Nau, K. L., Foster, E. S., Lindsey, K. R., Moritz, A. S., Summers, C. A., & Potteiger, J. A. (1997). Blood lactate concentration and perceived exertion differ after equivalent isokinetic work at three velocities. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 1220.

The responses of blood lactate concentration and rating of perceived exertion to bouts of isokinetic exercise in which the velocity, number of repetitions, and resistive load differed were studies.

Females (N = 35) completed as many repetitions as necessary to approximate 2600 J of work during three velocities (60, 180, 300 degrees/sec) of right knee flexion and extension on an isokinetic dynamometer.

Lactate was principally influenced by the number of repetitions and speed of contraction (the work done) while perceived exertion was principally influenced by the force and/or duration of the repetitive contractions (the effort exerted).

Implication. Lactate and perceived exertion are influenced by two different sets of factors in women and should not be expected to correlate highly. Perceived exertion is an estimate of how hard was the effort exerted while lactate is an index of the type of and total work done.

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