Zmiany zakresów ruchów w stawach kończyn górnych i

Zmiany zakresów ruchów w stawach kończyn górnych i

Journal of Health Sciences (J for the Ss H) 2013; 3 (5): 267-276
The journal has had 4 points in Ministry of Science and Higher Education of Poland parametric evaluation. Part B item 683.
© The Author (s) 2013;
This article is published with open access at Licensee Open Journal Systems of University Radom in Radom, Poland
Open Access
This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial
use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
CHANGES IN THE RANGES OF MOTION IN THE JOINTS OF THE UPPER AND
LOWER EXTREMITIES IN ELDERLY PEOPLE UNDER THE INFLUENCE OF
THE NORDIC WALKING TRAINING
Zmiany zakresów ruchów w stawach kończyn górnych i dolnych u osób starszych pod
wpływem treningu Nordic Walking
Monika Wiech1, Katarzyna Prusik1, Jakub Kortas1, Łukasz Bielawa1,
Zbigniew Ossowski1, Krzysztof Prusik1, Walery Żukow2
1
Plant of the Recreation and the Activity-based Tourism Academy of Physical Education
and Sport in Gdańsk, Poland
2
University of Economy, Bydgoszcz, Poland
Keywords: Nordic Walking, trening.
Słowa kluczowe: Nordic Walking, trening.
Abstract
The scope of the movement in the pond can be a valuable pointer for determining the
functional fitness of the limb. Results of measurements goniometrycznych assessments of the
impact used in progress of different physical exercises can be, of training process and the like
to the body of the individual, becoming one of indicators of the degree of training.
A characterization of changes of the scope of the movement in the fibular plain in
chosen ponds of upper limbs is a purpose of the work and bottom at persons aged 65-75 under
the influence of the Nordic Walking training. 46 women and 10 men aged 65-75, residing in
Gdańsk were provided with tests. The examined group carried out the health training leaning
against Nordic Walking made rich for stretching exercises (dynamic and static) during 12
weeks, with frequency 3 times during the week for 60 minutes. At the beginning and at the
end of the training cycle measurements of scopes of movements in chosen ponds were
conducted with SFTR method with the goniometer.
Presented findings of chosen scopes of movements in ponds attest to the high level of
the suppleness of examined seniors at the beginning and at the end of the training cycle,
writing them down into norms for considerably younger persons. Moreover the improvement
shows Nordic Walking sizes of all parameters to the effectiveness of the suggested health
training in the form.
Conclusions. The test results of presented tests shows that the 3-month's training
program can already bring expected effects in the form of increasing the scope of the
movement in ponds, leading to the improvement of quality of life and of improving the
physical fitness.
267
Streszczenie
Zakres ruchu w stawie może być wartościową wskazówką dla określenia
funkcjonalnej sprawności kończyny. Wyniki pomiarów goniometrycznych mogą być
wykorzystywane w toku oceny wpływu różnych ćwiczeń fizycznych, procesu treningowego
itp. na organizm osobnika, stając się jednym z wyznaczników stopnia wytrenowania.
Celem pracy jest charakterystyka zmian zakresu ruchu w płaszczyźnie strzałkowej w
wybranych stawach kończyn górnych i dolnych u osób w wieku 65-75 lat pod wpływem
treningu Nordic Walking. Badaniami objęto 46 kobiet i 10 mężczyzn w wieku 65-75 lat,
zamieszkałych w Gdańsku. Badana grupa realizowała trening zdrowotny oparty o Nordic
Walking wzbogacony o ćwiczenia rozciągające (dynamiczne oraz statyczne) w czasie 12
tygodni, z częstotliwością 3 razy w tygodniu po 60 minut. Na początku i na końcu cyklu
treningowego przeprowadzono pomiary zakresów ruchów w wybranych stawach metodą
SFTR za pomocą goniometru.
