Experiment 4 - Physiology

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Introduction Introduction

(%e

(%eleletatal l mumuscscleles s comcomprprisise e ababoutout )*

)*+ + of of tthe he mamammmmalals s bobody dy mmasass s anandd ac

accocoununts ts fofor r -*-*+ + of of a a huhumamanns s rereststinin me

metatabobolilic c rarate te ././aan n &0&0ieierarathth, , 1*1*2-2-3!3! (%eletal muscles are 4oluntary muscles that (%eletal muscles are 4oluntary muscles that sshohorrteten n or or cocontntraractct! ! TThe he cocontntraractctiiononss enerated by s%eletal muscles are used for enerated by s%eletal muscles are used for two functions' mo4ement and posture of the two functions' mo4ement and posture of the body!

body! 5or 5or a a s%eletal s%eletal muscle muscle contraction contraction toto oc

occucur r ththerere e mumust st be be a a neneurural al ststimimululusus,, calcium in the muscle cells, and enery from calcium in the muscle cells, and enery from AT ./an &0ierath, 1*2-3! The eneration AT ./an &0ierath, 1*2-3! The eneration of an action potential and the transduction of of an action potential and the transduction of el

elecectrtricical al enenerery y ininto to an an inintrtracacelellululalar r chemical sinal trier the interaction of the chemical sinal trier the interaction of the my

myofofililamamentents, s, namnamely ely actactin in anand d mymyosiosinn .Reconditi, et al!, 1*223! Muscle contraction .Reconditi, et al!, 1*223! Muscle contraction occurs because of the slidin mechanism of occurs because of the slidin mechanism of the myosin head on the actin, which forms a the myosin head on the actin, which forms a cross bride .Reconditi, et al!, 1*223!

cross bride .Reconditi, et al!, 1*223!

A muscle contraction that occurs in A muscle contraction that occurs in rreessppoonsnse e tto o a a ssttiimmuulluuss, , a a ttwwiittcchh, , iiss responsible for the eneration of an action responsible for the eneration of an action potential

potential in in a a muscle muscle fiber! fiber! (ince (ince eacheach muscl

muscle e comprcomprises ises indi4indi4idual idual musclmuscle e cellscells,, the contraction of indi4idual muscle cells, the contraction of indi4idual muscle cells, can cause 4aried contractions in the muscle! can cause 4aried contractions in the muscle! Th

The e didiffffererent ent dederree ee of of concontrtracactition on ththatat o

occccuurrs s iin n a a mmuusscclle e prprooduduccees s rraaddeedd responses! These responses are due to the responses! These responses are due to the chane in fre$uency of stimulation and the chane in fre$uency of stimulation and the ch

chanane e iin n tthe he nunumbmber er of of mmususclcle e cecellllss ssttiimmuullaatteed d tto o ccoonnttrraacct t ((cchhiiaaffffiinnoo,, &Reiani, 1*223!

&Reiani, 1*223! Th

Threreshsholold d is is ththe e lolowewest st lele4e4el l of of ssttiimmuullaattiioon n tthhaat t ttrriieerrs s a a mmuussccllee co

contntraractctioion! n! "f "f ththe e ststimimululus us is is inincrcreaeasesedd abo4e threshold, the strenth of contraction abo4e threshold, the strenth of contraction strenth will increase with stimulus intensity strenth will increase with stimulus intensity as more muscle fibers undero contraction! as more muscle fibers undero contraction! 6hen the stimulus strenth reaches a certain 6hen the stimulus strenth reaches a certain

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le4el, no further increase in tension occurs, le4el, no further increase in tension occurs, ssiinncce e aalll l mmuusscclle e ffiibbeerrs s aarre e aallrreeaaddyy contractin! The three basic staes that occur contractin! The three basic staes that occur durin a twitch are the latent period .the durin a twitch are the latent period .the time between the application of the stimulus time between the application of the stimulus and

and the the occuoccurrerrence nce of of contcontracractiotion3 n3 .7.7aai,i, 1*

1*2*32*3, , cocontntraractctioion n titime me .t.timime e frfrom om ththee contraction to the pea% of tension3, and the contraction to the pea% of tension3, and the rela#ation time .from the pea% tension to the rela#ation time .from the pea% tension to the point

point where where the the tension tension returns returns to to thethe baseline3!

