The mitral valve is on the left side of the heart. It lets blood flow from the upper to the lower heart chamber. Mitral valve regurgitation is diagnosed when the mitral valve in the heart does not close well, which causes blood to leak back from the left ventricle into the left atrium. Mitral valve regurgitation forces the heart to work harder to pump extra blood out of the heart.
Measurement of a track. The proper length for a competitive running track is 400 m (1,312.3 ft). Some tracks are not built to this specification, instead some are legacy to imperial distances like 440 yd (402.3 m). Prior to rule changes in 1979, distances in Imperial units were still used in the United States.
For the video game, see Track & Field (video game). Track and field is a sport which includes athletic contests established on the skills of running, jumping, and throwing. The name is derived from the sport's typical venue: a stadium with an oval running track enclosing a grass field where the throwing and jumping events take place. Track and field is categorised under the umbrella sport of athletics, which also includes road running, cross country running, and race walking. The foot racing events, which include sprints, middle- and long-distance events, race walking and hurdling, are won by the athlete with the fastest time.