ProNine Underload Training Bat – Bamboo – 33 Inch 27 oz

The ProNine Underload training bat is the fast half of speed training: a durable bamboo bat at 33 inches and 27 oz, light enough to swing faster than game weight and teach the body what faster feels like. Sold individually.

Training the Speed Side

Underload work is the overspeed principle from sprint and throwing programs applied to the swing: move lighter faster, and the nervous system learns to fire at rates a game-weight bat never demands. ProNine builds the Underload as a light bat to train speed, full stop.

Half of a System

The Overload bat is the strength half; this is the speed half. Alternate rounds of each, finish on the game bat, and keep the reps in tee and soft toss work where mechanics stay honest.

Where It Fits

Fastpitch players have their own tool in the FPWTB weighted fastpitch trainer, and path work belongs to the Ideal Path. The full rack lives in the training bats collection.

Like all ProNine training bats, it is built for tee work and soft toss: ProNine does not recommend training bats for live pitching, and that honesty is why they last.

ProNine Underload Bat Specifications

• Length: 33 inches
• Weight: 27 oz
• Material: Durable bamboo
• Sold as: Each

Is 27 oz really an underload?

For most adult players swinging 30-31 oz game bats, yes: a 3-4 oz drop is squarely in the common underload band. Youth players swinging lighter game bats should treat it as closer to game weight.

How many underload swings per session?

Quality beats volume: short, maximum-intent rounds with full recovery. When swing speed visibly drops, the set is over.