If you're someone that squats regularly and find it hard or even impossible to step up with any strength on one side, chances are you're favoring one leg in squatting.  Unliateral movements like the step up are great for training and exercise but can also be a sort of diagnostic tool.
Here Steph is showing strength in her left leg, fully extending it before she places the other foot on the box.


5 x 2 Back Squat
*all at the same weight (working sets)

10 minute AMRAP:
5 DB Lunges (25/35lb)
10 DB Front Rack Step Ups
5 DB Lunges
10 Burpees