Muscles are what protect your joints. I work a lot with hands, and often patients’ range of motion (ability to move) comes before they are physically able to tolerate the forces produced when using that hand.
Let me explain: you may be able to fit your hand around the lid of that tight jar. You may even be able to hold on tight enough to the lid to try and get it open. However, if the muscles around the thumb are not strong enough to reduce the 40 lbs of torque when you try to open the jar, that torque will be transferred to your joint. Then the non-contractile tissues, the ligaments and joint capsule, will be stressed instead of your muscles. These tissues do not tighten to resist force; rather, they act like a rope. They can only take a specific amount of force before they start to fray or snap. The more repeatedly you put force through the joint instead of the muscle, the more likely that tissue will begin to fail. Just because you can do something does not mean your muscles are strong enough to do it safely.