Foster, C., Fitzgerald, D. J., & Spatz, P. (1999). Stability of the blood lactate-heart rate relationships in competitive athletes. Medicine and Science in Sports and Exercise, 31, 578-582.

Speed skaters (M = 7; F = 6) were assessed during a deconditioned and conditioned phase of annual training. Cycle ergometry was used to assess work, heart rate, and ratings of perceived exertion at aerobic and anaerobic thresholds and during maximal exercise (a 3,000-m time-trial for females and a 5,000-m time-trial for males).

Physiological levels of training response changed between the two phases. However, neither heart rates at various thresholds nor ratings of perceived exertion were different between phases.

It was concluded that a single well-conducted evaluation may allow evaluation of training markers (e.g., heart rates and RPE) that may be longitudinally stable.

Some consideration of the inferences from this study is worthwhile.

Using elite athletes, this study showed that submaximal and maximal heart rates do not change appreciably with in- and out-of season trained states. Thus, using HR alone as the marker of training intensity (e.g., using heart rate monitors) will not tell an individual anything about the value of training or overload in any training phase. It is only when performance changes occur at a particular heart rate can any meaningful inference be made. However, this stability is not a characteristic of individuals who allow their trained states to differ quite considerably (e.g., "serious" recreational athletes). One should not use heart rates as an index of training intensity with elite athletes.

One should never expect ratings of perceived exertion to change with training phases unless they too are coupled with performance levels. RPEs are relative to an individual's perception of maximum effort and are therefore independent of the trained state or different performances levels across time. An individual will "try as hard as possible" and record a high RPE whether trained or untrained. One should not expect any difference. Using RPE as an index of "level of effort" will always be valid no matter what the performance standard or trained state of an individual or whether an elite or non-elite athlete.

That various thresholds of training change with training is not new. However, they are proving to be somewhat less valuable than once thought. It is now known that the aerobic threshold is only pertinent when individuals are in transition from an untrained to a trained state. It is not a concept for use with elite athletes who are normally in a relatively high state of general fitness no matter what time or phase of the year. It is also known that the level of work at the anaerobic threshold is not intense enough to produce any meaningful change in performance amplitude. Training stimuli/overloads have to be more intense than indicated at AnT.

Implications. Physiological indices of various thresholds change between out-of- and in-season training. Heart rates at those thresholds do not change. RPEs remain consistent indicators of work levels no matter what the phase of training. Both heart rates and RPEs are not particularly meaningful unless they are accompanied by some measure of performance. Since performance is a more valid index of performance change one should question why even measure heart rates or rate perceptions of effort.

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