anterior and a 24.25% average decrease in the gastrocnemius. Results were consistent for all participants. Similarly, when rating discomfort from walking without heels to walking with heels, the body map survey results indicate that participants noticed an average superior comfort of 2.7 points in the knees, 2.6 points in the calves, 3.9 points in the ankles, and 4.2 points in the feet on an ergonomic scale of 10 discomfort points. Thus, results showed that the removable heel helps reduce muscle fatigue and stress and therefore its related musculoskeletal problems.