The effects of shoe hardness on impact force characteristics during running were elevated using both a group and single subject analysis approach. It was hypothesized that non-significant shoe effects previously reported could have resulted from the experimental design and analysis procedures employed. The present study evaluated 18 runners using a single subject procedure in addition to a group design (Shoe Condition X (Subject X Shoe Hardness)). ANOVA analyses identified significant differences (p < 0.05) between mean impact forces for the soft shoe condition and mean maximum knee flexion angles for the hard shoe condition. Individual subject analyses identified no significant (p <0:05) impact force differences for eight subjects while I 0 subjects exhibited significant differences. A significant correlation coefficient of -0.59 between impact force and maximum knee flexion suggested that some accommodation took place on average but the extent varied among subject. Post-hoc group analyses identified a relationship (r = 0.59) between impact tester results and impact forces for one subgroup of subjects.The results support the hypothesis that subjects can and do respond differently to the same perturbation ·and that these differential responses can compromise group analysis results.
Journal of Human Movement Studies
Bates, Barry T. and Stergiou, Nikolaos, "Performance Accomodation to Midsole Hardness During Running" (1996). Journal Articles. 72.