Predicted and actual exercise discomfort in middle school children

The purpose of this study was to use a match-mismatch paradigm to examine children's exercise discomfort during an aerobic shuttle run. Thirty-four middle school females (n = 18) and males (n = 16) aged 11-14 yr participated. An Exercise Discomfort Index (EDI) was calculated as a rating of perceived exertion for the overall body (Children's OMNI Scale) x a rating of perceived muscle hurt (Children's OMNI Muscle Hurt Scale). Measurements were obtained immediately before (i.e., predicted) and after (i.e., actual) performance of the nationally standardized Progressive Aerobic Cardiovascular Endurance Run (PACER) shuttle test of aerobic fitness. Self-report physical activity and sport participation history were obtained before PACER performance. Two-way ANOVA (gender x assessment time point) showed a significant main effect for assessment time point: predicted EDI (means +/- SD = 25.9 +/- 20.1) was greater than actual EDI (means +/- SD = 19.4 +/- 17.8) for the total group (P = 0.021). However, neither the main effect of gender nor the gender x assessment time point interaction was significant. Idiographic analysis showed that overpredictors of discomfort reported less time (5.25 median h x wk(-1)) and engaged in less recreational activity than underpredictors (11.14 median h x wk(-1)). However, no significant relation (P = 0.508) was observed between PACER laps completed and exercise discomfort. The sample of middle school children in this study predicted greater exercise discomfort than actually experienced when performing a PACER test. It is possible that a discomfort construct plays an important role in the initiation and maintenance of children's aerobic exercise, providing a basis for physical activity interventions.