Update:
While grip training itself is unnecessary for bodybuilding, direct forearm work may contribute toward an impressive and balanced physique. Wrist curls, reverse wrist curls, hammer curls, and reverse curls work better than grip training. Nonetheless, many trainees find that gripping alone, especially on pulling exercises, develops their forearms well; direct work is a personal call.
The muscles of the hand and forearm adapted to grip objects. These muscles get trained naturally through the essential pulling movements. A row should address them sufficiently. This counts as grip training. Keep in mind that the muscles of the grip will never contribute power. They can only maintain it. Nonetheless, a strong grip can become a devastating tool in athletics. This applies especially in sports such as wrestling or football.
Two grip patterns emerge: the power grip and the precision grip. The power grip uses the full strength of the muscles. This means holding the object between all the partially flexed fingers in the palm. The thumb then applies counter-pressure. This holds the object firmly in place. The precision grip pinches the object between the flexor surfaces of some fingers with counter-pressure from the thumb. This emphasizes the refinement needed for small, accurate movements. Enhancing grip strength therefore requires placing the thumb in a position parallel to the fingers. This means you need the power grip.
Stabilizers activate with little or no movement. Muscles playing this role often have less potential for growth due to their anatomy. They are small but work with greater leverage. This perfectly describes the muscles of the hand and forearm. Stabilizers allow the prime movers to contract optimally. Muscles work optimally when stabilizers perform their role fully. Relaxing the stabilizing musculature during exercises in an attempt to improve form actually inhibits the prime movers from contracting intensely.
Many trainees find that a tight grip facilitates better performance in the big lifts. For example, squeezing the barbell tightly on the bench press tends to increase strength during the set. This may occur due to a better mind-muscle connection or other neural factor. Would a stronger grip enhance this effect, or does the mere act of holding the bar tightly, regardless of strength, lead to this effect? I do not know either way. I suspect the mere act ranks most important.
The wrist will slightly extend when closing the hand to maintain a favorable length-tension relationship for the involved muscles. The muscles attached can perform flexion, extension, abduction, adduction, pronation, and supination of the hand and wrist. They exist to transfer force from larger muscle groups, and although movement remains possible in all directions, these actions should occur unloaded to avoid joint stress. The hand alternates between positions of great mobility and stability. It remains most stable when grasping a heavy object. Pushing and pulling movements involve the safest ways to naturally train the muscles of the wrist and hand.
Wrist curls and reverse wrist curls can place shearing force on the wrists, like any single- joint exercise. Imagine trying to snap a pencil with your hands. This mimics the effect your wrist experiences during these movements. Pinch gripping may place too much stress on individual fingers, since this option adapted only for precision. The hand evolved to work as a unit. Many small muscles work simultaneously to maintain a grip. These choices undoubtedly train the muscles, but also pose an unnecessary risk.
Any exercise testing your ability to hold on to the weight will improve your grip. Gripping involves all the forearm and hand muscles. Squeeze your hand in a fist as tightly as possible. Take your other hand and feel the active forearm. You’ll notice that the muscles for both the front and back generate tension intensely. Simply grab an object with your hand almost fully wrapped around it. You have discovered the position that best and safely works all the involved muscles. You do not need to complicate this further.
If your grip needs strengthened, reconsider the issue first. You may require chalk. The diameter of the bars you use may feel too great. Do not rely on straps. First try to discover the root of the problem. In almost all cases, chalk and using less thick bars and handles will correct the matter.
Avoid grip training.