I very much dislike a situation in which a lifter trains very diligently only to miss makeable lifts due to a lack of skill, knowledge or proper strategy. This situation happens all too frequently in the execution of snatches and jerks.
I see many snatches that are lost because the lifter feels the need to squeeze the bar while dropping under to catch the weight overhead. Tightening the grip is unnecessary as the bar is not going to fall out of the hands. Furthermore tightening the grip causes tension that inhibits the rapid extension of the elbow. The arms should be pushing the body under the bar rapidly and this is best facilitated by a relaxed grip. “White knucklers” result in athletes hitting the deep squat with the elbows still partially bent and not in position to support the barbell overhead.
Remember the essence of athleticism is to contract and relax the muscles at exactly the precise moments required to make for a rapid and/or smooth movement pattern. Too many athletes are preoccupied with muscular contraction, and not nearly enough practice proper muscular relaxation. The full, simultaneous and rapid contraction of all the skeletal muscles is what happens during a grand mal seizure, hardly an athletic movement pattern.
The same problem of an excessively tight grip also inhibits many jerks from being completed. Many lifters are too tense during the execution of the jerk and anxiously tighten the grip while driving the weight overhead. This slows down the elbow extension and the weight is lost because the arms are not fully straightened when the split stance is achieved.
Why go to the trouble of explosively propelling the barbell overhead if you are going to inhibit the completion by overtightening the grip at the critical instant of completion? Relax your grip and make more lifts.