Baseball Training Topic #1
Why Using Overload and Underload Bats Works for All Levels of Baseball
Batting Exit Velocity — the speed at which the baseball is sent off of a ballplayer’s bat — is one of the hottest trends in baseball today. At the lower levels, it makes sense — harder hit balls get through for base hits, and eventually turn into more extra base hits and home runs. At the higher levels of baseball, colleges and professional scouts use exit velocity for showcases to see which players have bat speed. Research is showing that using different weighted bats, heavier and lighter and under the proper training protocols, can improve bat speed immensely, and consequently, improve a player’s on-field performance.

Why use Overload bats?
There have been different schools of thought in the past mentioning that swinging with a heavier weighted (Overload) bat or bat-like object does not help to improve bat speed. An example of this thought process would be swinging a bat 50–100 times with a “doughnut” weight on the end of the bat
at various levels of speed and intensity. Conceptually, overload bats are used differently here at Dream Big Athletics and among the top hitting instructors throughout the country in a much more beneficial fashion and would be categorized differently than simply a weight on a baseball bat. Firstly, a doughnut placed on a bat causes more of an end-load weight distribution. This likely causes many athletes, beginner or advanced, to alter their swing mechanics drastically and will not allow for an adaptation of a faster, more effective swing. This especially goes for youth athletes who have not yet
acquired higher levels of strength. At Dream Big Athletics, we use a 35-ounce bat as our heaviest implement for our most advanced hitters. The bat was purposefully made with even weight distribution, and is slightly lighter than the bat with the 12-ounce donut attached to it. It should also be noted that utilizing a contrasting method of training with both an overload bat and a lighter, underload bats has shown to develop extremely positive results in players’ bat speed, regardless of ability level.
I’ve spoken in the past about the post activation potentiation effect that varying resistance can create for athletes. Essentially using a heavier weight in an initial “burst” will increase higher threshold motor unit recruitment (the “faster twitch” type muscle fibers) which in turn can help the athlete move faster and more explosively with a lighter weighted object — in this case either their underload trainer or regular game use bat. It should be noted that we are not using the overload bats in these instances for fatigue purposes, but more so to prime an athlete’s Central Nervous System, preparing them to swing
faster and faster in the subsequent rounds of batting practice.
Why use Underload bats?
Using lighter weighted bats helps create the adaptation of the body moving faster and faster. It is similar to the concept of throwing underload/lighter baseballs/baseball-like objects with high intent to create faster arm speeds in higher level athletes. The body’s central nervous system begins to fire faster and is forced to work at a faster rate to recruit more motor units. The key here is that these light bats must be swung with maximal effort. Players not taking advantage of this concept and swinging with sub-maximal effort will unfortunately not create any positive adaptations for bat speed and overall swing effectiveness.
How does Dream Big Athletics use the Overload/Underload bats in
training?
After working with players a few times, we begin to evaluate their abilities and assess their strengths and weaknesses in their swings. We vary the bat selection on a consistent basis based on what players need the most. Players lacking strength will likely swing the Overload bat more than players who have higher levels of strength but lack bat speed. With those players we will implement more underload bats. Here is a basic example of what a bat speed development session at Dream Big Athletics wouldlook like:
These swings can be taken off the tee or in light batting practice, 3 to 4 times per week-
o 10 Overload constraint (wide stance, no stride drill, etc.) swings paired with 10 regular
bat swings
o 8 Overload swings paired with 8 medium Underload swings
o 12 lightest Underload swings
o 10 regular bat swings -maximal intent/test using the radar gun

What results have we seen?
Among 12 elite high school athletes who were tested over a three-month period on a consistent basis this summer (2018) at Dream Big Athletics, all increased their batting exit velocity by at least 4 mph or more. On average they increased by 6.5 mph, with one athlete gaining over 9 mph in 3 months. It should be noted that each of these individuals followed along a very detailed strength and power development program crafted by DBA Coaches during this 12-week period as well. Other athletes who participated in DBA’s Travel Baseball Program, the Illinois Patriots, over the course of this past year (August ’17 — July ’18) who followed similarly scaled training protocols saw incredible improvements as well. Youth players, ages 10U-14U, on average saw improvements of 10 mph in bat exit velocity, with one player jumping as high as 14 mph! High school athletes ages 15U-18U on average saw 12 mph jumps in exit velocity over the course of the training year, with one athlete getting as high as a 15 mph increase! It should be noted that Dream Big Athletics uses the concepts of Overload/Underload Training in conjunction with both properly tailored, age appropriate strength and conditioning protocols as well as professional baseball skill development instruction to yield results as stated above.

What tools can you use for Overload and Underload Training?
Many baseball companies throughout the United States have begun to provide various types of Overload and Underload Training Bats and tools to apply these concepts in baseball training. Seattle based Driveline Baseball has promoted the ‘Axe Handle Overload and Underload’ bats and they have
developed some incredibly positive results among athletes who use them. Another company, ‘Superspeed Slugger’ creates a variety of tools that can be used for bat speed training as well. The problem for many people is that these bats can be extremely expensive. At Dream Big Athletics we use a few different methods. Dream Big Athletics partner, the Keep Swinging Stix Wood Bat Company, has created various weight and length Overload and Underload bats for players of different sizes and abilities to train with. We have also two 35 oz. overload bats, one of which was ordered from the Baum Bat Company. We also have underload bats ranging from 20 to 26 ounces, many of which were old BESR bats donated to us as players found they could no longer use them in games. For younger trainees, we do not like going more than 6 oz heavier than their game bat, as a drastically heavier bat may cause a
drastic change in swing path and produce speed too slow for a positive effect.

In Closing
“Well, anyone can look good off the tee with the radar gun in front of them.”
(Statements of the like made by proponents against the concept of bat exit velocity being an essential aspect of training for today’s baseball player.)
This statement about bat exit velocity may be true to an extent, but highly downplays the effectiveness of this style of training. Bat speed and increased exit velocity can help players not only stand out at showcase events, which have become a primary method of college recruiting, but also with their overall performance in games against higher levels of competition from the youth through the professional ranks. Using the radar gun is a great way to motivate hitters by giving them a number to improve upon on a consistent basis. They compete against each other and challenge themselves to improve. Good swing mechanics via more efficient kinetic energy transfer can create optimal bat speed anyway. At DBA, we also train our hitters to pair their bat speed training with live at bats and batting practice with very short reaction times to ensure that time to contact and ability to optimally launch are both focused on along with bat speed.

This article was written by Dream Big Athletics Head Strength and Conditioning Coach and Lead Professional Baseball Instructor Bill Miller, Certified Strength and Conditioning Specialist (CSCS).
For more training insight visit us on Instagram @dreambigathletics and @billmillertraining.
Dream Big Athletics is hosting a Fall Baseball Developmental Training Program, starting Monday, September 10th for 14–18 year olds and Tuesday, September 11th for ages 6–13. Space is still open to register.
More information and to sign up can be found HERE.
Have A Question???
Reach Coach Bill directly via email at billmillerbaseball@gmail.com.
Contact Dream Big Athletics’ Staff about our various training programs offered throughout the year at dreambigathleticsil@gmail.com or by visiting www.dreambigatheltics.com.

September 5, 2018