It is unclear whether physiological measures monitored in an incremental treadmill test during a training season provide useful diagnostic information about changes in distance running performance.
Purpose: To quantify the relationship between changes in physiological measures and performance (peak running speed) over a training season.
Methods: Well-trained distance runners (34 males; VO2max 64 +/- 6 mL x kg(-1) x min(-1), mean +/- SD) completed four incremental treadmill tests over 17 wk. The tests provided values of peak running speed, VO2max, running economy, and lactate threshold (as speed and %VO2max). The physiological measures were included in simple and multiple linear regression models to quantify the relationship between changes in these measures and changes in peak speed.
Results: The typical within-subject variation in peak speed from test to test was 2.5%, whereas those for physiological measures were VO2max (mL x min(-1) x kg(-1)) 3.0%, economy (m x kg x mL(-1)) 3.6%, lactate threshold (%VO2max) 8.7%, and body mass 1.8%. In simple models these typical changes predicted the following changes in performance: VO2max 1.4%, economy 0.8%, lactate threshold -0.3%, and body mass -0.2% (90% confidence limits approximately +/-0.7%); the corresponding correlations with performance were 0.57, 0.33, -0.05, and -0.13 respectively (approximately +/-0.20). In a multiple linear regression model, the contribution of each physiological variable to performance changed little after adjustment for the other variables.
Conclusion: Change in VO2max in an incremental test during a running season is a good predictor of change in peak running speed, change in running economy is a moderate predictor, and lactate threshold and body mass provide little additional information.