Race walking shares many fitness benefits with running, research shows, while most likely contributing to fewer injuries. It does, however, have its own problem. Race walkers are conditioned athletes. The longest track and field event at the Summer Olympics is the 50-kilometer race walk, which is about five miles longer than the marathon. But the sport’s rules require that a race walker’s knees stay straight through most of the leg swing and one foot remain in contact (接触) with the ground at all times. It’s this strange form that makes race walking such an attractive activity, however, says Jaclyn Norberg, an assistant professor of exercise science at Salem State University in Salem, Mass.Race walking shares many fitness benefits with running, research shows, while most likely contributing to fewer injuries. It does, however, have its own problem. Race walkers are conditioned athletes. The longest track and field event at the Summer Olympics is the 50-kilometer race walk, which is about five miles longer than the marathon. But the sport’s rules require that a race walker’s knees stay straight through most of the leg swing and one foot remain in contact (接触) with the ground at all times. It’s this strange form that makes race walking such an attractive activity, however, says Jaclyn Norberg, an assistant professor of exercise science at Salem State University in Salem, Mass. Recent studies have found positive effects. A study conducted in Youngstown，Ohio，for example, discovered that greener areas of the city experienced less crime. In another，employees were shown to be 15% more productive when their workplaces were decorated with houseplants. The engineers at the Massachusetts Institute of Technology(MIT)have taken it a step further changing the actual composition of plants in order to get them to perform diverse，even unusual functions. These include plants that have sensors printed onto their leaves to show when they’re short of water and a plant that can detect harmful chemicals in groundwater. ＂We’re thinking about how we can engineer plants to replace functions of the things that we use every day,＂explained Michael Strano, a professor of chemical engineering at MIT. One of his latest projects has been to make plants glow(发光)in experiments using some common vegetables. Strano’s team found that they could create a faint light for three-and-a-half hours. The light，about one-thousandth of the amount needed to read by，is just a start. The technology, Strano said, could one day be used to light the rooms or even to turn trees into self-powered street lamps. In the future，the team hopes to develop a version of the technology that can be sprayed onto plant leaves in a one-off treatment that would last the plant’s lifetime. The engineers are also trying to develop an on and off＂switch＂where the glow would fade when exposed to daylight. Lighting accounts for about 7% of the total electricity consumed in the US. Since lighting ... ...
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