Start with a tall posture and your inner core engaged below the belly button. Vivian here is now going to do a single leg step up. She’s bringing her opposite arm up while also using her butt muscles to fully extend that hip up. She’s keeping her thigh strong by preventing the knee from buckling inwards, as well as also keeping her knee over the heel so it doesn’t go over her toes. Do 3 sets of 10 on each side. The single leg step-up will help you develop more strength in your hips and thighs to keep your knee strong and protect you from ACL knee ligament injuries. It’s also great for post ACL knee surgery rehab when you are ready for it.