Commercial Footwear with Lateral Torsional Stiffness that May Reduce Injury Risk in Army Basic Trainees

Abstract

Musculoskeletal injuries place a burden on the U.S. Military with estimates that 25% of men and 50% of women experience an injury in Army Basic Training. In 2016, 18% of Cadet basic trainees at the U.S. Military Academy (USMA) sustained a lower-extremity (LE) injury. In that sample, Cadets wearing shoes with mild to moderate lateral torsional stiffness (1.30 - 2.29 Newton [N] meters[m]) were 49% less likely to incur any type of LE injury and 52% less likely to incur an overuse LE injury than Cadets wearing shoes with minimal (<.0130 Nm) or extreme (>.0230 Nm) lateral torsional stiffness. PURPOSE: To identify athletic footwear, commercially available at West Point, NY, with mild to moderate lateral torsional stiffness characteristics. METHODS: Twenty (10 shoes men’s size 10, 10 shoes women’s size 8) new shoes of varying brands were included in this analysis. The Shoe Stiffness in Torsion Measurements device and methods of data collection described by Zifchock, were used to quantify lateral torsional stiffness. Each shoe was measured twice by a single rater and averaged for the overall analysis. Rater reliability analyses suggest the SySTM device is useful for repeatable measurements of lateral torsional stiffness. RESULTS: Six out of 20 shoes (2 men’s, 4 women’s) demonstrated mild to moderate lateral torsional stiffness to include; Men’s New Balance Minimus MT10GG, and Nike Flex 2017 RN; Women’s Sketchers Go Run 3, Asics Gel-Fit Sana 3, Nike Free TR 7 Selfie, and Nike Flex Trainer 7. Fourteen out of 20 shoes (8 men’s, 6 women’s) did not demonstrate mild to moderate lateral torsional stiffness. Of those 14 shoes, 13 demonstrated extreme lateral torsional stiffness; Men’s Nike Lunar Fingertap TR, Nike Retaliation TR, Nike Air Zoom Pegasus 34, Asics FuseX Rush, Asics Gel-Contend 4, Brooks Adrenaline GTS 18, and New Balance Trufuse 860v7; Women’s Under Armour Micro G Assert 7; Asics RoadHawk FF, Asics GT 1000-6, Brooks Ghost 10, Adidas Cosmic 2, and New Balance W940GP3. One demonstrated minimal lateral torsional stiffness; Women’s Asics Metrolyte Gem. CONCLUSION: We identified 6 shoes commercially available at West Point, NY, with mild to moderate lateral torsional stiffness. These shoe recommendations can inform Cadet basic trainees on footwear that may be protective of LE injury during USMA Army Basic Combat Training.