title: Congruency and responsiveness of perceived exertion and time-to-end-point during an intermittent isometric fatigue task.
abstract: The aims of this study were (1) to investigate the relationship between self-perception of effort and task duration in an intermittent isometric fatigue trial (IIF) and (2) to evaluate the capability of two assessment paradigms (perceived exertion; perceived task duration) to reflect changes in IIF intensity. Fifteen participants performed two IIF tasks of the knee extensors at intensities of 60 and 70 % of daily peak force, each separated by 48-72 h. Ordering of the tasks was counter-balanced and participants were blinded to the precise intensity of each IIF. A category-ratio scale (CR-10) and visual analogue scale were used during each IIF task to record measures of perceived exertion and perceived task duration, respectively. Measures were recorded at 10 % intervals across the relative duration of each IIF task. Pearson product-moment correlation coefficients revealed strong positive correlations (r > 0.99; p < 0.01) between completed task duration and both perceptual scales at the two IIF intensities. Separate two-way repeated measures ANOVAs of CR-10 and perceived task duration responses revealed significant main effects for time only (F [2.2,30.1] = 126.8; p < 0.001; F [2.6,36.8] = 117.2; p < 0.001, CR-10 and perceived task duration, respectively). The results suggest that perceived exertion and perceived task duration are equally effective predictors of IIF end-point. However, neither measure was sufficiently responsive to discriminate between 10 % changes in exercise intensity.
authors.affiliation: School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, UK. joseph.shepherd@ntu.ac.uk
authors.forename: Joseph
authors.initials: J
authors.lastname: Shepherd
authors.forename: Nigel
authors.initials: N
authors.lastname: Gleeson
authors.forename: Claire
authors.initials: C
authors.lastname: Minshull
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D018592:Cross-Over Studies; D004739:England; D015444:Exercise; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D018763:Muscle Fatigue; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D013997:Time Factors; D013998:Time Perception; D055815:Young Adult