Sometimes Functional Health just comes down to strategy. For example, when you carry a heavy bag–groceries, briefcase, luggage–you can hold it with your hand, requiring the small joints of your fingers to support it. You can rest it on your forearm so that your elbow does the work. Or you could put it up on your shoulder. Which option do you think causes the least amount of joint stress?…
When it comes to protecting your joints, carrying it on your shoulder is definitely the way to go.
A larger joint allows the weight of the bag to be distributed over a larger area, diffusing the burden; whereas with a smaller joint, the burden is much more concentrated, increasing the stress on the joint. The smaller the joint, the more intense the stress. More stress=more wear and tear=more risk of, or pain from, arthritis. So it is always preferable to use the largest joint available for the job.
The oft-heard recommendation to lift with your legs not your back (i.e. to squat down rather than bend forward from the waist) stems in part from this same rationale. Better to use your hips to bear most of the burden rather than your smaller spine joints.
TIP: When it comes to sparing your joints, one good strategy is to use the biggest joint possible for any given task.