125
COMPARATIVE ANALYSIS OF SELECTED COORDINATION
INDICATORS OF CROSS-COUNTRY SKIING WITH CLASSICAL
TECHNIQUE AND SKATING
B onisla K ačma , *Ma ina Ch ás ko á
**Radka Bačáko á, ***Vladimí Hojka
Cha les Uni e si y in P ague
Facul y o Physical Educa ion and Spo
Jose Ma iho 31, 162 52 P aha 6
[email p o ec ed], *m[email p o ec ed],
**[email p o ec ed], ***[email p o ec ed]
Abs ac
C oss-coun y skiing is ecommended as a pa o pos - ehabili a ion mo o egime. The
gliding s ep in classical echnique and V-1 ska ing a e he mos common used echniques in
he ec ea ional o m. The aim o he s udy was o clea ou how he mo o s e eo ype o
c oss-coun y skiing co esponds wi h bipedal walking. The used me hods we e he
synch onized ideo eco d wi h he su ace poly-elec omyog aphy in e ain (EMG). The
da a we e in e p e ed on he basis o he compa a i e c oss-co ela ion analysis o ac i a ion
s a s o he obse ed muscles. The emale skie compe ing in he na ional eam showed he
simila i y o phase mo es o muscles s abilizing he pel is and knee join bo h du ing walking
and c oss-coun y skiing (bo h echniques). The di e ence be ween c oss-coun y skiing and
walking was ound in phase muscles aking pa on he p opulsi e s eng h o locomo ion. I
was no possible o compa e he coo dina ion ela ionship o he ac i i y pai s: gliding s ep in
classical echnique – walking and V-1 ska ing – walking.
Keywo ds: c oss-coun y skiing, walking, elec omyog aphy.
1 Backg ound
C oss-coun y skiing belongs among cyclic s eng h-endu ance spo s wi h he egula wo k
o lowe and uppe limbs and unk muscles (Massaad e al, 2007). The e a e highe demands
on agili y o shoulde and hip join s du ing c oss-coun y skiing (Ila ský, 2005).
Acco ding o G ego y e al. and Vii asela e al. (G ego y e al., 1994, Vii asalo e al., 1997)
di e ences in kinema ics o c oss-coun y skiing be ween mo e and less success ul
compe i o s a e a ely published. The cause is obse ed in he high numbe o ac o s
in luencing i .
Pun um ixum is also c ea ed by uppe limbs du ing c oss-coun y skiing, as he skie was
going back o quad upedal mo emen . In he shoulde gi dle we suppose muscle coo dina ion,
which has i s equi alen in on ogene ic o ms o human locomo ion (Voj a, Pe e s 1995,
K ačma , 2007). Thanks o e ical body posi ion he quad upedal cha ac e o locomo ion is
unde s ood speci ically. Tha is gi en by he e ical body posi ion, which ini ia es he
unc ion o body s abilizing sys em, which was no s a ed ye in he ho izon al body posi ion
in he ea ly cou se o human mo emen on ogenesis in he phase o quad upedal locomo ion
(Véle, 2006, K ačma , 2007). Simila ly, his phenomenon is unde s ood om he poin o
iew o apes’ phylogeny by Vanča a (Vanča a, 2002).
126
Vys čilo á e al (Vys čilo á e al. 2007, Vys čilo á e al., 2008) conside he unc ion o m.
la issimus do si as he main muscle in he unk a ea and plexus b achialis c ucial o human
locomo ion ealized h ough he shoulde gi dle (c oss-coun y skiing, No dic walking,
c awling, climbing, c awl s oke in swimming). The muscle g oups o unk and s omach
e icien ly ans e s eng hs and s abilize unk (Wigge , 1998).
The c oss-coun y skie needs he balance skill (Gnad, Pso o á, 2005). I enables o ealize
ake-o and ollowing he longes possible slide on one leg (Ch ás ko á, 2009).
Classical echnique de eloped g adually by making he slide longe when walking on skis and
skis a e pa allel du ing he whole mo emen cycle. Locomo ion is ealized by al e na e wo k
o uppe and lowe limbs, which is necessa y o con ol by neu o-muscula coo dina ion in a
way he complex and con inuous mo emen was c ea ed (Ch ás ko á, 2009). Realiza ion o
all mo emen s should hen be wi h he same equency, maximal laxa ion and luency. Figu e
1 shows he cou se o he gliding s ep mo emen .
