Beach Girl Running

Running is a means of terrestrial locomotion allowing a human or an animal to move rapidly on foot. It is defined in sporting terms as a gait in which at some point all feet are off the ground at the same time. This is in contrast to walking, where one foot is always in contact with the ground, the legs are kept mostly straight and the center of gravity rides along fairly smoothly on top of the legs. The term running can refer to any of a variety of speeds ranging from jogging to sprinting. According to legend the first competitive running in ancient Greece took place in the year 776 BCE at Olympia, Greece.
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 uses more energy than walking to travel the same distance. 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.