We all know that you need strong legs to pitch but a new study, which isn’t even published yet, is telling us that they need to be stronger than we originally thought.
Jonathan Broxton, now with the Royals, needs his big tree trunk legs to handle his big frame (6’4″ – 295lbs) and produce his big fastball.
As always I will break down the geeky science then provide you with some practical applications that you can use to improve your game.
Lower-Extremtiy Ground Reaction Forces in Collegiate Baseball Pitchers
Authors: John A. Guido, Jr and Sherry L. Werner.
Before we get into the nitty-gritty details of this study let’s do background work.
Ground reaction forces are basically the amount of force that is exerted back to your body from the ground which is equal and opposite to the amount of force that you put into the ground. During a jump you push your feet into the ground and this force is redirected back up allowing you to get off the ground – the more force you put into the ground the higher you will jump. But if you want to be able to jump higher than you can now you need to get stronger so that you can put more force into the ground.
Ground reaction forces are measured in different directions. If you jump straight up you will be exerting vertical ground reaction forces. If you are running the majority of the forces being produced will be horizontal and when you need to slow down you will need to apply whats known as anterior or braking forces.
What this study did: This current study used 14 college baseball pitchers who were on average 175lbs and 5’10″ and threw 78mph. They had each pitcher throw 10 fastball strikes from a mound with a force plate built into it in order to measure the amount of force being put into the ground. They also filmed each pitcher during their deliver to figure out exactly when these forces where being produced during their delivery.
This current study did not measure the forces being produced by the back leg like the one that MacWillams performed back in 1998. If you want to learn more about the MacWillams study which concluded that more force being produced by the back leg translated into more throwing velocity check out this article that I wrote back 2010.
What they found out: The main finding of this study were that the ground reaction forces in an anterior or braking direction where approximately 245% of body weight whereas the MacWillams study only reported these forces to be equal to about 72% of body weight!!
This is a huge difference. The reason for this discrepancy might be that the pitchers in the current study threw harder and where bigger than in MacWillams study which did not report either. One of the main reasons the authors decided to perform this study was that there was only one previous study which measured in baseball players and it is a good thing they did.
Gagne’s front leg is about the apply the brakes!!!
The anterior or braking forces are very important to throwing velocity from a pitching mechanics point of view because it stops the forward momentum created by the back leg allowing the energy to be transferred from a strong and stable position. If you land and your front leg continues to move forward you won’t be able to transfer energy as efficiently and what’s known as an energy leak will occur.
Energy leaks are bad – you want to transfer as much energy as possible from the lower body to the upper body as possible in order to throw gas.
The authors did state in the abstract that “a correlation between braking force and ball velocity was evident.”
Here is an another article I wrote discussing the importance of front leg strength. Basically it states that pitchers who landed with their front leg bent/flexed and continued to bend/flex throughout the rest of the delivery didn’t throw as hard as those pitchers who had the strength to land with a bent/flexed leg and then straighten/extend this front leg throughout the pitching motion.
This video of Justin Verlander demonstrates his great front leg action allowing him to efficiently transfer energy and strike out hitters.
In regards to vertical ground reaction forces this current study reported forces of approximately 200% of body weight while the MacWillams study reported only 150%. The vertical forces are important because we need to transfer this energy up the kinetic chain.
What you can do: The authors of this study were nice enough to provide an exercise which they thought might be beneficial to help players get strong enough to handle the forces needed to achieve higher throwing velocity.
The exercise they suggest is basically a lunge where you start standing tall and balanced on one leg. You then fall forward and catch yourself with the opposite leg and immediately try to push yourself back up the starting position. The way they describe this exercise is much like a plyometric exercise where you try to minimize the amount of time your front foot stays on the ground. The speed and velocity that you push yourself back up is very important and when that begins to slow down you stop.
However this exercise can also be done with weights which will allow to work on absorbing more force but you won’t be able to push yourself back up as explosively. Both have their place on what is known as the strength velocity curve. Ideally you focus on the weighted version during the off-season in the weight room and then use that strength you’ve built up to make the plyometric version even more explosive.
Stick to reps between 4-10 per side with both the plyometric and weighted version for 3-5 sets. Even though you always land on the same leg when you throw it is very important to do the same amount of reps for both legs. In fact it might even be a better idea to do more reps on the leg you don’t land on (right leg or righties) because of the fact that you do so much landing on the other leg every time you pitch or throw.
Where is an example of basic forward lunge.
Graeme Lehman, MSc, CSCS