Time Flies When You're at RPE13: How Exercise Intensity Influences Perception of Time.

Hanson, NJ and Lee, TL. Time flies when you're at RPE13: How exercise intensity influences perception of time. J Strength Cond Res 34(12): 3546-3553, 2020-Previous studies have shown that there are some changes in our perception of time during exercise, but the relationship between intensity level and these perceptions is unclear. Therefore, the purpose of this study was to determine the effect of exercise intensity on prospective time estimations. Twenty-two trained runners (10 male, 12 female; age 25 ± 6 years) participated in three 30-minute treadmill runs that were perceptually regulated at rating of perceived exertion (RPE) levels of 13 ("somewhat hard"), 15 ("hard"), and 17 ("very hard"). Prospective time assessments, in which subjects estimated durations of 1, 3, 7, and 20 seconds, were obtained immediately before exercise, during (at 10 and 20 minutes), and after exercise. A 3 (RPE) × 4 (timepoint) × 4 (estimated duration) repeated-measures analysis of variance was completed. There was a significant main effect of RPE level (p = 0.013). Post hoc tests revealed that time estimations at RPE17 were significantly lower than those at RPE13 (p = 0.021). The main effects of timepoint and estimated duration were not significant (both p ≥ 0.05), and no interactions were present. However, there was a trend for time estimations to decrease in all conditions as exercise progressed, with a rebound after cessation of exercise. This study showed a clear effect of exercise intensity on time perception. Specifically, the subjects perceived time to pass by more slowly as intensity increased.

Pacing strategy during the final stage of a self-paced V̇O2max (SPV) test does not affect maximal oxygen uptake.

PURPOSE: Self-paced [Formula: see text] tests (SPVs) have shown to produce maximal oxygen consumption values similar to those from traditional protocols. These tests involve perceptually regulated stages in which subjects are asked to maintain rating of perceived exertion values of 11, 13, 15, 17 and 20 for 2 min each. What is not clear is how the last stage should be paced. The purpose of this study was to compare two different pacing strategies during the final stage. METHODS: Fourteen healthy, recreationally active individuals (11 men, 3 women) participated in a familiarization and two experimental laboratory visits. For both lab visits, a treadmill-based SPV was performed. In one of these SPVs, an aggressive pacing strategy was used; in the other, a conservative strategy was implemented. [Formula: see text], HR, [Formula: see text], [Formula: see text] and RER were recorded and compared between conditions. RESULTS: There were no differences in [Formula: see text] between the conditions [aggressive 58.8 ± 8.8 ml kg-1 min-1 (mean ± SD), conservative 58.3 ± 7.9 ml kg-1 min-1; p = 0.548]. There were also no differences in HR, [Formula: see text], or [Formula: see text] between the pacing strategies. There was a significantly higher RER found in the aggressive (1.25 ± 0.09) compared to the conservative (1.18 ± 0.07) strategy (p = 0.040). CONCLUSIONS: The pacing strategy that is implemented in the last 2 min of an SPV on a treadmill does not affect the maximal oxygen consumption that is elicited during that test. Either pacing strategy can be used for this protocol without compromising the results, when [Formula: see text] is the variable of interest.

Modality determines VO2max achieved in self-paced exercise tests: validation with the Bruce protocol.

PURPOSE: The Bruce protocol is traditionally used to assess maximal cardiorespiratory fitness (VO2max), but may have limitations, such as an unknown duration and large work rate increases. The use of self-paced VO2max tests (SPVs) may be beneficial if they are able to elicit similar maximal values in a set period of time. In addition, differences in modality between SPVs have not been explored. The purpose of this study was to compare SPVs, utilizing two different modes, with the Bruce (treadmill) protocol. METHOD: Thirteen healthy, recreationally active individuals (eight men, five women) volunteered and participated in three different laboratory visits with each utilizing a different VO2max testing protocol. The first visit consisted of the Bruce protocol test, and the remaining visits entailed a maximal SPV on a treadmill (TM SPV) and a cycle ergometer (CE SPV). RESULTS: There were no differences in VO2max values between the TM SPV and the Bruce protocol tests (55.6 ± 4.9 vs. 56.2 ± 6.8, respectively; p = .510). As expected, the CE SPV (48.3 ± 7.6) was significantly lower than the other two tests (p < .001). CONCLUSION: The TM SPV was as effective in eliciting an accurate VO2max as the Bruce protocol and did so with less incline and in less time suggesting that there are no changes in the limits of VO2max even when the test is self-paced and perceptually regulated.