I just have a quick question about strength and conditioning. Should we use full range of motion during exercises, so we can improve the range of motion in our joints, or should we stop at 90 degrees with a healthy individual with no joint problems?
Full range of motion is the best way to train individuals for two reasons: performance and joint stability. Ask any soft tissue specialist. People who complain of weight training injuries are the ones that have followed the stop at 90 degrees paradigm. There is plenty of evidence that partial range training actually has the long term consequence of destabilizing the joint, whether it is the shoulder or the knee joint. Also, both research and practical experience have shown that partial movements produce inferior results for improving sports performance. For example, full squats improve the vertical jump dramatically while half squats only marginally improve the vertical jump.
I hope this answers your question!