Acute to Chronic Workload Ratio

How much is too much? How much is enough?

When looking at load management, it’s important to be able to measure things objectively.

Research by Tim Gabbett is frequently referenced when it comes to monitoring training load. In this research Gabbett refers to the Acute:Chronic workload ratio. Put simply, this is the ratio between the work load done “today” vs the average workload of the previous 4 weeks.

There are many ways to measure workload to make the calculation. A simple example is to consider a runner.

To calculate the workload for a runner, they can use what is know as the Rate of Perceived Exertion, a subjective score from 0 to 10 which describes the difficulty of the training session as they perceived it. So a light jog might be considered a 4 or 5 out of 10, while a pace run in unfavourable conditions might be recorded as an 8 or 9.

To get a score for the run, we can multiply the RPE by the time of the run. So a difficult half hour pace run would be:

RPE 8 x Time 30min

8 x 30 = 240.

Keeping a training diary or using Garmin/Training Peaks/Strava data, you can build up an average score over 4 weeks.

What the study showed is that there is Acute:Chronic ratio “sweet spot” between 0.8 and 1.3. Not enough training can increase risk of injury as can spikes in training load.