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
Here we go with a geeky blog post about throwing mechanics. As you may or may not know I am in the midst of doing some research for my master’s degree where I am looking at the correlation of various lower body power tests and throwing velocity. As a result I am reading a lot about what the legs do during the act of throwing a baseball. Today I am taking a more in-depth look at the stride leg.
If you like this post you might like my post of the ground reaction forces of pitching where I discuss the trail leg in more detail.
Here we go.
Proper lead leg positioning at foot plant allows for optimal rotation of the hips, pelvis and trunk (Dillman, Fliesig, Andrews – 1993) which is crucial to provide the most effective transfer of energy through the kinetic chain.
The strength of the front leg is an important factor in creating optimal throwing velocity. Matsuo et al. (2001) demonstrated this when they measured 12 kinematic and 9 temporal parameters between high velocity and low velocity pitchers and found that the amount of flexion and extension of the front knee was significantly different between the two groups.
Matsuo et al (2001) identified four common knee movement patterns with their subjects. Eighty three percent of the high velocity versus 35% of the low velocity throwing group was classified as displaying either the “A” or “B” patterns which displayed more knee extension than the “C” or “D” patterns. Sixty nine percent of the high velocity group was categorized in the “A” pattern which showed small amounts of both knee flexion and extension (50-60 degrees) during the initial 60% of the time interval between front foot contact (0%) and instant of ball release (100%). From the 60% to the 100% interval time mark the knee extended from approximately 55 to 30 degrees. Only 9% of the low velocity group was classified as having the “A” pattern. At the other end of the spectrum is the “D” pattern where the front knee continued to flex from approximately 20 to 50 degrees throughout the entire pitching motion 0-100% time interval. Seventeen percent of the low velocity group demonstrated the “D” pattern while none of the high velocity group fell into this category.
This supports the data presented by Escamilla et al (1998) which reported that collegiate pitchers demonstrated knee extension just prior to maximum external rotation of the glenohurmeral joint during a fastball pitch. The front knee continued to extend throughout the throwing motion as the trunk moves forward and rotates towards the intended target during which time the arm accelerates. This ability to brace the front knee allowing for optimal forward trunk tilt and rotation was identified as a characteristic of high velocity pitchers by Elliott et al. (1998).
Similar knee movement patterns are also seen in elite level javelin throwers who display the ability to produce a clear double flexion extension pattern which is seen in the “A” pattern in the Matsuo et al.(2001) study. During the javelin throw the role of the front knee is to brace the body in order to aid in the transfer of energy from the ground up the kinetic chain to the trunk and upper extremity which are accelerating forward. (Whiting et al 1991)
High velocity cricket bowlers have also been shown to exhibit similar front knee movement patterns. Wormgoor et al. (2010) demonstrated that greater front knee extension at ball release was the biomechanical factor that correlated the highest with throwing velocity.
Ground Reaction Forces
After front foot contact the lead foot applies a braking force in order to slow down the forward momentum and begin to transfer the kinetic energy back and up the kinetic chain. When the arm is in maximal external rotation the front leg applies approximately 1.5 times body weight while also applying braking forces of nearly 0.75 times body weight. (MacWilliams et al. 1998)
This study also reported that high wrist velocity was highly correlated with both landing anterior shear force “braking”(r2=0.70) and landing resultant force (r2=0.88) at the point of ball release. Basically the more force exerted by the front leg translated into higher throwing velocities.
Campbell et al. (2010) reported high levels of EMG activity in the stride leg that exceed 100% of MVIC with the high values seen during the arm cocking (phase 3) and acceleration (phase 4). During the arm cocking phase the Gastrocnemius, Vastus Medialis, Rectus Femoris, Gluteus Maximus and Bicep Femoris produced mean values of 140, 166, 167, 108 and 99% of MVIC respectively.
During the arm acceleration phase the Gastroc, VM, RF, GM and BF produced mean values of 126, 89, 47, 170 and 125 of MVIC respectively. The stride leg functions to dynamically stabilize the hip and knee joints in a single leg stance to maintain standing posture for the trunk and upper extremity to pivot about in order to produce an efficient follow through.
Like I said this was going to be a geeky read but if you made it this far I thank you for your time. I am putting a big push on this thesis of mine so if you liked this kind of blog post there will be more to follow.