title: Determinants of time to fatigue during nonmotorized treadmill exercise.
abstract: Treadmill exercise is commonly used for aerobic and anaerobic conditioning. During nonmotorized treadmill exercise, the subject must provide the power necessary to drive the treadmill belt. The purpose of this study was to determine what factors affected the time to fatigue on a pair of nonmotorized treadmills. Twenty subjects (10 men/10 women) attempted to complete 5 minutes of locomotion during separate trials at 3.22, 4.83, 6.44, 8.05, 9.66, and 11.27 kmxh. Total exercise time (<or=5 minutes) was recorded. Exercise time was converted to the number of 15-second intervals completed. Peak oxygen uptake (Vo2) was measured using a graded exercise test on a standard treadmill, and anthropometric measures were collected from each subject before their entrance into the study. A Cox proportional hazards regression model was used to determine significant predictive factors in a multivariate analysis. Treadmill speed and absolute peak Vo2 were found to be significant predictors of exercise time, but there was no effect of anthropometric characteristics. Gender was found to be a predictor of treadmill time, but this was likely attributable to a higher peak Vo2 in men than in women. The results were not affected by the type of treadmill tested in this study. Coaches and therapists should consider the cardiovascular fitness of an athlete or client when prescribing target speed because these factors are related to the total exercise time that can be achieved on a nonmotorized treadmill.
authors.affiliation: Wyle's Life Sciences Group, Houston, Texas, USA. john.k.dewitt@nasa.gov
authors.forename: John K
authors.initials: JK
authors.lastname: De Witt
authors.forename: Stuart M C
authors.initials: SM
authors.lastname: Lee
authors.forename: Cassie A
authors.initials: CA
authors.lastname: Wilson
authors.forename: R Donald
authors.initials: RD
authors.lastname: Hagan
mesh_terms: D000886:Anthropometry; D005080:Exercise Test / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D008889:Military Personnel; D018763:Muscle Fatigue / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D016016:Proportional Hazards Models; D013997:Time Factors