Traditionally, lifters tend to use an alternated grip when working with heavy loads on the deadlift; that is, one hand being supine and the other prone.
Having both hands pronated while pulling the barbell provides the lifter with a symmetrical shoulder position which avoids the imbalance caused by the alternated grip.
[3] This difference in rotation between the shoulders can create imbalances in the muscles of the back over time.
During a snatch or clean, the lifter can exert forces up to 2-3 times the weight of the loaded barbell at rest, and the hook grip allows an athlete to maintain a grip on the bar during the phase of highest bar acceleration, the second pull.
As a result, it may cause pain or injury to the skin or thumbnail, although this can be overcome by regular training and gradually working with heavier loads.