This study compared anaerobic threshold (AT) obtained using a non-invasive protocol and one that involved lactate measures. Male endurance runners (N = 7) performed two different tests to identify AT. The first consisted of an all-out 500-m run, eight minutes rest, and 6 x 800-m at increasing velocities separated by one minute for lactate sampling to record a lactate minimum velocity. The second test consisted of increasing velocity every 200 m. The velocity associated with a downward deflection in heart rate defined the AT (Conconi). Direct lactate measures demonstrated an AT at a slower velocity than the Conconi protocol. To further validate the measures Ss attempted to run for 30 minutes at lactate minimum velocity and at the Conconi AT. At lactate minimum velocity Ss achieved a lactate steady state and completed the run. At AT athletes lasted a little more than six minutes and lactate values exceeded 6 mM. Implication. The Conconi test yields performance velocities that are greater than threshold based on lactate. It overestimates a sustainable velocity whereas the lactate minimum velocity describes a velocity that can be sustained and a steady-state achieved.
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