After collaborating with Major League Baseball on the largest performance study in professional sports history, WHOOP presented the results at the recent MLB Winter Meetings in National Harbor, MD. Via, Philadelphia Phillies General Manager Matt Klentak said the following about his organization’s use of WHOOP:

“That’s a new technology that was pitched to us last summer that we decided to invest in to try, ultimately, to keep our players healthy and to learn more about different ways to optimize their performance. It’s about objectivity and making better decisions. It’s not just about batting average and earned run average and on-field performance. It’s whatever data we can acquire that helps us make better decisions. … We’ve actually had some pretty interesting results about players who can learn about their own sleeping habits and ways they’ve been able to identify to keep themselves healthier and perform better. We’ll base whatever conclusions we make on what the data dictates. We’re still very much in the early phases of this. We’re still learning about it. But so far it’s provided some interesting developments.”

As Klentak pointed out in reference to his ballclub, there is still much to learn from athletes using WHOOP. In fact, we’re just scratching the surface of what we can find out.

Some of the most exciting possibilities for further research stem from what we discovered when comparing minor league baseball players’ WHOOP Recovery with data obtained from TrackMan (radar technology used by MLB and in some minor league parks) regarding pitch speeds and the velocity of the ball off the bat.

Below is a chart depicting players’ adjusted fastball speeds (the average velocity of the top 10% of a pitcher’s fastballs in that game vs. the same metric for the entire season) compared to their Recovery (on a scale of 0-100) on the day they took the mound:


The amount of data available for this analysis was minimal. However, within the small sample size there is a positive relationship between Recovery and fastball performance.

We saw something similar when examining the speed of the ball off the bat (only instances of line drives hit off fastballs were taken into account):


Like with pitchers’ fastballs, the exit velocity of batters’ line drives relative to their season averages were also faster when the players’ Recoveries were higher.

Some athletes were more sensitive to changes in Recovery than others, but it’s exciting that every player had a positive slope–they all performed better when their Recoveries were higher.

It’s very possible that this relationship isn’t actually linear. For example, some pitchers may be able to reach their peak fastball speed as long as their Recovery is above a certain level. Or, conversely, some hitters’ power might drop off dramatically only when their Recovery is extremely low.

These findings suggest the need for further research. If we can identify why some athletes are more sensitive to Recovery changes than others, we can better target those who would benefit most.

Previous Locker posts on the WHOOP MLB Performance Study:

Introduction: WHOOP and MLB Conduct Largest Performance Study Ever in Pro Sports

Part 1: Effects of Travel

Part 2: Athletes in the Outfield

Part 3: Empower Athletes, Improve Their Fitness