Grip Training for Baseball
Grip training for baseball is unique: it demands an all-around approach. You can't get away with doing only crushing (flexor) work and wrist curls, for example. You'll blow out your UCL in no time (trust me). You might add a little hump on your fastball and you'll have a quicker bat, but with baseball depending so much on the hands and grip, an abriged grip program will leave you at serious risk for injury.
To take full advantage of your grip training, you will want to maintain an antagonist balance, working your flexors and extensors, your pinch and crush grip, ulnar and radial deviation, pronation and suppination, extention and flexion.
All of this is a fancy way of saying vary your grip training.
The many benefits of a good grip program include: increased bat control and speed, sharper rotation on your breaking pitches, more movement on your fastball, more control and better arm action with your circle change, a few more velo points on your fastball, and a more powerful swing through the zone.
For pitchers, aside from the obvious benefits of a stronger grip, the main reason to focus on an all-around grip program is to protect the elbow. Having a strong grip and lower arm takes pressure off the UCL. There's a reason for this: the collateral ligaments hold the elbow joint together and prevent dislocation, and they are put under extreme stress when throwing. The flexor muscles of the forearm, however, attach at the elbow and also provide stability to the joint, and when these muscles are antagonistically strong, you have much more support in the UCL joint.
You will want to find what works best for you and tailor the routine to your position and strengths/weaknesses, but here's an example of a complete grip training program:
Baseball grip strength routine: twice a week
Day 1 (Monday)
1. Warm-up – light CoC gripper (Guide or Sport), 2 sets, 10–15 reps
2. 2 sets with moderate CoC gripper (No. 1 or No. 1.5), 5–8 reps
3. 1 set of 1–3 reps with tough CoC gripper (No. 1.5 or No. 2)
4. Wrist Reinforcer or Heavy Hammer II Leverage Bar – 3 sets with each hand, medium weight until fatigued, 15–20 reps
5. Rolling Thunder or thick-bar deadlifts – 2 sets moderately heavy, 6–8 reps
6. One Wicked Wrist Roller - burn out
7. Expand-Your-Hand Bands – 3 sets x 15 reps
Day 2 (Thursday)
1. Warm-up – light CoC gripper (Guide or Sport), 2 sets, 10–15 reps
2. 2 sets with moderate CoC gripper (No. 1 or No. 1.5), 5–8 reps
3. 1 set of 1–3 reps with tough CoC gripper (No. 1.5 or No. 2)
4. Wrist Reinforcer or Heavy Hammer II Leverage Bar – 3 sets with each hand, medium weight until fatigued, 15–20 reps
5. Rolling Thunder or thick-bar deadlifts – 2 sets somewhat heavy, 6–8 reps
6. Twist Yo' Wrist - medium weight until fatigued
7. One Wicked Wrist Roller - burn out
8. Expand-Your-Hand Bands – 3 sets x 15 reps
Zenith Gripper (Trainer or 1) - off days - 10-15 reps, 2-3 sets, active rest work
Expand-Your-Hand Bands - off days - 10-15 reps, 2 sets
Further reading:
IronMind Wrist/Forearm Strength Tools
Hand Grippers Training and FAQ
Elbow Injuries in the throwing Athlete
Grip Periodization for Baseball and Softball
Carousel photos Hunter Pence and Buster Posey by SD Dirk - CC BY 2.0