Comparison of 3km time-trial and 20m shuttle run test in the determination of maximal aerobic speed for aerobic endurance training

Maximal aerobic speed (MAS) is often used as a prescriptive tool for aerobic training. The primary aim of this study was to compare MAS determined using a 3km Time-Trial (3kmTT) and a 20m shuttle run test (SRT), with a secondary aim of deriving an equation that would enable the estimation of 3kmTT MAS from a SRT MAS. Seventy three male youth Australian Rules Football players (18.9 ± 1.4 years, 188.5 ± 8.0cm, and 82.3 ± 10.1kg) completed a 3kmTT and SRT and from this MAS was determined as the average speed for the 3kmTT and peak speed for the SRT. MAS determined by the 3kmTT (4.55 ± 0.29ms^-1) was significantly faster (p < 0.001) than SRT MAS (4.12 ± 0.13ms^-1), although they were strongly related (r = 0.90). Using linear regression we established an equation to predict 3kmTT MAS from SRT MAS [Predicted- 3kmTT MAS = (1.9555 x SRT MAS) - 3.503]. Using the equation, Predicted- 3kmTT MAS (4.55 ± 0.26 ms^-1) was not significantly different to actual 3kmTT MAS (p > 0.05). 95% Limits of agreement from Bland-Altman analysis between Predicted-3kmTT MAS and actual 3kmTT MAS were ± 0.24 ms^-1. In conclusion, despite a significant correlation, SRT MAS values were significantly slower than 3kmTT MAS. If players have only completed a SRT, 3kmTT MAS may be predicted with acceptable limits of agreement from SRT MAS.