There is a simple description of quantification of training that’s used by coaches and exercise physiologists alike: stress + strain = adaptation. Stress is an external, quantitative measurement of the exercise stimuli or load placed on the body, and strain is the internal response to that stress. When stress is applied, your body undergoes strain. Correctly applied, strain leads to adaptation, both general and specific.
For over fifteen years now, endurance athletes have used Training Stress Score (TSS) to plan, track, and improve fitness by applying a standard measurement in the form of training load. TSS is a measurement of stress and an excellent metric for quantifying the amount of training stress being applied to the system; however, it does not always give insight into the specific strain the body undergoes when stress is applied.
WKO5 introduces a new metric, Training Impact Score (TIS), to help quantify the specific strain the body undergoes in response to applied stress. TIS provides insight into the impact of training on your anaerobic and aerobic energy systems.
What is TIS?
Training Impact Score (TIS) uses your power data and your unique power-duration model to estimate the anaerobic and aerobic system impact of the applied training load of a workout, which provides deeper insight into how the workout will strain each system. Your TIS is based on the specific impact of the workout on your unique physiology. All energy systems contribute to endurance exercise efforts, but to fine tune your training to your unique physiology, it’s important to build a deeper and more specific understanding of the impact/strain on each system during exercise.
Anaerobic Training Impact Score
Training at levels near, at, and above Functional Threshold Power (FTP) results in a significant increase in anaerobic energy demand. Anaerobic Training Impact Score estimates the impact or strain your workout has on your anaerobic system (anaerobic glycolysis).