Did you master the first three Single Leg Exercises from the first installment?
Then I have Three More Essential Single Leg Exercises to build strength and stability around the hip and knee joints, to help prevent knee and leg injuries as well as build both balance and strength.
In this video I go over these three exercises and some variations of them:
Hamstring Curls using both furniture sliders and Stability Ball
Front Foot Elevated Lunge or Split Squat
Single Leg Pistol Squat to a Bench
Check it out.