Proceedings 2010. (2011), Vol 2, ISSN 1986-8154
INTRODUCTORY LECTURE
UVODNO PREDAVANJE
www.sportkon.com
BIOMEHANIČKE KARAKTERISTIKE
RAZVOJA MAKSIMALNE BRZINE
BIODYNAMIC CHARACTERISTICS OF
MAXIMUM SPEED DEVELOPMENT
Milan Čoh1 and Milan Žvan1
Fakultet za sport, Ljubljana, Slovenia
Faculty of Sport, Ljubljana, Slovenia
1
INTRODUCTORY LECTURE
doi: 10.5550/SP.2.2010.02
UDK: 796.13
UVODNO PREDAVANJE
COBISS.BH-ID: 2244888
Summary
Sažetak
The purpose of present review article is to bring together
some of the most important findings from the field of maximum speed development and from the aspect of biomechanical, motor and neuromuscular factors. Maximum
speed is a complex biomotor ability, which manifests itself
in real sports situations and is an important generator of
successfulness of sportsmen in various sports disciplines.
Efficiency of maximum speed is defined with frequency and
the length of stride. Both parametres are mutually dependant;
they also depend on the processes of central regulation of
motor stereotype. From the biomechanical point of view, a
running stride as a basic structural unit depends on eccentric-concentric muscular cycle of take-off action. Utilisation of
elastic strength in muscular-tendon complex and pre-activation of m. gastrocnemius is highly important in this segment.
Maximum speed is very limited hereditary biomotor ability
with characteristic of reduced possibility for controlling
movement. Cerebellum, coactivation of muscles in kinetic
chain and the frequency of activation of motor units play
important roles in controlling the activation of agonists and
antagonists. Primary goal of training is to create an optimal
model of motor stereotype in the zone of maximum speed.
Such process has to be long term and methodical.
Svrha ovog preglednog članka jeste da objedini neke od
najvažnijih pronalazaka sa polja razvoja maksimalne brzine
i aspekta biomehaničkih, motornih i neuromuskularnih
faktora. Maksimalna brzina je kompleksna biomotorna
sposobnost koja se manifestuje u stvarnim situacijama u
sportu i predstavlja važan generator uspe{nosti sportista u
raznim sportskim disciplinama. Efikasnost maksimalne brzine definisana je frekvencijom i dužinom koraka. Oba parametra su uzajamno zavisna; takođe zavise od procesa regulacije u centru motornih stereotipa. Sa biomehaničke tačke
gledi{ta, korak, kao osnovna strukturalna jedinica zavisi od
ekscentrično-koncentričnog mi{ićnog ciklusa pri akciji kretanja. Kori{tenje elastičnih snaga u mi{ićno-tetivnom kompleksu i prethodna aktivacija troglavog mi{ića lista je veoma
važna u ovom segmentu. Maksimalna snaga je veoma
ograničena naslednim biomotornim sposobnostima sa karakteristikom smanjene sposobnosti za kontrolu kretanja.
Mali mozak, koaktivacija mi{ića u kinetičkom lancu i frekvencija aktivacije motornih jedinica igraju važnu ulogu u
kontrolisanju aktivacije mi{ića agonista i antagonista. Primarni cilj treninga jeste da se stvori optimalan model motornog
stereotipa u području maksimalne brzine. Takav proces
mora biti dugoročan i metodičan.
Key Words: sprint, motor steretype, take off-action, controling movement, speed barrier.
Ključne riječi: sprint, motorni stereotip, akcija kretanja,
kontrolisanje kretanja, brzinska barijera.
Introduction
Uvod
Maximum speed is a product of the frequency and the length
of stride. Both parameters are mutually dependant; they are
also linked to the processes of central regulation of movement,
to the morphological characteristics, bio-motor abilities and
energetic processes. The relationship between the frequency
and the length of a stride is individually defined and automated. Changing one parameter results in the changes of a second
parameter as well. When a length of a stride is increased, the
frequency decreases and vice versa.
The maximum speed, which people produce in movement,
depends on various factors. These factors are related to
morphological and physiological characteristics, energetic
Razvoj maksimalne brzine proizvod je frekvencije i dužine
koraka. Oba parametra su zavisna jedan od drugog; takođe
su povezana sa procesom regulacije pokreta, morfolo{kim
karakteristikama bio-motornim sposobnostima i energetskim
procesima. Povezanost između frekvencije i dužine koraka
je pojedinačno definisana i automatizovana. Promena jednog
od ovih parametara rezultira promenom drugog takođe.
Kada se dužina koraka povećava, frekvencija se smanjuje, i
obrnuto.
Maksimalna brzina koju ljudi proizvode u kretanju, zavisi
od nekoliko faktora. Ovi faktori povezani su sa morfolo{kim
i fiziolo{kim karakteristikama, energetskim mehanizmima,
7
INTRODUCTORY LECTURE
UVODNO PREDAVANJE
Čoh, M., & Žvan, M.: BIODYNAMIC CHARACTERISTICS OF MAXIMUM SPEED... Proceedings 2010, 7-15
mechanisms, age, gender, bio-motor abilities, inter- and
intra-muscular coordination and optimal biomechanical
technique of movement. Locomotive speed in a form of
sprinting run is one of the most important abilities, which
defines the successfulness of sportsmen in many sports situations. From the genetic (hereditary) motor programme
aspect, speed can be classified into primary phylogenetic
human movements. In specific sports situations, speed is
being manifested in a form of a "three-segment model". The
model consists of speed, strength and coordination. Pondering of individual segments of this model depends on the
particularities of specific sports discipline.
staro{ću, polom, bio-motoričkim sposobnostima, inter i intra
muskularnom koordinacijom i optimalnom biomehaničkom
tehnikom izvođenja pokreta. Lokomotorna brzina u formi
sprinterskog trčanja je jedna on najvažnijih sposobnosti
koje defini{u uspe{nost sportiste u mnogim situacijama. Sa
apekta genetskih (naslednih) motoričkih sposobnosti, brzina
može biti svrstana u primarne filogenetske kretnje čoveka.
