Acute to Chronic Workload Ratio – new Sonda Sports system feature

Monitoring physical activity is the key to determine the right workload and minimize injury risk. It is easy to do with the help of sports tracking equipment as it provides a precise overview of an athlete’s condition. Calculating injury risk was always one of our main priorities and we’ve been working on a great new addition to the system statistics that will shed new light on workload. This feature is Acute:Chronic Workload Ratio – Exponentially Weighted Moving Averages (EWMA).

Calculating the Acute to Chronic Workload Ratio

To determine the acute to chronic workload ratio, it is crucial to first define what acute and chronic types of activity are. Acute workload is the current workload of an athlete, whilst chronic workload describes all the activities that the athlete’s tracking system recorded recently. To calculate ACWR, we take 3-7 days of activities for the acute workload and 21-42 days of activities for the chronic workload.

Interpretation of ACWR

To fully explain the meaning of ACWR, we would like to present a study showing workload changes in time. Increased volume and intensity of training have an undoubted influence on increased injury risk, while a lack of workload makes the athlete unprepared for the game. Finding a balance between the two is probably the biggest challenge every coach has to face. We have come up with ACWR to make this task easier.

Values of ACWR:

< 0.80 – the athlete is undertrained, injury risk increases

0.80 – 1.30 – ideal workload, low injury risk

1.50 – the athlete is overtrained, the risk of injury increases

Acute to Chronic Workload Ratio in the system –  how to start

In order to use the ACWR feature in Sonda Sports system, take the following steps:

Start day: choose the first day of your activities. You can pick any of the last 90 days

Chronic day: choose the time range of the training mesocycle (usually 3-6 weeks)

Acute day: choose the time range of the training microcycle (usually 3-9 days)

Player: pick one of your players.

Parameter: pick the parameter which you want ACWR to be based on (Total distance, Player Load, TRIMP, Sprints, Sprints by distance, External efficiency, Internal efficiency).

Once you have set everything, the system will generate a graph showing the acute to chronic workload ratio.