Mid Sweden University

The aim of this study was to correlate the anaerobic speed reserve and the maximal speed reserve with the distance capacity above the critical speed ( D '), derived from four different mathematical models, in a group of endurance runners. Twenty-two runners performed an incremental treadmill test to exhaustion, an all-out 40-m sprint and three time trials (800, 1,500 and 3,000 m) on an outdoor running track to determine an anaerobic speed reserve, a maximal speed reserve and D '. D ' was determined using linear distance-time ( D ' linear d - t ), linear velocity-time ( D ' linear 1/ t ), 2-parameter hyperbolic ( D ' 2-hyp) and 3-parameter hyperbolic ( D ' 3-hyp) models. A high correlation was observed between the anaerobic speed reserve and D ' linear 1/ t ( r =0.77; p <0.001), while moderate correlations were observed between the anaerobic speed reserve and D ' linear d - t ( r =0.69; p <0.001) and D ' 2-hyp ( r =0.63; p <0.003). The anaerobic speed reserve was not significantly correlated with D ' 3-hyp. High correlations were detected between the maximal speed reserve and D ' linear 1/ t , D ' linear d - t and D ' 2-hyp ( r =0.74 to 0.76; p <0.001) and a moderate correlation was detected between the maximal speed reserve and D ' 3-hyp ( r =0.58; p =0.01). These moderate- to high correlations with D ', especially when derived from models using two parameters, suggest the existence of similar mechanisms underpinning the variables.