Although this is going to be about muscles and joints, I will not bore you with anatomical diagrams. Look instead at these paintings of people socializing in large groups unafraid and having a great time. The 17th century painting by Pieter Brueghel, 19th century canvas by Auguste Renoir and a modern work by James Sparks, all portray the world which we've enjoyed for thousands of years, took for granted and temporarily lost almost overnight. When people talk about the quarant