Treadmill running using an RPE-clamp model: mediators of perception and implications for exercise prescription

Abstract

Purpose: The mediators of the perception of effort during exercise are still unclear. The aim of the present study was to examine physiological responses during runs using a rating of perceived exertion (RPE)-clamp model at the RPE corresponding to the gas exchange threshold (RPEGET) and 15% above GET (RPEGET+15%) to identify potential mediators and performance applications for RPE during treadmill running. Methods: Twenty-one runners (V˙ O 2max = 51.7 ± 8.3 ml kg−1 min−1) performed a graded exercise test to determine maximal oxygen consumption and the RPE associated with GET and GET + 15% followed by randomized 60 min RPE-clamp runs at RPEGET and RPEGET+15%. Mean differences for V˙ O 2, heart rate (HR), minute ventilation (V˙ E), respiratory frequency (FR) , respiratory exchange ratio (RER), and velocity were compared across each run. Results: After minute 14, V˙ O 2, RER and velocity did not differ across conditions, but decreased across time (p < 0.05). There was a significant (p < 0.05) condition × time interaction for V˙ E, where values were significantly higher during RPE-clamp runs at RPEGET+15% and decreased across time in both conditions. There were no differences across condition or time for HR, and only small difference between conditions for FR. Conclusions: HR and FR may play a role in mediating the perception of effort, while V˙ O 2, RER, and V˙ E may not. Although HR and FR may mediate the maintenance of a perceptual intensity, they may not be sensitive to differentiate perceptual intensities at GET and GET + 15%. Thus, prescribing exercise using an RPE-clamp model may only reflect a sustainable V˙ O 2 within the moderate intensity domain.