title: Impact of high-intensity interval duration on perceived exertion.
abstract: OBJECTIVE
  RPE is increasingly being considered as a viable tool beyond its original use for monitoring in-task exercise intensity. Research indicates that anticipated, in-task, and postexercise RPE values are often notably different from one another. An important new consideration is how perceptions are impacted by high-intensity interval training (HIT). This study aims to compare RPE responses before, during, and after continuous and HIT exercise trials.
  
  
  METHODS
  Twenty (11 females and 9 males; mean ± SD age, 22 ± 4 yr) overweight (mean ± SD body mass index, 29 ± 3 kg·m(-2)) and unfit (mean ± SD V˙O2peak, 28 ± 5 mL·kg·min(-1)) participants completed a 20-min heavy continuous (HC) trial and three 24-min severe-intensity interval trials that utilized 1:1 work-to-recovery ratios: 30 s (Severe Interval-30), 60 s (Severe Interval-60), and 120 s (Severe Interval-120). Exertion was assessed using the Borg CR10 Scale. Data were analyzed using repeated-measures ANOVA and pairwise comparisons.
  
  
  RESULTS
  Anticipated exertion was highest in the Severe Interval-120 trial (5.8 ± 2.0; P < 0.05) compared with other trials. Exertion increased from beginning to end in all trials (P < 0.05), with the greatest increases observed within the HC trial. Session RPE for the Severe Interval-120 trial (6.4 ± 2.3) was higher than those for all other trials (P < 0.05), and session RPE for the Severe Interval-30 trial (3.7 ± 1.8) was lower than that for the HC trial (4.9 ± 1.6; P < 0.05).
  
  
  CONCLUSIONS
  These findings suggest that 30-s HIT protocols limit the perceptual drift that occurs during exercise, in comparison to HC exercise. Moreover, performing more intervals of shorter durations appears to produce lower postexercise RPE values than performing fewer intervals of longer duration and equal intensity. Because effort perception may influence behavior, these results could have implications for the prescription of interval training in overweight sedentary adults.
authors.affiliation: 1School of Physical Education and Exercise Science, University of South Florida, Tampa, FL; 2School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, CANADA; 3School of Sport and Health Sciences, University of Exeter, Exeter, UNITED KINGDOM; 4Bayfront Medical Center, St. Petersburg, FL; and 5Department of Anthropology, University of South Florida, Tampa, FL.
authors.forename: Marcus W
authors.initials: MW
authors.lastname: Kilpatrick
authors.forename: Nic
authors.initials: N
authors.lastname: Martinez
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Little
authors.forename: Mary E
authors.initials: ME
authors.lastname: Jung
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Jones
authors.forename: Nick W
authors.initials: NW
authors.lastname: Price
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Lende
mesh_terms: D015992:Body Mass Index; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D050177:Overweight / Q000503:physiopathology*; D010465:Perception / Q000502:physiology*; D010806:Physical Education and Training / Q000379:methods*; D005082:Physical Exertion / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult