2013年6月四级单项选择阅读理解附讲解详解

　　Walking, if you do it vigorously enough, is the overall best exercise for regular physicalactivity. It requires no equipment, everyone knows how to do it and it carries the 47 risk ofinjury. The human body is designed to walk. You can walk in parks or along a river or in yourneighborhood. To get 48 benefit from walking, aim for 45 minutes a day, an average of fivedays a week.

　　Strength training is another important 49 of physical activity. Its purpose is to build and 50bone and muscle mass, both of which shrink with age. In general, you will want to do strengthtraining two or three days a week, 51 recovery days between sessions.

　　Finally, flexibility and balance training are 52 important as the body ages. Aches and pains arehigh on the list of complaints in old age. The result of constant muscle tension and stiffness ofjoints, many of them are 53 , and simple flexibility training can 54 these by making musclesstronger and keeping joints lubricated (润滑 ). Some of this you do whenever you stretch. Ifyou watch dogs and cats, you’ll get an idea of how natural it is. The general 55 is simple:whenever the body has been in one position for a while, it is good to 56 stretch it in anopposite position.

　　47. H. lowest

　　48. J. maximum

　　49. D. component

　　50. I. maintain

　　51. A. allowing

　　52. G. increasingly

　　53. B. avoidable

　　54. K. prevent

　　55. L. principle

　　56. C. briefly