baseline3! (%elet

(%eletal muscle al muscle fatifatiue ue is defined asis defined as the decreasin force or contraction of the the decreasin force or contraction of the mus

muscle cle in in resresponsponse e to to contcontractractile ile actacti4ii4ityty!! Muscle fatiue can be caused by a number Muscle fatiue can be caused by a number of factors such as the loss of AT in the of factors such as the loss of AT in the m

mususclcle e whwhiich ch rresesulults ts to to cecessssatatiion on of of con

contratractiction, on, decldecline ine in in concontratractiction on due due toto cchhememiiccaal l iinnhhiibbiittiion on of of mmuussclcle e ffiibbeer r ccoonnttrraaccttiioon, n, aannd d tthe he ddeeccrreeasase e iin n tthehe st

stimimulaulatition on of of nener4r4es es to to crcreaeate te imimpulpulsesess $uic% enouh to maintain the stimulus and $uic% enouh to maintain the stimulus and ca

caususe e cacalclciuium m rereleleasase e ..lalacece, , 77aamamadada,, 8ruton, &6esterblad, 1*2*3!

8ruton, &6esterblad, 1*2*3! "n

"n ththis is e#e#peperirimementnt, , ththe e efeffefect ct of of raded response, load, pulse, fre$uency, and raded response, load, pulse, fre$uency, and muscle fatiue on the contraction of the fro muscle fatiue on the contraction of the fro a

aststrorocncnememiuius s wawas s dedetetermrminined ed ususinin  aa

Frog Dissection Frog Dissection

Th

The e frfro o wawas s dodoubublele9p9pitithehed d anandd usin a scalpel or sharp scissors, the s%in of usin a scalpel or sharp scissors, the s%in of the fro was cut around its abdomen! The the fro was cut around its abdomen! The s%in was peeled down and off the les of the s%in was peeled down and off the les of the fro and it was %ept moist at all times with fro and it was %ept moist at all times with Riners solution! A lass probe was used to Riners solution! A lass probe was used to e#pose the sciatic ner4e from between the e#pose the sciatic ner4e from between the thih muscles down to the %nee! A 1:9cm thih muscles down to the %nee! A 1:9cm piece

piece of of stron stron thread thread was was then then slippedslipped under the Achilles tendon at the heel of the under the Achilles tendon at the heel of the fro and it was securely tied to the tendon! fro and it was securely tied to the tendon! The

The asastrotrocnemcnemius ius musmuscle cle was was carcarefuefullylly dis

dissecsected ted away away frofrom m the the tibtibio9io9fibfibula ula bonebone and it was left attached to the %nee! The and it was left attached to the %nee! The foot, thih muscles, and the other muscles foot, thih muscles, and the other muscles was remo4ed, lea4in the sciatic ner4e and was remo4ed, lea4in the sciatic ner4e and a

aststrorocnecnemimius us atattatachched ed to to ththe e %ne%nee! e! ThThee tibio9fibula bone ;92* mm was cut below tibio9fibula bone ;92* mm was cut below tthe he %n%nee ee ususiin n bobone ne sshehearars s or or ststroronn scissors! The femur was then cut close to the scissors! The femur was then cut close to the hip joint! <astly, the muscle was %ept in a hip joint! <astly, the muscle was %ept in a etri dish until it was ready to mount!

etri dish until it was ready to mount! A

A PrPrococededurures es fofor Kr Kymoymogrgrapaphh A!2 Graded Response

A!2 Graded Response T

Thhe e mmuussclclee99nneerr44e e sseett99up up wwaass prepared in the

prepared in the %ymoraph! The Kymoraph%ymoraph! The Kymoraph was then set at slow paper speed and the was then set at slow paper speed and the

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inter4al until a

inter4al until a twitch was produced! twitch was produced! ==ololtaetae and response to twitch heiht was recorded! and response to twitch heiht was recorded! The process was continued until there was The process was continued until there was no increase in twitch heiht obser4ed with no increase in twitch heiht obser4ed with an

an inincrcreaease se in in 4ol4oltatae! e! ThThe e rerespspononse se inin heiht aainst 4oltae was plotted!

heiht aainst 4oltae was plotted!

