The number of shoulder and elbow injuries in youth baseball pitchers is on the rise and we consistently see these injuries for performance physical therapy. In response, consistent efforts have been made to better monitor the amount of stress taken by pitchers after each visit to the mound.
For many years, this was done by simply limiting the number of innings an athlete could pitch and setting a specific number of rest days between outings. More recently, pitch counts have become the standard for tracking a pitcher’s workload. However, while this change is an improvement, pitch counts do not tell the entire story.
What pitch count fails to account for is the varying intensities between throws. For example, a throw at 100% effort has a very different intensity than a throw at 50%. This is why efforts have been made in recent years to more accurately track the intensity, or workload, of a pitcher while on the mound.
A Better Method to Track Stress: Workload
According to athletic physical therapy, a more reliable measure of stress is the acute to chronic workload ratio (ACWR). Acute workload refers to the average workload of a single day over the past 9 days, whereas chronic workload refers to the average one-day workload over the past 28 days.
Research by sports scientist Tim Gabbett has shown that spikes in acute workloads, such as quickly increasing pitch count to more than the body is used to, can increase the risk of injury.
Calculating Your ACWR
There are two main ways to calculate the acute to chronic workload ratio.
The first is to use a series of formulas using pitch count and a subjective rating of perceived exertion (RPE), ranging on a scale of 1–10.
- Calculate acute workload by multiplying the number of high-intensity throws (around 70% of full effort or more) by the athlete’s RPE.
- Calculate chronic workload by calculating the weekly acute workload average of the past four weeks.
Once you have the acute and chronic workload, divide the acute workload by the chronic workload to get the ACWR.
The second and perhaps much simpler method is to use wearable technology. For example, in recent years, technology has become available to track the stress on a pitcher more accurately after an outing.
Sensors such as the MotusTHROW can accurately measure the amount of force placed on an athlete’s elbow during each throw. This data can be applied to calculate the ACWR to safely and effectively determine when a pitcher needs rest or is ready for their next high-intensity outing.
If you’d like to learn more about keeping your son or daughter safe on the mound, our experienced athletic physical therapy and injury rehabilitation team in Bethesda can help!