Two Wheel Blogs

TSB = Training Stress Balance

TSB is a metric, a number, intended to provide an estimate of your performance ability on a given day.

TSB is the difference between your long term, or chronic, training load (CTL) and your short term training load, also known as acute training load (ATL)

Think of your CTL as your base of fitness. Your CTL number roughly corresponds to your attained ability to do work over a long period of time. An untrained cyclist, having done little or no work, will have a low CTL. A single cycling workout may require significant rest and recovery time. A trained cyclist, on the other hand, will be able to do larger amounts of work repeatedly, and with less need for prolonged recovery. The trained cyclist has accumulated a base of fitness which allows him to absorb a greater training load each day.

But even a trained cyclist will succumb to a larger than average training load applied too often. A cyclist accustomed to riding 25km per day at a given output level won't be able to suddenly increase his training load to 50km per day at the same intensity. He might be able to do it for a short time, but within days he would need to lighten his training load.

The increase from 25km per day to 50km per day at the same intensity level represents a doubling of the cyclist's near-term, or acute training load. When recent training levels have been higher than usual, relative to our longer term training load levels, we feel tired and we need recovery. After a short span of lighter than normal training we feel fresh again.

TSB is an approximation of that near-term (ATL) vs. long-term (CTL) relationship. A positive TSB indicates recent training has been light when compared to the level of training we've become conditioned to. A positive TSB therefore indicates a high probability we'll be able to perform at a high level. A negative TSB indicates we've taken on heavier recent training loads than those we're conditioned to, meaning decreased chances if outstanding performance and increasing need for recovery.