A!1 /ffect of <oad A!1 /ffect of <oad

Th

The e fefemumur r wawas s clclamampeped d anand d ththee thread was attached to the Kymoraph le4er thread was attached to the Kymoraph le4er arm! The weiht pan was haned under the arm! The weiht pan was haned under the muscle and recorded as the 0ero <oad oint! muscle and recorded as the 0ero <oad oint! The Kymoraph le4er was adjusted so that The Kymoraph le4er was adjusted so that any contraction in the muscle was recorded any contraction in the muscle was recorded in the upper part of the drum! The drum was in the upper part of the drum! The drum was rotated at a 4ery low speed then the muscle rotated at a 4ery low speed then the muscle wa

was s ststimimululatated ed wiwith th a a sisinnle le mama#i#imamall 4o

4oltltaae! e! ThThe e prprococesess s wawas s ththen en e4ee4ery ry 2*2* sseecoconnddss! ! 55ii44e e rramams s wwaas s aaddddeed d aanndd sti

stimulmulateated d witwith h a a sinsinle le pulpulse! Anotse! Another her :: rams was added and stimulated aain after rams was added and stimulated aain after 2* seconds! More weihts were added until 2* seconds! More weihts were added until th

the e cocontntraractctioion n heheiiht ht wawas s drdrasastiticacallllyy red

reduceduced! ! The The weiweiht ht liflifted ted by by the the musmusclecle aainst the contraction heiht was plotted! aainst the contraction heiht was plotted! <astly, the wor% done as a function of the <astly, the wor% done as a function of the weiht lifted was plotted!

weiht lifted was plotted!

An

An iin n vviittrroo preparation preparation of of thethe a

aststrorocncnememiuius s mmususclcle e wawas s mamadede! ! ThThee %ymor

%ymoraph drum aph drum was set was set at moderate speedat moderate speed then the muscle was stimulated at ma#imal then the muscle was stimulated at ma#imal 4oltae once and it was allowed 2: seconds 4oltae once and it was allowed 2: seconds reco4ery! The muscle was %ept moist at all reco4ery! The muscle was %ept moist at all tim

times es witwith h RinRinerers s solsolutiution! on! The The musmusclecle was stimulated twice then it was rested for was stimulated twice then it was rested for an

anotother her 2: 2: sesecoconds nds anand d ththe e mumuscscle le wawass stimulated aain with - consecuti4e stimuli! stimulated aain with - consecuti4e stimuli! The process was continued with increasin The process was continued with increasin number of stimuli until the muscle ceased to number of stimuli until the muscle ceased to con

contratract! ct! The The numnumber ber of of musmuscle cle twitwitchtcheses was recorded at each fre$uency!

was recorded at each fre$uency!

B

B PrPrococededurure foe for Pr Powower Ler Laa > > Mountin the muscle for recordin Mountin the muscle for recordin

The

The Force Force TrTransducer ansducer was securely was securely m

mouountnted ed iin n tthehe micmicroroposposititioneionerr mountinmountin brac%et!

brac%et! The The cable cable was was plued plued into into thethe bac% of

bac% of thethe Bridge Pod. Bridge Pod. A small metric ruler A small metric ruler was taped to the side of the

was taped to the side of the micropositioner micropositioner to use as a reference when adjustin heiht! to use as a reference when adjustin heiht! The

The Bridge Bridge PodPod was connwas connectected to ed to thethe Pod Pod Port

Port on on "n"nput 2 put 2 of of ththe e oowewer<r<ab>ab>! ! ThThee bipolar

bipolar stimulator stimulator handle handle was was mounted mounted toto the rin usin a clamp! The femur of the the rin usin a clamp! The femur of the fro was clamped to the rin stand usin a fro was clamped to the rin stand usin a

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micropositioner

micropositioner was adjusted such that the was adjusted such that the a

aststrorocnecnemimius us wawas s peperprpenendidiculcular ar to to ththee tab

table! Thele! The micropositioner micropositioner was raised usin was raised usin the adjustment %nob so that the muscle was the adjustment %nob so that the muscle was 4ertical but not under tension! The muscle 4ertical but not under tension! The muscle was rinsed with Riners solution to %eep it was rinsed with Riners solution to %eep it mo

moisist! t! ThThe e bibipopolalar r ststimimululatator or wawas s ththenen positioned

positioned such such that that both both stimulus stimulus leadsleads were touchin the middle of the muscle! The were touchin the middle of the muscle! The 8?@ .B93 leads from the stimulator handle 8?@ .B93 leads from the stimulator handle were attache

were attached to d to thethe Output Output .B93 connectors .B93 connectors on the front of the ower<ab>!

