Running is a method of terrestrial locomotion allowing humans and other
animals to move rapidly on foot. Running is a type of gait characterized
by an aerial phase in which all feet are above the ground (though there
are exceptions).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 vaults over the stance leg or legs in an inverted
pendulum fashion. A feature of a running body from the viewpoint of
spring-mass mechanics is that changes in kinetic and potential energy
within a stride occur simultaneously, with energy storage accomplished
by springy tendons and passive muscle elasticity. The term running can
refer to any of a variety of speeds ranging from jogging to sprinting.
Running in humans is associated with improved health and life
expectancy.
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