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Lower Extremity Strength and Recovery Time in Youth Baseball Pitchers: A Pilot Study

I was very intrigued by coming across this study for many reason. One big reason was the fact that it was more research on youth baseball!

With the amount that these young kids are playing, they are really putting a toll on their body, and it will soon catch up to them as they begin to develop.

In Little League, there are specific pitching guidelines that pitchers have to follow (Pitch Smart listed below). With that being said, anything above 75 pitches will require 4 days of rest. In some of my previous posts about workload, we understand that it’s more than just pitch counts, and the biggest reason why is central nervous system fatigue.

This study mainly focused on recovery times. Are youth pitchers really able to pitch again after a sub maximal pitch count?


Previous research looked at upper extremity strength in teenage pitchers after a bout of pitching (100 pitches). Like other studies, the researchers noticed a drop off in velocity paired with an alteration in mechanics.

In this same study, the researchers noticed a significant drop off in isometric shoulder strength in multiple muscle groups, and concluded that at least 3 days of rest were needed before another pitching performance.

Even I think that they were being a little too generous with those results, especially after 100 pitches.

When studying the lower body in pitching, it has been shown that a lack of lumbopelvic control was associated with increased injury rates and more days missed in professional baseball pitchers. Interestingly, those with greater lumbopelvic control had a lower WHIP and higher innings pitched. Basically, these pitchers were healthier because they used their body better.

However, these metrics have not been studied in the youth population, which is where this study came about.


15 pitchers (ages 8-11) from a local little league participated in this study. Since little league has pitch limits, they used the player’s birth date from the previous season as their determined maximal pitch count.

The pitchers completed a lower extremity manual muscle testing (MMT) immediately before and after a bout of pitching. The same MMT was performed every day for the following 4 days in order to determine when these strength levels would return back to baseline.

*Since this was a pilot study, I’m interested to see in the future if there will be an experimental group who performs a strength and conditioning program to see if strength levels will return sooner*

Pitch velocity was recorded for each throw, and RPE (Pictorial Children’s Effort Rating Table) was recorded after each inning.

The muscles were tested bilaterally (on both sides of the body) in the following order:

  • Glute Max on the drive leg and stride leg
  • Hamstrings on the drive leg and stride leg
  • Gastrocnemius on the drive leg and stride leg
  • Glute Medius on the drive leg and stride leg
  • Quadriceps on the drive leg and stride leg

The bullpen session began with 8 warm-up pitches (is this enough?). The maximal number of pitches was determined by the league age from the previous year. Only fastballs were thrown during the bullpen.

What’s interesting is that the pitchers threw sets of 8 pitches and were “allowed” 30 seconds of rest between each set of pitches. They were basically throwing until exhaustion! Which will definitely effect the results of the study later on.

The bullpen was stopped when:

  • Pitchers reached their maximum pitch count
  • a 9/10 was reached on the PCERT
  • Any pain or discomfort was felt
  • or a 5% drop off in velocity was seen

Again, the MMT was performed immediately after the session and was followed every day for 4 days. The pitchers were instructed to monitor soreness and “treat as usual after a regular season game”.


The average number of pitches thrown was 48, with the average throwing velocity of 46 mph.

12 of the 15 pitchers were able to reach their maximal pitch count before reaching a 9 on the PCERT.

None of the pitcher sin this study were fully recovered by the time the Little League guidelines allowed them to throw again. If we look back to the methods, is this because the bullpen was most certainly NOT game like?

Since the pace of play is definitely faster in little league, these younger pitchers still should have been resting between these “sets”. They only reported to giving them 30 seconds. Did any of these kids go longer than 30 seconds? These results were not reported.

The muscle groups with the most significant changes in strength levels included:

  • Stride leg hamstrings
  • Stride leg glute medius
  • Stride leg quadriceps

The slightly older pitchers (10-11 years old) had lower levels of strength, indicating that they were using their legs more than the younger players.


Before getting into these results a little deeper, let’s talk about the current status of youth baseball.

Here is what will significantly increase risk of injury:

  • year-round play
  • failure to rest from pitching for multiple months of the year
  • playing on multiple teams
  • 100+ games in one calendar year
  • early specialization
  • pitching while fatigued (36x more likely)

Of these 15 pitchers in the current study, some of them were multi-sport athletes. These demographics were correlated to recovery times. Guess what they found?!


This should not surprise you. If anything, it should really open your eyes up to the reality of the situation. With the amount of “skill development” that a lot of young kids are put through, they forget that they’re supposed to be athletes and not robots.

Looking back at the risk factors of getting injured, the biggest one is pitching while fatigued. This study becomes more important now because the young kids who reached the 9 on the scale at the end of the bullpen were already “too late”. The PCERT may not adequately show physiological fatigue.

So, how do we go about this now?

Here are two options:

  • Still monitor pitch counts, but still also include how the athlete is feeling. There’s no need to continually push athletes to reach their max pitch counts
  • Immediately following a pitching performance, get into a good strength and conditioning program that includes lower body strength, stability, and endurance

Keeping the youth healthy,

Jarad Vollkommer, CSCS


Livingston, J.L. and Tavoukjian, N.M. (2018). Lower extremity strength and recovery time in youth baseball pitchers: A pilot study. Journal of Strength and Conditioning Research.

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