on the front of the ower<ab>! (ettin up the software

(ettin up the software Cs

Csinin  ththe e cocompmpututerer, , oowewer<r<abab>> was

was openopened! ed! <ac<ac@ha@hart>rt>;!* ;!* was was laulaunchenched!d! The

The Frog Muscle Folder Frog Muscle Folder was chosen from was chosen from tthhee Experiments Experiments GalleryGallery tthheen tn thhee Frog Frog Muscle

Muscle SettingsSettings fifile le wawas s opopeneened! d! A A twtwo9o9 ch

chanannenel l ememptpty y dadata ta fifile le apappepearareded! ! ThThee 8r

8ridide e ood d wawas s seselelectcted ed frfrom theom the Force Force channel pop9up menu! The %nob on the front channel pop9up menu! The %nob on the front of the 8ride od was used to adjust the of the 8ride od was used to adjust the sinal so that it read zero! The DK button sinal so that it read zero! The DK button was clic%ed to start the ne#t e#ercises!

was clic%ed to start the ne#t e#ercises!

8!2 The raded response 8!2 The raded response

The muscle was %ept moist and it The muscle was %ept moist and it wa

was s mamade de susure re ththat at botboth h leleadads s frfrom om ththee

sc

screreen en ininststruructctioions ns wewere re fofolllloweowed! d! ThThee o

owewer<r<ab> ab> ststimimululatated ed ththe e mumuscscle le wiwithth increasin strenth and the results for each increasin strenth and the results for each contraction was recorded!

contraction was recorded!

8!1 /ffect of load on contraction force 8!1 /ffect of load on contraction force

The muscle was %ept moist and the The muscle was %ept moist and the stimulator handle was positioned correctly! stimulator handle was positioned correctly! Th

The e poposisitition on of of ththe e mimicrcropopososititioionener r wawass no

noteted d ususinin  ththe e ruruleler r anand d ththis is wawas s ththee reference position! "n <ab@hart>,

reference position! "n <ab@hart>, SetupSetup waswas ch

chososen from then from the e memenu bar andnu bar and Stimulator Stimulator wa

was s seselelectcteded! ! ThThe e 4a4alulue e in in 4ol4olts ts fofor r ththee supram

suprama#imal a#imal stimstimulus ulus 4olta4oltae e calculcalculatedated was inputted in the

was inputted in the AmpAmplitlitude ielude ieldd or theor the Dutput field! "n <ab@hart>,

Dutput field! "n <ab@hart>, Macro Macro from the from the m

menenu u babar r wawas s sselelececteted d tthehen n ththee Muscle Muscle T

Teensnsioion.n. The The on9on9scrscreen een insinstrtructuctionions s werweree fo

follllowowed ed to to rerecorcord d ththe e dadatata! ! AAftfter er eaeachch recordin, at least 2* seconds was waited to recordin, at least 2* seconds was waited to al

allolow w ththe e mumuscscle le to to rerecoco4e4er r bebefofore re ththee m

miiccrrooppoossiittiioonneerr wwaassrraaiisseed d bby y oonnee millimeter! At the end of the recordin, the millimeter! At the end of the recordin, the micropositioner

micropositioner was returned to its oriinal was returned to its oriinal position

position and and the the tension tension of of the the muscle muscle waswas rel

releaseased ed by by turturninnin  the the adjadjustustmenment t %nob%nob!! The results were recorded in table )9E!

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The muscle as %ept moist at all times The muscle as %ept moist at all times and

and the the stistimulmulatoator r handhandle le was was pospositiitioneonedd correc

correctlytly! ! "n "n <ab@ha<ab@hart>,rt>, Macro Macro was chosen was chosen form the menu bar then

form the menu bar then Stimulus Fre!uencyStimulus Fre!uency was

was selselectected! ed! The The on9on9scrscreen een insinstrutructictionsons were

were follfollowed! owed! The The owerower<ab> <ab> stimstimulatedulated the muscle with

the muscle with twin pulses )**ms, 1**ms,twin pulses )**ms, 1**ms, 2

2***m*mss, , ::**mmss, , aannd d 11*m*ms s aappaarrtt! ! //aacchh re

recorcordidin n apappepeareared d in in a a seseparparatate e blblococ%!%! 6

6hehen n tthe he rrececorordidin n wawas s cocommplpletete, e, aa "omment

"omment was added to each bloc% of data was added to each bloc% of data with the stimulus inter4al! The results were with the stimulus inter4al! The results were recorded in Table )9F!

recorded in Table )9F!