F
ig. 1 The mo emen cou se du ing he gliding s ep in c oss-coun y skiing classical
echnique
The mo emen cycle o he gliding s ep can be di ided o: ake-o , weigh ans e , glide and
a m wo k. This s yle is used mainly in skiing uphill, e en ually on he la e ain by less
s eng h equipped indi iduals. Take-o is ealized om he ski skid when he ake-o ski is
s opped. I is ealized by a g adual ex ension o knee, hip and inally ankle join s. The ake-o
phase is inished by emo ing he ake-o ski om he su ace.
The glide phase is longe han he ake-o phase. The posi ion o body’s cen e o g a i y is
changed; he dynamic balance is ealized. The glide quali y depends on he e iciency o he
p e ious ac i i y – he ake-o . I is also a p epa a ion o he nex ake-o . The skie ’s body
mo es o “o e hang” – i is sligh ly leaned o wa d. The skie ge s o one-leg s and; only he
gliding ski is ouching he su ace.
The a m wo k is coo dina ed wi h lowe limbs. They co espond wi h each o he in he s ep
s a phase and ake-o phase (Ila ský, 2005).
F ee echnique – ska ing. Ska ing is mo e p og essi e in compa ison wi h classical echnique.
The ake-o ski is placed on he snow in he V posi ion and hen u ned on he inne edge.
The ake-o is ealized du ing he glide. Skiing is mo e luen and demands on ake-o
iming a e no as high as in classical echnique. The ake-o om he inne ski edge is
suppo ed by bo h poles push-o , which is mo e e icien han he al e na e push-o used in
he gliding s ep (Gnad, Pso o á, 2005). Figu e 2 shows he mo emen cou se o V-1 ska ing.
The ake-o s a s wi h a sligh ly bended knee and inishes wi h he g adually ex ended lowe
limb. Fo he igh di ec ion o he ake-o and i s e icien use he unk is sligh ly bended
o wa d. In he ake-o phase he unloaded leg is ac i ely ans e ed pas he ankle o he
ake-o leg c ossways o wa d so i had in he momen o placing on snow i s ini ial speed in
a glide; accele a ion is eached by ha . The unk is pe manen ly kep in a sligh lean o wa d
(Ila ský, 2005).
127
V-1 ska ing wi h he asymme ical mo emen o a ms is he slowes ska ing. The e is only
one push-o o bo h igh and le s eps o legs. V-1 ska ing wi h he asymme ical
mo emen is he mos used ype o ska ing among wide popula ion. The skie does only one
push-o and wo s eps wi h lowe legs. Be e skie s a e able o do he push-o on he igh o
le side acco ding o e ain condi ions. This ska ing is used when he skie is less balanced
du ing he glide on one ski.
F
ig. 2 The mo emen cou se o V-1 ska ing wi h asymme ical mo emen o a ms
Ou s udy looked in o he le el o coo dina ion simila i y o bo h ypes o c oss-coun y
skiing wi h he mo o s e eo ype o ee bipedal walking. Compa ison was ealized in he
compe i ion skie , a membe o Czech na ional eam. I was he mos pe ec a ailable mo o
s e eo ype conside ed by an expe .
2 Me hods
In a-indi idual compa a i e analysis was ealized a he membe o junio Czech na ional
eam in c oss-coun y skiing. 60 wo king (s ep) cycles du ing walking we e e alua ed, hen 60
cycles du ing he gliding s ep o he classical echnique and 60 cycles du ing V-1 ska ing.
Measu ing was ealized on snow o a high quali y, in -8°C, on c oss-coun y acks in No é
Měs o na Mo a ě.
We ha e used he su ace poly-elec omyog aphy (De Luca, 1993) wi h he synch onized
ideo eco d measu ed by he po able de ice on he basis o EMG, ca ied on he spo sman
body: pa e ning 200 1.s-1, il a ion 29 Hz - 1200Hz wi h he ime in a iable τ = 0,04 s
(Me le i, Pa ke , 2004). I had se en pai s o la elec odes wi h he diame e 7mm, dis ances
o cen es we e 25mm, ea h connec ion and sa ing da a in o own memo y. See Vys čilo á e
al. (Vys čilo á e al., 2008).
