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Does Bat Speed Training Work?

Jul 18, 2023

                                            Overload/Underload Bat Speed Training

Does Bat Speed Training Work?

Swinging weighted bats, using a bat weight on deck, or doing an overload/underload bat speed program, have all been ways hitters have used to try to increase their bat speed.

 The question is:

 Do those work?

 Today, we're going to talk about overload/underload bat speed training.

Before I share any research, I will tell you my experience, having tried them as a player and coach.

Overload/Underload bat speed training is like taking a supplement from GNC.

  •  If a 13-year-old kid takes a supplement, they won’t see results.
  •  If an adult takes a supplement and doesn’t work out, they won’t see results.
  • If an adult takes a supplement, eats clean, AND works out, they will likely see a result.

The supplement probably helped about 5%, and that’s only for adults who were also eating clean and working out.

Overload/Underload bat speed training is the same as taking a supplement, from my experience.

If you start doing it with a kid too young, you won’t see results; if anything, it could mechanically get them into bad habits.

If you do it with a college player who works out, eats clean, and hits regularly, you might see a 5% benefit.

Hitters must move well before doing any overload/underload bat speed training. They need to have good movement first.

Everyone asks what age to start, but there isn’t an age range because players develop at different rates.

So, the answer is that it depends on how well the hitter moves. Hitters should do overload/underload bat speed training when:

 1. They have good mechanics.

 2. They understand their swing

 3. They need more power

That is my opinion on overload/underload bat speed training. Let’s now dive into some of the research that’s been done.

I read a study by Coop Derenne and David Szymanski, “Effects of Baseball Weighted Implement Training: A Brief Review.

A few interesting highlights I found in the study.

College and former college players were the only overload and underload testing group.

Each group did see an increase in bat speed.

Another thing to note in the study:

“Furthermore, the findings of DeRenne et al. (13) indicated that if the bats are no more than 12% lighter or heavier and have the correct heavy/light/ standard resistance load ratios, bat velocities would significantly increase.”

So, if you do overload/underload bat speed training, you don’t want to use a bat above or below 12% weight of your regular game bat.

Experience from professionals:

Mookie Bats did overload/underload bat speed training this past off-season. This year he has seen an increase in bat speed.

However, he also gained weight.

Via Fox Sports:

"The decision to bulk up was prompted by a visit to Driveline Baseball. The data-driven performance facility is known more for its work optimizing pitchers, but this winter the Dodgers’ hitting coaches took a contingent of players to the site to see if anything might be gained from the experience. While bat speed was a focus for all, Betts was also told he needed to get stronger. 

Betts showed up to camp this year "beefed up" — as the former vegan put it — particularly compared to last season, when he launched a career-high 35 homers despite at one point dropping to 167 pounds. He came in this year at 178 and has only lost a couple of pounds through the course of the season. 

Dodgers hitting coach Robert Van Scoyoc began Betts on a bat speed program that the seven-time All-Star believes could be playing a role in his power surge. As part of the program, hitters will swing bats with differently distributed weights — some loaded in the barrel, some loaded in the handle; some heavier, some lighter — as Betts showcased on his YouTube page in a workout at Dodger Stadium this offseason"

As mentioned earlier, overload/underload bat speed training can be beneficial. But it’s like taking a supplement.

The player needs to be ready: 

  • From a movement standpoint
  • From a physical standpoint
  • From a mental standpoint

If all they do is swing weighted bats and do nothing else, they will unlikely see results.  


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