Running is a method of terrestrial locomotion by which humans
and other animals move rapidly on foot. Running is a gait with 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 co-occur, with energy storage accomplished by springy
tendons and passive muscle elasticity. The term "running" can refer to a
variety of speeds ranging from jogging to sprinting. It is hypothesized
that the ancestors of humankind developed the ability to run for long
distances about 2.6 million years ago, probably to
hunt animals. Competitive running
grew out of religious festivals in various areas. Records of competitive
racing date back to the Tailteann Games in Ireland between 632 BCE and
1171 BCE, while the first recorded Olympic Games took place in 776 BCE.
Running has been described as the world's most accessible sport.