Forearm strength is more crucial than you would imagine. It not only improves grip strength, but it also helps to avoid injuries. Weak forearm strength might also have an impact on your workout. Lifting weights, such as dumbbells, will become more difficult if you lack the strength to correctly hold them. In addition, strong forearms help prevent injury. When punching or hitting a heavy bag, if you are weak at holding onto objects, you are likely to be injured. The same thing goes for those who exercise with kettle bells or other weight-based training tools; if you are weak, you are more likely to hurt yourself during a move that requires force to be applied rapidly and accurately toward the body. Finally, strong forearms make it easier to lift heavy objects. This is particularly important if you plan to work out of a garage or small room where lifting items is necessary to use various equipment. If you aren't strong enough to handle a pair of dumbbells, for example, you'll need to find something else to work out with. There are two main groups of muscles that control the strength of the forearm: flexors and extensors. Flexors shorten when they contract while extensors lengthen when they contract.