ATHLETIC FOOTWEAR AFFECTS BALANCE IN MEN

Stable equilibrium during locomotion is required for both superior per formance of sports and prevention of injuries from falls. A recent rep ort indicated that currently available athletic footwear impairs stabi lity in older men. Since this discovery, if confirmed, seems important to both competitive athletes and the physically active general public , we performed an experiment using similar methods on a younger popula tion. We tested the hypothesis that midsole thickness is negatively, a nd hardness positively related to dynamic equilibrium, in 17 healthy a dult men (mean(s.d.) age 33(11.13) years) via a balance beam method. S ubjects walked along a 9-m long beam at 0.5 ms(-1) once barefoot and s ix times wearing identical pairs of experimental shoes which differed only in midsole hardness and thickness which spanned the respective ra nges currently available in footwear. Falls from the beam (balance fai lures) were quantified. Balance failures varied significantly in relat ion to midsole hardness and thickness, and there was a strong trend to ward interaction of these variables (P = 0.09). Midsole hardness was p ositively related to stability, and midsole thickness was negatively r elated, which confirms the previous report. Hence, shoes with thick-so ft soles, similar to modern athletic footwear and 'walking shoes', des tabilize men, and shoes with thin-hard soles provide superior stabilit y. The pair with the poorest stability (A 15 - thick; 12.34 balance fa ilures per 100 m) produced 217% more balance failures than those assoc iated with the best stability (A 50 - thin; 3.89 balance failures per 100 m). Since most types of athletic footwear and many other shoes inc orporate midsoles with hardness and thickness associated with poor sta bility, we conclude that both athletic performance and public safety c ould be enhanced through stability optimized footwear.