8!) Tetanus 8!) Tetanus

Th

The e mumuscscle le wawas s %e%ept pt momoisist t at at alalll ttimimes es anand d tthe he sstitimmululatator or hahandndle le wawass positioned

positioned correctly! correctly! "n "n <ab@hart>,<ab@hart>, Macro Macro was chosen from the menu bar and

was chosen from the menu bar and TetanusTetanus was

was selselectected! ed! The The on9on9scrscreen een insinstrutructictionsons were

were follfollowed! owed! The The owerower<ab> <ab> stimstimulatedulated the muscle for one second with continuous the muscle for one second with continuous pulses

pulses at at inter4als inter4als )**ms, )**ms, 1**ms, 1**ms, 2**ms,2**ms, :*m

:*ms, and 1*ms!s, and 1*ms! "omments"omments were added to were added to the data to indicate the stimulus inter4al! the data to indicate the stimulus inter4al!

8!: Muscle 5atiue 8!: Muscle 5atiue

The muscle as %ept moist at all times The muscle as %ept moist at all times

sel

selectected! ed! The The on9on9scrscreen een insinstrtructiuctions ons werweree fol

followlowed! ed! The The oweower<ar<ab> b> stistimulmulateated d thethe muscle continuously with a stimulus inter4al muscle continuously with a stimulus inter4al of

of 1*1*ms ms fofor r -* -* sesecocondnds! s! ThThe e rerecocordrdinin duration was ): secon

duration was ): seconds! After the recordinds! After the recordin st

stopoppedped, , aa comment comment was added to the data was added to the data trace called

trace called Fatigue. Fatigue.

Analysis for PowerLa! Analysis for PowerLa! 8!2 The raded response 8!2 The raded response

Mar#er

Mar#er ..MM3 3 wwaas s ppllaacceed d oon n tthhee baseline

baseline of of the the wa4eform wa4eform in in the the 5orce5orce cha

channelnnel! The! The $aveorm "ursor $aveorm "ursor was placed was placed at the top of the last contraction pea%! The at the top of the last contraction pea%! The pea%

pea% heiht heiht for for each each of of the the pea%s pea%s waswas rreecocorrdededd! ! TThhe e ddaatta a iin n TTaabblle e ))99) ) wwaass re

recocordrdeded, , ststarartitin n at at ththe e lalast st popoinint t anandd wor%in bac%wards to the beinnin of the wor%in bac%wards to the beinnin of the trace! 5rom the data, the minimum 4oltae trace! 5rom the data, the minimum 4oltae re$uired was determined to elicit a ma#imal re$uired was determined to elicit a ma#imal contraction called the ma#imum e#citation contraction called the ma#imum e#citation 4ol

4oltatae! e! The The 4al4alue ue for for the the supsupramrama#ia#imalmal stimulus was determined by multiplyin the stimulus was determined by multiplyin the 4oltae by 2!:! The 4alues were recorded in 4oltae by 2!:! The 4alues were recorded in Table )9:!

Table )9:!

8!1 The effect of load on contraction force 8!1 The effect of load on contraction force

T

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baseline

baseline 4alue 4alue and and called called thethe preload orce. preload orce. T

Thhee ra% ra% t%it%itc& tc& ororcece wwiitth thh thee $aveorm$aveorm "ursor

"ursor wawas s dedetetermrminined ed by by plplacacinin  ththee cursor on the ma#imum 4alue in the bloc%! cursor on the ma#imum 4alue in the bloc%! The results were entered in Table )9E! (teps The results were entered in Table )9E! (teps 1

1 anand d - - wewere re rerepepeatated ed fofor r ththe e ototheher r 2*2* bloc%s!

bloc%s! TheThe net t%itc& orcenet t%itc& orce was calculated was calculated by

by subtractin subtractin thethe preload preload valuevalue from thefrom the ra% t%itc& orce

ra% t%itc& orce 4alue! 4alue!

8!

