“Everyone wants to be flexible, and there is no question that a certain amount of motion is good and useful. Certainly, stiffness isn’t good and useful. The problem is that too much flexibility can be devastating.”
The problem is that flexibility without the strength to control it will lead to injury, and today’s obsession with yoga and Pilates have lost track of that obvious fact. If you can bend a joint beyond your ability to control it with muscle strength, you risk either tearing the muscles, tendons, or ligaments that support the joint, OR damaging the joint surface itself through abnormal pressure upon it.