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 (RPE_GET) and 15% above GET (RPE_GET+15%) to identify potential mediators and performance applications for RPE during treadmill running.

Methods

Twenty-one runners (${\dot{V}\mathrm{O}}_{2}$_max = 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 RPE_GET and RPE_GET+15%. Mean differences for ${\dot{V}\mathrm{O}}_{2}$, heart rate (HR), minute ventilation (${\dot{V}}_{E}$), respiratory frequency (${\mathcal{F}}_{R})$, respiratory exchange ratio (RER), and velocity were compared across each run.

Results

After minute 14, ${\dot{V}\mathrm{O}}_{2}$, 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 ${\dot{V}}_{E}$, where values were significantly higher during RPE-clamp runs at RPE_GET+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 ${\mathcal{F}}_{R}$.

Conclusions

HR and ${\mathcal{F}}_{R}$ may play a role in mediating the perception of effort, while ${\dot{V}\mathrm{O}}_{2}$, RER, and ${\dot{V}}_{E}$ may not. Although HR and ${\mathcal{F}}_{R}$ 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 ${\dot{V}\mathrm{O}}_{2}$ within the moderate intensity domain.