Abstract. Volume 5, No. 1, 2013, 1 8 UDC :

Transcription

1 EXERCISE AND QUALITY OF LIFE Volum 5, No. 1, 213, 1 8 UDC : Rsarch articl EFFECT OF MAXIMUM VOLUNTARY ISOMETRIC CONTRACTION OF ANTAGONIST MUSCLES IN MAX TORQUE AND RATE OF TORQUE DEVELOPMENT OF AGONIST MUSCLES IN AND UN WOMEN Dspoina Tsrpi, Anastasia Papavasilioy, Chrystala Pantli, Xnofontos Anthi, Elni Bassa and Christos Kotzamanidis * Laboratory of Coaching and Sport Prformanc Dpartmnt of Physical Education and Sport Scinc Aristotl Univrsity of Thssaloniki, Thssaloniki, Grc Abstract Th purpos of this study was to compar th ffct of antagonist maximum voluntary isomtric contraction on th torqu and th rat of torqu dvlopmnt of th agonist muscls in ankl joint in traind and untraind womn at angl joint. Twlv untraind and twlv traind womn handball playr participatd in th study. An isokintic dynamomtr CYBEX Norm was usd for th valuation of torqu. Initially th Maximal Voluntary Isomtric Contraction (MVIC) both for plantar(pf) and dorsi flxors(df) was valuatd. Aftrwards th subjcts prformd 3 maximal isomtric contractions of plantar flxor for 1 scond, with 1 minut brak btwn trials. Aftr 1 minuts complt rst, 3 conscutiv maximal dorsiflxion contractions and immdiatly aftr that thr maximal PF contraction wr prformd for th valuation of th rvrsal ffct DF on PF. Th following paramtrs wr valuatd bfor and aftr DF contraction:plantar flxion MVIC, Maximal Rat of Torqu Dvlopmnt (MRTD), tim of MRTD and th RTD for th priod 3, 5, 1 and ms aftr th torqu onst. Th statistical analysis showd that th rvrsal ffct was prsntd only for th traind group for th MRTD and RTD 3. Ths rsults dmonstratd that th xistnc of th rvrsal ffct of th antagonists is not appard always in untraind groups and spcially for th joint angl it is affctd by th training background only for slctiv paramtrs of muscl contraction. Kywords: rvrsal of antagonists, traind, untraind, MVIC,RTD * Corrsponding author. Laboratory of Coaching and Sport Prformanc, Dpartmnt of Physical Education and Sport Scinc, Aristotl Univrsity of Thssaloniki, Univrsity Campus, Thssaloniki, Grc, -mail: kotzaman@phd.auth.gr 213 Faculty of Sport and Physical Education, Univrsity of Novi Sad, Srbia

2 D. Tsrpi t al. Introduction Th Rat of Torqu Dvlopmnt (RTD) shows th chang of torqu in tim, from th onst of torqu to th tim of apparanc of th maximum isomtric torqu. Ths two paramtrs can b affctd both by motor nurons and muscular paramtrs (Andrsn &Aagaard, 6). It is known that th rlation btwn torqu-spd and nuromuscular activity appar som diffrncs, dpnding from th angular position of th masurd torqu (Simonau, Martin & Van Hock, 7). An intrsting point for th RTD nhancmnt was th Golgi Tndon Organ (GTD)function as statd by prvious studis. Grabinr(1994) suggstd that th RTD can b positivly affctd during a maximal isomtric contraction prcdd by a contraction of th antagonist muscl. This phnomnon is calld Rvrsal of th Antagonist (REV). According to this phnomnon th practivation of antagonist muscls could probably causs bttr prformanc during th contraction of agonist muscls. Kabat (1952), basd on Shrrington s concpt (1947), introducd th ida of REV, prtnding that lmntary rflxs intract to triggr a mor complx procss to coordinat agonist and antagonist action. This could b th xplanation about th rlation btwn REV and Golgi tndon organs (GTOs) function bcaus whn a muscl is contractd inhibits th function of agonist muscl and facilitats th antagonist, through Ib affrnt. Th xact natur of this mchanism has not xprimntally bn idntifid compltd though svral nuronal or muscular mchanisms hav also bn proposd (Roy t al., 199). Rgarding th ffct of REV on muscl prformanc two cass hav bn analyzd: th pak torqu and th RTD. Initially th REV ffct was tstd in hmipartic subjcts whr pak torqu nhancmnt was obsrvd (Bohannon, 1985). Howvr, this was not always th cas for th halthy popl, whr in othr cass positiv ffct (Kamimura, 7; Kamimura, t al 9; Roy t al., 199) whil in othrs no ffct (Bohannon, Gibson, & Larkin, 1986) was rportd. Untill now th ffct of th rvrsal was studid on two cass for strngth and RTD nhancmnt. Th majority of cass rportd an ffct only on RTD and not for th maximal torqu (Gabril, Basford, & An, 1997; Gabril, Basford, & An, 1; Kamimura, 7). Howvr a rcnt study (Kamimura, Yoshioka, Ito, &Kusakab, 9) rportd REV ffct on maximal torqu. Th xplanation of thir rsults was basd on th fact that thy usd a contraction of th on scond instad of two sconds which th prvious studis did,considring that GTO ffct lasts about on scond. Analyzing furthr th rlvant litratur it was rvald that th REV ffct has not xtnsivly masurd in joint angl and spcially thr was no comparison btwn traind and untraind popl. Th last cas is vry important if it is considrd that th possibl highr valus of strngth could caus a highr strain on GTO and consquntly nhancd rvrsal ffct. For this rason th purpos of this study was th invstigation of REV ffct in angl join and th diffrncs which may xist btwn traind and untraind prsons. Mthod Participants Th sampl was consistd of 12 untraind and 12 traind handball womn. Handball playrs playd in th first and scond division of Grk championship whil untraind wr studnts of th 2

