Weighted Bat Training: Pros, Cons and How to Use It

By BK, Athletic Hitting Development
Complete Hitters Aren’t Born. They’re Built… and Earned.

Weighted bat training works when it’s done right: alternating a slightly heavier bat, a slightly lighter bat and your game bat can add bat speed. Done wrong, with a bat that’s too heavy or too many tired swings, it trains a slower, sloppier swing.

Parents ask me about weighted bats all the time. Usually after a teammate showed up with a new set. My answer is always the same: it’s a tool, not a plan.

Bat speed lives in the Strength & Explosiveness pillar of a Complete Hitter. Overload and underload bats can be part of that work. Here are the honest pros, the cons and how we use them at AHD.

1. Do weighted bats actually increase bat speed?

Yes, with a big “if.” A 2009 research review in the Journal of Strength and Conditioning Research found that training with heavier and lighter bats improved bat swing velocity. The same review recommended warming up with a bat close to game weight, roughly within 12 percent of it.

For a 30-ounce bat, 12 percent is about 3.5 ounces. That’s a small change. Not a sledgehammer.

Heavier isn’t automatically better. In a small 2021 study of nine high school players, a group that trained three weeks with a 45-ounce bat didn’t gain significantly more bat speed than the group that just swung a standard bat. Small study, but it fits what I see every week.

The bat should change the speed. Not the swing.

2. What are the pros of weighted bat training?

• Overload builds strength in the swing pattern. A slightly heavier bat makes the body work harder through the same move.
• Underload teaches speed. A lighter bat lets the hitter feel what it’s like to move faster than normal.
• It rewards intent. Most hitters never practice swinging at 100 percent. Short weighted sets make every swing a max-effort swing.
• It’s cheap and simple. A heavy bat, a light bat, the game bat and 10–15 minutes.
• It’s measurable. Test bat speed the same way every couple of weeks and you’ll know if it’s working.

3. What are the cons and risks?

Most of the problems come from too much weight, too many swings or using the bat for the wrong job.

• Too heavy changes the swing. The barrel drops, the hands cast, the body slows down to manage the weight. Now you’re grooving a different, slower move.
• Too many swings teach tired swings. Once the speed drops, the set is over. Fatigue reps don’t make anybody faster.
• The donut on deck. The same review warned against warming up with the popular donut ring. It produced the slowest bat speed. More on that in Do Weighted Bat Warm-Ups Add Bat Speed?
• Dry swings don’t time anything. Weighted work has no pitch, no timing and no decision. Speed that never meets a moving ball isn’t game speed.
• It can hide the real problem. If a hitter is slow because his sequence is off, a heavier bat just makes a bad move stronger.

4. How do you use overload and underload bats the right way?

Here’s the simple version we use with hitters 13 and up who already have a sound swing.

1. Warm up firstMove, get loose, then a few easy swings with the game bat. Never start cold with the heavy bat.
2. Heavy batA few full-intent dry swings with a bat only slightly heavier than game weight. Same swing, same finish.
3. Light batA few swings with a slightly lighter bat. Move it as fast as you can. Controlled violence.
4. Game batA few swings with the game bat. This is the one that counts, so it always comes last.
5. Repeat and stopTwo or three rounds, rest between rounds. When the speed drops or the swing changes, you’re done.
6. Take it to a ballFinish with front toss or live at game speed so the new speed meets a moving pitch.

Parents, film one round from the side every couple of weeks. Line up the heavy-bat swing next to the game-bat swing. If they don’t look like the same swing, lighten the heavy bat or drop it for now.

Two or three short sessions a week is plenty. It’s the same dose we use in Bat Speed Drills That Transfer to Games.

5. Who should use weighted bats, and who should wait?

Weighted bats make a good swing faster. They don’t build the swing.

• Good fit: a high school or college hitter with a sound swing and some strength base who wants more speed.
• Wait: a hitter who casts, drops the barrel or loses posture with the game bat. Fix the swing first.
• Wait: a hitter who is fast in the cage and late in games. That’s usually timing, not bat speed.
• Pair it: with strength and rotational power work. The bat can’t outrun the body swinging it.

AHD hitters build Mechanically Advantaged Angles (MAA) first. Then speed work has something good to make faster. For the body side, read Increase Bat Speed With Rotational Power.

6. Where should a hitter start?

Before you buy a set of weighted bats, find out what’s actually holding your hitter back. The free SwingChecker™ takes about 3 minutes and ranks the top priority across all 4 pillars.

If it’s speed and strength, the Athletic Development course is 24 lessons for $139, one-time price, and Lessons 1–3 are free. If it’s the swing, start with Swing Structure & Mechanics. Aggressive and athletic, built the right way. It’s a great day to hit!!

AHD • BACKSPIN2/2

THELESSON.

• A tool, not a plan
• Fix the swing first
• Train speed early, while fresh
• Prove it against a moving ball

Complete Hitters Are Built…Earned.

AHDBackSpinAthletic Hitting Development

Want to go deeper? Read Bat Speed Drills That Actually Transfer to Games and The On-Deck Donut Myth.

Quick answers

Sources: Szymanski, DeRenne & Spaniol, “Contributing Factors for Increased Bat Swing Velocity,” Journal of Strength and Conditioning Research (2009) · Crocker, Dow & Kraft, “Effects of Various Training Techniques on Bat Velocity of High School Baseball Players,” Arkansas Tech University (2021)

Don’t collect drills. Build a complete hitter.

Complete Hitters Aren’t Born. They’re Built… and Earned.