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导读: 形容鱼游泳的句子篇一《鱼的游泳》 ...

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形容鱼游泳的句子篇一
《鱼的游泳》

形容鱼游泳的句子篇二
《鱼儿游泳》

形容鱼游泳的句子篇三
《一天到晚游泳的“鱼”》

形容鱼游泳的句子篇四
《会游泳的鱼》

《会游泳的鱼》我们时常会看到鱼儿在水中快活地游来游去,自由自在。可是,你们不知道为什么会游泳吧?现在我就讲一有趣的故事来说明其中的原因。  很久很久以前,鱼是生活在陆地上,不会游泳的。一个春天,一只老鱼去郊外玩,它很热,于是去河里洗个澡。老鱼一踏入水中,觉得很舒服,于是跑到河的中间洗。突然老鱼惨叫一声“啊”,一大堆的鱼跑来,只见老鱼已经溺水身亡了。鱼儿们的眼泪像断了线的珍珠,伤心极了。鱼儿们回到家中,商量着以后怎么样才能不会溺水身亡?突然,一只小鱼说:“我有办法了,你们跟我来!”有一只鱼问:“干什么?”小鱼说:“你来就知道了!”其他的鱼都很疑惑不解,不知道小鱼的葫芦里卖的是什么药?  小鱼带着大伙来到了上帝面前。小鱼说:“上帝,我们的老鱼因为去河里洗澡,不小心溺水身亡,我想问您,怎么样才能不会发生这样的事?”上帝笑着说:“这好办,只要你们学会了游泳,不就行了吗?”小鱼疑惑地说:“上帝,我们很愚蠢,我想请您给我们施个游泳的法吧!”上帝说:“这倒是个好主意,可是如果你们学会了游泳,就不能在陆地上行走了。你们愿意吗?”大家商量了一下,都同意了,这就样,上帝施了个法术,鱼儿们的脚都不见了,变成了鱼鳍。从此以后,鱼儿们不能在陆地上行走,只能在水里游泳,鱼儿们高兴得有的手舞足蹈,有的跳着优美的舞蹈,还有的唱起动听的歌。  鱼儿们是因为害怕溺水身亡,才会去向上帝请求施游泳法。所以,鱼现在在水里生活。   (指导老师:姚锦勇)  

形容鱼游泳的句子篇五
《做一条反向游泳的鱼》

形容鱼游泳的句子篇六
《鱼并非天生会游泳》

形容鱼游泳的句子篇七
《鱼类游泳速度分类方法的探讨》

第17卷第5期

2010年9月

中国水产科学

JournalofFisherySciencesofChina

V01.17No.5

September2010

・综述・

鱼类游泳速度分类方法的探讨

王萍,桂福坤,吴常文

(浙江海洋学院浙江省海洋养殖装备与工程技术重点实验室,浙江舟山316000)

摘要:游泳速度是评价鱼类游泳能力的重要指标。本文对常用的几种鱼类游泳速度概念和分类方法进行了总结。目前,以时间长度作为分类标准可将游泳速度分为巡航游泳速度(Cruisingswimmingspeed,T>200min)、长时游泳速度

(Prolongedswimmingspeed,200rain>T>20s)、冲刺游泳速度(Bumtswimmingspeed,T<20s)3类。但由于时间长度的

选择缺乏令人信服的依据,很多学者并未遵循这一时间界定标准进行各类试验,致使游泳速度的界定ff{现混乱,从而

使以时间长度作为分类依据的方法失去意义。作者综合多数学者的研究方法,以鱼类的游泳状态作为依据,重新对鱼

类游泳速度进行分类,并在这一分类基础上拓展引申出最大探顶游泳速度这一新概念,并对其推求方法和实际意义进

行了探讨。根据新的分类方法,鱼类游泳速度主要分为5大类:最优巡航速度(Optimum度(Maximumsustainedswimming8peed)、临界游泳速度(Critical

swimming

swimming

swimming

speed)、最大续航速

domed

speed)、最大探顶游泳速度(Maximum

speed)、冲刺游泳速度(Burst

swimming

speed)。其他游泳速度概念基本可以按照上述分类进行归并。借助最

大探顶游泳速度这一概念,作者进一步探讨了其与最大续航速度、临界游泳速度3者之间的联系,认为在某种程度E这3种游泳速度作为评价鱼类游泳能力的指标具有一致性。[中国水产科学,2010,17(5):1137一1146]