U specifičnim situacijama u sportu brzina se manifestuje u
obliku „trodelnog modela“. Taj model se sastoji od brzine,
snage i koordinacije. Ponderisanje pojedinačnih segmenata
ovog modela zavisi od pojedinosti specifičnih sportskih disciplina.
Neuro – muscular
aspects of speed
Neuro-muskularni
aspekti brzine
Take-off action in sprinting stride is a key generator for development of maximal speed. Movement of sprinters is evaluated according to their horizontal velocity. The largest inhibitor
in this movement is gravitational force; therefore, sprinters
need to primarily develop sufficiently large vertical reactive
force on the surface in a take-off action, which in itself consists of three phases. The first phase is placing a foot on the
surface, followed by the amortisation phase and extension
phase. Take-off action of stride in sprinters is the best example
of eccentric-concentric muscular cycle (stretch-shortening
cycle). In eccentric phase a certain amount of elastic energy
is being accumulated in a muscular-tendon complex, which
can then be utilised in the second phase. When looking at the
production of reactive force onto a surface, muscles in the
eccentric phase need to develop as large force as possible in
as short time as possible. Transition time needs to be as short
as possible and has an important effect on the efficiency of
eccentric-concentric contraction. Tendons and ligaments,
which resist the extension, can store up to 100 % more elastics energy than muscles (Luhtanen & Komi, 1980; Mero, Komi,
& Gregor, 1992). Pre-activation of m. gastrocnemius (calf
muscle) is extremely important for the mechanics of take-off;
this muscle is being activated 80 milliseconds prior to foot
touching the surface (see Figure 1). Pre-activation creates a
stiffness of plantar flexors (muscles) in the moment when the
front part of the foot touches the surface. Increased stiffness
of the muscles together with the minimal amplitude of movement in an ankle joint enables better transfer of elastic energy
from eccentric to concentric contraction (Kyrolainen et al.,
2001; Mero et al., 2006). When loaded during sprint, tendons
elongate up to 3-4% of their length, any elongation above this
limit represents a potential danger for rupture. Tendons and
ligaments act as springs, which store elastic energy. Excessive
elongation of tendons results in transformation of elastic energy into heat, namely into chemical energy. High temperature
of cells – fibroblasts and collagen molecules, which are building
material for tendons, could facilitate the possibility for injuries
of this part of locomotive apparatus (Huiling, 1999).
In the second phase an extension of muscular – tendon complex
takes place, whereas previously stored elastic energy is being
utilised in a form of efficient propulsion of sprinters stride. The
main absorber in this phase is m. quadriceps (thigh muscle).
Increased co-activation of agonists and antagonists (m. vastus
laterali, m. biceps femoris, m gastrocnemius and m. tibialis)
increases the stiffness of knee- and ankle joints. In this way, the
entire leg is being prepared for contacting the surface. Increased
stiffness of ankle joint in sprint reduces the consumption of
chemical energy in the following muscles: m. gastrocnemius – m.
lateralis – m. medialis and m. soleus (Kuitunen, Komi, & Kyrolainen, 2002). Muscular activation of plantar flexors and the
Započinjanje sprinterskog koraka (kretna faza) jeste ključni
generator za razvoj maksimalne brzine. Najveći inhibitor u
ovom kretanju je sila gravitacije; upravo iz tog razloga sprinteri prvenstveno moraju dovoljno razviti snažnu silu vertikalne reakcije na povr{inu u fazi akcije započinjanja pokreta, koja i sama sadrži tri faze. Prva faza postavlja stopalo na
podlogu i praćena je fazama amortizacije i ekstenzije. Kretna
faza koraka sprintera je najbolji primer ekscentrično-koncentričnog mi{ićnog rada (ekstenzivno-kontraktivnog rada).
U ekscentričnoj fazi određena količina energije elastičnosti
se akumulira u mi{ićno-tetivnom kompleksu, i može biti
kori{ćena u drugoj fazi. Kada posmatramo stvaranje reaktivne sile na podlogu, mi{ići u ekscentričnoj fazi treba da
razviju {to je moguće veću silu u {to je moguće manjem
vremenu. To prelazno vreme treba da bude {to kraće i ima
važan uticaj na efikasnost ekscentrično-koncentrične kontrakcije. Tetive i ligamenti koji se opiru ekstenziji mogu
pohraniti do 100% vi{e energije elastičnosti nego mi{ići
(Luhtanen i Komi, 1980; Mero, Komi i Gregor, 1992). Pre-aktivacija mi{ića gastrocnemiusa (mi{ića lista) je veoma
važna za mehaniku kretanja; ovaj mi{ić se aktivira 80 milisekundi pre nego {to stopalo dodirne podlogu (vidi Sliku 1).
Pre-aktivacija uzrokuje ukočenost plantarnih fleksora (mi{ića)
u trenutku kada prednji deo stopala dodiruje povr{inu.
Povećana ukočenost mi{ića zajedno sa minimalnom amplitudom pokreta u skočnom zglobu omogućuje bolji prenos
energije elastičnosti iz ekscentrične u koncentričnu kontrakciju (Kyrolainen i saradnici, 2001; Mero i saradnici, 2006).