3 Resea ch design
The case in a-indi idual compa a i e analysis s udied h ee di e en o ms o locomo ion.
The a iable ha was no obse ed was locomo ion speed; he manipula ed a iable was a
wo king (s ep) cycle du ing c oss-coun y skiing wi h he classical echnique, ska ing on skis
and ee bipedal walking.
E e y obse ed ac i i y was measu ed six imes in 20 seconds in e als wi h 3 minu es b eaks
o ans e da a om he eco de o PC. 60 wo king cycles we e e alua ed om e e y
ac i i y. We ha e measu ed muscles on igh side o he body in he pel is a ea and lowe
limb. Fu he mo e, we ha e localized elec odes also con a la e ally on he muscle m.
gas ocnemius sin, capu medialis. Table 1 shows he su ey o he obse ed muscles.
128
Tab. 1 Su ey o he obse ed muscles wi h se sensi i i y o scanning channels [mV]
muscle channel sensi i i y [mV]
locomo ion walking gliding s ep V-1 ska ing
m.glu eus maximus dx 0,05 0,1 0,05
m. glu eus medius dx 0,2 2 1
as us medialis dx 0,05 0,2 0,1
m. gas ocnemius dx, cap. medialis 0,1 0,1 0,1
m. ibialis an e io dx 0,2 0,2 0,2
m. gas ocnemius sin, cap. medialis 0,2 0,2 0,2
EMG da a we e p ocessed in he Ma lab so wa e in o he o m o ma ices o c oss-
co ela ion alues o phase shi s o decisi e muscle ac i a ion s a s. We ha e e alua ed he
a e age wo king cycle (n=60) o e e y obse ed locomo ion ype. The s udy did no deal
wi h he diagonal phenomenon and la e ali y in c ossed locomo ion pa e n.
4 Resul s
Tables 2, 3, 4 s a e ma ices o c oss-co ela ion alues o phase shi s o decisi e muscle
ac i a ion s a s o an a e age wo king cycle (n=60). The e e en ial muscle was chosen m.
ibialis an e io dx.
Tab. 2 Ma ix o c oss-co ela ion alues o phase shi s o decisi e muscle ac i a ion
s a s o an a e age wo king cycle (n=60) du ing ee bipedal walking
Phase shi o
walking m.glu .
max.dx
m.glu .
med.dx
as .
med.dx
m.gas .
dx cap.med. m. ib.an .dx
m.gas .
sin c.med
m.glu .max.dx 0 38% 47% -34% 42% 17%
m.glu .med.dx 0 0 4% -29% 5% -21%
as .med.dx 0 0 0 27% -11% -30%
m.gas .dx c,med. 0 0 0 0 -38% 47%
m. ib.an .dx 0 0 0 0 0 -26%
m.gas .sin c.med 0 0 0 0 0 0
Tab. 3 Ma ix o c oss-co ela ion alues o phase shi s o decisi e muscle ac i a ion
s a s o an a e age wo king cycle (n=60) du ing he gliding s ep o he classical
echnique in c oss-coun y skiing
Phase shi o he
gliding s ep m.glu .
max.dx
m.glu .
med.dx
as .
med.dx
m.gas .
dx
cap.med. m. ib.an .dx
m.gas .
sin c.med
m.glu .max.dx 0 -1% 0% -4% 2% 46%
m.glu .med.dx 0 0 2% -3% 2% -2%
as .med.dx 0 0 0 -5% -1% 44%
m.gas .dx c,med. 0 0 0 0 5% 49%
m. ib.an .dx 0 0 0 0 0 45%
m.gas .sin c.med 0 0 0 0 0 0
Tab. 4
Pha
s
ska
m.gl
m.gl
as
m.g
a
m. i
b
m.g
a
w
1
G aph
1
5 Di
s
The ol
l

C
w
m
M
a ix o
s a s o
a
mo emen
s
e shi o
V
ing
u .max.dx
u .med.dx
.med.d
x
a
s .dx c,me
d
b
.an .dx
a
s .sin c.m
e
w
alkin
g
1
s ep cycle
1
EMG e
c
and V-1
s
cussion
l
owing disc
C
oss-co
e
e e en ial
w
alking as
m
uscles o
c oss-co
e
a
n a e age
w
o a ms
V
-1
m.
g
ma
x
0
0
0
d
.
