Dynamics of the Power-Duration Relationship during Intermittent Team Sports Exercise.

Abstract

To 1) determine whether critical power (CP), W' and W' reconstitution kinetics (W' REC ) are altered by high-intensity team-sport specific intermittent exercise; 2) examine the accuracy with which W' balance (W' BAL ) is estimated by the W' BAL model; 3) examine whether physiological variables assessed during ramp incremental exercise and the 3-min all-out test, explain exercise-induced changes in the power-duration relationship. CP, W', and W' REC were determined during a repeated all-out test, which comprised a 3-min all-out test and a 2-min all-out test, separated by 90 s, in 13 recreationally active team-sport players. The test was performed in a rested condition (control) and immediately following a 40-min (40-IST) and 80-min (80-IST) intermittent sprint test. CP assessed after the 40-IST (222 ± 57 W) and 80-IST (213 ± 49 W) were not different from control (222 ± 52 W; P > 0.05). W' REC was also not significantly different from control (0.08 ± 0.02 kJ·s -2 ) after the 40-IST (0.07 ± 0.02 kJ·s -2 ) or 80-IST (0.07 ± 0.02 kJ·s -2 ; P > 0.05). W' was lower than control (13.5 ± 4.0 kJ) after the 40-IST (10.1 ± 4.0 kJ) and 80-IST (9.1 ± 3.5 kJ) (both P < 0.05). After the 40-IST, W' BAL was not significantly different from the value predicted from the W' BAL model (10.9 ± 2.4 kJ; P > 0.05), but W' BAL was overestimated by the model following the 80-IST (10.7 ± 2.6 kJ; P < 0.05). There were considerable interindividual differences in the changes in the power-duration relationship following exercise, which were not related to physiological variables assessed in the control condition. CP and W' REC are not altered after intermittent exercise, but W' is decreased, with considerable heterogeneity in the changes in the power-duration relationship between individuals. These results have important implications for the application of the W' BAL model to describe intermittent exercise performance.