Kada su opterećene za vreme sprinta, tetive se izdužuju za
3-4%, i za svako izduživanje preko ovoga postoji potencijalna opasnost od njihove rupture. Tetive i ligamenti pona{aju
se kao opruge koje skladi{te elastičnu energiju. Preterano
izduživanje tetiva rezultira pretvaranjem elastične energiju
u toplotnu, ili bolje rečenu u hemijsku. Visoka temperatura
ćelija - fibroblasta i molekula kolagena, koje su gradivna
materija tetiva, mogu ublažiti uslove za potencialne povrede
ovog dela lokomotornog aparata (Huiling, 1999).
U drugoj fazi dolazi do ekstenzije mi{ićno-tetivnog kompleksa, gde se prethodno akumulirana elastična energija koristi
kao efikasan pogon sprinterskog koraka. Glavni apsorber ove
faze je m. quadriceps (bedreni mi{ić). Povećana ko-aktiviranost agonista i antagonista (m. vastus laterali, m. biceps
femoris, m gastrocnemius i m. tibialis) pojačava ukočenost
skočnog i zgloba kolena. Na ovaj način kompletna noga se
priprema za kontakt sa podlogom. Povećana ukočenost
skočnog zgloba u sprintu smanjuje potro{nju hemijske energije u sledećim mi{ićima: m. gastrocnemius, m. lateralis -m.
medialis i m. soleus (Kuitunen, Komi i Kyrolainen, 2002).
8
knee extensors increases in the pre-activation phase in proportion with the increase of speed. In addition, pre-activation of
m. triceps surae together with the stretching reflex facilitates
high degree of stiffness of muscles in the extension phase of the
take-off.
Zbornik radova 2010, 7-15
Aktivacija plantarnih fleksora i opružača kolena povećava
pre-aktivacionu fazu proporcionalno sa povećanjem brzine.
Pored toga, pre-aktivacija troglavog mi{ića lista (m. triceps
surae) zajedno sa refleksom istezanja ublažava krutost mi{ića
u ekstenzivnoj fazi početka kretanja.
Slika 1: Ciklus relaksacije i kontrakcije mi{ića kod sprinterskog koraka (Komi, 2000)
Figure 1: Stretch – shortening cycle in the stride of sprinters (Komi, 2000)
Extension of muscular and tendon complex is managed and
coordinated with two motor reflexes: monosynaptic stretch
reflex and the polysynaptic reflex of Golgi tendon organ.
These two reflex systems form a recurring coupling for maintaining the near optimal muscle length (reaction to stretching)
and the reaction to excessive elongation of tendons. Receptors
of stretch reflex – muscle spindles are placed parallel to muscle
fibres. When muscle is being extended as a result of external
force acting on it, muscle spindles also extend. As a result of
muscle spindle extension, alpha motor neurons are being
activated, which in turn activate reflex contraction of elongated muscles as a reaction to stretching. Golgi tendon organs
are placed serially with muscle fibres. These receptors react
exclusively to the forces, which are being developed in the
muscles and do not react to any changes in length. If muscle
effort increases rapidly, Golgi tendon complex prevents muscular contraction. Subsequent decrease of muscular effort
prevents injuries to muscles and tendons (Jacobs, Ingen, &
Schenau, 1992; Zatsiorsky & Kraemer 2009). In the phase
when foot is placed on the surface and in the amortisation
phase, extensors are being elongated and they produce contraction in the same muscle on the basis of stretch reflex. At
the same time the effort of large muscles activates Golgi tendon
organ, which prevents activity of the muscle. As a result of
specific training, activation of Golgi tendon organ is being
inhibited and thus athletes can withstand large forces at landing
without decreasing produced force of the muscles.
Ekstenzija mi{ićnog i tetivnog kompleksa je određena i koordinisana sa dva motorna refleksa: monosinaptički refleks
na istezanje i polisinaptički refleks Goldžijevog aparata. Ova
dva refleksna sistema tvore spregu za održavanje optimalne
dužine mi{ića (reakcije na istezanje) i reakcije na preveliko
izduživanje tetiva. Receptori refleksa na istezanje mi{ićna
vretena nalaze se paralelno sa mi{ićnim vlaknima. Kada je
mi{ić izdužen pod uticajem neke spolja{nje sile, mi{ićna
vretena se takođe izdužuju. Rezultat njihovog izduživanja
jeste aktivacija alfa-motornih neurona koji pokreću kontraktivni refleks izduženog mi{ića kao reakciju na istezanje.
Goldžijev aparat serijski je postavljen sa mi{ićnim vlaknima.
Ovi receptori reaguju isključivo na sile proizvedene unutar
mi{ića, dok uop{te ne reaguju na bilo kakve promene dužine. Ako se mi{ićna sila brzo povećava, Goldžijev kompleks
sprečava kontrakciju. Naredna povećanja mi{ićne sile sprečavaju povrede mi{ića i tetiva (Jacobs, Ingen i Schenau, 1992;
Zatsiorsky i Kraemer 2009). U fazi kada se stopalo postavlja
na podlogu i u fazi amortizacije, ekstenzori se izdužuju i
proizvode kontrakciju u određenom mi{iću upravo zbor
refleksa na istezanje. U isto vreme sila velikih mi{ića aktivira Goldžijev aparat koji sprečava aktivnost mi{ića. Kao rezultat specifične vrste treninga aktivacija Goldžijevog tetivnog
aparata se inhibira i sportisti mogu podneti veliku silu pri
kontaktu sa podlogom bez smanjenja proizvedene sile mi{ića.
9
INTRODUCTORY LECTURE
UVODNO PREDAVANJE
Čoh, M. i Žvan, M.: BIODINAMIČKE KARAKTERISTIKE RAZVOJA MAKSIMALNE...