关键词:游泳能力;最优巡航速度;最大续航速度;临界游泳速度;最大探顶游泳速度;冲刺游泳速度中图分类号:¥917

文献标识码:A

文章编号:1005—8737一(2010)05一l137—10

游泳能力对于鱼类和很多水生动物的生存至

关重要,游泳行为是多数鱼类逃避敌害、猎食、迁徙、求偶和躲避灾害环境的重要手段【1-3]o鱼类游泳能力通常以游泳速度和游泳时间加以描述。Plaut【41

态下要求鱼类可持续游泳20s~200min,并最终出现疲劳;冲刺游泳状态下游泳时间一般小于20S,视

鱼的种类和规格等多种因素而定峥7。。很显然,按照上述分类方法,任何一种游泳状态下,游泳速度都可以是变化的,但习惯上巡航游泳常常被认为是在恒定速度下的游泳状态。然而多数学者在研究过程中,并未遵循这一时间划分方法来界定巡航速度和长时

游泳速度,如Beamish[83建议采用4h、Brett掣钊建

和Hammerbl曾利用游泳时间将鱼类游泳能力划分为巡航游泳能力(Cruisingswimming

performance

或Sustainedswimmingperformance)、长时游泳能力(Prolongedswimmingperformance)和冲刺游泳能力(Burstswimmingperformance),分别对应3种游泳速度,即巡航速度(Cruising

swimming

swimming

议采用6h、Fisher等oIO-11]以12h和24h作为巡航时间标准;临界游泳速度(Criticalswimmingspeed)是反映长时游泳能力的一个重要方法,但在进行临界游泳速度测定时,如果时间步长较大而速度增幅较小,同时试验鱼类具有较强的游泳能力时,临界游泳速度的测定时间也会远远超出上述时间界定。更为

speed或Sustained

speed)、长时游泳速度(Prolongedswimming

swimming

speed)和冲刺游泳速度(Burstspeed)。在

上述分类方法中,巡航游泳状态下要求鱼类可持续

游泳200min以上,并未出现疲劳现象;长时游泳状

收稿日期:2009—11-29:修订日期:2011)-01—12.

基金项目:国家863计划项目(2006AAl00301);国家科技支撑计划项目(2007BAD43807,2006BAD09A13)。作者简介:王萍(1977一),讲师,硕士,主要从事海洋生物学研究.E-mail:wp77319@163.corn

通讯作者:桂福坤(1976一),男,副教授,从事海洋设施渔业研究.Tel:13567691640;E.mail:Gui2237@163.com

中国水产科学

第17卷

重要的是,尽管采用时间长度作为划分标准已被部分学者采纳[t2--14]但是譬如采用200rain作为定义

巡航游泳速度的界定标准似乎缺乏生理学或生态学上的依据,因此采用时间划分方法界定鱼类游泳能力和游泳状态确实看不出其意义所在,而且容易导

法发现,以鱼类的游泳状态作为分类依据,从生理学上分为有氧游泳状态(Aerobicswimming)和无氧运动状态(Anaerobicswimming)。这2种游泳状态分别对应持续游泳状态(Continuousswimming)和短暂游

泳状态(Transiemswimming)。短暂游泳是一种冲刺

致分类错乱而引起误解。本文综合多数学者的研究方法,以鱼类的游泳状态作为依据,重新对鱼类游泳速度进行分类,并在这一分类基础上拓展引伸出最

大探顶游泳速度这一新概念。1传统的鱼类游泳速度分类

游泳状态,运动主要依靠白肌肉组织,持续时间一般

不超过15~20st¨’15|,处于无氧运动状态。持续游

泳是一种较长时间游泳状态,运动主要依靠红肌肉

组织,一般处于有氧运动状态,但很多情况也会伴随

白肌肉组织的运用,如持续游泳处于变速游泳情况

或者游泳速度较大时Ll¨7l。无论在哪种状态下游

以时间长度为标准的鱼类游泳速度分类方法显然存在不足,为此笔者通过分析大量学者的研究方

泳,鱼类均可能出现疲劳情况。鱼类游泳能力的传

统分类结构如图1所示。

图1

Fig.1

传统的鱼类游泳速度分类示意图

Traditionalclassificationofswimmingspeedsoffishes

1.1恒速游泳(Steadyswimming)

最优巡航速度(Optimum咖isiIlgs埘mmingspeed)

