By Nikki Reiter
Do you plan your workout intensity? Does this ever deter you from your workout effort, or maybe deter you from starting the workout altogether?
Research has been published comparing rating of perceived exertion (RPE) responses before, during and after continuous and ‘high-intensity interval training’ (HIIT) exercise trials.
Apparently, RPE has been shown to change in relation to the same session, depending on ‘when’ it is asked.
Here’s how it went: 20 unfit individuals went through a single 20-minute heavy continuous effort as well as a series of workouts involving 30, 60 and 120s maximal intervals, with an equal work-to-recovery ratio. Exertion was assessed using the Borg CR10 Scale (a scale of 1-10, with 10 being ‘maximal’) in anticipation of, during and after the workouts.
The result: Anticipated exertion was highest when participants were about to do the 120s intervals trial. 30s HIIT protocols limit the ‘perceptual drift’ (a change in exertion perception) that occurs during exercise, especially compared to heavy, continuous exercise. Overall, RPE tends to increase throughout a workout, making it most difficult to complete a longer, continuous ‘interval’ (like 20 min) at a heavy exertion level.
What this means: By keeping intervals at 30s, the perception of workout exertion is kept at a minimum. Further, performing more intervals of shorter duration appears to produce lower post-exercise RPE values than performing fewer intervals of longer duration and equal intensity.
A final comment: This research did put unfit individuals through the HIIT task. The population may not match that of experienced runners, but I think we can still expand the results based on basic human motivation and the idea that effort perception can influence behavior. While baseline fitness may differ, we all fall victim to days of reduced motivation…and sometimes experience dictating how hard the workout will be is even more of a dissuading factor. With exercise tolerance having been shown to be limited by perception of effort, better to reframe the workout into something manageable (more, shorter intervals) than skip the workout altogether!
Nikki Reiter is a Biomechanist and certified NCCP Performance Coach in Endurance Running. She offers online gait analysis through Run Right Gait Analysis. Visit her website www.run-right.ca for more information.