Bases loaded in a big game, 3-2 pitch… ball 4. I watched a fastball go arm side high at a high school baseball game as the pitcher looked in with frustration. From somewhere next to me I heard what was obviously the voice of a concerned father, “you’re flying open”. Then I heard it again from the dugout and the kids coach, “HEY! Stay closed a little longer…”. Then again from the outfield, “keep the glove side closed dude!”.
It’s hard to be on the island when things aren’t going well. Some days you just don’t have it and when you don’t have it everyone else seems to have all the answers.
Maybe you are just “flying open” though?
Maybe it’s so noticeable that 3 people from over 100ft away were able to spot it with the naked eye? Then you stop and think about it, do these people even know how to define “flying open”? Do I know how to define it?
How do I even know if “flying open” is why my command was poor? Is there research promoting this?
Baseball in many cases is an oral tradition where baseballisms are passed down generation to generation. The term “flying open” is one that gets tossed around at nearly any level and can be heard echoing off the walls of nearly any venue.
In this blog we are going to get deep into the weeds and define what Trunk Rotation is and how to measure it. We will look at and define what it means to “fly open”. Spoiler alert. There is no research that correlates flying open with poor command. We will have to talk about command another time in a deeper blog on the topic but you can ignore the “stay closed” remarks from parents, coaches and teammates moving forward. The reality is they just want you to throw strikes but have found a creative way to say it so they don’t have to feel so direct.
With all of that out of the way let’s dive in and investigate how to best understand Trunk Rotation…
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 trunk rotation…
1. Assess
- To establish what “flying open” might look like we have to first determine what a normal range for trunk rotation might look like.
Generally speaking different arm slots require different rotation from the trunk. Over the top can mean a more extended and laterally tilted trunk while a side arm slot can mean more of a flexed trunk with nearly no lateral tilt at the time of foot plant.
So we have to account for both of these type of throwers when discussing an “acceptable” range of trunk rotation. Again this is generally speaking… but we can identify a trunk too open or too closed as the following…
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- A trunk too open when the front foot plants into the ground. We generally look for the trunk to be around 10 degrees of rotation at the point of foot plant. If the trunk is substantially above 10 degrees this tells us the trunk has rotated too early into foot plant
making it difficult for the athlete to get into a
good position with the trunk through the rest of the throwing motion. This ultimately will cause timing issues in peak rotational velocity impacting the Kinetic Chain and 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.
- A trunk too open when the front foot plants into the ground. We generally look for the trunk to be around 10 degrees of rotation at the point of foot plant. If the trunk is substantially above 10 degrees this tells us the trunk has rotated too early into foot plant
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- A trunk too closed when the front foot plants into the ground. We generally look for the trunk to be around 10 degrees of rotation at the point of foot plant. If the trunk is substantially below 10 degrees this tells us the trunk is rotating too much
into foot plant making it difficult for the athlete to get into a good position with the trunk through the rest of the throwing motion. This ultimately will cause timing issues in peak rotational velocity impacting the Kinetic Chain and 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.
- A trunk too closed when the front foot plants into the ground. We generally look for the trunk to be around 10 degrees of rotation at the point of foot plant. If the trunk is substantially below 10 degrees this tells us the trunk is rotating too much
According to our data sets an athlete can be “too open” or “fly open” at the time of foot plant but its important to note that an athlete can also be “open” by definition and be ok. If an athlete is throwing from a high slot and rotates his trunk at the time of foot plant to 8 degrees open, its fine and part of his natural ability to create rotation while throwing from a higher slot.
In this case if you are a coach, parent or teammate and you are observing with the naked eye from 100ft away its important to realize that in real time determining the difference of 5 degrees is an impossible task. The guy throwing and who looks to be “opening early” could in fact be “opening early” but that might also be part of what makes him who he is as a pitcher. “Flying open” implies you are breaking that 10 degree line we have established but a further question we have to ask is can a pitcher fix this in game, in real time? The reality is the probably cannot.
Let’s move to Feel in our mechanics progression and begin to talk about how we would actually go about making a change to someones trunk rotation.
2. Feel
Feels are movements we specifically 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 Trunk Rotation…
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 Trunk Rotation…
Prayer Feels-
We like Prayer Feels because with the stick they provide feedback of trunk direction. The goal is to hold the tip of the stick back as the pelvis rotates. This provides the athlete some sense of outside feedback on successfully holding the trunk and how long they need to hold the trunk during the throwing motion. A reminder here that this is to simply provide a cue or cues to begin the drill process with.
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.
Pivot Picks-
Hop Back Throw-
Janitors-
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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.
indicator 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. 
