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
2023-09-17
22
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/3020903.html
相关试题推荐
[originaltext]M:Thisisyourannualperformanceevaluation.W:SohowdidId
[originaltext]M:Doyougoouttowork?W:Notregularly.Iworkathomemosto
[originaltext]M:Doyougoouttowork?W:Notregularly.Iworkathomemosto
[originaltext]W:Wouldyouliketoseeamenu?M:No,thankyou.Ialreadyknow
[originaltext]W:Wouldyouliketoseeamenu?M:No,thankyou.Ialreadyknow
Whatanimalsswimfrombirth?Allmammalsexeptmanand______.[originaltext]
[originaltext]W:Howareyougettingon,White?AreyoustillworkingfortheM
[originaltext]M:Helen,canIhavealookatyournewspaper?W:Sure,goahead.
[originaltext]M:Canyoutellmethetitleofthisoilpainting?W:Sorry,Id
[originaltext]M:Canyoutellmethetitleofthisoilpainting?W:Sorry,Id
随机试题
Manyoftheemployeesthinktheircareerpathbeginsduringtheiremployment
WhatisthelowesttemperatureintheAntarctic?[br][originaltext]TheAn
Fire,scientistsagree,helpedgiverisetoasuccessful,thrivinghumanpop
项目管理层是()。A.其管理以企业确定的项目成本为目标,体现现场生产成本控制中
2008年与2007年相比,在校生增长率超过25%的专业有几个?() A
A.托烷生物碱的反应, B.Keller-Kiliani反应 C.与硫酸的呈
电力、自来水等行业属于()。 A.完全垄断行业 B.完全寡头行业
津液不足证的临床表现不见A.口渴咽干 B.皮肤干燥 C.五心烦热 D.尿少
下列关于客运索道使用安全管理在日常检查方面的叙述中,正确的是()。A.对设
安全管理的核心制度是()。A.安全教育培训制度 B.安全检查制度 C.安全
最新回复
(
0
)