Source notes

The workout written in a plan is not the same thing as the strain experienced by the person doing it. The authors distinguish external load, the work performed, from internal load, the body’s and mind’s response during exercise. Distance, speed, and weight lifted describe the former; heart rate and perceived effort can describe aspects of the latter. Their framework explains why identical sessions can produce different responses between athletes, or for the same athlete on different days. The central argument is to interpret completed work alongside the response it actually produced.

The distinction also depends on timing. In the authors’ terminology, next-day soreness or fatigue describes a consequence of training, not the internal load experienced during it. Those observations can still be useful, but they answer a different question. Likewise, a heart-rate measure that is useful during sustained endurance exercise may be a poor description of the demands of resistance exercise.

How Does This Show Up in Real Life?

Imagine an athlete completing a familiar run at the usual pace, but finding it substantially harder. The distance record says the planned work was completed. The effort report says something different about the experience. Neither record needs to be wrong. The authors argue that putting such information together can help a coach understand how someone is coping, especially when conditions are comparable. The paper does not provide a score that diagnoses fatigue or dictates the next workout. Instead, it changes the question from “Did I complete the session?” to “What did that session demand from me?” This is also why more detailed tracking of movement is not automatically a complete picture of training. The practical contribution is a framework for interpretation, not a personal exercise prescription.

The framework is primarily about athletes, and its proposed benefits are conceptual rather than a measured improvement from testing one monitoring system. Some important internal responses cannot be measured adequately during ordinary training. No single measure captures all demands. The paper does not establish universal thresholds, individual outcome predictions, or lasting benefits from adopting the framework.

Why We Cite It

For Alpekin, this could guide how differences in progress are described. A user should not be labeled a poor responder merely because a prescribed schedule produced less improvement than someone else’s. Alpekin could distinguish uncertainty about the stimulus received from uncertainty about the person’s capacity to adapt, avoiding an unsupported personal judgment.

Take this as a way to make training information more intelligible. A number becomes useful when its meaning and context are clear. The goal is not to collect every possible signal, but to avoid asking a single measurement to answer questions it cannot resolve.