Modeling Intermittent Running from a Single-visit Field Test

This study assessed whether the distance-time relationship could be modeled to predict time to exhaustion (TTE) during intermittent running. 13 male distance runners (age: 33 +/- 14 years) completed a field test and 3 interval tests on an outdoor 400m athletic track. Field-tests involved trials over 3600m, 2400m and 1200m with a 30-min rest between each run. Interval tests consisted of: 1000m at 107% of CS with 200m at 95% CS; 600m at 110% of CS with 200m at 90% CS; 200m at 150% of CS with 200m at 80% CS. Interval sessions were separated by 24h recovery. Field-test CS and D were applied to linear and non-linear models to estimate the point of interval session termination. Actual and predicted TTE using the linear model were not significantly different in the 1000m and 600m trials. Actual TTE was significantly lower (P=0.01) than predicted TTE in the 200m trial. Typical error was high across the trials (range 334-1709s). The mean balance of D remaining at interval session termination was significantly lower when estimated from the non-linear model (-21.2 vs. 13.4m, P<0.01), however no closer to zero than the linear model. Neither the linear or non-linear model could closely predict TTE during intermittent running.