Effects of Priming Exercise on (V) over dotO2 Kinetics and the Power-Duration Relationship

BURNLEY, M., G. DAVISON, and J. R. BAKER. Effects of Priming Exercise on (V) over dotO(2) Kinetics and the Power-Duration Relationship. Med. Sci. Sports Exerc., Vol. 43, No. 11, pp. 2171-2179, 2011. Purpose: This study aimed to investigate the influence of prior heavy- and severe-intensity exercise on the oxygen uptake ((V) over dotO(2)) kinetics and the power-duration relationship. Methods: Ten cyclists performed 13 exercise tests during a 4-wk period, consisting of a ramp test to determine the gas exchange threshold (GET) and the peak (V) over dotO(2), followed by a series of square-wave tests to exhaustion under three conditions: no prior exercise (control), prior heavy exercise (6 min at a work rate above GET but below critical power [CP)], and prior severe exercise (6 min at a work rate above the CP). Pulmonary gas exchange was measured throughout the exhaustive exercise bouts and the parameters of the power-duration relationship (CP and the curvature constant, W') were determined from the linear work-time model. Results: Prior heavy exercise increased the amplitude of the primary (V) over dotO(2) response (by similar to 0.19 +/- 0.28 L.min(-1), P = 0.001), reduced the (V) over dotO(2) slow component trajectory (by 0.04 +/- 0.09 L.min(-2), P = 0.002), and increased the time to exhaustion (by similar to 52 +/- 92 s, P = 0.005). The CP was unchanged (control vs prior heavy: 284 +/- 47 vs 283 +/- 44 W; 95% confidence interval, -7 to 5 W), whereas the W' was increased by heavy-intensity priming (16.0 +/- 4.8 vs 18.7 +/- 4.8 kJ; 95% confidence interval, 0.3-5.2 kJ). Severe-intensity exercise had a similar effect on the (V) over dotO(2) kinetics but had no effect on the time to exhaustion, the CP (275 +/- 45 W), or the W' (16.7 +/- 4.7 kJ). Conclusions: Prior heavy-intensity exercise primes the (V) over dotO(2) kinetics and increases the amount of work that can be performed above the CP.