Effect of Prior Exercise above and below Critical Power on Exercise to Exhaustion


Medicine & Science in Sports & Exercise: May 2005 - Volume 37 - Issue 5 - pp 775-781
Basic Sciences: Original Investigations

Purpose: The aim of the present study was to ascertain whether the intensity of prior exercise altered the time to exhaustion at critical power (CP).

Methods: Eleven participants volunteered to take part in the study (mean ± SD: V̇O2max 4.1 ± 0.5 L·min−1; age 30.1 ± 7.2 yr; body mass 74.6 ± 9.1 kg) and completed three trials to exhaustion at their CP under differing prior exercise conditions: 1) a control trial (CON); 2) a trial preceded by three 60-s efforts at 110% CP (severe); and 3) a trial preceded by three 73-s efforts at 90% CP (heavy). All trials followed a 5-min baseline at 50 W.

Results: Time to exhaustion was significantly lengthened after prior heavy exercise (1071 ± 18 s) when compared with CON (973 ± 16 s, F = 9.53, P = 0.006). However, there was no effect on TTE after prior severe exercise (967 ± 16 s). Oxygen deficit was significantly reduced from that in CON (3.8 ± 0.2 L) after prior heavy (3.2 ± 0.3 L) and prior severe exercise (3.1 ± 0.3 L, F = 10.95, P = 0.001). Concurrently, there was a significant reduction in the magnitude of the V̇O2 slow component (SC) in the trials with prior exercise (197 ± 34 and 126 ± 19 mL·min−1 after heavy and severe exercise, respectively) when compared with CON (223 ± 31 mL·min−1, F = 9.62, P = 0.006).

Conclusion: Prior heavy exercise does appear to improve the time to exhaustion at CP by ∼10% and is associated with a reduction in the V̇O2 SC. However, the reduction in the SC, with no change in performance after prior severe exercise, suggests that a reduced SC may not necessarily lead to improved TTE.

1Chelsea School Research Centre, University of Brighton, Eastbourne, UNITED KINGDOM; and 2Laboratory of Human Movement Studies, Faculty of Sports Sciences and Physical Education, University of Lille, FRANCE

Address for correspondence: Helen Carter, Ph.D., Chelsea School Research Centre, University of Brighton, Gaudick Road, Eastbourne, BN20 7SP, United Kingdom; E-mail: H.Carter@bton.ac.uk.

Submitted for publication July 2004.

Accepted for publication January 2005.

©2005The American College of Sports Medicine