By BK, Athletic Hitting Development
Complete Hitters Are Built… It’s Earned!
Key takeaways
- In 69 players from 12–14 through college, warm-up swings with heavy or light bats did not raise bat speed in any age group.
- The researchers advise less-experienced teens to skip weighted or lightened bats for warm-up swings.
- Even dry swings changed attack angle in some groups, so the warm-up isn’t neutral. Check the path with a real ball.
- Warm up with your game bat, at game speed, and get your timing going.
The donut makes the bat feel light. It doesn’t make the bat faster.
A bat donut makes the game bat feel light, but it doesn’t make the swing faster: in 69 players from 12–14 through college, heavy or light warm-up bats didn’t raise bat speed in any age group. Warm up with your game bat at game speed and time the pitcher instead.
Train it: Athletic Development Masterclass →That’s not my opinion. That’s what the radar said.
1. What the study tested
Researchers took 69 baseball players in age groups from 12–14 all the way through university and randomly assigned them to warm up with a normal bat, a heavy bat or a light bat. Then they measured bat speed and attack angle.
The result was simple. Warm-up swings with heavy or light bats did not raise bat speed in any group. Not the 12-year-olds. Not the high schoolers. Not the college players.
Something else showed up. Attack angle shifted after normal-bat dry swings in the 12–14 group and in the university group. And the authors went a step further: they advise less-experienced adolescents to avoid weighted or lightened bats for warm-up swings altogether.
2. Feel vs Real on deck
Every hitter knows the feeling. Swing the heavy bat, drop the donut, and the game bat feels like a toothpick. That’s the feel.
The real is what the bat actually does. In this study, the heavy and light bats didn’t move the needle on bat speed. If you want the full story on why what a hitter feels and what’s happening don’t always match, read Feel vs Real in Hitting.
A light feeling isn’t a fast swing.
Here’s my coaching read. Bat speed isn’t in the arms. It’s built from the ground up: ground, hips, core, then hands. A heavy bat on deck mostly loads the arms and hands. It doesn’t teach the body to sequence faster. That work gets done in training, through the Strength & Explosiveness pillar, not in the 90 seconds before you hit.
ON-DECK REALITY CHECK
GAME BAT.GAME SPEED.
- Heavy bat: no bat speed gain.
- Light bat: no bat speed gain.
- Warm-ups can shift attack angle.
- Rehearse the swing you’ll use.
A LIGHT FEELING ISN’T A FAST SWING.
3. Why attack angle matters more than you think
The study found attack angle moved in some groups. That tells you the warm-up isn’t neutral. What you rehearse on deck can show up in the box.
A young hitter’s path is still being built. You want the barrel above the ball, the barrel working behind the hands (bat lag), and a path that matches the plane of the pitch. Those are Mechanically Advantaged Angles. An MAA is an advantage, not a rule, but it’s an advantage you don’t want to scramble right before an at-bat.
So the warm-up job is to rehearse the swing you’re about to use, with the bat you’re about to use, at the speed you’re about to use it.
4. What to do on deck instead
- Game bat onlyLeave the donut in the bag. Warm up with the bat you’ll hit with.
- Get athleticA few loose, easy swings to find your setup and athletic position. Start athletic. Stay athletic. Finish athletic.
- Build to game speedFinish with a few full-intent swings. Not max effort chaos. Your real game swing.
- Time the pitcherLoad and launch with the pitcher’s delivery. See It, Time It. Your timing is warming up too.
- Know your planWalk up knowing your heater zone. Ready for the heater, adjust to the hanger.
5. For parents and coaches
If your 13-year-old has been swinging a weighted bat on deck for years, don’t panic. Just stop. Based on this study, he isn’t losing anything by putting it away, and the authors specifically say kids at his experience level should skip it.
Coaches running team practice: build one on-deck routine for the whole roster and stick to it. Then look at the cage, not the on-deck circle, to grow bat speed. If you want to know where speed actually comes from, start with How to Increase Bat Speed With Rotational Power.
And if you’re not sure what your hitter needs most, the swing, the strength, the processor or the mental approach, find out before you buy another training gadget.
Quick answers
Does swinging a weighted bat on deck increase bat speed?
In a study of 69 players from ages 12–14 through college, warm-up swings with heavy or light bats did not raise bat speed in any age group.
Should youth hitters use a bat donut?
The researchers advise less-experienced adolescents to avoid weighted or lightened bats for warm-up swings. Warm up with the game bat instead.
Why does the game bat feel lighter after a donut?
That’s feel, not real. The bat feels lighter, but in this study the measured bat speed didn’t go up.
What’s the best on-deck warm-up?
Game bat, a few easy swings to find your athletic position, a few full-intent game swings, and timing your load to the pitcher’s delivery.
Can on-deck warm-up swings change a hitter’s swing path?
Yes. In the study, attack angle shifted after warm-up swings in some groups, so the warm-up isn’t neutral. Rehearse the swing you’re about to use, with the bat you’re about to use.
Research: Li H et al., “Impacts of dry swing intervention on bat speed and attack angle: an analysis of core intervention factors,” Frontiers in Sports and Active Living (2025). Findings are from the published abstract; 69 baseball players split across several age groups means small groups, and it did not test fastpitch softball players.
Don’t collect drills. Build a complete hitter.
Complete Hitters Are Built… It’s Earned!
This article is part of the AHD guide Bat Speed & Power Training. Start there for the full picture and every related article.