INTRODUCTORY LECTURE
UVODNO PREDAVANJE
Čoh, M., & Žvan, M.: BIODYNAMIC CHARACTERISTICS OF MAXIMUM SPEED... As reversible contraction of muscles represents an integral part
in many sports movements, it needs to be specially trained
and taught. Training of jumps with reversible contraction has
nowadays become an integral part of speed training in sportsmen. These so-called plyometric jumps and plyometric training produce high quality results in the development of take-off strength. In order for such training to be successful, a long
term all-around preparation with other means and methods
of strength training is required. On the other hand, plyometric
jumps can cause serious injuries in sportsmen.
The time from a foot being placed on a surface until the end
of take-off in the stride of sprinters lasts between 80 – 100
milliseconds. The cumulative contact time is shorter in better
sprinters and longer in worse sprinters. The shorter the time
of contact, the better the frequency and the higher is force on
a surface. The relationship between the contact phase and the
flight phase in sprinters stride is 20: 80. The largest reactive
force of the surface is noticed 30 to 40 milliseconds after the
first contact with the surface (Mann & Spraque, 1980). According to Mero, Komi, & Gregor (1992), the vertical reactive
force of the surface in sprinters reaches 200% to 300% of their
body weight. The largest reactive force of the surface is in
sprinters developed in the middle phase of the contact – the
phase of maximal amortisation (see Figure 2). In order to develop maximal locomotive speed, the largest possible force
needs to be developed in the shortest possible time. Mastering
the optimal mechanics (technique) of sprinting run is a condi-
Proceedings 2010, 7-15
Kako reverzibilna kontrakcija mi{ića predstavlja integralni
deo mnogih sportskih pokreta, treba biti uvežbavana i učena posebno. Treniranje skokova kao reverzibilne kontrakcije danas je postalo sastavni deo treniranja brzine sportista.
Ovi, takozvani, pliometrijski skokovi i pliometrijski treninzi
daju veoma kvalitetne rezultate u razvoju kretne (startne)
snage. Da bi takvi treninzi bili uspe{ni, potrebna je dugoročna sveobuhvatna priprema sa drugim sredstvima i metodama treninga snage. Sa druge strane, pliometrijski skokovi
mogu prouzorkovati ozbiljne povrede sportista.
Vreme od trenutka kada se stopalo postavlja na podlogu do
kraja kretne faze korakasprintera traje između 80 -100 milisekundi. Kumulativno vreme kontakta je kraće kod boljih
a duže kod lo{ijih sprintera. [to je kraće vreme kontakta,
bolja je frekvencija i veća sila koja deluje na podlogu. Veza
između faze kontakta i faze leta u sprinterskom koraku je
20:80. Najveća sila reakcije na podlogu primećuje se 30 do
40 milisekundi posle prvog kontakta sa podlogom (Mann i
Spraque, 1980). Prema Mero, Komi i Gregor (1992) vertikalna sila reakcije podloge kod sprintera dostiže 200% do
300% od njihove telesne težine. Najveća reaktivna sila
podloge javlja se u srednjoj fazi kontakta -fazi maksimalne
amortizacije (vidi Sliku 2). Da bi se razvila najveća lokomotorna brzina, treba proizvesti najveću moguću silu za {to
kraće vreme. Ovladavanje optimalnim načinom (tehnikom)
Slika 2: Ciklus relaksacije i kontrakcije mi{ića kod sprinterskog koraka (Komi, 2000) Razvijanje sile reakcije podloge (z, y,
x) u fazi kontakta sa njom.
Figure 2: Stretch – shortening cycle in the stride of sprinters (Komi, 2000) Development of reactive force of the surface (z,
y, x) in the contact phase of sprinters stride
10
Zbornik radova 2010, 7-15
tion for the utilisation of the force, which is being generated
by the neuro-muscular system.
sprinterskog trčanja predstavlja uslov za kori{tenje sile koju
proizvodi neuro -mi{ićni sistem.
Dynamics of speed development
Dinamika razvoja brzine
Development of maximal speed follows certain rules, which are
based on the level of bio-motor abilities, morphological characteristics and the degree of biomechanical efficiency and rationalisation of movement. In the development of locomotive
speed there are three basic phases: phase of starting the acceleration, phase of maximal speed and phase of deceleration.
Parameters that to the greatest extent generate the change of
speed are length and frequency of stride. In the first phase an
athlete develops 80-90% of his maximal speed. Between 50–80
metres sprinters generally achieve their maximal speed. After
80-90 metres speed begins to decrease.
During the starting acceleration both the frequency and the
length of stride increase. The duration of contact in sprinters
stride is shortening and the time of flight increases. With a shorter duration of contact the type of strength changes as well.
Namely, during the starting acceleration, where the duration of
contact is relatively long, the most important bio-motor ability
is power strength of concentric modality. In the subsequent
phases of sprinting run the duration of contact is shorter and the
importance of elastics energy increases significantly (Figure 3).
In the phase of maximum speed both frequency and the length
of stride are relatively constant, the proportion between the
contact and flight phases of sprinters stride is also stabilised. The
zone, where sprinters achieve their absolute maximum speed
is very limited. In principle, the best sprinters can only fulfil this
ability at the distance of maximum 10 to 20 metres. The zone
of maximal speed is located somewhere between 60 and 80
metres in men and between 50 and 70 metres in elite women.
