有关游泳的英语阅读

Many experts believe that swimming is the ideal all-round exercise. People of all ages and levels of fitness can take part. Swimming, especially the front crawl which requires steady, rhythmic movements, helps to develop aerobic fitness, suppleness, and muscular strength. If, however, you are swimming for fitness you will need to do three or four hard sessions a week. The water supports the body so there is little stress or impact on tendons, ligaments, and joints. This does not strengthen bones, but it does make swimming safer than land-based activities for those whose bones are weakened by osteoporosis. It also makes swimming especially suitable for those who suffer from knee or back problems, or who are slightly overweight. Swimming can also be helpful for people with asthma or bronchitis. Although swimmers are less injury-prone than those involved in high-impact sports which involve running or jumping, they can still suffer overuse injuries. Most injuries affect the shoulder (see swimmer's shoulder). They are usually caused by either poor technique or lack of muscle balance. Competitive swimmers are particularly prone to overuse injuries so they supplement their swimming with land-based training (especially weight training) to rectify muscle imbalances and strengthen muscles. Injuries can also be reduced by using a variety of strokes that develop different muscles of the body: the front crawl helps develop the arms and chest; backstroke develops flexibility of the shoulders; breast-stroke develops the upper arms, chest, thighs, and hips; and the butterfly develops the whole upper body. Although an excellent activity, swimming in cold water may not be a suitable part of a slimming programme because it can stimulate the deposition of fats under the skin to act as an insulating layer.