3 Effct of MVIC in traind and untraind womn Dpartmnt of Physical Education and Sport scinc. Anthropomtric data ar prsntd in tabl 1. All participants wr familiar with th tsting protocol and thy gav thir writtn consnt, having bn informd for th procss. Th xprimntal procss was complid with th Ethics standards providd by th Aristotl Univrsity of Thssaloniki. Tabl 1. Anthropomtric data of th participants Group Ag (y) Hight (cm) Body mass (Kg) Traind 24,23 ± 31 1,68 ±,5 61 ± 6,11 Untraind 22,13 ± 1,84 1,73 ±,4 6,91 ± 7,94 Instrumntation Dynamomtry: Th isokintic dynamomtr CYBEX Norm (Lumx Corporation, Ronkohoma, NY), according to manufacturing instructions rgarding alignmnt of th spcific platform that has th dynamomtr for th masurmnt of th ankl joint. Exprimntal protocol Th xprimntal protocol was consistd of thr stags. Participants in th first stag prformd 3 maximum isomtric contractions of th plantar flxors for 1 scond with 1 minut rst priod btwn thm. Thy rstd for 1 minuts off th machin and thy prformd th scond stag of th protocol. Participants in scond stag prformd 3 maximal 1 scond maximal dorsiflxion isomtric contractions. In th third stag thy prformd maximal 1 scond plantar flxion for th valuation of th REV. Tsting For th MVIC both of plantar and dorsiflxors th participants prformd 15 2 submaximal isomtric contractions with gradually incrasing intnsity with 3 minuts rst intrval. Participants wr instructd to produc thir maximal torqu. Vrbal motivation and visual fdback of th torqu output was providd during th tsts. Th highst torqu valu was markd on th monitor and st as targt to ovrcom for th rst trials. This procdur was rpatd until th torqu of th thr bst trials was not lss than th 95% of th bst on. Th trial with th highst torqu valu was furthr analyzd and usd as targt valu for th REV valuation.all tsts wr prformd on th dominant foot, at supin position, with hips flxd at 6º. Th kn was st at full xtnsion and th angl btwn th plantar surfac of th foot and th tibia was st at 9º. Th rotation axis of th dynamomtr was approximatly alignd with th rotation axis of th ankl. Nonlastic Vlcro straps stabilizd th foot on th platform and th subjct s trunk and thigh on th dynamomtr s chair. Hight and body mass wr masurd using stadiomtrand a digital scal rspctivly, with subjcts in light clothing and no shos. Hight and body mass wr rcordd to th narst.1 cm and.1 kg, rspctivly(sahaly, Vandwall, Driss,& Monod, 1). 3

4 D. Tsrpi t al. Analysis of data For RTD, torqu onst was dfind as th first point in tim whr torqu rachd 5 standard dviations of its baslin.aftrwards th following paramtrs wr analysd. Th mthod of calculating th rat of torqu dvlopmnt was th following using Matlab packag: Maximal RTD,tim to Maximal RTD and th RTD in th 3, 5, 1, and ms Intrval. Statistical analysis.th program Statistica was usd for th statistical analysis. As dpndnt variabls wr dfind: th valus of maximum torqu, th rat of torqu dvlopmnt (RTD) and th tims in which appard ths variabls.following indpndnt variabls wr usd: th group (traind-untraind), tim of contraction, th angl masurmnt ( ) and th typ of contraction (isomtric, only maximum or rvrsal). In th analysis of data th modl of analysis of varianc was usd: ANOVA for rpatd masurmnts. Th Tuky tst was usd for post-hoc analysis and lvl of significanc was st at p>.5. Rsults Th comparison in MIVC rvald statistical significant diffrncs in traind prsons in all conditions (p <.5), howvr no rvrsal ffct was obsrvd in both of th two groups (p >.5) m N * * * * UN Figur 1. Rvrsal Effct on MVIC Statistical analysis showd a tndncy for a rvrsal ffct on MRTD howvr this ffct was not significant (p >.5). Highr valus for MRTD was obsrvd in all xprimntal conditions in traind group but it was not statistically significant (p >.5) 4

