MMV #075: The Science Behind the Lead Leg Block
Jun 03, 2024
TMVP #013: 5 Keys to Gaining Velocity
In this episode, I walk through 5 of the most important things to gaining velo.
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The lead leg is an important component of throwing velocity.
An effective lead leg transfers energy from the lower body up the chain into the upper body.
A poor lead leg is simply leaking energy and leaving velocity on the table.
Today, I want to walk you through a motion capture bullpen with one of my players.
Specifically I want to show you two components of the lead leg:
1. Lead knee flexion
2. Lead knee extension velocity
Lets dive in.
1. Lead Knee Flexion
Lead knee flexion is simply telling us how flexed the front knee is.
We want to look at this when the front foot lands and how it moves into ball release.
The vertical axis in the graph above represents knee flexion.
The higher the number, the more flexed the knee is.
The horizontal axis represents time, going from earlier in the delivery to later.
The blue vertical line represents when the front foot lands and the yellow line represents when the ball is released.
The thick blue line going across the graph shows the range of this player's knee flexion and the dashed line in the middle of the shaded area represents his average lead knee flexion during the session.
You can see that he lands with about 53º of flexion. This is good!
Typically we want to see the knee land in between 45-55º.
As he goes from front foot plant to ball release you can see his knee continues to flex.
This is not what we want.
We want the lead knee to start extending as quickly as possible.
By continuing to flex the front knee he is leaking energy created from the back leg.
Now, he does start extending the knee before ball release.
At ball release he is at about 48º of flexion.
You don't need to get all the way to 0º (leg completely straight), but closer to 20º or less is ideal.
Now for lead knee extension velocity.
2. Lead Knee Extension Velocity
Extension velocity is measuring in degrees per second how fast the lead knee is extending at any point.
What that means is you don't necessarily have to extend the knee very far in order to have a high peak velocity.
Lets look at the same player's from above lead knee extension velocity.
I like to look at what the velocity is at ball release.
The higher this number the better.
This player is around 214º per second. This is on the slower side with the ideal velocity being > 400º per second.
What is the cause and how do you fix it?
The pelvis is at the center of all of this.
If you want to improve your lead leg block, you need to improve the way your pelvis rotates.
Lets back track to the lead knee flexion.
It isn't shown in the graphs but this players pelvis is only rotated open around 16º at foot plant.
The ideal range is between 35-50º.
For reference, if your belt buckle is facing directly towards 3rd base (1st base if left handed) that is 0º.
Belt buckle facing directly home is 90º.
In order to extend the lead leg, the hips need to rotate.
If the hips are late, the lead leg is going to extend late.
Which is why this player does start extending the lead knee once the hips open enough.
You can still have a poor block while rotating the hips on time, but this is one of the leading causes.
From a velocity standpoint, it could just be the player can't rotate fast.
Or the potential issue is because his hips are late to open, they don't have as much time to reach a peak velocity.
Conclusion
I would first focus on improving the lead knee extension pattern before worrying about the velocity.
There are many ways to go about it but, things I would do are:
- Core velocity belt drills
- Back leg loading based drills that set up rotation better
- Posterior step backs
- Rotational step backs
- Drop steps
- Hip mobility exercises if player is limited (IR or ER focus)
Mechanics can be messy, but having access to a motion capture system like this helps create a clear plan because you can be objective with your evaluation process.
That's all for today.
See you next week!
Do you want your own mechanics evaluated like the player above?
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This is going to be a pitching mechanics and pitch design focused camp.
- Motion capture and force plate bullpen
- Trackman and edgertronic pitch design session
- Personalized drill package
- Pitching presentations all weekend
Limited to 10 players.
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