I personally Love the deficit deadlift. Even when I was terrible at them I could instantly feel my gluteus and quads turn on more than when I just pulled from the floor. And there is a great reason for this, greater range of motion. In the game of life, added strength through greater range of motion sounds like a recipe for success.
Louie Simmons of Westside Barbell uses many different methods for his squat, deadlift and bench lifters. He cycles box height, bar depth, and deficit height to keep the training always moving forward. The deficit deadlift is a great tool to practice the initial pull from the floor for those that can keep the spinal posture intact. Increasing your awareness of spinal posture will help you from getting injured when pulling from the floor at maximal load.
As I will note in the Strength Development, the height of the plate will be variable or in the case that you do not have the hip flexibility or hamstring flexibility, you will use no plate at all. Once again, your spinal posture is paramount to any weight or deficit in the deadlift.
So lift happy, and do not expect to automatically use your 1RM as a base number. Expect 10-15% less strength for every 2 inches you go deficit. Don't go over 4".
8 SDHP 75/55
8 Walking Lunge
8 Mountain Climbers
2 Wall Climbs
Deficit Deadlift 2-4"
5X3 Across All Sets.
*key is to not go over 25 reps while building up to your heavy load.
Handstand Push Ups