Watts, P. B., Jensen, R. L., Gannon, E., Harney, R., & Kobienia, R. (1998). Protocol duration effect on lactate threshold during intermittent cycle ergometry. Medicine and Science in Sports and Exercise, 30(5), Supplement abstract 1863.

This study determined if stage duration had an effect on lactate threshold determination during intermittent graded exercise testing on a cycle ergometer. Ss (N = 13) completed incremental cycle ergometry tests with stage durations of two, four, and six minutes.

It was found that stage durations of two minutes or less resulted in an overestimation of lactate threshold expressed as absolute power output. The criteria for determining lactate threshold with either (1) as the first increase of 1.0 mmol/l after which blood lactate accumulation continued to increase by 1.0 mmol/l or greater, or (2) as the point at which blood lactate accumulation first attained or exceeded 4.0 mmol/l, influenced the threshold value regardless of the mode of expression or protocol stage duration.

Implication. Lactate threshold values will differ with different durations of incremental steps. The criteria used to determine the lactate threshold will affect the threshold value. Lactate threshold values are largely a matter of the protocol used and the criteria established for declaring a threshold. Without such knowledge the absolute value of a lactate threshold is meaningless and unreliable.

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