Deadlift Grip Q&A
Question: when should I switch to the alternate grip in the Deadlift?
Answer: when the weight becomes too heavy for overhand grip.
I see a number of people execute all of their deadlifts via the alternate grip (mixed grip) -- where one hand is supinated and the other is pronated. The contrasting forces, one pulling and one pushing, allow the hands to hold more weight.
Why do I say wait to switch your grip until the weight becomes too heavy? In many cases, one's potential in the deadlift is limited by grip strength. If you switch your grip too early, you'll fail to reap the benefits that come from overhand grip; practicing this method will only prove beneficial after you switch grips and begin to pull really heavy weight.
Note: I don't recommend learning to pull with the alternate grip once you hit your big numbers. If you think you're ready to make a switch, deload and practice the alternate grip with lighter weight. Progressively work up in poundage so that you feel comfortable pulling via this method. After time, the movement will become more natural, even normal. But, even at this point, don't neglect the more conventional overhand grip; incorporate both pulls into your routine.