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Optic Flow Influences Perceived Exertion and Distance Estimation but not Running Pace


Medicine & Science in Sports & Exercise: August 2014 - Volume 46 - Issue 8 - p 1658–1665
doi: 10.1249/MSS.0000000000000257
Applied Sciences

Purpose This study aimed to examine the effect of variations in optic flow on perceived and actual running pace and RPE.

Methods Twelve male moderately trained competitive runners performed a self-paced 5-km running reference time trial followed by a three 5-km running self-paced trials under different optic flow conditions (R NORM = actual running speed, R SLOW = actual speed − 25%, and R FAST = actual speed + 25%). Participants were asked to self-report RPE when they thought they had reached each kilometer.

Results There was no difference in the 5-km completion times (P > 0.05) or actual pace (P > 0.05) between the optic flow conditions. A greater distance was covered between the perceived kilometer points during R SLOW compared with R NORM (P < 0.01) and R FAST (P < 0.01). RPE (normalized for running distance) was lower during R SLOW compared with R NORM (P < 0.01) and R FAST (P < 0.01).

Conclusions Different rates of optic flow lead to an apparent compression or elongation of perceived distance during running, with slow optic flow resulting in an increased ratio of perceived to actual running distance. Pacing was not different in the slow optic flow condition, despite lower perceived exertion, which is contrary to the predictions of the RPE template model, hazard scores, and estimated time limits.

School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UNITED KINGDOM

Address for correspondence: Dominic Micklewright, PhD, School of Biological Sciences, The University of Essex, Wivenhoe Park, Colchester, Essex, United Kingdom. CO4 3SQ; E-mail:

Submitted for publication August 2013.

Accepted for publication December 2013.

© 2014 American College of Sports Medicine