Przedstawione wyniki badań wybranych zakresów ruchów w stawach świadczą o
wysokim poziomie gibkości badanych seniorów na początku i na końcu cyklu treningowego,
wpisując ich w normy dla znacznie młodszych osób. Ponadto poprawa wielkości wszystkich
parametrów wskazuje na efektywność zaproponowanego treningu zdrowotnego w formie
Nordic Walking.
Wnioski. Wyniki prezentowanych badań dowodzą, że już 3-miesięczny program
treningowy może przynieść oczekiwane efekty w postaci zwiększenia zakresu ruchu w
stawach, doprowadzając do poprawy jakości życia i polepszenia sprawności fizycznej.
Introduction
In order to hold and to accumulate the health and to prevent the appearance of
illnesses the man must learn to include the move for one's everyday duties, independently for
the age. Population becoming outdated and keeping her company degeneration of the level of
physical activity of the population, creates the problem of universal falling into decline on the
health about epidemic sizes (Sikorski, 2010), meanwhile joy from surviving the age should be
the same, as the luck in earlier lifespans. The rising number of evidence proves about the fact
that the pace of the ageing of the body of the man is subject to physiological alterations,
mainly on the road of changes of the physical activity and dietary conditioning. These factors
cause that the old age becomes happy, bright and full of new experience (Marchewka,
Dąbrowski, Żołądź, 2012, Cieślicka i wsp. 2011, Napierała i wsp, 2009). The systematic
physical activity is one of important factors positively stimulating the life of an elderly man,
and the insufficient activity can support of motor malfunction. Although the motor activation
of elderly people is a difficult task extremely, she is exquisitely important, since a better
health condition of the elderly is a high level of the self-reliance and self-services, and in
consequence smaller costs of the health and social care. The regular physical activity helps to
stabilize universal in the older century of illness and the complaint, so as: hypertension,
268
atherosclerosis, osteoporosis, diabetes, coronary disease, as well as to bring the stress or the
obesity under control, moreover lowers the risk of infection and against ruling opinions
contributes to reduce pain complaints in illnesses of the arrangement of move. The physical
training is regular "with cure-all, inexpensive and available to everyone, not-having of side
effects, pleasing and recognised by medical circles" (Marchewka, 2012).
Individuals healthily ("in an optimal way") growing old "are clear and pleased with the
life, perceiving oneself as younger and not shunning from the contact with the young
generation (...), without limitation of function, skillful mentally, optimistically turned towards
people and taking an active part in the life of the neighborhood" (Duda, 2012).
The elderly can regain willingness to plant the healthy physical activity, feeling more
safely, looking more enjoyably with the fashionable equipment which they can use
into the simple, safe and comfortable way (Sokołowski i wsp., 2010). Nordic Walking gives
such a possibility.
Nordic Walking is rhythmical and aerobic activity of big skeletal muscles, bringing
numerous health benefits, through the improvement in power, power, endurance,
coordination, deuce, reduction in the fatty tissue (Sikorski, 2010; Ossowski, Prusik, Kortas et
al. 2010; Sokeliene, Cesnaitiene, 2011), molding the silhouette, relieving the spine, the
improvement in the mood what is particularly important for elderly people (Hartvigsen,
Marso, Bendig et al. 2010; Sokołówski, 2010), as well as enabling to increase the scope of the
movement in ponds. He/she doesn't demand great effort and the ability in addition (Sikorski,
2010).
Degenerative changes of ponds are stated already before the twentieth year of age, and
after the eightieth year of age are noticeable in the entire population. Degenerative changes of
ponds concern all components of their structure: in the bone structure reaches to senile
osteoporosis bones, causing among others lowering bone bases, cartilages and synovial
capsules, trailers of tendons and muscles undergo calcifications, muscles through the slope in
them contents of water become less elastic, individual muscle fibers disappear, a muscle mass
reduces for the connective tissue (Zembaty, 1989).