5 Effct of MVIC in traind and untraind womn 1 1 c / S m N UN TRIALS Figur 2. Rvrsal Effct on MRTD Th statistical analysis showd a rvrsal ffct only for th traind group (p <.5). No ffct was obsrvd for th untraind group c s 15 M 1 5 * UN Figur 3. Rvrsal ffct on th tim for MRTD Th analysis of this paramtr showd rvrsal ffct only for th traind group (p <.5) but not for th untraind on (p >.5). In all cass th valus for th traind group wr highr for th untraind group (p <.5). 5

6 D. Tsrpi t al * * * c S / m N UN Figur 4. Rvrsal ffct of RTD during th first 5msc of MIVC For th 1 msc RTD no rvrsal ffct was obsrvd in both group (p >.5). A tndncy for nhancmnt and highr valus in all cass was obsrvd in traind group compard with untraind on without bing significant. 1 1 c / S m N UN Figur 5. Rvrsal ffct on RTD during th first 1 msc of MIVC No rvrsal ffct was obsrvd for both of th two groups for th RTD during th first msc (p >.5). Howvr th valus of th traind group wr highr compard to untraind on but without bn significant. 6

7 Effct of MVIC in traind and untraind womn c 5 / S m 4 N 3 1 UN Figur 6. Rvrsal ffct on RTD during th first msc of MIVC Th statistical analysis showd that thr ar no statistically significant diffrncs btwn fforts and groups (traind-untraind). Discussion Th obtaind rsults indicat that REV did not affct in RTD but obsrvd a statistically significant diffrnc in pak torqu btwn th traind and untraind womn. Rgarding th rat of torqu dvlopmnt diffrncs wr found btwn th fforts but not btwn groups. Th ffct of rvrsal on th torqu ar conflicting, sinc in othr cass thr was an incras of output torqu (Kamimura, 7; Kamimurat al., 9), and in othr cass not (Bohannon, 1985;Grabinr, 1994; Gabrilt al., 1). Th diffrncs in th rsults compard with thos of prvious rsarch may b du: Using diffrnt protocols, Smallr sampl compard with othr invstigators, Exprimnt on diffrnt sampls. Howvr that found bttr rsults in th traind group, although not statistically significant, thy should troubl us so to s if th phnomnon of rvrsal of antagonists can b usd to implmnt nw training protocols. Th bst rsults in th traind group probably du to th fact that traind individuals hav practicd to b fast nrgy transfr in myotndon systm during a movmnt. Th dtaild study of th phnomnon it is ncssary to allow th undrstanding and th furthr practical application. 7

8 D. Tsrpi t al. Rfrncs Andrsn, L. L., & Aagaard, P. (6) Influnc of maximal muscl strngth and intrinsic muscl contractil proprtis on contractil rat of forc dvlopmnt. Europan Journal of Applid Physiology, 96(1), Bohannon R. W. (1985). Kn xtnsion torqu during rpatd kn xtnsion-flxion rvrsals and sparatd kn xtnsion-flxion dyads. Journal of Amrican Physical Thrapy Association, 65(7), Bohannon R. W., Gibson D. F., & Larkin P. (1986).Effct of rsistd kn flxion on kn xtnsion torqu, Physical Thrapy, 66, Gabril, D. A., Basford, J. R., An, K. N. (1997). Rvrsal of antagonists: ffct on lbow xtnsion strngth and nduranc. Archivs of Physical Mdicin and Rhabilitation, 78(11), Gabril, D. A., Basford, J. R., & An, K. N. (1). Th rvrsal of antagonists facilitats th pak rat of tnsion dvlopmnt. Archivs of Physical Mdicin and Rhabilitation, 82, Grabinr, M. D. (1994). Maximum rat of forc dvlopmnt is incrasd by antagonist condition contraction. Journal of Applid Physiology, 77, Kabat, H. (1952). Studis on nuromuscular dysfunction XV: Th rol of cntral facilitation in rstoration of motor function in paralysis. Archivs of Physical Mdicin and Rhabilitation, 33(9), Kamimura, T. T. (7). Potntiation of kn xtnsor contraction by antagonist conditioning. Journal of Physiological Anthroppology, 26(4), Kamimura, T., Yoshioka K., Ito S., & Kusakab T. (9). Incrasd rat of forc dvlopmnt of lbow flxors by antagonist conditioning contraction. Human Movmnt Scinc, 28, Sahaly, R., Vandwall H., Driss, T., & Monod, H. (1). Maximal voluntary forc and rat of forc dvlopmnt in humans importanc of instruction. Europan Journal of Applid Physiology, 85(3 4), Shrrington, C. S. (1947). Th Intgrativ Action of th Nrvous Systm. Nw Havn, CT: Yal Univrsity Prss. Simonau, A. M., Martin, A., & Van Hock, J. (7).Effcts of joint angl and ag on ankl dorsi- and plantar-flxor strngth. Journal of Elctromyography and Kinsiology, 17(3),