In short; mix grip is ok every once in a while for heavy lifts, the rest of the time use overhand grip or hook grip. The following is our reasoning for always lifting with an overhand grip, specifically as it relates to the deadlift strength portion of our program. This does not apply for competitions, WODs and max effort deadlifts.
Yes, you are stronger when you are lifting mixed grip, but you are at an advantage when training with a double overhand grip or hook grip for CrossFit and longevity. Completing your deadlifts with an overhand grip during our strength portion of the daily programming will translate into better grip strength in WODs and when lifting heavy cleans. If you start with a mixed grip in your deadlift, you will have no where to go when your grip starts to fail!
It can also help to keep us from creating or increasing imbalances. Using a mixed grip puts our shoulders in different positions when lifting, which isn't ideal if you already have any shoulder imbalances, especially when lifting heavy weights for high reps. Using a mixed grip can also cause you to slightly rotate towards the palm open side as you lift. This isn't a problem if you use mix grip every once in a while, but you can see how it may be an issue if you continually deadlift this way.
This article is a very extensive step by step guide to the proper deadlift. Skip to the section on "Grip" to read about why we use double overhand grip when deadlifting most often.
On a side note there are some great cues in this article on hand placement if your hands hurt during deadlifts.
The proper way to grip the bar on Deadlifts is low hand. Hold the bar lower, close to your fingers. Put it on top of your main callus not above them. This stops the bar from folding and squeezing your skin. Your hands will no longer hurt and you’ll quit forming big callus that easily tear.
See you all Thursday for some deadlifts!