Scope of the movement in the pond, that is "articular angle between outermost
locations of one body part with account second neighboring" (Erdmann, Zieniawa, 2011), can
be a valuable pointer for determining the functional fitness of the limb. A fact is material, that
on account of surrounding the pond with soft tissues - a synovial capsule, ligaments and with
muscles, the scope of the movement is dependent from their flexibility which is quite
changeable (Erdmann, Zieniawa, 2011). One should examine two kinds of the scope of the
269
movement, i.e. practicing (result of the work of the muscles responsible for making it) and
passive (effect of putting outside power) (Weiss, Zembaty, 1983). Between different stretches
of the human body or the bone goniometry, being cannon deals with measurements of angles
of anthropometry. Dynamic goniometry deals with the scope of the movement in individual
ponds of the organism (Malinowski, Bożiłow, 1997). Indicating the scope of the movement in
ponds is one of essential methods of estimation of the functional state and the measure of the
result of a calculation of physiotherapy (Zembaty, 1989). Results of measurements
goniometric assessments of the impact also used in progress of different physical exercises
can be, of training process and the like to the body of the individual, becoming one of
indicators of the degree of training (Drozdowski, 1987). Programming burdening in the health
training of persons in the Middle Ages and older one should first try for keeping the current
functional state, in the next stage whereas to aspire for achieving the greater physical fitness
(Ossowski, Prusik, Prusik, 2009).
General rules of the dosage of exercises in the health training without the account
whether it regarding the creation of the health, of primitive or secondary prevention, are
similar. Mainly endurance forms of exercises include in the duration determined, depending
on health needs,, the frequency and intensity (Kuński, 2003). The physical training improving
scope of the movement, suppleness, scope of bending ponds and the level of the deuce are a
limiting factor number of falls, causing many fractures but in consequence of many vital
complications (Marchewka, 2012).
In Poland he doesn't still have uniform standards of the mobility of joints. Certain
hampering divergences are met interpersonal comparing results. An age isn't taken into
account examined, although changes in the motor organ happening as a result of growing old
lead the mobility for impoverishing the basic function he is which, and so they conducted
research method by O.A. Russe and J.J. Gerhardt - SFTR (International method of
measurement and of record of movements in ponds published through ISOM- International
Orthopeadic Measurements Standard). In this method norms were considered in an individual
age brackets. He owes his name to the first letters determining appropriate plains in English,
in which all moves are examined (Schlaaff method):
-Motoricity S - sagittal - fibular plain
-Motoricity F - frontal - coronal plane
-Motoricity T - transverse - crosswise
-Motoricity R - rotation - torsion
270
Aim of work is characterization of changes of the scope of the movement in the fibular
plain in chosen ponds of upper limbs is a purpose of the work and bottom at persons aged 6575 under the influence of the Nordic Walking training.
Material and testing methods
46 women and 10 men aged 65-75, inhabited were provided with tests in Gdańsk. The
examined group carried out the health training leaning against Nordic Walking.
Classes were conducted in Oliwa forest during 12 weeks, with frequency 3 times
during the week for 60 minutes. On every classes seniors were subjected to the current control
using monitors of the action of the heart of the company Polartec, in the destination of
keeping established intensity on the level 40-60 % HRmax, moreover the route of every
training was registered with organising a Garmin company having a GPS. Every training
individual consisted of three components: preliminary, main and final. Every warm-up was
conducted with using small sticks to Nordic Walking, and for her finishing dynamic
stretching and respiratory exercises were applied. A weight training and needling postural
muscles were entered into the main part. In part final exercises stretching, loosening and
quieting down were applied, taking the respiratory university class into account. They gave
classes with constant method variable with elements of rest. They conducted research in the
laboratory of a physical effort of the academy of physical education and Sport in Gdańsk in
late morning hours. To the program they were passed exclusively persons without health
contraindications. Decision to allow to the program a general practicioner took.
