Effects of Prolonged Running on Ground Reaction Force Patterns Wearing Shoes of Different Midsole Durometers (Fatigue)

309 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.Selected force events and the relative timing of their occurrence, were chosen for evaluation from the GRF curves obtained from 15 subjects, 18 to 49 years, running "as hard as possible." GRFs were measured on a force platform at the start, middle, and end of one hour of running. Testing took place on two days when shoes of different midsole durometers (40 and 70 DSs) were worn. The protocol allowed assessment of the effects of both fatigue, and different DSs, on GRFs. The data were analysed using repeated measures ANOVA and Bonferroni t procedures. Several significant differences were found. The 15 subject mean value of the vertical ground reaction second maximum force (VGRSMaF), which occurred approximately 100 milliseconds after initial foot contact, as different according to the shoes worn, and changed as a result of the prolonged running. A significant shoes x time interaction was found, indicating the two DSs elicited different subject responses as a result of prolonged running. Since the VGRSMaF occurs late enough to be mediated by the nervous system, a change in this force event may indicate a fatiguing of the mediation mechanism. Many running injuries appear to be related to repeated microtraumas, and if an increase in this force increases the microtraumas, one might be placing oneself at greater injury risk. In addition, different individual responses were found. For several subjects it appeared that running in 40 DSs might lessen their risk of injury compared to running in 70 DSs. As well, some subjects appeared to maintain similar GRF patterns regardless of either prolonged running or wearing different DSs.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD