Straightening your knee in an open kinetic chain situation increases the flexion moment from the limb weight (F) and the ankle weight (F). At full extension the entire weight is perpendicular to the moment arm while at ~90 degrees, barely any weight acts perpendicular. What is the muscle force of the quad at the following angles? 0 degrees (full extension) 45 degrees 70 degrees How much more force is required when your leg is at full extension compared to at 70 degrees? +M -M