Effect of warm-up on cycle time trial performance

Purpose: This study was designed to determine the effect of warm-up on 3-km cycling time trial (TT) performance, and the influence of accelerated VO2 kinetics on such effect. Methods: Eight well-trained road cyclists, habituated to 3-km time trials, performed randomly ordered 3-km TT after a) no warm-up (NWU), b) easy warm-up (EWU) (15 min comprised of 5-min segments at 70, 80, and 90% of ventilatory threshold (VT) followed by 2 min of rest), or c) hard warm-up (HWU) (15 min comprised of 5-min segments at 70, 80, and 90% VT, plus 3 min at the respiratory compensation threshold (RCT) followed by 6 min of rest) VO2 and power output (SRM), aerobic and anaerobic energy contributions, and VO2 kinetics (mean response time to 63% of the VO2 observed at 2 km) were determined throughout each TT. Results: Three-kilometer TT performance was (P < 0.05) improved for both EWU (266.8 +/- 12.0 s) (-2.8%) and HWU (267.3 +/- 10.4 s) (-2.6%) versus NWU (274.4 +/- 12.1 s). The gain in performance was predominantly during the first 1000 in in both EWU (48% of gain) and HWU (53% of gain). This reflected a higher power output during the first 1000 in in both EWU (384 W) and HWU warm-up (386 W) versus NWU (344 W) trials. The mean response time was faster in both EWU (45 +/- 10 s) and HWU (41 +/- 12 s) versus NWU (52 +/- 13 s) trials. There were no differences in anaerobic power output during the trials, but aerobic power output during the first 1000 in was larger during both EWU (203 W) and HWU (208 W) versus NWU (163 W) trials. Conclusions: During endurance events of intermediate duration (4-5 min), performance is enhanced by warm-up irrespective of warm-up intensity. The improved performance is related to an acceleration Of VO2 kinetics.