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
41
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 he 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/3635952.html
相关试题推荐
[originaltext]It’scommonknowledgethatmusiccanhaveapowerfuleffecto
[originaltext]Toooftenyoungpeoplegetthemselvesemployedquitebyaccid
[originaltext]Toooftenyoungpeoplegetthemselvesemployedquitebyaccid
[originaltext]I’dliketosharewithyoutodaymyexperiencewithanewapp
[originaltext]I’dliketosharewithyoutodaymyexperiencewithanewapp
[originaltext]M:So,whatexactlyareyoudoingtoprotecttheelephantshere?
[originaltext]Aworld-championbodybuilderhasnomoremusclesthandoesa
[originaltext]Manyayoungpersontellsmehewantstobeawriter.Ialway
[originaltext]Manyayoungpersontellsmehewantstobeawriter.Ialway
[originaltext]Overthepastdecade,theenvironmentalmovementhasexploded
随机试题
Mostpeoplepicturesharks【C1】______huge,powerful,frightening【C2】______rea
Itisacommonplaceamongmoraliststhatyoucannotgethappinessbypursu
[originaltext](1)FebruaryisBlackHistoryMonthintheUnitedStates,when
在液塑限联合测定法中,对测定精度影响最大的试样是靠近()的那个试样。A.液限
目前认为引起自身免疫性肝炎的主要因素为A.环境 B.病毒感染 C.遗传 D
属于医疗保健机构提供婚前卫生指导的是A.性卫生知识教育 B.遗传病诊察
共用题干 UnderstandingAutism1Autism(孤独症)i
Thechangeinthatvillagewasmiraculou
随机存储器(RAM)的特性是()。A、只读不写 B、不读只写 C、可读可写
挂失止付是指失票人将丧失票据的情况通知给()的一种方式。A:银行B:付款人C
最新回复
(
0
)