Bar them, we would not be able to breathe or digest. In addition, these allow childbirth, posture and stability.
We think rarely about our muscles when we think about our general health. Yet, they take up 40% of our total mass, and no animal, let alone any human, could live without them.
We have three main groups of muscles: the skeletal muscles, the visceral muscles, and the cardiac (heart) muscle. The first group is a voluntary and the last two involuntary muscle groups. (In this case voluntary and involuntary means whether we can decide to use the muscle to pull something: a wrist, a knee, a corner of a lip). Although the common wisdom has it that our muscles number about 640, that is based on counting the skeletal muscles and ignoring for instance such muscles as the tiny, tiny ones that makes our hair stand up when we have a fright or feel deeply emotionally moved. (There are about 5 million hair follicles on our bodies). Therefore, it is much more accurate to consider that we have millions of muscles. And we cannot gain or lose them through the course of an ordinary life: we can merely bulk them up by working them out (that’s called hypertrophy) and shrivel them to mere ghosts of themselves by sitting on the couch the whole day long (called atrophy). Each muscle contains special cells, called fibers, which allows the muscle to contract. This contraction then gets conveyed to the bone by means of a tendon to which both the muscle and the bone is connected. Muscles can only pull by such contraction, not push.
Muscle health comprises of great hydration, eating a balanced meal, exercising for at least 30 minutes a day, and then not forgetting to stretch, warm up or cool down.
If we hope to stay young and healthy deep into our eighties, doing the simple things mentioned above, will be part of achieving that, and at least keep us limber, spry and warm in the winters (our muscles supply almost 85% of the heat of the body) on the journey.