Is Your Lead Leg Why You Aren’t Throwing Harder?


Many coaches today teach that players need a strong “lead leg block”. You see coaches everywhere today teaching that players must “straighten” their lead leg during the throwing motion. This idea of “straightening” your lead leg however is a bit over simplified. In this post we are going to talk about the different ways to evaluate the lead leg and help you fully grasp its role.  

At KineticPro we identify and correct mechanical issues in a 3 step process. Below we will dive into each step explaining what to look for when evaluating and correcting issues with the lead leg block… 



Step 1. Assess

  • When identifying a problem with Lead Leg Block we are looking for the following 2 major issues when using within our 3MotionAi biomechanics reports. Note: The lines you see on the below graphs represent Front Foot Plant, Max External Rotation and Ball Release in left to right order. 


    • A lead leg too bent from front foot plant to ball release. We generally look for the lead leg to be around 45 degrees of flexion at the point of foot plant. If the lead leg is substantially above 45 degrees this tells us the lead leg has flexed too deep into foot plant
       making it difficult for the athlete to get into a good position with the lead leg through the rest of the throwing motion. This ultimately can cause a problem stabilizing the lead legs extension and also the athlete producing lead knee velocity. These issues with the lead leg can impact the energy delivered to the kinetic chain. This lack of energy through the kinetic chain ultimately can slow the accelerating of the arm and in return can reduce ball velocity.


    • A lead leg that doest extend rapidly enough from MER to Ball Release. We generally look for the lead leg to be around 45 degrees of flexion at the point of foot plant. If the lead leg doesn’t move from 45 degrees to less knee flexion in above 200 degrees per second this can be anindicator that the athlete is not producing the needed ground force to provide adequate energy to the kinetic chain. This ultimately will cause timing issues in peak rotational velocity impacting the ability to deliver energy to the arm. This lack of energy to the arm ultimately slows the accelerating of the arm and in return can reduce ball velocity. 





Using 3MotionAi we went back in our database and pulled some biomechanics data on 20 different pitchers. We then categorized them into high ball velocity and low ball velocity groups. We wanted to see if the data collected in research aligned with the data collected against our population. Below you will find our data… 


It’s clear to see that the average for each category aligns well with the data we see in research of the past. However take special note of the following players…

  • Player 3- This player has the lowest lead leg extension velocity of the high ball velocity group. However he has the highest velocity of the entire group! 
  • Player 4- This player has a substantially high knee flexion angle but still produces 95 mph.
  • Player 20- Produces substantial lead knee extension but only produces 189 degrees per second and only 84 mph. 

How can this be? How can individual players be so off? Some of these players defy research of the past and still produce elite ball velocity. Some do what is required by research of the past but cannot produce elite ball velocity. Lets talk about this further in our assessment section “editors notes”.


  • Note: these guidelines to understanding what a “good” lead leg looks like are great when first evaluating a lead leg. However biomechanics are not absolutes. Not everyone who throws hard has a “good” lead leg. These guidelines should be used to evaluate and should provide context for a coach/ player to consider trying a possible change. Biomechanics provide objective data so we can make educated decisions in development. There is no such thing as “perfect” mechanics. There are not “good” or “bad” mechanics. The human body develops and achieves high performance through a lifetime of compensations. Proceed with caution when choosing to make any change. Be sure to measure this change in time with biomechanics to assure an objective determination on if changes have made an impact. 


Step 2. Feel

Feels are movements we have designed to deliver the specific “feeling” of a moment. The goal behind feels should be to help an athlete identify the right movement while allowing them to reinforce cuing to execute the needed movement in the throwing motion. Lets look into what feels can potentially help us understand how to fix the issue of Lead Leg Block…

Note: Feels should be the time a coach can teach/ educate or an athlete can wonder. It’s an athletes time to define “good” in movement and start to create “cues” that might possibly help them create the outcome they are looking for in the movement.

Lets look into what feels can potentially help us understand how to fix the issue of Lead Leg Block…


Banded Punches-

We like banded punches at KP because though constrained this movement expresses the full function of the lead leg. When doing banded punches it is important to recognize that the continued rotation of the pelvis over a properly flexed lead leg can organically create extension velocity of the lead knee. Players should not be trying to fully extend their lead knee before ball release. They should instead be focused on a firm connection to the ground with the front foot and should be cuing continued rotation of the pelvis to bring lead knee extension velocity at the right time. 

Step 3. Drill

Drills are where we begin to introduce the feeling or cue into the throwing motion. We move from most constrained to the least constrained of drills in order to transfer the correction of movement to the mound. Our goal is to get comfortable with a new movement and through time in drills we can begin to release the active thought associated with the drill thus transferring it to the movement we will see during competition. 

Note: Drills do not fix the problem. Drills are created to help an athlete build more conscious corrections to the problem. We simplify the movement and give the athlete a better chance at success by constraining the movement. IF you are not actively evaluating the movement to determine if the cue you are using is working then you are ultimately not getting much from the drill itself. Athletes must develop a quality feedback loop and understand what they are looking for to determine if a movement can be defined as successful. Video, 3MotionAi or other objective tools are a necessity for improvement. The coaches “eyes” are subjective and should not be your only source of correction/ approval. 


For lead leg block improvements we like the following drills to help athletes develop awareness…


Roll-In V1-


Roll-In V2-


Walking Wind Ups-

Want to get started training with KP? We offer both remote and in person training (Tampa FL). 
To get started with remote training: Click Here 
To get started with in person training: Click Here

Want more KP? Be sure to check us out on our social media channels…
Youtube: @KP3
Twitter: @Kinetic_Pro
Instagram: @KineticProPerformance