Is Throwing Hard (Not Curves) Linked to Tommy John?

For years, parents and coaches worried that curveballs wrecked young elbows. The research points somewhere else: how much a kid pitches, pitching while tired, and, yes, throwing hard. Here's what the evidence says, mostly from the American Sports Medicine Institute (ASMI), the group behind much of the pitching injury research.

Why fastballs stress the elbow

Throwing a ball hard puts a lot of stress on the inside of the elbow, particularly the ulnar collateral ligament (UCL). Every muscle and joint from the legs to the fingers is working to create speed, and the UCL helps hold the elbow together while it happens. ASMI's position is direct: pitchers with high ball velocity are at increased risk of injury, and the higher the velocity, the more important it is to follow workload guidelines.

What about curveballs?

According to ASMI, biomechanical and epidemiologic research has not shown a strong connection between curveballs and elbow injuries. That doesn't mean a 10-year-old should be throwing them. ASMI says a youth pitcher may not have the physical maturity, control and coaching to throw a curve with good mechanics, so the order should be: basic throwing, then fastball, then changeup. MLB's Pitch Smart guidelines agree, recommending fastballs and changeups for ages 12 and under, and breaking pitches only after a consistent fastball and changeup for ages 13 and up.

The rise of Tommy John surgery

Tommy John surgery reconstructs a torn UCL. Dr. Frank Jobe first performed it in 1974 on pitcher Tommy John, who returned to pitch for many more years.

ASMI describes an "epidemic" rise in pro pitchers needing the surgery and links it to a similar sharp rise in adolescent pitchers years earlier. In many cases, the injury in a young pro started while they were an amateur. Surgeons usually find a ligament that has frayed over time from overuse and repetition. Today's kids can play competitive baseball almost year-round, and research shows a strong link between too much competitive pitching and arm injuries.

Recovery is long, physically and emotionally. And it's not a shortcut: ASMI calls the idea that pitchers throw harder after surgery a misconception, and notes that 10% to 20% of pitchers never make it back to their previous level.

Protecting young pitchers

The main risk factors ASMI lists for adolescent pitchers: the amount of competitive pitching, pitching while fatigued, pitching on multiple teams, pitching year-round, playing catcher when not pitching, poor mechanics and poor conditioning. So:

• Follow pitch counts and rest days. See our Pitch Smart table and rest guide.
• Take months off. Pitch Smart recommends at least four months off from throwing every year (from competitive pitching for ages 15–18), with 2–3 continuous months.
• Watch for fatigue. ASMI lists slower velocity, lost accuracy, an upright trunk, a dropped elbow and more time between pitches. Stop when you see them, or when there's pain.
• Vary speeds. ASMI recommends pitchers vary their speeds instead of trying to light up the radar gun on every pitch. It's easier on the elbow and good pitching.
• Work on mechanics and conditioning. See the mechanics of pitching and baseball arm care.

A radar gun is a useful tool here, used the right way: to set a baseline, track healthy progress, and spot a velocity drop that says it's time to stop. Not to chase a number every pitch.

Don't just throw hard. Throw smart.

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