Let me tell you about a Tuesday afternoon last week.

I was in the clinic with an eighteen-year-old pitcher. He is a good high-school prospect. He sat on my table with his arm in a sling. His MRI showed a grade 2 UCL sprain. He is looking at six to eight weeks of modified throwing. Maybe more.

I asked him when he first felt it. He said it happened last weekend in the 6th inning on a fastball to the seven-hole hitter.

But here is what he didn’t know. His elbow didn’t break down that day. It had been building for weeks. Maybe months/years. The problem was already there. We just had not seen it yet.

This is how UCL injuries usually work. I talk about this a lot in the UCL Mastermind. The UCL behaves differently at different points of the year. It does not act like other ligaments. It is not like the ACL. When the pitcher feels symptoms, the damage is already present. When the MRI of MSKUS confirms it, you are past prevention. You are managing a situation that has been growing for a long time.

Okamura and his team recently provided some new knowledge. They showed us what happens inside the medial elbow during a normal throwing session. Their recent work should change how every serious baseball program thinks about pitcher monitoring. This includes MLB organizations and travel-ball teams.

Here is the study.

They looked at twenty-six high school pitchers. Each pitcher threw 100 full-effort pitches. They used diagnostic ultrasound before and right after the session.

This is what they found.

• The medial elbow joint gap got wider by 21% percent.

• UCL stiffness dropped by 32% percent.

• The flexor-pronator muscles lost 18% of their stiffness.

These are not small changes. These are large shifts in the structures that protect the elbow. This is also part of normal adaptation for pitchers. But the size of the changes matters.

And remember. This was after one hundred pitches. Not a full game. Not a tournament weekend. Just one session.There is another part of this study that matters.

We already know that elbow valgus torque is important for injury risk. More torque means more stress. More stress means higher risk. That part is simple physics.

For a long time, we could only measure torque in a lab with motion capture. That is not realistic for most programs. But now we have wearable sensors. Devices like Driveline Pulse Throw and the Motus sleeve can track torque on the field. They are not perfect but they give usable information.

Okamura’s team used these sensors while also measuring tissue changes with ultrasound. They found that the normalized maximum valgus torque predicted how much the UCL broke down after throwing. Higher torque meant more UCL stiffness loss. This is the first time we have seen this in a controlled study.

One result that caught my eye

The pitchers with weaker shoulder abduction strength had greater UCL changes. This lines up with what we already see in our work. It is one reason we use monitoring systems and why I believe in regular in-season testing.

The good news is that shoulder strength can change. You cannot change bone structure or genetics. But you can improve shoulder strength with eight to twelve weeks of good programming.

The real question you should be asking yourself. Are you measuring it? Are you tracking it over the season? Are you stepping in when you see a problem? Or are you waiting until the elbow hurts?

There was one more important detail in the study.

Changes in flexor-pronator stiffness were linked to thoracic spine posture. This happened at the point of maximum shoulder flexion. It means the way a pitcher’s mid-back moves affects how hard the forearm must work to protect the elbow.

We saw this all the time with the Twins. Pitchers with stiff mid-backs could not reach the positions they needed. Their scaps did not move well. Their shoulders did not rotate well. So they compensated. And the elbow took the hit.

This is why you must test thoracic mobility. Address limits. Track changes over time. I use simple tests for this every week.

Don’t forget to check the lats!

Many programs skip this. They wait until the athlete is in pain. Then they try to fix it. By that point the problem has already grown.

As always …

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