Maximal speed is always a product of optimal stride length and
the frequency of stride. Authors Donatti (1996) and Mackala
(2007) state that there are no differences in the length of stride
between the elite and sub-elite sprinters, differences exist only
in the frequency of stride. Therefore, frequency of stride is one
of the most important parameters of maximal speed of stride
(Mero, Komi, & Gregor, 1992; Delecluse et al., 1995; Donatti,
1996). In the last phase of sprinting run, between the 80 and
100 metres, velocity begins to decrease on a scale of .5 to 1.5
metres per second. Deceleration is caused by central and peripheral fatigue of sprinters. Central fatigue is manifested as an
error in the muscle activation, meaning that the number of
active motor units and the frequency of neuro-muscular impulses decrease. This results in a lower degree of inter- and intra-muscular coordination, which is eventually being manifested
with the decrease in frequency of steps, particularly in the last
10 metres of 100-metre sprint run. Central fatigue is correlated
to the smaller activity of cortical and sub-cortical centres (Semmler & Enoka, 2000). Increased fatigue at the end of 100-metre
sprint run is also caused by peripheral nerves and metabolic
processes in the muscles. In the last 10-metres the duration of
contact and the length of stride increase. The control of movement is during this phase of speed at the lowest level. This
mostly depends on the quality of sprinters, as the disruption of
these parameters is smaller in best sprinters than in the runners
of medium quality.
Razvoj maksimalne brzine prati nekoliko pravila koja se
baziraju na nivou bio-motoričkih sposobnosti, morfolo{kih
karakteristika i stepena biomehaničke efikasnosti i racionalizacije pokreta. Kod razvoja lokomotorne brzine postoje tri
osnovne faze: faza započinjanja ubrzanja, faza maksimalne
brzine i faza usporavanja. Parametri koji u velikoj meri
menjaju brzinu jesu dužina i frekvencija koraka. U prvoj
fazi sportista razvija 80-90% njegove maksimalne brzine.
Između 50-80 metara sprinteri ostvaruju maksimalnu brzinu.
Posle 80-90 metara brzina počinje da se smanjuje.
Za vreme početnog ubrzanja frekvencija i dužina koraka se
povećava. Dužina kontakta se smanjuje a povećava se vreme leta. Sa kraćim vremenom kontakta menja se takođe
vrsta snage. Naime, kod startnog ubrzanja, gde je vreme
kontakta prilično dugo, najvažnija bio-motorička sposobnost
je snaga koncentričnog tipa. U sledećim fazama sprinta
kontakt sa podlogom je kraći i značajno se povećava važnost
elastične energije (Slika 3).
U fazi maksimalne brzine frekvencija i dužina koraka su
prilično konstantni, i odnos između faze kontakta i faze
leta se takođe stabilizuje. Zona u kojoj sprinteri dostižu
njihovu apsolutno najveću brzinu je veoma ograničena. U
principu, najbolji sprinteri ovu sposobnost mogu ispoljiti na
distanci od maksimalno 10 do 20 metara. Zona maksimalne
brzine nalazi se negde između 60 i 80 metara za mu{karace,
i 50 do 70 metara za vrhunske sportistkinje. Maksimalna
brzina uvek je proizvod optimalne dužine i frekvencije koraka. Autori Donatti (1996) i Mackala (2007) tvrde da ne
postoji razlika u dužini koraka između vrhunskih i ostalih
sprintera, nego da ta razlika postoji samo u njihovoj frekvenciji. Zbog toga frekvencija koraka predstavlja jedan od najvažnijih parametara maksimalne brzine (Mero, Komi i
Gregor, 1992; Delecluse i saradnici, 1995; Donatti, 1996).
U poslednjoj fazi sprinterskog trčanja, između 80 i 100
metara, brzina počinje da opada za 0,5 do 1,5 metar u
sekundi. Do usporavanja dolazi zbog centralnog i perifernog
zamora sprintera. Centralni zamor ispoljava se kao gre{ka u
aktivaciji mi{ića, {to znači da broj aktivnih motornih jedinica i frekvencija nervno-mi{ićnih impulsa opada. Ovo dovodi do manjeg stepena inter i intra-muskularne koordinacije,
koja na kraju smanjuje frekvenciju koraka, naročito u poslednjih 10 metara u 100 metarskom sprintu. Centralni zamor
je u korelaciji sa smanjenom aktivno{ću kortikalnih i sub-kortikalnih centara (Semmler i Enoka, 2000). Povećani
zamora na kraju sprinta na 100 metara je takođe uzrokovan
perifernim nervima i metaboličkim procesima u mi{ićima.
U poslednjih 10 metara vreme kontakta sa podlogom i
dužina koraka rastu. Kontrola kretanja je na najmanjem
nivou u ovoj fazi. Ovo najvi{e zavisi od kvaliteta sprintera,
jer je remećenje ovih parametara kod najboljih manje nego
kod sprintera srednjeg kvaliteta.
Inter muscular coordination
of speed development
Inter muskularna
koordinacija razvoja brzine
In order to understand the dynamics and the changes of
stride frequency and length in the realisation of maximal
speed, the function of central neural system needs to be
explained. Muscle force is not only defined by the amount of
Kako bismo razumeli dinamiku i promene u frekvenciji i
dužini koraka pri postizanju maksimalne brzine, treba biti
obja{njena funkcija centralnog nervnog sistema. Mi{ićna
sila nije određena samo mi{ićnom masom, nego i stepenom
11
INTRODUCTORY LECTURE
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Čoh, M. i Žvan, M.: BIODINAMIČKE KARAKTERISTIKE RAZVOJA MAKSIMALNE...
INTRODUCTORY LECTURE
UVODNO PREDAVANJE
Čoh, M., & Žvan, M.: BIODYNAMIC CHARACTERISTICS OF MAXIMUM SPEED... Proceedings 2010, 7-15
included muscle mass, but also by the degree of participation
of individual muscle fibres. In order to manifest muscle force,
muscles need to be activated in a certain way. Coordinated
movement of several muscle groups depends on inter-muscular coordination. Basic characteristic of elite sprinters is
efficient coordination of activated fibres in individual muscles
and muscle groups. These sprinters have better inter- and
intra-muscular coordination. Neural system generates muscle
force in three ways: with activation and deactivation of individual motor units, with a frequency of releasing of motor
units and with synchronisation of motor units. All three ways
are based on the motor units, which represent basic elements
in the working of neuro-muscular system. Every motor unit
consists from motor-neuron, which is located in the spinal
cord, and from the muscles fibres, which are being innervated.
