Motion
Humans leap from one leg to the other while running. Each leap raises the center of gravity during take-off and lowers it on landing as the knee bends to absorb the shock. At mid arc, both feet are momentarily off the ground. This continual rise and fall of bodyweight expends energy opposing gravity and absorbing shock during take-off and landing. Running on a track requires more energy per unit distance than walking to cover the same distance. As reported by Hall et al. males on a track running at a pace of 2.82 m/s use 1.41 times as much energy to travel the same distance as walking at a pace of 1.41 m/s, with similar values on a treadmill. Therefore, running is less efficient than walking in terms of calories expended per unit distance, though it is faster.
In 2004, scientists at the University of Utah and Harvard University hypothesized that the ability of humans to sustain long-distance endurance running may have been instrumental in the evolution of the human form.
Read more about this topic: Running
Famous quotes containing the word motion:
“On board ship there are many sources of joy of which the land knows nothing. You may flirt and dance at sixty; and if you are awkward in the turn of a valse, you may put it down to the motion of the ship. You need wear no gloves, and may drink your soda-and-brandy without being ashamed of it.”
—Anthony Trollope (1815–1882)
“in the mind of man,
A motion and a spirit, that impels
All thinking things, all objects of all thought,
And rolls through all things.”
—William Wordsworth (1770–1850)
“A field of water betrays the spirit that is in the air. It is continually receiving new life and motion from above. It is intermediate in its nature between land and sky.”
—Henry David Thoreau (1817–1862)