Prior Exercise Impairs Subsequent Performance in an Intensity- and Duration-dependent Manner

Prior constant-load exercise performed for 30-min at or above maximal lactate steady state (MLSS) significantly impairs subsequent time-to-task failure (TTF) compared with TTF performed without prior exercise. We tested the hypothesis that TTF would decrease in relation to the intensity and the duration of prior exercise compared with a baseline TTF trial. Eleven individuals (6 males, 5 females, aged 28 ± 8 yrs) completed the following tests on a cycle ergometer (randomly assigned after MLSS was determined): () a ramp-incremental test; () a baseline TTF trial performed at 80% of peak power (TTF); () five 30-min constant-PO rides at 5% below lactate threshold (LT), halfway between LT and MLSS (Delta), 5% below MLSS (MLSS), MLSS, and 5% above MLSS (MLSS); and () 15- and 45-min rides at MLSS (MLSS and MLSS, respectively). Each condition was immediately followed by a TTF trial at 80% of peak power. Compared with TTF (330 ± 52 s), there was 8.0 ± 24.1, 23.6 ± 20.2, 41.0 ± 14.8, 52.2 ± 18.9, and 75.4 ± 7.4% reduction in TTF following LT, Delta, MLSS, MLSS, and MLSS, respectively. Following MLSS and MLSS there were 29.0 ± 20.1 and 69.4 ± 19.6% reductions in TTF, respectively ( < 0.05). It is concluded that TTF is reduced following prior exercise of varying duration at MLSS and at submaximal intensities below MLSS. Prior constant-PO exercise, performed at intensities below MLSS, reduces subsequent TTF performance. Subsequent TTF performance is reduced in a linear fashion following an increase in the duration of constant-PO exercise at MLSS