From the contraction characteristics point of view, motor units
can be divided into slow and fast motor units. Slow motor
units are specialised for the extended use at the relatively low
speed. They consist of small motor-neurons with a low threshold of release and they are adapted to aerobic activities.
Fast muscular or motor units are specialised for relatively short
lasting activities, which require manifestation of large strength,
speed and a high degree of force development. They consist
of large motor-neurons with a high threshold of release, axons
with high speed of implementation and muscle fibres, which
Slika 3: Faza ubrzanja i EMG mi{ićne aktivnosti
Figure 3: Acceleration phase and EMG muscle activity
uče{ća pojedinačnih mi{ićnih vlakana. Da bi ispoljili snagu,
mi{ići moraju biti aktivirani na određen način. Usklađen
pokret nekoliko mi{ićnih grupa zavisi od inter-muskularne
koordinacije. Osnovna karakteristika vrhunskih sprintera je
efikasna koordinacija aktiviranih vlakana u pojedinim mi{ićima
i mi{ićnim grupama. Ovi sprinteri imaju bolju inter i intra
-muskularne koordinaciju. Nervni sistem proizvodi mi{ićnu
silu na tri načina: aktivacijom i deaktivacijom pojedinačnih
motornih jedinica, frekvencijom otpu{tanja (aktiviranja)
motornih jedinica i njihovom sinhronizacijom. Sva tri načina odnose se na motorne jedinice, koje predstavljaju osnovni elemenat u radu nervno-mi{ićnog sistema. Svaka motorna jedinica sastoji se od moto-neurona, koji se nalaze u
kičmenoj moždini, i mi{ićnih vlakana, koji se inervi{u. Kada
to posmatramo sa strane karakteristika same kontrakcije,
motorne jedinice mogu da se podele na spore i brze. Spore
su posebno određene za dugotrajne radnje na prilično
malim brzinama. Sastoje se od malih moto -neurona sa niskim
pragom inervacije (aktivacije) i prilagođene su aerobnim
aktivnostima. Brze mišićne ili motorne jedinice specijalizovane su za aktivnosti prilično kratkog trajanja, koja zahtevaju ispoljavanje velike snage, brzine i visok stepen razvoja
sile. Čine ih veliki moto -neuroni sa visokim pragom oslobađanja, aksonima sa velikom brzinom prenosa, i mi{ićnim
are adapted to powerful anaerobic activities. Motor units
follow the “all or nothing” law, meaning that any motor unit
in any time is either active or inactive. The fastest speed of
shortening of fast muscle fibres is four times faster than in slow
muscle fibres (Zatsiorsky & Kraemer, 2009). Human muscles
in general consist of motor units with slow or fast action.
Sprinters and sportsmen, who are required to develop large
speed or force in a unit of time, have predominantly motor
units with fast actions.
In willing contractions, the activation of muscle fibres depends on the size of motor-neurons with a “size principle”
being applied. First, small motor-neurons with a low threshold
of excitation are being activated. With increasing demands
for development of large force, larger motor-neurons with
the fastest contraction twitch and highest threshold of excitation are being recruited as last. Mixed muscle types consist
of motor units with slow and fast activation regardless of the
degree of muscular effort and the speed being manifested.
vlaknima prilagođenim snažnim anaerobnim aktivnostima.
Motorne jedinice koriste „sve ili ni{ta“ princip, {to znači da
je svaka motorna jedinica, u bilo koje doba, ili aktivna ili
neaktivna. Najveća brzina skraćivanja mi{ićnih vlakana je
četiri puta veća nego kod sporih vlakana (Zatsiorsky i Kraemer, 2009). Mi{ići čoveka se u principu sastoje od brzih ili
od sporih motornih jedinica. Kod sprintera i sportista, od
kojih se očekuje da razviju veliku brzinu ili snagu u jedinici
vremena, preovladavaju brza.
U voljnim kontrakcijama, aktivacija mi{ićnih vlakana zavisi
od veličine moto-neurona sa primenjenim „principom veličine“. Prvo, aktiviraju se mali moto-neuroni sa niskim pragom
„buđenja“. Sa povećanjem potrebe za razvojem velike sile,
veći moto-neuroni, sa mogućno{ću najveće kontrakcije, se
grče i konačno dolazi do najvi{eg praga njihovog nadraživanja. Me{oviti tipovi mi{ića sastoje se od brzih i sporih motornih jedinica, bez obzira na stepen mi{ićnog napora ili
manifestovane brzine. Samo vrhunski utrenirani sportisti
12
Zbornik radova 2010, 7-15
Only highly trained sportsmen manage to activate motor
units with fast activation. Realisation of maximal locomotive
speed is related to the high coordination of movement. In
a cycle of sprinters stride, there are more than 60 lower-leg
muscles active, which have to work in a synchronised and
coordinated way. In execution of precise movements, motor
units usually do not work at the same time. In order to
produce maximal force, which is one of the key factors of
maximal speed, the largest amount of slow and fast motor
units needs to be recruited as well as the maximal frequency of release and simultaneous work of motor units in a
period of maximal voluntary effort. Primary goal in the
speed training is creation of optimal movement model,
which is based on the coordination of muscle group work.
