Why You Should Stop Throwing Weighted Balls for Velocity

By: Dr. Carmen Jansante, PT, DPT, CSCS

Undefeated Physical Therapy & Performance

Increasing throwing velocity is on the mind of almost every baseball and softball athlete. Because of that, weighted-ball and plyometric ball programs have become extremely popular. They’re marketed as the fastest way to gain velocity—but the truth is, they often come at a massive cost to the long-term health of your arm.

As a physical therapist who works with throwing athletes every day, I want to break down why weighted-ball programs can be dangerous, what the research actually shows, and what you should be doing instead to build long-term, sustainable velocity.

Throwing Is Already Extremely Stressful on the Arm

Throwing a baseball is one of the most violent movements in all of sports. During maximal external rotation—your layback position—the elbow experiences approximately 60 pounds of force. Keep in mind:

• A regulation baseball weighs 5.0–5.25 ounces.

• That tiny object still produces massive torque on your elbow, shoulder, and wrist.

Now imagine taking that same movement and adding extra load.

Weighted-ball programs often include balls ranging from 7 ounces all the way up to 32 ounces—which is nearly seven times heavier than a regulation baseball. If a 5-ounce ball already creates 60+ pounds of stress, what do you think happens when you more than double, triple, or even multiply the load by seven?

You’re drastically increasing the force absorbed by the ligaments, tendons, and muscles in the arm—especially the UCL (your Tommy John ligament).

What the Research Actually Shows

Weighted-ball advocates often promise quick velocity gains—but the research paints a much different picture.

1. Increased Injury Risk

A major study found that 25% of players in weighted-ball programs sustained a shoulder or elbow injury during or after the program.

These weren’t small tweaks—these were injuries that impacted their season.

2. Professional pitchers using weighted balls get hurt more

A recent analysis (Shanley et al., 2024–2025 preliminary professional data) showed:

• Higher injury rates in pitchers who used weighted-ball training compared with those who didn’t.

• Multiple exposure-based comparisons all pointed to the same conclusion: weighted balls = more injuries.

3. Increased stress on the UCL

Research from Reinold et al. (2018) showed that weighted balls:

• Increase elbow torque

• Increase stress on the UCL

• Increase external rotation beyond natural limits

More external rotation might sound good for velocity—but it comes at the cost of your ligament health.

4. Mechanics get altered

Dr. Glenn Fleisig and Dr. James Andrews—two of the top throwing researchers in the world—have shown that weighted balls:

• Alter throwing mechanics

• Change arm slot

• Cause compensation patterns

A heavier ball naturally pulls the arm down or forces the athlete to artificially raise the arm slot to compensate. Either way, those mechanics don’t translate to the mound—but the damage does.

Why the “Strong Arm” Myth Is Wrong

Many athletes (and coaches) think throwing velocity comes from a “strong arm.”

That’s not true.

The arm finishes the throw. It does not create the throw.

Velocity comes from:

• Lower body power

• Core rotation

• Ground reaction force

• Sequencing

• Timing

• Mechanics

The arm simply transfers the energy produced by the entire body.

If your body isn’t doing the work, your arm will—and that’s how injuries happen.

So What Should We Do Instead?

If weighted balls are risky, what actually works to safely build velocity?

1. A Customized Arm Care Strength Program

This should target the muscles most active during throwing:

Rotator Cuff

• External rotation

• Internal rotation

• Sidelying ER w/towel

• Full-can raises at 45° (scaption)

Scapular Stabilizers

• Serratus anterior (punches, wall slides, bear crawls)

• Lower trap (Y raises, prone Y’s)

Posterior Shoulder + Decelerators

• Prone T’s and I’s

• Reverse fly variations

• Eccentric-focused work

These muscles allow the arm to withstand—and safely decelerate—the forces of throwing.

2. Lower Body Strength Training

Research clearly shows that most throwing force originates from the glutes and core.

That means your training MUST include:

• Squats

• Trap bar deadlifts

• Split squats

• Lateral lunges

• Hip rotation strength work

If your lower body is weak, your arm pays the price.

3. Rotational Core Training

Throwing is a rotational sport.

This means training needs to include:

• Med ball rotational throws

• Anti-rotation exercises

• Pallof variations

• Cable/T-band rotations

• Hip-to-shoulder sequencing drills

4. A Graded, Progressively Loaded Throwing Program

This is the safest and most effective way to build velocity.

A proper program includes:

• Gradual volume increases

• Long toss 1+ times per week

• Planned ramp-up phases

• Deload weeks

• Varying intensity (not max-effort every session)

• Mechanical efficiency focus

This approach builds skill and arm resilience—not just momentary velocity spikes.

5. What Weighted Balls Can Be Used For

Weighted balls aren’t completely useless—they’re just misused.

Acceptable uses:

• Light warm-up

• Slightly heavier balls (6–7 oz)

• Low-intent patterning

• Feeling the arm path

• Tempo work

NOT acceptable for:

• Max-effort throws

• “Pull-downs”

• Slam throws into a wall

• High-volume velocity sessions

Max-effort weighted-ball training is where most of the injury risk exists.

Final Thoughts

Yes—weighted balls can increase velocity quickly.

But they also significantly increase injury risk, alter mechanics, and put the arm under stress levels it was not built to handle.

If your goal is to stay healthy, durable, and dominant on the mound or field, the best approach is:

• Full-body strength

• A targeted arm care routine

• Rotational power

• A structured throwing program

• Smart workload management

At Undefeated Physical Therapy & Performance, this is exactly what we specialize in.

Need Help With an Arm Care or Velocity Program?

I’d love to help you build an arm care program that fits your body, your mechanics, and your goals.

📲 Text me directly: 412-627-2131

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Let’s get your arm strong, healthy, and built for the long