Stronger knees are the result of a variety of factors: the strength of the calves and glutes, the flexibility of the hips and hamstrings and the suppleness of the ankle joint. Strong knees require all the surrounding muscle groups that work in alignment with the joint to be capable of absorbing sudden load, help the joint stiffen when needed and allow it to move freely when necessary. Knee Strength is a workout that addresses all this. Keep it in your favorite workouts and go through it often for strong, healthy, knee joints.
Extra Credit: no rest between sets.