Speed is highly rigid ability with a strong fixated programme in
the central-neural system. Shortage of neuro-muscular coordination is one of the limiting factors of speed as the possibility
for optimal control of movement decreases with the increase
in speed of movement. The larger the speed, the higher is
deviation from the ideal movement model. Control of movement
is at the lowest level precisely in the conditions of maximal
speed. Maximal speed belongs in the category of so-called
terminal movements, which have precisely set structure with
uspevaju da aktiviraju brze motorne-jedinice. Ostvarivanje
maksimalne lokomotorne brzine povezano je sa visokom
koordinacijom pokreta. U jednom ciklusu sprinterskog koraka, aktivno je vi{e od 60 mi{ića donjeg dela noge, koji
moraju da rade na jedan sinhronizovan i koordinisan način.
U izvr{avanju preciznih pokreta, motorne jedinice obično
ne rade u isto vreme. Da bi se proizvela maksimalna sila,
koja je jedan od ključnih faktora postizanja maksimalne
brzine, mora da bude pokrenut najveći broj sporih i brzih
motornih jedinica, a takođe i maksimalna frekvencija inervisanja i simultanog rada motornih jedinica u periodu maksimalnog voljnog napora. Primarni cilj u treningu brzine
jeste stvaranje optimalnog kretnog modela koji počiva na
usklađivanju rada mi{ićnih grupa.
Brzina je veoma „kruta“ sposobnost sa prilično određenim
karakteristikama u centralnom nervnom sistemu. Nedostatak
neuro-muskularne koordinacije jedan je od limitirajućih
faktora brzine jer sposobnost za optimalnom kontrolom
pokreta opada sa porastom brzine. [to je veća brzina, to je
veća devijacija od idealnog modela kretanja. Kontrola pokreta je na najmanjem nivou upravo u periodu maksimalne
brzine. Takva brzina spada u kategoriju takozvanih terminalnih pokreta koji imaju tačno određenu strukturu sa defiSlika 4: Motorička kontrola mi{ića agonista i antagonista – merni protokol izokinetičkih parametara
Figure 4: Motor control of agonist and antagonist muscles – measurement protocol isokinetic parameters
a defined beginning and end of movement (Latash, 1994).
One of the most important problems in motor control is a
role of agonist and antagonist muscles and their direct effect
on kinematics and dynamics of movement through appropriate type, intensity and time sequence of the muscle force
effect. In fast terminal movements, such as sprinting, development of force is a key factor of movement efficiency. Variables of motor programme are force of agonist muscles,
maximal force of antagonist muscles, time delay of antagonist
muscles, time of achieving the maximal force of antagonist
muscles, co-activated relationship of muscles in the function
of their place in kinetic chain, length of a move, terminal
position, starting position, time length of a move and the
nisanim početkom i krajem kretanja (Latash, 1994).
Jedan od najvećih problema u motoričkoj kontroli jeste
uloga mi{ića agonista i antagonista, i njihov direktan uticaj
na kinematiku i dinamiku kretanja, koristeći odgovarajući
način, te na intenzitet i vremenske intervale efekta mi{ićne
sile. U kretnjama sa brzim intervalima, kao {to je sprint,
razvoj snage sile je ključni faktor efikasnosti kretanja. Varijable motoričkog programa su sila mi{ića agonista, maksimalna sila antagonista, vreme „ka{njenja“ antagonista,
vreme postizanja maksimalne sile antagonista, ko-aktivaciona povezanost funkcije mi{ića u kinetičkom lancu, dužine
pokreta, terminalne pozicije, startne pozicije, vremensko
trajanje i brzina pokreta (vidi Sliku 4). Razvoj maksimalne
13
INTRODUCTORY LECTURE
UVODNO PREDAVANJE
Čoh, M. i Žvan, M.: BIODINAMIČKE KARAKTERISTIKE RAZVOJA MAKSIMALNE...
INTRODUCTORY LECTURE
UVODNO PREDAVANJE
Čoh, M., & Žvan, M.: BIODYNAMIC CHARACTERISTICS OF MAXIMUM SPEED... Proceedings 2010, 7-15
Slika 5: EMG aktivacije mi{ića donjih ekstremiteta u fazi maksimalne brzine (Dolenec i Čoh, 2002)
Figure 5: EMG activation of muscles of lower extremities in the phase of maximal speed (Dolenec & Čoh, 2002)
speed of a move (see Figure 4). Development of maximal
speed requires very subtle inter-muscular coordination of
muscle groups of lower extremities. The most important are
the following muscles: m. gluteus maximus, m. tibialis anterior, m. soleus, m. gastrocnemius, m. rectus femoris, m. biceps
femoris, m. vastus lateralis (see Figure 5). Identifying strategic
muscles, which generate the take-off force, is very important
from the sports training point of view in order to optimise
technique and prevent any injuries.
In the take-off phase muscles develop the reaction force with
a magnitude of 280 to 350 kp in a time interval of 85– 5 milliseconds (Luhtanen, & Komi 1980; Čoh, 2002). Some studies from the field of electromyography and isokinetics of sprinters
stride have revealed that m. biceps femoris (hamstring muscle)
is one of the most important muscles in developing maximal
speed ( Mero et. al., 1986; Zatsiorsky, 2000; Komi, 2000). This
muscle often gets injured during the sprinting training, therefo-
14
brzine zahteva veoma suptilnu inter-muskularnu koordinaciju mi{ićnih gruba donjih ekstremiteta. Najvažniji su sledeći
mi{ići: m. gluteus maximus, m. tibialis anterior, m. soleus,
m. gastrocnemius, m. rectus femoris, m. biceps femoris, m.
vastus lateralis (vidi Sliku 5).
