Here are some quick tips to build massive forearms and bone-crushing grip strength.
1. Train your Forearms at the end of your workouts at least 3x's per week.
2. Do finger pulls and handshake exercises with kettlebells. Also, add kettlebell training to your general workouts. Martial artists and strongmen have been using kettlebells for centuries and they have some of the best forearm strength and grip.
3. Avoid using lifting aids as much as possible. I do not even own lifting straps or hooks.
4. Do your hanging leg raises free-style without ab straps.
5. Perform towel pull-ups if you can.
6. Standard weight exercises that are great include; behind the back wrist curls, and reverse curls.
7. Use Fat Grips (they make your lifting bars thicker and are much cheaper than buying fat bars).
8. Use Heavy Grips. These grippers are the best. They go from 100lbs. all the way up to 500lbs!
9. A forearm developer is also a great forearm tool. It is essentially a broomstick with a rope attached to it. You attach your weights and roll it up.
10. Last, but not least, the simple and highly under-rated/unused exercise of towel wringing. Soak a towel and wring out the water.