大巡航(续航)速度(Maximum

swimming

恒速游泳状态,一般称为巡航(续航)游泳

cruismgspeed/Sustained

(Cru哦swimming/Sustainedswi仃mmO‘¨’。这一状

态下鱼类的游泳速度通常根据研究目的不同而采用

speed)进行描述。当然,还有学者提出最

foragings诵mming

优索饵游泳速度(Op矗mumspeed)

第5期王萍等:鱼类游泳速度分类方法的探讨

或引申出的最优迁徙游泳速度(Opium

nli础

swimmingspeed)、最优生长游泳速度(Optimumgrowingswimming

speed)等其他概念¨¨9I,都可归于最优巡航

速度。

巡航速度在航空领域常指飞行器在单位距离上消耗能量最少的飞行速度,是一种经济航速。但在研究鱼类游泳时,这一速度很难量化定义,因为涉及鱼的生长等一系列问题,一般指鱼类持续索饵、自然

迁徙等无约束条件下的持续游泳速度‘18-19]。巡航

游泳状态下,鱼类不出现疲劳现象,但显然这一条件取决于巡航时间(Sustained

swimming

time),即在某

一规定的巡航时间内,鱼类能够保持持续恒速游泳状态并未出现完全疲劳现象,即可认为其处于巡航游泳状态,其对应的游泳速度即为巡航速度。然而,

尽管有学者曾试图以200rain作为巡航时间的统一界定h5’12|,并且也得到部分学者的采纳,但由于缺乏令人信服的生理学或生态学依据而并没有得到一

致认同。目前关于巡航时间的界定主要集中于以下

4种时间长度:200

min、6h、12h、24

h。显然,根据研究目的的不同,可以有多种巡航速度,但作为评价鱼类巡航游泳能力的指标,最优巡航速度和最大巡航

(续航)速度应用最广[i1,18-21],而且也更为贴切。

最优巡航速度(Optimum

cruising

swimmingspeed)

是指在满足某一目的和约束条件下,鱼类处于最佳游泳状态时对应的速度,此时鱼类未出现疲劳现象,显然研究目的和约束条件是多样的。例如,Ware¨8o从

生物能量学的角度对红大麻哈鱼(OncorhynchusM惋)

进行了研究,认为红大麻哈鱼的最优巡航速度与体长

的0.4次方成正比,这一规律同样也适用于鱼的索饵巡航速度。很显然在Ware看来,从生物能量学的角度看最优巡航速度并不是越低越好,这一结论也得到

Hammer陇1的鱼类生长试验证实。另外,Trump等‘19]从鱼类迁徙的角度计算了最优巡航速度;Blaxter[7j建议以2BUs的相对速度作为多数鱼类的最优巡航速度。到目前为止,关于最优巡航速度的各种定义、大小和研究方法等仍然没有取得统一的结论,这也为试验测试和对比分析带来很大闲难”Jo

最大巡航(续航)速度(Maximum

cn_lising,sIlsIained

swimmingspeed)是指鱼在某一给定时间内所能承受

的最大恒定游泳速度,以鱼最终出现疲劳为参照依

据。习惯上,多数学者采用最大续航速度(Maximum

sustainedswimming

speed)概念,因为巡航常常意味

着非疲劳状态,在此笔者同样沿用这一习惯。显然,

最大续航速度与给定时间有关,一般而言最小时间

长度大于20S,因为若游泳时间仅维持在208以内,

多数鱼类处于短暂的冲刺游泳状态【¨]。最长时间跨度理论上可以没有限制,但是给定的时间跨度

越长,最大续航速度越小。最大续航速度一般无法

直接测定,但可以通过试验测定多组次的续航时间

(Sustained

swimming

time),采用数学方法回归插值获

得任意给定续航时间下的最大续航速度¨1|。具体

测量时,常常以给定时问内一定概率(如50%【2引或10%【l¨)的试验对象出现疲劳时对应的速度作为

最大续航速度,或者以所有个体的平均续航时间等

于给定时间时所对应的游泳速度作为最大续航速度o

10-11

Jo前者常常用于小个体大样本情况,后者常

用于大个体小样本情况。

1.2变速游泳(Unsteadyswimming)

