Changes

There are various ways of measuring the impact of exercise and these measures are often termed "training impulse", or TRIMP ('''TR'''aining '''IMP'''ulse). The simplest approach is to use training volume (mileage or time), but it is better to use heart rate. There are various heart rate methods to establish training load with varying degrees of complexity and sophistication. It is also possible to use perceived exertion or other metrics. It should be remembered that [[All models are wrong]], especially when we are trying to model something as sophisticated as the human body. Running at an easy pace for a long distance creates different training stresses from a shorter distance at a high intensity, and the two cannot really be equated in a usable model. However, some metric is important if we are to evaluate and understand a training program. TRIMP can be used to calculate [[Training Stress Balance]], a method for evaluating the effect of training over time.