What is physical exertion?

Famous quotes containing the words exertion and/or physical:

    Compare society to a boat. Her progress through the water will not depend upon the exertion of her crew, but upon the exertion devoted to propelling her. This will be lessened by any expenditure of force in fighting among themselves, or in pulling in different directions.
    Henry George (1839–1897)

    Let us hope ... that by the best cultivation of the physical world, beneath and around us; and the intellectual and moral world within us, we shall secure an individual, social and political prosperity and happiness, whose course shall be onward and upward, and which, while the earth endures, shall not pass away.
    Abraham Lincoln (1809–1865)