变速游泳(Unsteadyswimming)是指鱼类在不断

变化的速度下持续游泳直到疲劳为止。理论上,应包括增速游泳(Incremental

swimming)和减速游泳

(Decrementalswimming)2种状态,但目前几乎所有学者均采用增速游泳方法对鱼类变速游泳能力进行测

试。严格而言,变速游泳还应包括不规则游泳状态

(Irregularswimming),即速度大小和方向不恒定,如鱼

类在波浪作用下的游泳状态即属于这一情况,但将这种问题独立研究似乎更为合适,因此本文暂不考虑这一问题。

目前,临界游泳速度(Critical

swimm崦掣划)是描

述变速游泳能力所广泛采用的评价指标【12,24埘],采用增速游泳方法进行测试,是指鱼在一定的时间步长和

流速增长规律下,所能达到的最大游泳速度。临界游

泳速度的测试受时间步长和速度增幅的影响,目前关于这一问题仍然存在很大分歧,有些学者认为时间步

中国水产科学第17卷

长和速度增幅对鱼的临界游泳速度无显著影响【27翻】,有的学者认为这种影响是显著的。舡31|,也有学者认为在一定范围内这种影响是可以忽略的‘M训。鉴

于这种情况,目前很多学者趋向于采用时间步长为20~60rain(推荐为30min),而以速度增幅为1/4~l丹

倍的%。(临界游泳速度)作为测试手段”剖。

与最大续航速度的测试方法相比,临界游泳速度的测试方法可以大大减少测试样本和测试时

间[5.27J,但显然临界游泳速度的测试时长在很大程

度上取决于速度增幅和时间步长,不合适的增量选取也会导致测试时间过长‘5,2"/,33]o为缩短临界游泳速度的测试时间,Jain等Ⅲ1提出了一种渐进速度测

试法(Ramp

velocity

test)。该方法在最初的5~6

min

之内将速度迅速提升到75%的以扪然后再每隔

30

min增速1次,直至鱼f{j现疲劳。Farrell忉1提出采

用恒加速测试法(Constantaccelerationvelocity

test),

时间步长仅1min,实际上是临界游泳速度普通测试

方法的一种特殊情况,即短时间步长。该方法可以大大缩短测试时间,但却往往会产生较高的临界游泳速度测试结果。

尽管临界游泳速度被广泛用于评价鱼类的游泳能力,但学者普遍承认临界游泳速度的确定尚缺乏可信的生理学和生态学依据bJ。实际上,如果放

弃对较短测试时间的追求,临界游泳速度在某种程

度上可以被认为是某种实际潮流规律下鱼类游泳

能力的评价指标。在实际海域中,海水流动是满足一定潮流规律的。以规则半日潮为例,潮流流速由零增长至最大流速时约需3

h12

min,然后由最大速

度降至零时同样约需3h

12

min,并不断重复这一过

程。前者为增速过程,直接对应临界游泳速度目前

所采用的测试方法;后者为减速过程,目前尚无学者对这一过程的鱼类游泳能力进行研究。从鱼类游泳能力的实际意义出发,笔者希望鱼类可以顺利地完成整个流速增减过程,即能够在这一潮流规律下持

续游泳约6

h24

min,而不出现疲劳。显然对特定的

鱼和环境而言,能否顺利完成这一过程,取决于最大潮流流速。当鱼完成这一过程,刚好达到疲劳状态,

此时这一最大潮流流速即称为最大探顶游泳速度(Maximum

domedswimming

speed)。最大探顶游泳速

度很难直接测定,需要结合潮流规律、最大续航速度和最大续航时间关系等因素采用半经验半理论的方

法进行推算测定,后文将对这一问题作专门讨论。

1.3冲刺游泳(Burstswimming)

冲刺游泳速度(Burst

swimming

speed)对应鱼的

冲刺游泳状态,常常是鱼在捕食、避敌、环境应激反

应情况下的游泳行为,对鱼的生存有着至关重要的影响o¨J。冲刺游泳是一种无氧运动行为,持续时间

一般不超过15~20s[6-7],可分为恒速(Sprints)和加速(Accelerations)2种游泳状态L34J。研究表明,一般

情况下对多数鱼类而言,冲刺游泳速度都可近似采

用10BL/s进行估算,而与鱼的种类无关[22’3}36J,但

对如金枪鱼这样具有很强爆发速度的鱼类而言,这一计算方法则不够准确b】。冲刺速度与持续时间有关,随时间增长呈指数形式迅速下降¨剖。同时冲刺

速度也和鱼的规格相关,如果采用绝对速度,冲刺速度与鱼的体长成正比关系,如果采用相对速度,则与鱼的体长成反比关系LSJ。

2最大探顶游泳速度(M痢m哪domed鲫jlIlmil-g

叩-eed)

