Grip is a very over looked variable if you ask me. Grip is essential throughout our everyday demands and can play a roll in injuries at the upper body believe it or not as well as it could be a factor in some reasons why you are not progressing faster in certain lifts.
Check this out:
If the elbow flexors, like the biceps are too strong for the forearm flexors, uneven tension accumulates in the soft tissue and results in elbow pain”.
The health of your shoulder and rotator cuff has been correlated to the strength of your grip. It has been discovered that a weak grip can hinder shoulder abduction and external rotaion and as a result can lead to asking too much from the rotator cuff weakness leading to over use injuries.
A powerful grip can be an indicator of how overall strong you are. Shake someones hand, you can tell if they are strong or not. Your day to day grip can also be used as an indicator of your bodies readiness and whether or not you are in a state of fatigue, believe it or not. If on monday you are able to hold a bar really tight and then tuesday you are not, this could actually be signs of neural fatigue, lack of sleep, over training, nutrition assesment amongst a few other factors.
Here are a few ways to improve your grip strength:
1) Take part in more natural human gripping tasks or sports such as gardening, using tools, climbing, trees or ropes, jiu jitsu. Carrying things or anything working with your hands, as there are a ton of muscles in the hands that need to be worked.
2) Perform Pull Ups using all type of hand positions for grip. Under hand, neutral, one hand under one hand over the bar, & especially using a fat grip. The larger surface area creates something your day to day grip may not be used to. For this you can wrap a towel or 2 around the bar.
3) Carry and pick heavy stuff up. Dead lifts are a great option. Try a any style of realitivly heavy Dead Lifts for a set of 10 then hold the final rep at the top. This will give a large amount of tension to the forearms. Also try carrying some dumbells, one at a time, with one hand or one each hand for long distances.
Give this a shot! Hope it helps!