0
0
e
d
0
c
o d o he
ska ing wi
ussion is
m
e
la ion al
u
muscle w
a
he do sa
l
he a e a
g
e
la ion al
u
w
o king cy
c
g
lu .
x
.dx m.
g
me
d
0
4
%
0
0
0
0
0
0
0
0
0
0
g
liding s
e
1 s ep cyc
l
selec ed w
o
h asymme
m
ainly base
d
u
es o deci
s
a
s chosen
m
l
lexo o
g
e wo kin
g
u
es o phas
e
c
le (n=60)
d
g
lu .
d
.dx a
s
med
.
%
1
%
0
1
%
0
0
0
0
0
0
0
0
e
p
l
e
o
king cycl
e
ical mo e
m
d
on:
s
i e muscl
e
m
. ibialis
a leg. W
e
g
cycle (n
=
e
shi s o d
e
d
u ing V-1
s
.
.
dx
m.gas
dx
cap.m
e
%
4%
%
-13
%
0%
0
0
0
V
1
e
o ee bip
m
en o a m
s
e
ac i a io
n
an e io d
x
e
desc ibe
=
60) in he
e
cisi e mus
c
ska ing wi
h
.
e
d. m. ib.an
0%
%
1%
0%
14
%
0
0
V
-1 ska ing
1
s ep cycle
edal walki
n
s
n
s a s (T
a
x
. o i s
s
iming o
in e al -
5
c
le ac i a i
o
h
asymme
.dx
m.gas
sin
c.me
d
-44
%
-19
%
-49
%
%
-48
%
-22
%
0
n
g, he glidi
n
a
bles 2, 3,
s
peci ic u
n
he o he
o
5
0% o +5
0
1
o
n
ical
.
d
%
%
%
%
%
n
g s ep
4). The
n
c ion in
o
bse ed
0
%. The
29

130
posi ions o he ac i a ion s a o m. ibialis an e io dx. has he alue 0%. The low
pe cen age alues mean he ime simila s a o decisi e muscle ac i a ion o wo
conside ed muscles.
 iming o local maximums o muscles (g aph 1), and
 he a ea size unde he EMG cu e o he a e age wo king (s ep) cycle, which is a
p obabili y quan i y and poin s o dynamics o muscle wo k quan i y.
Phase shi s o M. glu eus maximus dx., on con a y o m. glu eus medius dx. (walking 38%,
gliding s ep -1% and V-1 ska ing 4%) indica e a signi ican a ini y o c oss-coun y skiing
compa ed o walking. The same can be ound in he ela ionship o his muscle o ou mo o
ma ke m. ibialis an e io dx. (42%, 2%, and 0%). We could disc e ely conclude ha du ing
c oss-coun y skiing m. ibialis an e io dx. ge s mo e in o he pos u al ole, oge he wi h m.
glu eus medius dx. The cha ac e o EMG cu e p o es ha as well. In all ee ypes o
locomo ion he muscles m. glu eus medius dx. and m. ibialis an e io dx. a e simila in
muscle ac i a ion s a s, mo eo e , he ac i a ion s a is same in ska ing. Muscles m. ibialis
an e io dx and m. glu eus medius dx. ha e e y simila s a o decisi e muscle ac i a ion
(5%, 2%, and 1%) in all h ee o ms o locomo ion. He e we can alk abou e y simila
coo dina ion ela ionships. These wo e y impo an muscles o walking show he mu ual
close ela ionship among walking, he gliding s ep and V-1 ska ing. I esul s om bipedal
o m o locomo ion, when he s ep s a phase and he pel is s abili y is kep in ans e sal
le el.