最大探顶游泳速度具有非常明确的实际意义,

对于海洋鱼类养殖海区选址具有重要而直接的参考

价值。但如上所述,最大探顶游泳速度很难直接测定,需要借助间接手段进行推求。仍然以规则半日潮为例,潮流大小和方向呈周期性变化,潮流大小受半日周期(即半日内完成1个潮流周期变化,1日内完成2个潮流周期变化)和半月周期(半个月完成1个潮流长周期变化)控制,可用下式表示m】:

M=‰.sin(29。t)+K‘‰.sin(髦矿sin(2。a1

C』mn

JC

c£)(1)

式中,K为任意时刻流速大小,‰‘sin(餐£)Y拌la

周期流速变化,【.‰.sin(2;//"t).sin(2万t)为半月周

1real

1L

第5期

王萍等:鱼类游泳速度分类方法的探讨

期流速变化。‰=(k+K),2,为平均流速幅值;k

和K分别表示大、小潮期间最大流速;K=(Vm—K)

/(%+K),为流速波动系数;%=12.4h,为半日周期;T。=14.75d,为半月周期。作为对鱼类游泳能

力的研究,无需考虑长周期的流速变化,半日周期

(12.4h)流速变化对检验鱼类的游泳能力已足够长,

因此式(1)可仅考虑右端第一项,且用大潮最大流速代替平均流速,即:

14,=1I..sin(簪t)

(2)

JL

在整个半日周期te(O,死)内,流速出现2次最

大值,数值相等但方向相反。在测试鱼类游泳能力

时无需考虑方向问题,因此只需考虑tE(0,叫2)时

间段,在这一时段内,流速由零增长至最大值后再降至零。在上式中,k即是笔者寻求的最大探顶游泳

速度。

欲求得k,必须将其与鱼类游泳能力关联。根据部分学者¨¨¨的研究表明,鱼类的最大续航时间与续航速度满足幂函数关系:

T=aV6

(3)

式中,y为续航速度;T为续航速度为V时对应的最大续航时间;a,b为系数,通过试验测定。将(2)带入(3)可得:

T=a・瞄・sin6(筝£)

(4)

JC

上式即为在任意时刻对应的潮流流速下,鱼类的最大巡航时间。已知鱼类的临界游泳速度(Critical

swimming

speed)计算公式[121为:%。=以+[(tth;)×以]

(5)式中,玑血为临界游泳速度;以为鱼类疲劳的前一流

速;以为流速增幅;tf为在最后流速段内持续的游泳

时间;毛为时间步长。上式右端第二项表明,鱼类在给定速度段内的游泳时间是线性叠加的,即在该速度段内鱼的体力被认为是均匀分配的。在此同样采

用上述假定,即在公式(4)中,如果将研究时段咒,2

分成很多时间微段山,则每个时间微段对应1个速

度段和1个最大巡航时间r,并且在该速度段内游泳

时间满足线性叠加的假定,因此对应时间微段山内

的体力消耗比例为dt/T,将体力消耗在整个时间段孔/2内进行积分,最终结果将等于1,即意味着体力

完全消耗,于是有:

Z耻手出=・j

fo加j磊丽1山=・(6)

上式中,只要知道系数a和b,即可采用数值积分的

方法获得最大探顶游泳速度圪,因此测定最大探顶

游泳速度实际上归结为测定最大续航时间和续航速

度,从某种意义上说,最大探顶游泳速度与最大续航时间或巡航速度是等价的。最大续航时间和续航速度的测定具有较好的稳定性,不存在时间步长和流速增幅影响问题,而且测试方法简单,因此也可保证最大探顶游泳速度的稳定性。3讨论

3.1改进的鱼类游泳速度分类

游泳速度是鱼类游泳能力最为直接的评价指

标,主要包括巡航(续航)游泳速度、冲刺游泳速度、临界游泳速度,这些指标在包括概念定义、测试方

法、环境影响因素、内在联系等方面已得到了大量学

者的广泛研究,Hammer【51和Plantl4]对此做了较为

全面的讨论。然而,在游泳速度的界定和分类方面却不够准确,提出以时间作为不同游泳状态(或游泳能力)的界定缺乏足够的说服力,导致在巡航时间的界定上无法取得统一。同时又将耐久力游泳能力

swimming

performance)概念与巡航(续航)

