Energy system contribution during 200- to 1500-m running in highly trained athletes

<b>Purpose</b>: The purpose of the present study was to profile the aerobic and anaerobic energy system contribution during high-speed treadmill exercise that simulated 200-, 400-, 800-, and 1500-m track running events.<br /><br /><b>Methods</b>: Twenty highly trained athletes (Australian National Standard) participated in the study, specializing in either the 200-m (<i>N</i> = 3), 400-m (<i>N</i> = 6), 800-m (<i>N</i> = 5), or 1500-m (<i>N</i> = 6) event (mean O₂ peak [mL·kg^-1·min^-1] ± SD = 56 ± 2, 59 ± 1, 67 ± 1, and 72 ± 2, respectively). The relative aerobic and anaerobic energy system contribution was calculated using the accumulated oxygen deficit (AOD) method.<br /><br /><b>Results</b>: The relative contribution of the aerobic energy system to the 200-, 400-, 800-, and 1500-m events was 29 ± 4, 43 ± 1, 66 ± 2, and 84 ± 1% ± SD, respectively. The size of the AOD increased with event duration during the 200-, 400-, and 800-m events (30.4 ± 2.3, 41.3 ± 1.0, and 48.1 ± 4.5 mL·kg^-1, respectively), but no further increase was seen in the 1500-m event (47.1 ± 3.8 mL·kg^-1). The crossover to predominantly aerobic energy system supply occurred between 15 and 30 s for the 400-, 800-, and 1500-m events.<br /><br /><b>Conclusions</b>: These results suggest that the relative contribution of the aerobic energy system during track running events is considerable and greater than traditionally thought.<br />