Maximal endurance time at VO2max

Introduction: There has been significant recent interest in the minimal run ning velocity which elicits (V) over dot (2max). There also exists a maxima l velocity, beyond which the subject becomes exhausted before (V) over dot (2max) reached. Between these limits, there must be some velocity that perm its maximum endurance at (V) over dot (2max), and this parameter has also b een of recent interest. This study was undertaken to model the system and i nvestigate these parameters. Methods: We model the bioenergetic process bas ed on a two-component (aerobic and anaerobic) energy system, a two-componen t (fast and slow) oxygen uptake system, and a linear control system for max imal attainable velocity resulting from declining anaerobic reserves as exe rcise proceeds. Ten male subjects each undertook four trials in random orde r, running until exhaustion at velocities corresponding to 90, 100, 120, an d 140% of the minimum velocity estimated as bring required to elicit their individual (V) over dot (2max). Results: The model development produces a s kewed curve for endurance time at (V) over dot (2max), with a single maximu m. This curve has been successfully fitted to endurance data collected from all 10 subjects (R-2 = 0.821, P < 0.001). For this group of subjects, the maximal endurance time at (V) over dot (2max) can be achieved running at a pace corresponding to 88% of the minimal velocity, which elicits (V) over d ot (2max) as measured in an incremental running test. Average maximal endur ance at (V) over dot (2max) is predicted to be 603 a in a total endurance t ime of 1024 s at this velocity. Conclusion: Endurance time (V) over dot (2m ax) can be realistically modeled by a curve, which permits estimation of se veral parameters of interest; such as the minimal running velocity sufficie nt to elicit (V) over dot (2max), and that velocity for which endurance at (V) over dot (2max) is the longest.