游泳能力进行区分,致使鱼类游泳能力的概念分类更显复杂,容易产生误解。笔者认为巡航时间与研究对象的种类、规格和生活习性有关,而且应视研究目的而定,无需统一界定。目前,越来越多的学者倾

向于使用临界游泳速度(Criticalswimmingspeed)评

价鱼类的游泳能力。临界游泳速度被普遍认为是鱼是一种可复验的游泳速度忉],然而这些看法都仅仅

(Endurance

类处于最大耗氧状态下的一种游泳速度m瑚],而且

形容鱼游泳的句子篇八
《游泳池里的鱼作文

游泳池里的鱼作文

游泳池里的小鱼

302班 许人新

以前,每当同学们问:“你会不会游泳?”我就不知该怎么回答。如果我说“我不会。”又怕同学笑话。我很想学游泳,可不敢下水。直到去年暑假前,我还是一个“旱鸭子”。

去年暑假的一天,爸爸在振石大酒店的游泳馆给我报了个名,叫我去学游泳。开始,我死也不敢去游,可爸爸偏要我去学。我在爸爸的威逼利诱下,来到了振石游泳池更衣室,换上了泳装,进入了游泳池。

开始学游泳了,老师先教我们学憋气。第一次练习憋气时,我就喝了一口“酸梅汤”,呛得我直咳嗽。第二次憋气时,我又喝了一口“酸梅汤”,我想今天真倒霉!连喝了两口水。接着,老师叫我们练习漂浮在水面上,第一次我先是自己拿着扶板漂,第二次,老师扶着我们漂浮。让我们一个一个地轮流,老师还说:“谁不乖的话,我就把手松了。”轮到我了,老师扶着我到了水池中间,老师才把我拉回了池边。可我紧张得嘴吧直发抖。爸爸见我发抖,而且抖得很厉害,就把我抱了上来。到了最后,老师教我们蹬脚。老师做了个示范,接着叫我们一个一个做。该我了,老师说“蹬!”我就蹬了出去,老师说我做得很好,我顿时有了信心。

经过一个暑假的艰苦训练,我终于学会了蛙泳、仰泳、蝶泳„„从此,我渐渐地爱上了游泳。爸爸夸我说:“你这只‘旱鸭子’变成了游泳池时的‘小鱼’了。”

现在,如果你再问我会不会游泳,我会说:“我可是游泳池里的‘小鱼’了。”

形容鱼游泳的句子篇九
《鱼是天生的游泳高手吗?》

形容鱼游泳的句子篇十
《鱼式游泳训练方法》

Perpetual Motion FreestyleIn 10 Lessonsby Terry Laughlin

Learn at your Own Pacein your Own Pool

Be your Own Best Coach

Build a Better Stroke and a Better Brain!User Guide to the

Total Immersion Self-Coached Workshop

Self-Coached Workshop User’s Manual

The Self-Coached Workshop (SCW) is the most important TI learning tool to date. Many people think our most important innovation was teaching human swimmers to be fishlike. I believe teaching them to be empowered is equally valuable. The SCW is designed to help you acquire self-improvement savvy along with swimming skill; it doesn’t just teach you how to move; it teaches you how to think about and feel movement via these innovations in practice methods:

1. Swim Early and Often During the 1990s, attendees at TI’s Weekend Workshops swam 25 yards of whole stroke to record video and stroke count, then practiced six hours of drills before attempting another 25 of whole stroke. Our books and videos also recommended completing the entire drill sequence with relatively little whole-stroke. Because we were concerned that old habits could take over if students resumed swimming before new habits had taken hold, we hoped to create muscle amnesia – eradicating inefficient patterns and replacing them with efficient ones.

Over the past decade, we’ve steadily increased the amount of whole-stroke throughout the progression, but in ways designed to minimize the potential for practicing struggle. We do that in SCW by recommending brief ‘pieces’ (3 to 7 strokes) of whole stroke at regular intervals, starting with the first drill. This is to help you: (1) Remember the purpose of a particular drill; (2) Give each new focal point undivided attention; and (3) Integrate new mini-skills into the whole.

