Weighted Balls: Who Should Use Them and Who Shouldn't

Weighted balls are one of the most argued-about tools in pitching. Some pitchers gain velocity with them. Some get hurt. Both things are true, and the difference is mostly in who uses them and how.

What they do

Throwing balls heavier than a baseball (overload) and lighter than a baseball (underload) changes the demand on the arm. Heavier balls build strength in the throwing pattern. Lighter balls let the arm move faster than usual. Plyo balls thrown into a wall with constraint drills are also used to clean up arm path and build capacity at lower intensity.

Where the risk is

MLB's 2024 injury study listed weighted-ball training among the possible contributors to rising injuries, alongside harder bullpens and year-round throwing, according to coverage of the report. The gains from these programs often come with more range of motion in the shoulder and more arm speed, and both raise the stress on the elbow.

The tool is not the whole problem. The problem is high-intensity throwing layered onto arms that are not ready, with no one adjusting the plan.

Who is a reasonable candidate

• Physically mature, usually well into high school or older
• Has a base of strength training
• Has a healthy arm with no current pain
• Has reasonably efficient mechanics
• Has a coach who prescribes the loads, the volume and the rest, and who watches the throws

Who should wait

• Pitchers who have not gone through most of their growth
• Anyone with elbow or shoulder pain, or coming back from injury without clearance
• Pitchers who are not yet lifting
• Anyone planning to follow a program found online without supervision

How to use them well

• Individualize. The right loads and volumes depend on the pitcher. This is why we only use them when prescribed.
• Time it. Higher-intensity weighted work belongs in the off-season, not stacked on a heavy game schedule.
• Count the throws. Weighted throws are throws. They go into the weekly total.
• Do the low-intensity work first. Plyo drills and capacity building come before pulldowns and max-effort throws.
• Stop at pain. Soreness in the muscles is expected. Pain in the elbow or shoulder joint is a stop sign.

Weighted balls are a tool for some pitchers at the right stage. For a 13-year-old who has never lifted, the faster path to velocity is growing, getting stronger and throwing well.