whoever thinks strength dose not matter in a fight is dreaming.Technique is essential along with great cardio but speed and espically strength can be the deciding factor is many matches.You could have beter technique then your opponent but if he is stronger then you it may take you a long time to tap him out...espically when your on the bottom,espically if he has even a little wrestling experience...nevermind jits training thats tough.Having an iron clad grip along with great forearm strength is a huge advantage when you use it to control the arms or neck or whatever so they cant wiggle free while you lock on the sub,this is espically good in the street if you ever have to get arm control and escape the bottom position and get to your feet.Their are many ways to train for this, however i think wrist curls are most effective ways to train it...try it out and see how its works for you.