U kretnoj fazi mi{ići razvijaju reaktivnu silu jačine 280 do
350 kp u vremenskom intervalu od 85 – 5 milisekundi
(Luhtanen, & Komi 1980; Čoh, 2002). Neke studije iz područja elektromiografije i izokinetike sprinterskog trčanja
ustanovile su da je m. biceps femoris (mi{ić zadnje lože
buta) jedan od najvažnijih mi{ića u razvoju maksimalne
brzine (Mero et. al., 1986; Zatsiorsky, 2000; Komi, 2000).
Ovaj mi{ić često biva povređen za vreme treniranja sprinta,
i zato je prevencija toga, uz pomoć adekvatnog treninga,
veoma važna. Uvežbavanje maksimalne brzine, sa aspekta
fizičke pripreme sportista, povezano je sa tehnikom trčanja,
koju je posebno te{ko kontrolisati u uslovima maksimalne
Zbornik radova 2010, 7-15
re its prevention with adequate training is very important.
Training of maximal speed is from the aspect of physical preparation of sportsmen related to the running technique, which
is particularly difficult to control in the conditions of maximal
speed. Optimal neuro-muscular coordination is the main limiting factor of maximal speed. Therefore, the forming of correct
dynamic stereotype is a long term process, which has to have
precisely defined technique and has to begin with the early age
of sportsmen.
brzine. Optimalna neuro-muskularna koordinacija je glavni
ograničavajući faktor maksimalne brzine. Iz tog razloga,
formiranje pravilnog dinamičkog stereotipa predstavlja dugotrajan proces, koji mora da ima tačno definisanu tehniku
i mora da počne u ranom uzrastu sportiste.
Reference
Latash, M. (1994). Control of Human movement. Human
Kinetics. Champaign, Illinois: Human Kinetics Publishers.
Luhtanen, P., & Komi, P. (1980). Force-, power – and
elasticity relationship in walking, running and jumping.
European Journal of Applied Physiology, 44(3),
279–289.
Mackala, K. (2007). Optimisation of performance through
kinematic analysis of the different phases of the 100
meters. IAAF, 22(2), 7–16.
Mann, R., & Spraque, P. (1980). A kinetic analysis of ground leg during sprint running. Research Quarterly for
Exercise and Sport, 51, 334–348.
Mero, A., Komi, P., & Gregor, R. (1992). Biomechanics of
sprinting running. Sport medicine, 13(6), 376–392.
Mero, A., Luhtanen, P., & Komi, P. (1986). Segmental
contribution to velocity of centre of gravity during
contact at different speeds in male and female sprinters. Journal of Human Movement Studies, 12, 215–
235.
Semmler, J., & Enoka, R. (2000). Neural contributions to
the changes in muscle strength. V. Zatsiorsky (Ed.),
Biomechanics in sport: The scientific basis of performance, (pp. 3–20), Oxford: Blackwell Science.
Schmidt, R. (1990). Motor control and learning. Champaign, Illinois: Human Kinetics Publishers.
Zatsiorsky, V. (1995). Science and practice of strength
training. Champaign, Illinois: Human Kinetics Publishers.
Zatsiorsky, V. (2000). Biomechanics in sport: performance
enhancement and injury prevention. Oxford: Blackwell
Scientific.
Zatsiorsky, V., & Kraemer, W. (2009). Nauka i praksa u
treningu snage. Beograd: Data status.
Čoh, M. (2008). Biomechanical Diagnostic Methods in
Athletic Training. Ljubljana: Institute of Kinesiology,
Faculty of Sport.
Čoh, M. (2002). Application of biomechanics in track and
field. Ljubljana: Faculty of Sport, Institute of Kinesiology.
Delecluse, C., Van Coppenolle, H., Willems, E., Van
Leemputte, M., Diels, R., & Goris, M. (1995). Influence of high resistance and high-velocity training on
sprint performance. Medicine and Science in Sports
and Exercise, 27(8), 1203–1209.
Donati, A. (1996). Development of stride length and stride
frequency in sprint performances. New Studies in Athletics, 34(1), 3–8.
Hay, J. (1993). The biomechanics of sports techniques (4
ed.). Prentice Hall.
Huiling, P. (1999). Elastic potential of muscle. V: Strength
and power in sport. Ed.: Komi, P.V. 1999. The encyclopaedia of sport medicine. Blackwell science.
Ilić, D. (1999). Motorna kontrola i učenje brzih pokreta.
Beograd: Zadužbina Andrejević.
Jacobs, R., & Ingen Schenau, G. (1992). Intermuscular
Coordination in a Sprint Push-Off. Journal of Biomechanics, 25(9), 953–965.
Komi, P. (2000). Stretch-shortening cycle: a powerful model to study normal and fatigue muscle. Journal of
Biomechanics, 33(10), 1197–2006.
Kuitunen, S., Komi, P., & Kyrolainen, H. (2002). Knee and
ankle joint stiffness in sprint running. Medicine & Science in sport & exercise, 34(1), 166–173.
Kyrolainen, H., Belli, A., & Komi, P. (2001). Biomechanical factors affecting running economy. Medicine &
Science in sport & exercise, 8, 1330–1337.
Received: September, 18th 2010
Correspodence to:
Milan Čoh, PhD
Fakulteta za {port
Gortanova 22
10000 Ljubljana
Slovenia
Phone: 386 41 72 93 56
E-mail: Milan.Cohªfsp.uni-lj.si
Primljeno: 18. septembra 2010. godine
Korespodencija:
dr Milan Čoh
Fakulteta za {port
Gortanova 22
10000 Ljubljana
Slovenija
Telefon: 386 41 72 93 56
E-mail: Milan.Cohªfsp.uni-lj.si
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INTRODUCTORY LECTURE
UVODNO PREDAVANJE
Čoh, M. i Žvan, M.: BIODINAMIČKE KARAKTERISTIKE RAZVOJA MAKSIMALNE...
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