2. Break Mini-Skills Into Micro-Skills When a skill is new, the fewer ‘parts’ it has -- the fewer thoughts it requires -- the better. TI has always taught via a series of mini-skills, gradually assembled into a more complex skill. SCW breaks down mini-skills even further, presenting micro-skills called Rehearsals or Tuneups. In Rehearsals, you stand in place; in Tuneups you move a short distance.

• Rehearsals highlight an element that requires keen attention, prior to attempting a

new drill or movement. By rehearsing first, you initiate a pattern-memory in your

brain that is more likely to persist when you expand focus to two or more aspects at once. Static practice (not moving down the pool) also allows for deeper focus.

Rehearse for 30 to 60 seconds. Repeat rehearsals as long as you feel they help.

Tuneups are moving, but very brief, practice -- usually 10 yds or less. (You may sequence several reps to cross a pool.) Why short duration? (1) To minimize the need to breathe, when it’s best to treat breathing as a separate skill. (2) Like rehearsals, they’re designed to of a more complex drill or whole stroke, not to imprint the whole movement.

E.G. Our first drill, Superman Glide, is a Tuneup – for which you Rehearse by standing with arms extended. SG is designed, in part, to let you focus intently on neutral head position via a series of related Focal Points including: (i) Relax neck and shoulder muscles; (ii) Feel your head is “weightless;” (iii) “Aim’ your Laser Beam. Each can be practiced in a set of repeats dedicated only to that thought or face – first in SG, then in Whole Stroke. SG makes focus easier because it’s a relatively simple skill.

Tuneups are most valuable: (1) when learning a new drill or skill; and (2) when your practice includes more drills than whole stroke. The more familiar you become with any skill, the less you need to Rehearse or Tuneup. Even so, don’t hurry to drop them from your practice.

3. Minimized Kicking Nearly every lesson includes this warning: “Don’t turn this into a kicking exercise.” SCW is the first TI self-coaching tool to make this TI drills have always relied to some extent on kicking-for-momentum because: (1) It takes time to tweak and imprint key positions. (2) You need momentum to gain that time and not sink. (3) When your movements are non-continuous you must kick to maintain momentum and body position.

This dependence on kicking had the potential to fatigue and frustrate new swimmers, many of whom had an inefficient kick. It also had the potential to create a kicking habit that could be difficult to unlearn.

Because an economical 2-Beat Kick (2BK) is the default choice for tireless distance swimming, we want the first steps in our progression to imprint relaxed, streamlined leg action. This will prepare you for later lessons designed to teach 2BK coordination. Thus many activities—such as Skate--previously taught via pool-length repeats are now choice, your kick should be relaxed and your attention on the fine points of the drill, rather than getting to the end of the pool.)

Thus many steps suggest that you: (1) Use SG to establish the sense of weightlessness which permits relaxed streamlined legs; (2) After a few moments transition into Skating or another drill) seeking to maintain a sense of weightless, easy travel; and (3) STOP and restart when your kick becomes labored. Focus on streamlining, not kicking, to extend glide. Stay fresh. Imprint ease.

Three Learning Steps: Balance, Streamline, Propel

The central learning principle that separates TI from traditional swim instruction is that we always teach via a sequence of three skills – Balance, Streamline, Propel. No matter the stroke, no matter the student or her goal, we teach in that order. We do so for two reasons: • This order reflects their impact on your efficiency: Balance will make the biggest difference by far. Streamlining will improve your swimming nearly as much. Propelling

better is not unimportant, but will create change that’s relatively harder to notice.

This order also reflects how easily you can learn the component skills. Balance skills involve large body parts and simple coordination; you can sense them more easily and master them more quickly. Streamlining skills start out fairly simple, then become a bit more challenging. Propelling skills involve fine motor skills and complex coordination. They require keen attention (and attention itself is a skill that takes time to learn) and great patience. •

Balance means ‘in harmony with the water.’ It’s also the foundation without which skilled movement is impossible -- on land and in water. Balance provides both physical control and mental calm by replacing semi-panicky reflexes with the possibility to sort thoughtfully through choices that impact every skill step that follows. Among the four strokes, balance is most delicate in crawl, but once learned, allows you to swim almost any distance. If you tire while running, you can always walk. Balance gives swimmers a ‘walking option.’

Streamlining comes in two forms. In Passive Streamlining, the simpler of the two, you shape your body to be longer, sleeker, more hydrodynamic. In Active Streamlining, you stroke in ways that move your body forward, rather than moving the water around. Your greatest energy savings – and therefore increases in both endurance and speed — come from Streamlining.

