A well-thrown curveball is one of the most effective weapons in pitching. When it breaks correctly - 11-to-5 or 12-to-6 on the clock face - it is nearly unhittable at any level. When it stays flat, it is a batting practice fastball with worse velocity. The difference is in the grip, the release, and thousands of repetitions training your fingers and arm to fire in the right sequence.
The five products below give you the equipment and knowledge to build that sequence correctly - from the actual baseballs you train with to the pitching aids and books that accelerate the learning curve.
| Product | Type | Best For |
|---|---|---|
| Rawlings Official MLB Baseball | Game baseball | Grip training with correct feel |
| SKLZ Pitching Trainer Pro | Mechanical trainer | Feedback on release mechanics |
| Bownet Pitching Aid Training Tool | Target system | Location and zone training |
| ”The Art of Pitching” by Tom Seaver | Instructional book | Technique and mental approach |
| PowerNet Baseball Pitching Target | Portable target | Backyard training setup |
1. Rawlings Official MLB Baseball
Training with game-quality balls matters more than most pitchers realize. Budget practice balls have different seam height, leather texture, and weight distribution compared to official baseballs - and seam height is directly relevant to curveball grip. The Rawlings Official MLB Baseball uses the same specifications as the big leagues: wool-wound core, full-grain leather cover, and 108 raised red stitches that sit at the correct height for a proper curveball grip.
Pros:
- Game-spec seam height crucial for developing accurate curveball grip muscle memory
- Durable full-grain leather holds up through extended bullpen sessions
- Training on MLB specs removes equipment as a variable when transitioning to game settings
Cons:
- More expensive than practice-grade balls - use for bullpen work, not batting practice
- Not necessary for early learning stages - budget balls are fine for flat-ground warmup
2. SKLZ Pitching Trainer Pro
The SKLZ Pitching Trainer Pro is designed specifically to give a pitcher feedback on release mechanics during solo training. The device attaches to the hand and provides tactile resistance that teaches the correct wrist snap and finger positioning at release - the exact mechanics that produce curveball spin. It is one of the few training aids with a direct mechanical link to breaking ball development.
Pros:
- Direct mechanical feedback on wrist snap and finger position at release
- Usable for solo training without a catcher
- Builds muscle memory for correct release more efficiently than repetition alone
Cons:
- Feedback is tactile, not visual - works best paired with video review
- Less useful for advanced pitchers who already have solid release mechanics
- Requires patience to learn correct resistance during early sessions
3. Bownet Pitching Aid Training Tool
Location is the other half of a useful curveball - sharp break into the dirt is only valuable if it started in the right zone. The Bownet Pitching Aid training system provides a visual target and location feedback during bullpen sessions, helping pitchers develop command alongside pure breaking ball mechanics. Setting up Bownet targets for specific curveball spots (low and away, back-foot to right-handed batter) accelerates zone command development.
Pros:
- Visual target system develops command alongside mechanics
- Immediate feedback on location without requiring video analysis
- Portable and quick to set up for bullpen or flat-ground sessions
Cons:
- Location feedback only - does not address grip or release mechanics
- Best used after mechanics are established, not during early development
- Requires adequate space to set up and throw safely
4. “The Art of Pitching” by Tom Seaver
Tom Seaver won three Cy Young Awards and entered the Hall of Fame with one of the most mechanically precise deliveries in baseball history. His instructional book breaks down every aspect of pitching from mechanics and preparation to in-game strategy and mental approach. The curveball chapters are particularly detailed, covering grip variations, release points, arm speed, and how to set up the breaking ball with fastball tunneling.
Pros:
- Written by one of the game’s all-time great technicians - the information is sound
- Covers mechanics, strategy, and mental game in one volume
- Useful for pitchers at every level from high school through adult leagues
Cons:
- Physical book rather than video instruction - supplement with film study
- Published decades ago - some sections reference outdated training conventions
- Conceptual learning requires patience to translate to physical execution
5. PowerNet Baseball Pitching Target
The PowerNet Baseball Pitching Target is a portable, freestanding target system with clearly marked strike zone sections. Unlike the Bownet which emphasizes pitch-aid mechanics, the PowerNet focuses purely on location training - mount it anywhere with enough clearance and throw. For curveball development specifically, it allows pitchers to target the lower half of the zone where a well-executed curveball should land.
Pros:
- Affordable portable target for backyard or park training
- Clear visual zone sections provide immediate location feedback
- Durable enough for regular practice use
Cons:
- No mechanical feedback - purely a location training tool
- Wind can affect stability of freestanding setup
- Not a substitute for a live catcher with real-time coaching feedback
What to Look For When Building a Curveball Training Setup
Grip consistency. Every curveball session should start with grip practice before throwing. Use a Rawlings or game-grade baseball to train your fingers to find the correct seam pressure consistently across hundreds of repetitions.
Mechanics before speed. Throwing curveballs at maximum effort before mechanics are grooved is how pitchers get hurt. Start at 50-60% effort with correct rotation, build to full effort only when the movement is consistent at lower velocities.
Video review. A phone on a tripod capturing your release point from the side and behind is one of the most valuable training tools available. Check your wrist position at release against the grip you intended to use.
Rest and volume. Breaking balls put stress on forearm pronators and elbow ligaments. Limit breaking balls to 20-30% of total pitch count in bullpen sessions when developing the pitch. Arm care between sessions is not optional.
Final Thoughts
Build your curveball training setup starting with the foundation: Rawlings Official MLB Baseballs for grip training, the SKLZ Pitching Trainer Pro for release mechanics, and Tom Seaver’s book for the conceptual framework. Add a Bownet or PowerNet target when you are ready to layer in location work. The curveball is not a natural pitch - it is a learned skill that rewards systematic, patient development more than raw arm talent.
Frequently asked questions
At what age should a pitcher start throwing a curveball?+
Most pitching coaches and sports medicine physicians recommend waiting until at least age 14-16 before introducing breaking balls. Young arms are more susceptible to UCL strain from curveball mechanics. Focus on fastball mechanics, changeup, and location first. When the arm is physically mature and mechanics are sound, a well-taught curveball adds minimal injury risk.
Does throwing a curveball damage your elbow?+
Research is mixed, but the current consensus is that poor mechanics cause arm injuries more than the curveball itself. A curveball thrown with correct wrist, forearm, and elbow alignment creates no more stress than a well-thrown fastball. What causes injury is overthrowing, improper arm slot, and early arm fatigue from high pitch counts.
What is the best training tool to improve curveball spin?+
A dedicated pitching trainer like the SKLZ Pitching Trainer Pro provides tactile feedback on grip and release point, which are the two variables that control curveball spin rate and axis. Pairing a trainer with a radar gun to measure velocity consistency will give you objective progress tracking as spin and command improve.