I learned of this exercise from Jeff Connors, head strength and conditioning coach at East Carolina University. I worked for Coach Connors when he was at the University of North Carolina.
Coach Connors uses this exercise with athletes who have back problems that prevent them from doing heavy spinal loading exercises like squats, deadlifts, cleans, etc.
This exercise will quickly have your quads and glutes burning and I agree with Coach Connors that this is a great lower body exercise for those that need to limit spinal loading.
In the video I am using a home made suspension training system but this could easily be performed by using ropes tied to a stable surface overhead.