Effective Propulsion in the TI Method means to direct ‘available’ forces, rather

than generating muscular forces. Gravity and body mass are a ‘free’ source of power, which can minimize reliance on muscular force. You then convert Force (horsepower) into Locomotion by concentrating on holding water, rather than moving water back.

In every stroke, in every skill, in every question or decision that arises, if you address

Balance first, then Streamlining, then Propulsion, you minimize the potential for frustration or confusion and maximize the potential for clarity and success. The SCW will teach you as much about using this framework to answer questions as it does about swimming

movements.

The 10 lessons of SCW are organized into the Balance group, Lessons One to Three; the Streamlining group, Lessons Four to Seven; and the Propulsion group, Lessons Eight to Ten. We’ve organized it this way because each group requires distinct forms of thinking, practicing and adjusting. You’ll maximize success at each step -- and ultimately in how you steps that precede it.

Balance Lessons

The first three lessons are designed to encode key body positions and practice habits. These include:

• • Improved self-perception and body control are both essential to mastering the movements. When teaching yourself, you replace a coach’s guidance with a ‘mental blueprint’ for each movement. Self-Perception allows you to compare each drill repeat with the blueprint or with another repeat, then make the right adjustments. Body Control allows you to move according to plan, rather than in response to discomfort. The cognitive skills help you plan a practice session, decide when to continue or interrupt a repeat, when to drill or swim, etc. Most Balance drills are Tuneups and seemingly quite simple. Despite that simplicity, you’ll gain much by devoting at least a couple of hours to them. Any swimmer who has

experienced discomfort, felt as if you were sinking, or found it difficult to relax the kick will benefit immensely from ‘too much’ Balance practice.

Streamlining Lessons

The middle four lessons teach Streamlining skills entirely specific to freestyle. The

Streamlining sequences are SpearSwitch (Lessons Four and Five), SwingSwitch (Lesson Six) and OverSwitch (Lesson Seven).While the long-term value of Balance drills is mainly in tuneup and renewing comfort and sense-of-control, Streamlining drills can become a core element of practice sets for months, if not years. Practice repeats during this part of SCW

will be longer because (1) they include regular breathing; and (2) Active Streamlining skills have more ‘moving parts’ to coordinate, requiring more repetitions to hone awareness and movement.

Effective Propulsion Lessons

The final three lessons in the SCW call on smaller movements, subtler awareness and advanced coordination. The skills taught in this group take years, rather than weeks or months, to develop. Indeed it’s more accurate to say the skills taught in this part of the SCW will never be “finished.”

There’s no set time from for progressing to Propulsion skills or lessons. A fair rule of thumb would be to practice Streamlining for at least 10 to 20 hours first. Self-coached swimmers will have more success with Lessons Eight to Ten if the movements targeted by Lessons Four to Seven have become accurate and consistent. On the other hand, don’t be overly cautious about experimenting with them. An essential principle of practicing-to-improve is to identify a weak spot in your current skill set then focus on strengthening it. Attempting new or advanced skills is one way to do so.

LESSON SUMMARIES

This section of the User Guide explains the value of the skills taught in each lesson, and how each prepares you for those that follow, and for whole-stroke. LESSON ONE: Relax Into “Weightlessness”

Have you ever seen a fish that wasn’t horizontal while swimming? Fish and aquatic

mammals are naturally designed for aquatic (i.e. horizontal) balance. Humans, as terrestrial mammals, are naturally designed for land (i.e. vertical) balance. Most of us recognize that the cost of imbalance in the water is more drag and fatigue, less speed. But the true cost is actually far greater.

In fact, few swimmers even recognize it as a balance problem. It feels more like a sinking problem and is virtually universal among new swimmers. It leaves feelings ranging from discomfort to being at risk. Poor balance is the reason one’s first attempt to cross the pool can feel like a “near death experience.”

We’re not in real danger, but who can think clearly when you feel that way. Imbalance is a simple matter of buoyancy and gravity. Buoyancy pushes our air-carrying lungs up, while gravity pulls our dense lower body down. That has costs far beyond what most people realize.

1. A sagging lower body increases drag considerably.

2. Survival strokes exhaust you quickly and are utterly ineffective for propulsion.

3. But unrecognized costs in mental energy may be greatest of all.

相关热词搜索:形容游泳的句子 形容不会游泳的句子 形容鱼游泳的成语

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