Does Reactivity To Accelerometry Occur In A Single Swimming Trial? A Randomized, Crossover Study

Abstract

PURPOSE: Recent research has suggested that awareness of being monitored can influence the habitual physical activity behaviour of participants. This reactivity effect appears to also occur in single bouts of physical activity. However, it is presently unknown whether this acute reactivity effect exists in aquatic environments. The purpose of this study was, therefore, to test the hypothesis that reactivity would also occur in water-based studies. METHODS: Fifty-six healthy, recreational swimmers (31 men, age 22 ± 2 yr; 25 women, age 22 ± 1 yr) volunteered to participate in this ethically approved study. On two separate occasions, the participants randomly completed a 20-min swimming bout at a self-selected pace wearing (A) or not wearing (NA) a head-mounted accelerometer. Evidence of reactivity was defined as a statistically significant change in swimming distance covered (in m) in the A condition compared with the NA condition. Situational motivation, perceived performance, and perceived exertion were also assessed in both A and NA conditions. RESULTS: Swimming distance covered was longer (829 ± 202 vs. 811 ± 204 m) and perceived exertion was more strenuous (13.0 ± 2.4 vs. 12.2 ± 2.1) during the A condition compared with the NA condition (P < 0.05). Perceived performance and situational motivation were not significantly different between conditions (P > 0.05). CONCLUSIONS: These results indicate that the acute reactivity effect is likely to be present in aquatic environments and may threaten the internal validity of physical activity assessments in water-based studies.