首页
登录
职称英语
[originaltext] A world-champion body builder has no more muscles than does a
[originaltext] A world-champion body builder has no more muscles than does a
游客
2024-06-16
29
管理
问题
A world-champion body builder has no more muscles than does a 90-pound weakling. So what makes him so strong? What other qualities does be need?
Muscles are made of thousands of stringy fibers—a number that is fixed during childhood—which contract when doing work. Strength does not depend on the number of fibers but on the function of their thickness and how many of them contract simultaneously.
Exercise actually damages the muscles. During the recovery stage, the muscle fibers increase in size. Exercise also trains more muscle fibers to work at one time. If a muscle is weak or untrained, for example, only about 10 percent of its fibers will contract, whereas up to 90 percent of the fibers in a weight lifter’s bulky biceps will contract.
Aside from strength, two other ingredients go into making an athlete: fitness and endurance. Fitness is related to the condition of the heart. During exercises, there is an increase in the amount of blood returning to the heart from the muscles. A typical volume for a runner at rest is about 5 quarts a minutes, compared with 30 quarts during a vigorous trial. This greater volume means more work for the heart a muscular balloon that expands and contracts to take in blood and squeeze it out. Like any other muscle, the heart enlarges and gets stronger with routine exercise.
Endurance, or the length of time muscles can work, depends in part on how much fuel—in this case sugar—the muscles can store. A muscle that is continually exercised until it is exhausted of sugar tends to store more when it refuels at the next meal. And more sugar can translate into greater endurance the next time the muscle is put to the test.
选项
A、Because the fibers of his muscles are very thick.
B、Because he has more muscles.
C、Because his muscles are made of more stringy fibers.
D、Because the number of his muscles was fixed during his childhood.
答案
A
解析
Why is a world-champion body builder very strong?
转载请注明原文地址:https://tihaiku.com/zcyy/3637169.html
相关试题推荐
[originaltext]W:UAReservations.MayIhelpyou?M:I’dliketomakereservation
[originaltext]W:UAReservations.MayIhelpyou?M:I’dliketomakereservation
[originaltext]M:Hello,mayIspeaktoMr.Hebert?W:Sorry,heisinameeting.
[originaltext]M:Hello,mayIspeaktoMr.Hebert?W:Sorry,heisinameeting.
[originaltext]M:Iwanttostudylawintheuniversity.What’syouridealjobin
[originaltext]W:WhendidyouarriveinNewYork?M:Iplannedtoarrivethereon
[originaltext]W:Whysolate?Thetrainleft40minutesago.M:I’msorry,butIg
[originaltext]W:Goodmorning,sir.CanIhelpyou?M:I’mlookingfor5or6cus
[originaltext]W:I’dliketotalktoMr.Smith.M:He’snotherebutMr.Blackis
[originaltext]M:Iheardyouhadacceptedanofferfromabigcorporation.W:Yes
随机试题
Howmanywomenscientistsreceivedthisyear’sAWARDfellowship?[originaltext]
[originaltext]Abitofrainandwindinsummercanbenice.Butbadstorms
市政公用工程中,混凝土配合比设计要经过四个步骤,其中在施工配合比设计阶段进行配合
患者,女,43岁。G3P1,有原发性痛经病史,月经第二天下腹剧烈疼痛,大汗淋漓,
国外某研究机构针对网上购物行为进行调查,随机抽取2万名网络购物消费者,对其进行“
建设单位应当将大型的人员密集场所和其他特殊建筑工程的消防设计文件报送公安机关消防
肾病综合征的常见病理类型如下所列,除了A.膜性肾炎 B.系膜增生性肾小球肾炎
某公立幼儿园教师李某在工作中粗暴虐待儿童,对于不听话的儿童采取往嘴里涂抹芥末膏或
附子,干姜,石膏,肉桂,天花粉,石决明,青皮,牡蛎,陈皮,枳壳,编排以上饮片的斗
碾压石灰稳定土基层时,含水量应控制在最佳含水量的( )范围内。A.±1 B.±
最新回复
(
0
)