Effects of shoe type on cardiorespiratory responses and rearfoot motion during treadmill running.

Running kinematics and physiological responses to high intensity submaximal treadmill running in training shoes and racing flats were evaluated. Eight women (mean age = 21.9 yr) completed a peak VO2 test on the treadmill (mean peak VO2 = 49.2 ml.kg-1.min-1). In two subsequent testing sessions, subjects completed 15-min runs at a speed corresponding to 90% of peak VO2 (range = 9.9-13.4 km.hr-1) while wearing training shoes and racing flats (balanced order assignment). No significant time effect or time by shoe condition interaction was observed for the rearfoot motion variables. Maximum rearfoot angle and total rearfoot motion averaged 42% and 13.9% higher, respectively, for the racing flat (P less than 0.05). There were significant increases over time for VO2, VE, HR, and RPE, indicating an increase in cardiorespiratory response and the perception of effort over the course of the 15-min run. Thus, metabolic and perceptual indications of fatigue at the end of the run emerged but were not accompanied by rearfoot motion changes in either running shoe. These results indicate that rearfoot motion is a function of shoe design and did not change during 15 min of high intensity running.