Managing and Monitoring Fatigue in Baseball Players


How to Manage Ballplayers In-Season

It’s the most wonderful season of the year: BASEBALL SEASON!

You just dedicated an entire winter to get bigger, faster, and stronger both in the weight room and the cage/mound.

Now, it is time to apply those gains to the field where it matters the most!

However, an important training variable to consider is recovery. For the professional and the high-school athlete, baseball season is very long and gruesome.

Although there is a ton of research on increasing on-field performance, there is not a lot on monitoring fatigue in baseball players!

Therefore, we must monitor our players from head to toe, day in and day out.

Here are some ways we can monitor our athlete’s performance.


For a pitcher, one of the most important variables to continually train for is throwing velocity, and it is important to continually grow.

We must be cognizant of what the athlete’s body is capable of when it comes to high-performance throwing.

By tracking pitching velocity throughout the season, we can see if the athlete is staying around his “average”, or deviating below that average.

Continuous research shows that a decrease in in-season throwing velocity may be a sign of chronic fatigue. When comparing the first 2 innings to the athlete’s last 2 innings, velocity drops off.

When a pitcher becomes fatigued during the game, he must compensate to maintain his performance, which can be troublesome.

Along with throwing velocity, throwing mechanics also change when a pitcher is fatigued. Previous research has demonstrated that fatigued pitchers show decreased trunk flexion (getting the ‘nose over the toes’), which puts unneeded stress on the throwing elbow.

Notable changes in trunk flexion can also change the kinematics of the entire throwing motion.

For example, there is a decreased range of motion in both the shoulder and knee joint (on the plant foot).

A decrease in throwing velocity over the course of the season may be due to an accumulation of innings pitched; and, more specifically, the amount of pitches being thrown.

By tracking average pitch counts for each pitcher, we can closely monitor the amount that each pitcher should be throwing, or not be throwing in a game.

There is a negative correlation between pitch counts and performance: the higher the pitch count (above the average), the lower the chance that performance will be up-to-par.

However, thanks to ASMI, we have a generalized chart to follow that relates the amount of pitches thrown to days of rest needed.

Screen Shot 2017-03-27 at 2.15.12 PM

From PitchSmart

As a coach, I found that by sticking to pitch counts and physically looking at the mechanics of my pitcher throughout the game, I’m able to see how many pitches he can throw before his mechanics start to die down.

This way, I’m also able to individualize the amount of pitches he can throw leading up to his next outing, and the amount of days of rest that he needs.

Performance can also be an indicator of fatigue. Not only on-field performance, but test-based performance as well.

For example, some research shows that a decrease in vertical jump height may be a sign of chronic fatigue, as this relates to rate of force development (which is a huge proponent in baseball performance).

The vertical jump may not be the most specific to the game of baseball. Thanks to Graeme Lehman, we know that the lateral broad jump is much more specific to the game of baseball. We can use this test on a weekly basis since it is quick and simple!


This may be the most important: ASK YOUR ATHLETE!

We can obtain all this cool objective data, but sometimes it may not mean much. When we get subjective experiences from players, it can make all the difference.

It also shows your players that you truly care about how they feel.

Before every summer game, I asked every one of my players how they felt on a scale of 1-10 (perceived recovery status, or PRS).

A 1 is equivalent to saying, “I feel like crap” and a 10 is equivalent to “I feel like I can run a marathon” (not exactly, I’m exaggerating a bit). You get the point!

There is some interesting research showing that we can predict an individual’s performance based on the grouping of his/her PRS.

For example, between 0 and 2, you should expect a decline in performance; between a 4 and 6, you should expect similar performance; between a 7 and 10, you should expect improved performance.

This specific labeling of data has been used in heavy resistance training research, and hasn’t been validated from a practical standpoint. However, I still see some value to it.

I digress…

There was one game when I had to choose between which two pitchers I wanted to start in the game. I based my decision on how ready and how recovered each player felt.

For example, “yeah coach, I’m like an 8 today” compared to the player who told me a “6” …” that’s it, you’re on the bump” I said.

Anyway, we can also use session rating of perceived exertion (RPE). Although used mostly in aerobic and anaerobic training research, it has some sort of carry over to the field.

Using RPE may be a way to quantify how your player is feeling at the end of the game. Over time, you can correlate this data point to his PRS!

To create a specific number, multiply your players verbal number (how they feel after the game) by the duration of the game (in minutes).

The Science-y Stuff

These specific metrics may not be practical to the average baseball player. However, I believe it is still of importance for you to read and learn about.

When we weigh ourselves, the number output is simply how fast we are accelerating into the ground thanks to gravity. An increase or decrease in this number doesn’t tell us a whole lot of information.

However, when we use body composition measurements, we get a better “microscopic” view of what may be going on inside the body.

Specifically, we want to look at fat-free mass and fat mass. Due to a very long season, a decrease in body mass may be coming from either one of these sources. It would be nice if there was a way to measure this…oh wait…


Skin folds and small bioimpedance machines can help us out.

In simple terms, skin fold measurements allow the individual to compute fat mass and fat-free mass. The more data you collect, the greater the possibility for trends to occur.

To make things simple, use the 3-site test. Based on the viewing of this article, I could either write a separate article on how to perform the test, or I can email you step-by-step directions.

A hand-held bioimpedance machine can range anywhere from $35-50 on the internet. Although it is not the most accurate measurement for body fat percentage (± 3.5%) as there are a host of factors that can manipulate the results, it is still a very simple and timely way to assess body composition.

Another avenue to take is grip strength. Research has shown that overall readiness and chronic levels of fatigue can be “labeled” with grip strength numbers on a dynamometer. I would like to play around this idea with all of the kids I coach and see if there are any correlations between RPE and grip strength.


The author of the article I am referencing brings up another interesting topic in managing fatigue. There is no literature on specific indicators of fatigue for position players.

However, he mentions that one variable that we can look at is running speed. It seems great and all, but is it practical to measure running times during the game when we have so many other important things to be focusing on?

Possibly, this can be a job for one of the parents that watch in the bleachers.

The only metrics that I would even want to keep track of is home-to-first, stolen bases, and first-to-third. Most importantly, we can train for decreasing steal time.

By monitoring pitch counts, RPE and PRS, throwing velocity, performance and performance tests, and body composition, we may be on the right track in monitoring and managing fatigue in baseball players!

Stay healthy,

Jarad Vollkommer, CSCS


Suchomel, T.J. (2014). Monitoring and managing fatigue in baseball players. Journal of Strength and Conditioning Research 36(16), 39-45.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s