@doublexcanflex profile picture
Dean Jackson @doublexcanflex

5 elbow surgeries, 1 hip surgery, 10 regen injections, impingement. Thrown upper 90s low 80s. Learn from my experience 👇

Joined October 2016
  • Tweets 3,505
  • Following 828
  • Followers 11,140
623 Photos and videos
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Dean Jackson@doublexcanflex
3 Jan 2019
If you like slow motion footage of pitchers who throw hard then you're going to enjoy this YouTube playlist youtube.com/playlist?list=PL…

Slow Motion Videos of High Level Pitching Mechanics

youtube.com
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Dean Jackson retweeted
Theia
@theiamarkerless
Jun 2
What changes in a pitcher’s delivery when velocity increases? Dean Jackson (@doublexcanflex) puts that question to the test using #Theia3D, comparing velocity against full-body kinematics across throws. Learn what changes as pitchers move closer to max output: theiamarkerless.com/blog/dea…
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Dean Jackson retweeted
Chris Langin
@LanginTots13
28 Oct 2025
Reiss Knehr getting us started @DST_Arizona this offseason with on-field mocaps courtesy of the reliable @doublexcanflex — Mr. Biodex himself. Capturing several throws from 80–95% effort (in 2–3% increments) to analyze individual context and better understand how mechanics shift — relative to expectation — when moving from 80 to 100% effort. Also running grouped averages of his max-effort throws for more traditional analysis.
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If your self image of what you could be is much bigger than what you are right now, and that keeps you from doing the things needed to get better because you don’t want people (or yourself) to think you are less than that self image you have You will never be what you could be
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Two throws from two different days. Both were 85 mph. One was painful (shoulder impingement), the other was very comfortable as I warmed up to higher velos
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Most sense it’s ever made. Improving my body’s ability to lay back (t spine extension, ribcage mobility, scapular posterior tilt) and handle the energy going into layback allowed me to move through the positions needed to for me to throw 85
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It wasn’t about doing mechanical work to change the positions I move through, it was about improving my body’s ability to handle load through the ranges of motion that need to be loaded
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Huge mistake I used to make: Trying to do as much as I could possibly recover from I’d try and hit that right on the nose, and about 1/2 of the time I’d get it. The other 1/2 I’d overshoot. I literally never undershot
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Eventually I’d realize I would have to deload to give my body time to catch up. Weeks of training that could have been done so much more efficiently, plus the time spent away during the deload
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Now I purposely undershoot and do slightly more each week. Almost never overshoot with any trainees anymore, and the results are WAY better I’ve found doing slightly less than you could do each week adds up to MUCH more than overshooting then deloading
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My job isn’t to keep the athletes that train with me from struggling, it’s to make sure they struggle in the right amounts on the right things
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Plenty of times I’ll purposely make myself unavailable when athletes think they need me, because in that specific situation I don’t think they do and I think they’re using me as a crutch. Me being available in that moment gets in the way of their development
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I strongly believe you will not be as good as you can be if you don’t eventually become self-sufficient
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IMO the older you get, the harder it is to commit the amount of yourself you need to Job, significant other, kids, rent, other people’s expectations of you, obligations from every direction If you struggle committing when younger, you will absolutely quit when it gets HARD
Dean Jackson@doublexcanflex
25 Feb 2024
Consistent high performance is so difficult because you need to bring a lot of attention to detail to basically everything, forever If you’re not actually about that life you can’t constantly fake it, it will beat you down and you’ll stop
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Consistent high performance is so difficult because you need to bring a lot of attention to detail to basically everything, forever If you’re not actually about that life you can’t constantly fake it, it will beat you down and you’ll stop
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1. What’s the root problem 2. What are the factors that contribute to that problem 3. How do you manipulate those factors both positively and negatively
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Consistently see guys try and escape problems that come up for them. Get away from it, think about easier / no stress things, alcohol, video games, TV, phone, etc When you come back to reality, your problems will still be there. You’re just going to have less time to solve them
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I really think there’s one way to throw as hard as possible IMO there’s different ways to throw hard because there’s lots of pieces involved and with a high enough ceiling you can ride one piece But currently I think there’s one way to use all of them as efficiently as possible
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As a reliever, learning how to do your pregame throwing bullpen warm ups in a way that preps you for the game if you get in, but also doesn’t take away from your ability to throw tomorrow at full capacity if you get told to sit down is insanely important
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