The Single Leg RDL is not only a progression of the bilateral RDL but can also be used in your knee injury prevention and athletic development.
The Single Leg RDL increases your glutes, hamstrings, and lower back strength. It also improves your hip stability and balance. When you look at it from a sports performance perspective, it will strengthen your posterior chain which will help improve your top-end speed and running mechanics.
Perform the Single Leg RDL by balancing on one leg holding a kettlebell or dumbbell in opposite hand. With the balancing leg slightly bent and back flat, bend forward at the waist until kettlebell is just above the floor. You can also lower the kettlebell all the way to the ground, if possible, to a complete stop in order to be more stable during the concentric portion of the movement as you flex the glute to extend the hip and return to starting position.
Do 3-4 sets of 8-10 reps per leg during your next training session. Use this exercise as an accessory movement to you squats and deadlifts.