When compa ing muscle ac i a ion s a s o m. ibialis an e io dx. and m. gas ocnemius dx.,
capu medialis we ind he bigges di e ence in walking, when he i s named muscle
p ecedes he o he by 38% o he wo king cycle, in he gliding s ep i ollows by 5% and in V-
1 ska ing e en by 14%. Thanks o hese big di e ences (be ween walking and he gliding s ep
43% and walking and V-1 ska ing 52%) we a he conside he speci ics o c oss-coun y
skiing in gene al. This phenomenon is p obably in luenced by he mo e di icul keeping he
on -back balance in a glide on one ski (do sal plan a sense o keeping he posi ion and
mo emen ) on con a y o dynamic balance in one-leg s and when walking. In walking i is
a he a mo emen (a g adual cou se o he highes s ess on he oo o wa d wi h he
ollowing do sal lexion); meanwhile in c oss-coun y skiing he pos u al unc ion o he
muscle ensu ing a he he posi ion is mo e ob ious he e. In c oss-coun y skiing in gene al
he EMG cu e is again shakie ; i indica es he ecip ocal balancing he on -back posi ion
o he oo . The g ea e po ion o pos u al unc ion is also p o ed by he g ea e po ion o
“pos u al backg ound” o he EMG in ake. Cu es s ay on con a y o walking in places o
hei local minimums on ela i ely highe ampli ude. F om he poin o iew o he a ea unde
he EMG cu e, he e a e he highes demands on m. ibialis an e io dx. du ing he gliding
s ep, he lowes du ing V-1 ska ing. The muscle m. gas ocnemius dx., capu medialis a e
s essed in his sense in he o de : he gliding s ep, V-1 ska ing, walking. This muscle also
ha e he highes alues o phase shi di e ences be ween c oss-coun y skiing in gene al and
walking. The o de is again walking - gliding s ep - V-1 ska ing.
 M. gas ocnemius dx, capu medialis s. m. glu eus maximus dx: -34%, -4%, 4%,
 m. gas ocnemius dx, capu medialis s. m. glu eus medius dx: -29%, -3%, -13%,
 m. gas ocnemius dx, capu medialis s. as us medialis dx: 27%, -5%, 0%,
 m. gas ocnemius dx, capu medialis s. m. ibialis an e io dx: -38%, 5%, 14%.
This phase muscle, which decisi e unc ion in human locomo ion is ealizing and inishing
oo ake-o he su ace, shows he gene al di e ence o c oss-coun y skiing as one g oup
( he gliding s ep and V-1 ska ing) on con a y o walking on he o he side.
The o he gene al di e ence o walking and c oss-coun y skiing shows he mu ual
coo dina ion ela ionship o muscle ac i a ion s a s o m. glu eus maximus and as us
131
medialis. In walking we ind he phase co ela ion o 47% delay o as us medialis, in c oss-
coun y unning 0% and 1%. Howe e , he knee s abilize as us medialis on con a y o
walking has signi ican ly g ea e a ea unde he cu e in he gliding s ep, app oxima ely 200%
and in V-1 ska ing e en app oxima ely 470%. This ac deno es c oss-coun y skiing in
gene al as an ac i i y which signi ican ly s esses he knee s abilize as us medialis.
Recommenda ion o pos - ehabili a ion egime hen accen s speci ically ska ing on skis. The
iming o decisi e muscle ac i a ion s a s in he muscles as us medialis dx. and m. glu eus
medius dx. is e y in e es ing. These wo muscles s a ac i a ion e y simila ly in walking
and bo h ypes o c oss-coun y skiing ( alues 4%, 2%, 1%). Bo h hese muscles s abilizing
hei co esponding s uc u e (knee, pel is) coope a e so in hei s abilizing unc ion in all ee
ypes o locomo ion. I is possible o say ha om he poin o s abiliza ion c oss-coun y
skiing (bo h he gliding s ep and V-1 ska ing) and walking e y simila . And ha is despi e
he ac ha he s anding leg in walking goes h ough he suppo phase and s and on one
place o he solid suppo and in c oss-coun y skiing his leg inds i sel in a glide. We may
ouch he essence o c ea ing dynamic balance in one-leg suppo s and in c oss-coun y
skiing. The pe ec ly lea ned echnique o c oss-coun y skiing has in i sel such a quali y o
dynamic balance, which app oaches he balance o he s anding leg in walking, when he
c ea ed poin o suppo (punc um ixum) does no mo e.
The muscle m. ibialis an e io dx. inds i sel in coope a ion wi h bo h abo e men ioned
s abilizing muscles - as us medialis dx. ( alue o he phase shi in he gliding s ep – 1%, in
V-1 ska ing 0%) in c oss-coun y skiing in gene al, meanwhile i p ecedes (-11%) in walking.
