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🦾 Meet the $119 Sleeve Solving Baseball's Biggest Problem
Arm injuries are up 170%, but one man is trying to change that.

Happy Wednesday,
Arm injuries in baseball have never been worse.
Tommy John surgeries are up 170% since 2010. MLB pitchers are spending more than twice as many days on the injured list as they were 15 years ago. And 50% of youth pitchers now report shoulder or elbow pain during a single season.
Everyone seems to agree that it’s a problem—but no one can agree on how to fix it.
Jason Colleran thinks that’s because we’ve been solving the wrong problem.
This week, Jake and I talked to Jason, a biomechanics expert and the founder of Kinetic Arm, a patented sleeve that helps throwers stabilize their shoulder and elbow during the most vulnerable moments of a throw.
In a landscape full of velocity-chasing and junk science, Kinetic Arm is an outlier—one that aims to reduce elbow torque by ~30% and give athletes a better shot at longevity.
But the product is only part of the story.
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5 Takeaways From Our Conversation With Jason Colleran

Jason Colleran (right), founder of Kinetic Arm
1. The data is damning—and it’s been ignored.
MLB’s own studies link rising arm injuries to max-effort throwing, both in games and in training. Yet those trends persist at every level. Why?
Jason’s view: it’s either incompetence or negligence.
“If you know the data, and you choose not to act on it, you flat out hate kids.”
2. The injury pipeline starts in Little League.
36 high schoolers threw 95+ mph at the 2024 Perfect Game Showcase. Just 3 did in 2018.
Over 50% of youth pitchers report shoulder or elbow pain during a single season.
60% of youth baseball surgeries are due to overuse.
The issue isn’t just mechanics—it’s incentives. Velocity gets kids scouted. Health doesn’t.
3. Kinetic Arm fills a gap training alone can’t fix.
Jason originally ran a facility for injured athletes but couldn’t scale his knowledge. So he built the Kinetic Arm as a way to externally reduce stress during throwing.
The sleeve is designed to:
Offload torque at the shoulder and elbow
Support the arm through passive ranges (where muscles can’t stabilize)
Reduce injury risk without limiting mobility
It’s not just for recovery. It’s a prehab device that helps athletes extend their careers.
4. The cultural resistance is real—but fading.
The pushback from coaches and purists? Expected. But Jason’s approach is simple:
“They’ll say, ‘Where’s the proof?’ I say, go read the reviews.”
He’s not trying to sell a miracle product—he’s trying to get coaches and parents to stop repeating the same mistakes. And as MLB players start wearing it under their team-issued sleeves, the tide is turning.
5. We don’t need another 10-year study—we need common sense.
In medicine, Jason says it takes 10–17 years for research to become standard practice. In baseball, that lag is lethal.
Until systems catch up, his advice is simple:
Ask athletes how they feel
Stop doing things just because they’re “tradition”
Don’t wait for injury before doing something preventative
Why It Matters:
From weighted ball programs to cookie-cutter training templates, baseball’s injury problem is a result of flawed incentives. Kinetic Arm doesn’t claim to be a fix-all—but it’s a powerful step in the right direction.
It proves that:
• Preventative gear doesn’t have to limit performance
• Scalable products can help correct unscalable coaching
• The health of an athlete shouldn’t be left up to chance
📩 And don’t forget: Bottom of the Ninth is back this Friday with the top three stories in sports and business from the week.
See you then,
Tyler & Jake
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