Muscles
Take up one idea. Make that one idea your life — think of it, dream of it, live on that idea. Let the brain, muscles, nerves, every part of your body, be full of that idea, and just leave every other idea alone. This is the way to success.
The medical literature tells us that the most effective ways to reduce the risk of heart disease, cancer, stroke, diabetes, Alzheimer's, and many more problems are through healthy diet and exercise. Our bodies have evolved to move, yet we now use the energy in oil instead of muscles to do our work.
Just as we develop our physical muscles through overcoming opposition — such as lifting weights — we develop our character muscles by overcoming challenges and adversity.
You have a right to say no. Most of us have very weak and flaccid 'no' muscles. We feel guilty for saying no. We get ostracized and challenged for saying no, so we forget it's our choice. Your 'no' muscle has to be built up to get to a place where you can say, 'I don't care if that's what you want. I don't want that. No'.
Living the past is a dull and lonely business; looking back strains the neck muscles, causing you to bump into people not going your way.
I suppose leadership at one time meant muscles; but today it means getting along with people.