8!- - ThThe e efeffefect ct of of ststimimululus us frfre$e$ueuency ncy onon contraction force

contraction force T

Thhe e ddaatta a wweerre e ee##amamiinened d ffrromom /#ercise - and there were fi4e bloc%s of /#ercise - and there were fi4e bloc%s of re

recocordrded ed dadatata! ! 5o5or r eaeach ch dadata ta blblococ%, %, ththee ma#imum contraction force of the first and ma#imum contraction force of the first and sec

second ond pea%pea%s s werwere e detdetermermineined d usiusin n thethe mar

mar%er %er and and wa4wa4efoeform rm curcursorsor! ! The The resresultultss were recorded in Table )9F!

were recorded in Table )9F!

8!) Tetanus 8!) Tetanus

T

Thhe e ddaatta a wweerre e ee##amamiinened d ffrromom /#ercise ) and there were fi4e bloc%s of /#ercise ) and there were fi4e bloc%s of re

recocordrded ed dadatata! ! ThThee maximumaximum m contrcontractionaction orce

orce ffoor r eeaacchh stimulation stimulation re!uencyre!uency waswas de

detetermrmiinened d anand d tthe he reresusulltts s wewere re ththenen recorded in Table )9;!

recorded in Table )9;!

'aseline

'aseline wawas plas placeced in d in ththee Force Force channelchannel im

immemedidiatatelely y prprioior r to to ststimimululatatioion! n! ThThee wa4efo

wa4eform cursor was rm cursor was used to used to determdetermine theine the ma#imum contraction force and these 4alues ma#imum contraction force and these 4alues w

weerre e rrececoorrdded ed iinnclcluuddiinn  tthhe e ttiimme e oof f ma

ma#i#imamal l ststimimululatatioion n in in TTaablble e )9)9! ! ThThee contraction force at t 2,:,2*,2:,1*,1:, and contraction force at t 2,:,2*,2:,1*,1:, and -*

-* ssececononds ds wewere re dedetterermiminened d afaftter er tthehe sti

stimulmulatiation! on! The The resresultults s werwere e recrecordorded ed inin Table )9!

Table )9!

"esults and Discussion "esults and Discussion (. )ymograp&

(. )ymograp&

(.( Graded response (.( Graded response

"n this acti4ity, a sciatic ner4e still "n this acti4ity, a sciatic ner4e still attached to an isolated s%eletal muscle of a attached to an isolated s%eletal muscle of a toa

toad d was was subsubjectjected ed to to incincreareasinsin  stistimulmulusus 4

4oollttaae e oof f --, , ))!!:, :, EE, , FF!!:, :,   aannd d 221 1 ==!! Ky

Kymomorraph aph wawas s usused ed whwhicich h shshoweowed d ththee anal

analoue oue rereististratration ion of of resresponsponses es of of thethe sc

sciaiatitic c nerner4e 4e memeasasurured ed wiwith th ththe e aiaid d of of aa metric ruler!

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#ale $%

#ale $%Graded response without weihtGraded response without weiht 6ithout weiht

6ithout weiht =

=oollttaaee HHeeiiht ht oof f tthhe e ppeea% a% ..mmmm33 -- 22 ) )!!:: FF E E 2121 F F!!:: 22))   2)2) 2 211 22:: 2 2 4 4 6 6 8 8 110 0 112 2 1144 0 0 5 5 10 10 15 15 20 20 Figure $%

Figure $% Graded response without weiht Graded response without weiht

The threshold 4oltae which is the The threshold 4oltae which is the mi

mininimumum m ststimimululus us rere$ui$uirered d to to ininducduce e aa response is -=! As the stimulus 4oltae is response is -=! As the stimulus 4oltae is increased beyond the threshold 4oltae, the increased beyond the threshold 4oltae, the heiht of the pea% enerated by the response heiht of the pea% enerated by the response

(.* Eect o +oad (.* Eect o +oad

"n this acti4ity, the effect of load was "n this acti4ity, the effect of load was iin4n4esestitiaateted d wiwitth h : : : : cecentnta4a4o o cocoininss at

attatachched ed to to an an isisololatated ed s%s%eleletetal al mumuscsclele subjected with increasin stimulus 4oltae! subjected with increasin stimulus 4oltae!

#ale &%

#ale &%Graded response with weihtGraded response with weiht 6ith : : centa4os weiht

6ith : : centa4os weiht =

=oollttaaee HHeeiiht ht oof f tthhe e ppeea% a% ..mmmm33 -- ** ) )!!:: - -E E 2222 F F!!:: 2222   2)2) 2 211 22:: 2 2 4 4 6 6 8 8 110 0 112 2 1144 0 0 5 5 10 10 15 15 20 20 Figure &%

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at which muscle shortens dependin on the at which muscle shortens dependin on the load it has to bear .Meijer, 2;3!

load it has to bear .Meijer, 2;3!