This si ua ion ela es o s ep dynamics. In walking he m. ibialis an e io d.x ac i a ion
p ecedes oo ead, so a e he ead he obse ed s abilizing muscles we e ac i a ed ( as us
medialis dx. and m. glu eus medius dx.). M. ibialis an e io dx. in compa ison wi h he o he
s abilizing muscle m. glu eus medius dx. b ings alues o he phase shi 2% and 1% in c oss-
coun y skiing, in walking he alue is 5%. This change o he phase shi in walking on he
con a y o he pai m. ibialis an e io d. and as us medialis dx. (5% on con a y o -11%)
ela es logically o keeping on -back posi ion on he gliding ski.
Ou chosen “walking ma ke ”, m. ibialis an e io dx., in ela ion o he side pel is s abilize ,
m. glu eus medius dx. has simila phase shi s wi h li le essen ial di e ences in iming.
Walking 5%, he gliding s ep 2%, V-1 ska ing 1%. This phenomenon again shows he
kinesiology ela ionship o all h ee obse ed ypes o locomo ion. In he cou se o EMG
cu e o m. ibialis an e io dx in he g aph 1 we can show signi ican local maximums in
walking, phase cha ac e ized. The cu e cha ac e is mo e explosi e in bo h ypes o c oss-
coun y skiing, he ampli ude does no decline o ze o ( onic backg ound), he muscle
esponds o he equi emen o keeping pos u e in he egime o dynamic balance in a glide.
Tables 2, 3, 4 also s a e phase shi s o he con a-la e al muscle m. gas ocnemius sin, capu
medialis. The muscle inclusion in V-1 ska ing is no suppo ed by he wo k o shoulde gi dle
and is no discussed la e . Compa ison wi h a simila esea ch abou he kinesiology con en
o spo mo emen in c oss-coun y skiing is no possible as he e is no simila opic in Czech
and o eign sou ces.
Conclusion
C oss-coun y skiing di e s om walking in gene al in iming o decisi e muscle ac i a ion
s a mainly in phase muscles m. glu eus maximus dx., m. gas ocnemius dx., capu medialis
s. as us medialis dx., m. ibialis an e io dx. The muscles wo king o s abiliza ion, such as
m. glu eus medius dx. and as us medialis dx., wo k in a e y simila iming in walking and in
c oss-coun y skiing in gene al. In m. ibialis an e io dx., ou chosen walking ma ke
(explained abo e), we ha e ound he muscle pe sis ence in a ce ain onic ension in he a eas
132
o local minimums in c oss-coun y skiing, in walking he EMG eco d shows a mo e phase
cou se.
We ind signi ican ly g ea e a eas unde he EMG cu e in as us medialis dx. in c oss-
coun y skiing.
Fo he pos - ehabili a ion mo o egime we ind he use mo e in insu iciency o pel is
s abiliza ion and a e knee join ope a ions. The muscle cha ac e is ics o ac i a ion o he
obse ed s abilizing muscles app oach he cha ac e is ics o ee bipedal walking as he basic
and also he na u al o m o human locomo ion. On he basis o measu emen s o ou selec ed
muscles i is no possible o s a e, which o he obse ed ypes o c oss-coun y skiing is mo e
ela ed o ee bipedal walking.
The s a ed conclusions a e alid wi h ega d o he esea ch o m – he case s udy o he
woman skie on a e y high pe o mance le el (Czech na ional eam) wi h high expe ly
judged le el o coo dina ion.
The esea ch was suppo ed by he g an o he Czech Republic g an agency ma ked GAČR
406/08/1449 and he esea ch aim o Cha les Uni e si y in P ague, Facul y o Physical
Educa ion and Spo , suppo ed by he Minis y o Educa ion ma ked MSM 0021620864. The
au ho s hank he Ana omy and biomechanics depa men a he Facul y o Physical
Educa ion and Spo in P ague o analysing da a in he Ma lab so wa e.
133
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________________________________________________________
Doc. PaedD . B onisla K ačma , CSc., Mg . Ma ina Ch ás ko á, Mg . Radka Bačáko á,
Mg . Vladimí Hojka