Passage 1 Questions 1 to 5 are based on the following passage. According to Daniel Lieberman, a professor of human evolutionary biology at Harvard University, “People have been running barefoot for millions of years, and it has only been since 1972 that people have been wearing shoes with thick, synthetic heels.” Research published in Nature, the international weekly journal of science, compared the impact generated by runners with running shoes versus barefoot. Daniel Lieberman and his colleagues studied the biomechanics (生物力学) of shod versus barefoot runners and found that the way barefoot runners typically land is more comfortable and may help avoid repetitive impact stress injuries. Many studies suggest that modern running shoes may in fact increase the risk of injury and that runners wearing cheap running shoes have fewer injuries than those with more expensive trainers. According to a study published in the British Journal of Sports Medicine, athletic footwear has been associated with frequent injury thought to result from repetitive impact. The researchers found that the more expensive athletic shoes claim cushioning impact, yet account for 123% greater injury frequency than the cheapest ones. As more research suggests that naked feet are preferable to high-tech trainers, minimalist footwear like Nike Free and Five Fingers is gaining popularity. Nike Free footwear is designed to strengthen the muscles in the foot by providing less constriction. Vibram, a leading manufacturer of high-performance rubber soles, has developed a line of “barefoot performance footwear” known simply as FiveFingers®. Vibram FiveFingers® looks more like a ‘foot glove’ than a running shoe and represents a radical departure from the look and function of traditional shoes. So the next time you get a moment to take an invigorating walk or jog, don’t reach for those running shoes. If you decide to take off those shoes and go “au natural” or try out the new biomechanical wonders, break into the shoe gradually to prevent muscle cramps or other discomforts.