(., Eect

(., Eect o Pulse Fre!uency- Teo Pulse Fre!uency- Tetanus andtanus and Muscle Fatigue

Muscle Fatigue Thi

This s e#pee#perimriment ent aimaims s to to detedetermirminene tthhe e eeffffeecct t of of ppululsse e ffrree$$ueuenncycy! ! uullssee fre$uency is the number of action potentials fre$uency is the number of action potentials e

enenerarateted d peper r miminunutete! ! (t(timimululatatinin  ththee is

isololatated ed s%s%eleletetal al mumusclscle e twtwicice e wiwith th ththee sh

shorortetest st titime me ininteter4r4al al wiwith th 2: 2: sesecocondndss rela#a

rela#ation between the tion between the stimstimuli will uli will resulresult t inin an increase of force enerated! "f the force an increase of force enerated! "f the force of contraction with each subse$uent allows of contraction with each subse$uent allows the muscle to fully rela#, it would be treppe! the muscle to fully rela#, it would be treppe! Treppe, also %nown as the staircase effect, is Treppe, also %nown as the staircase effect, is where there is more force produced than the where there is more force produced than the pre4ious

pre4ious muscle muscle twitch! twitch! "f "f the the muscle muscle isis stimulated repeatedly with stimuli arri4in stimulated repeatedly with stimuli arri4in con

consecsecutiuti4ely 4ely witwith h shoshort rt timtime e intinter4er4al, al, itit w

woouulld d bbe e wwaa44e e ssuummmmaattiioonn! ! 66aa44ee su

summmmatatioion n reresusultlts s to to a a ststroronener r mumuscsclele

of muscle fatiue will result in the decrease of muscle fatiue will result in the decrease o4er time of the force!

o4er time of the force!

*. Po%erla' *. Po%erla' *.(

*.( Graded Graded responseresponse

Table -! Graded response of fro muscle to Table -! Graded response of fro muscle to increasin stimulus increasin stimulus = =oollttaaee 11!!: : ?? - - ?? --!!: : ?? -- **!!**2222;; **!!**22::)) **!!**11--11 ) )!!:: **!!**2222FF **!!**22::EE **!!**11--11 E E **!!**2211:: **!!**22;;:: **!!**11--11   **!!**22)):: **!!**11**EE **!!**11--11 2 211 **!!**22EE:: **!!**11--11 **!!**11--11 Th

The e e#e#peperirimement nt prpropopososed ed ththat at asas ten

tensision on on on the muscle increathe muscle increasedsed, , forforce ce of of contraction would increase until a phase at contraction would increase until a phase at whi

which ch an an addadditiitionaonal l tentensiosion n wouwould ld caucausese stability of the enery that was obser4ed! stability of the enery that was obser4ed!

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5iure -! /ffect of load on contraction force 5iure -! /ffect of load on contraction force

T

Thhe e eeffffeecct t oof f ssttrreettcchhiinn  tthhee sarcomere on the force of contraction of fro sarcomere on the force of contraction of fro ss%e%elletetaal l mmuussclcle e wwaas s rreeccoorrdeded d uussiinn ower<ab and I@hartJ software! The deree ower<ab and I@hartJ software! The deree of

of sasarcrcomomerere e ststreretctch h wawas s dedetetermrminined ed byby rai

raisinsin  the force the force tratransdnsduceucer r to to whiwhich ch thethe a

aststrorocnecnemimius us mumuscscle le wawas s atattatachched ed anandd measurin the resultin chanes in baseline measurin the resultin chanes in baseline on the software in rams! The resultin force on the software in rams! The resultin force of contraction of the muscle at ma#imum of contraction of the muscle at ma#imum response stimulation was also measured in response stimulation was also measured in rams!

rams!

phenomena

phenomena of of summation, summation, tetanus, tetanus, andand e4

e4enentutual al fafatitiuue e of of ththe e mumuscscle le anand d ththee respecti4e fre$uencies at which each were respecti4e fre$uencies at which each were obser4ed!

obser4ed!

1!) Tetanus 1!) Tetanus Th

This is e#e#peperirimement nt prpro4o4idides es rerelalatitiononshshipip am

amon on frfre$e$uenuency cy of of sisimumulalatition on anand d ththee rreessuullttiinn  ccoonnttrraaccttiioon n ffoorrcce e oof f tthhee 

aassttrrooccnenemmiiuus s mmuussccllee! ! ((uummmmaattiionon,, inc

incompompletlete e tettetanuanus, s, and and comcompleplete te tettetanusanus,, are characteristics of muscle contraction that are characteristics of muscle contraction that were obser4ed by radually increasin the were obser4ed by radually increasin the fre$uency stimulation!

fre$uency stimulation!

1!: Muscle 5atiue 1!: Muscle 5atiue

"n

"n orordeder r to to obobseser4r4e e ththe e ononseset t of of fatiue, the stimulator was set to complete fatiue, the stimulator was set to complete te

tetatanunus s as as dedetetermrminined ed in in ththe e prpre4e4ioiousus e#periment!

e#periment!

'onclusion 'onclusion

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"eferences "eferences /

/anan, , 8!8!,&0,&0ieierarathth, , ! ! .1.1*2-*2-3! 3! /#e/#ercrcisisee metabo

metabolism and lism and the molecular reulatiothe molecular reulation n of of s%eletal muscle adaptation! @ell Metabolism! s%eletal muscle adaptation! @ell Metabolism! d#!doi!orB2*!2*2EBj!cmet!1*21!21!*21

d#!doi!orB2*!2*2EBj!cmet!1*21!21!*21

Mei

Meijerjer, K! , K! .2.2;3;3!! Muscle Muscle Mec&anics Mec&anics T&eT&e Eect

Eect o o Stretc& and Stretc& and S&ortening S&ortening on on S#eletal S#eletal Muscle Force

Muscle Force! Cni4ersity of ! Cni4ersity of TwTwente!ente!



llaaccee, , ??!!, , 77aammaaddaa, , TT!!, , 88rruuttoonn, , !!,, 6esterblad, H! .1*2*3! Muscle fatiue' from 6esterblad, H! .1*2*3! Muscle fatiue' from ob

obseser4r4atatioions ns in in huhumamans ns to to unundederlrlyiyinn mechanisms studied in intact sinle muscle mechanisms studied in intact sinle muscle ffibibrreses! ! //ururopopeaean n ouourrnanal l of of AApppplilieded 

hhyyssiioollooyy, , 2222**..2233, , 229922::! ! ddooii'' 2*!2**FBs**)129*2*92);*9*

2*!2**FBs**)129*2*92);*9*

Re

Recocondindititi, , M!M!, , 8r8rununelellolo, , /!/!, , <i<inanariri, , M!M!,, a

as$s$uauale le 8!8!, , ?a?ararayayanannan, , TT!!, , aanininene, , !!

"r4

"r4inin, , M! M! .1*.1*22223!M3!Motiotion on of of myomyosin sin headhead do

dommaiains ns duduririn n acactti4i4atatiion on anand d ffororcece de4elopment in s%eletal muscle! roceedins de4elopment in s%eletal muscle! roceedins of the ?ational Academy of (ciences, 2*; of the ?ational Academy of (ciences, 2*; ..22FF33, , FF11--EE99FF11))**! ! ddooii'' 2*!2*F-Bpnas!2*2;--*2*;

2*!2*F-Bpnas!2*2;--*2*;

(chiaffino, (!, &Reiani, @! .1*223! 5iber (chiaffino, (!, &Reiani, @! .1*223! 5iber Ty

Types in pes in Mammalian (%eletal MusclesMammalian (%eletal Muscles hysi

hysioloicoloical al Re4ieRe4iews, ws, 2.)3, 2.)3, 2))F92:2))F92:-2!-2! doi'

doi' 2*!22:1Bphysre42*!22:1Bphysre4!***-2!1*2*!***-2!1*2*

7

7aaii, , ?! ?! .1.1*2*2*3*3!M!Mecechahaninism sm of of lalatetencyncy rreellaa#a#attiioon n iin n ffrroo  ss%%eelleettal al mmuussccllee!! /#perimental @ell Research, -2E.2;3, -*-L /#perimental @ell Research, -2E.2;3, -*-L -*! doi'2*!2*2EBj!ye#cr!1*2*!*:!*2

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