The following research methods were applied: test of the references, measurement of
the scope of the movement in ponds with the goniometer, test of the volume of classes in 3
monthly mezocykle training, a statistical analysis and concluding. All achieved results from
measurements were written with three numbers according to the following scheme:
a) From the body he/she enrolls movements of the extension and all run movements as
first in the element
b) He/she enrolls moves of the bend and all conducted movements to the body as last
c) Home position which as a rule position 0 is °, is written inside, compound of three
numbers, of element.
Results
The angle size in the practicing extension in the hip joint before beginning the 3month's training cycle achieved the mean 7.7 ° and 7.5 ° appropriately in the right and left
limb at examined women (the population norm of the scope of the movement in this pond is
5 °). After finishing him these values grew about close the 44%. At examined men these sizes
271
look as follows: 8.4 °in a right lower limb and 8.1 ° in left, undergoing the improvement about
over the 30% and staying on the angle high level than at examined women after the finished
cycle. At both of sex we observe the greater percentage improvement in the left limb,
however the angle result remains better at a right lower limb. Bending the hip joint grew
about over the 10% at examined women and men, however women in this respect reached
considerable values about nearly 10 ° both at the beginning and at the end of training cycle.
Bending the glenohumeral joint at everyone examined achieved maximum correct equal result
90 ° in both measurements. We observe differences in wheedle this pond to the benefit of
women in the initial and final test which they reached before commencing experiment on
average 40.9 °in the right upper limb and 41.7 ° in left (the population norm of the scope of
the movement in this pond is 35 °). The improvement in the scope of the movement in the
glenohumeral joint at examined women took out close 3 ° in both limbs, however at men 5.2 °
in right and 4.3 ° in the left upper limb what constitutes the percentage significant difference
in proportion to results achieved by women.
Passive scope of the movement in the hip joint (extension) at the beginning of the
cycle at examined women was about 2.5 ° bigger than practicing, however after the
completion of cycle the difference increased to nearly 4 °. At men in initial tests this
difference took out almost 3.5 °, in final tests grew (as similarly as at women) to 4 °. Passive
bending the hip joint at the beginning of the cycle differed towards the active movement about
over 3 ° at women in both limbs and about 3.4 ° and 4.2 ° appropriately in the right and left
limb amongst men. In the final test at women this difference took out over 4 °. In the group of
men the recalled difference increased to 5.5 -6 °. Both practicing and passive bending the
glenohumeral joint achieved the same recalled values equal of 90 °. The passive extension in
this pond in the initial test differed from the practicing scope of the movement about 4.3 ° in
the right limb and 5 ° in left at examined women and about 4.1 ° (laws) and 2.6 ° (left)
amongst men. In the final test a difference of the size was gained 5.7 ° (laws) and 6.1 ° (left)
in the female group and close 5 ° in both limbs in the male group.
Tbl. 1. Changes of the size of the scope of the movement in chosen ponds of women under the
influence of the 3-month's training cycle examined and men aged 65-75.
Right
Initial (˚)
Final (˚)
Difference
Left
(%)
Initial (˚)
Hip joint
272
Difference
Final (˚)
(%)
Move
correction/
bend
-motoricity
practicing
♀ (n = 46)
7.7 - 0 - 10.3 - 0 - 33.7 - 0 - 7.5 - 0 - 10.1 - 0 - 34.6 - 0 98.6
♂ (n = 10)
109.2
10.7
99.2
109.5
10.4
8.4 - 0 - 11.0 - 0 - 30.1 - 0 - 8.1 - 0 - 10.6 - 0 - 30.8 - 0 88.0
97.5
10.8
87.9
97.0
10.3
-motoricity
passive
♀ (n = 46)
10.2 - 0 - 14.3 - 0 - 40.2 - 0 - 10.1 - 0 - 14.4 - 0 - 42.5 - 0 101.7
♂ (n = 10)
113.5
11.6
102.7
113.6
10.6
11.6 - 0 - 14.9 - 0 - 28.4 - 0 - 11.7 - 0 - 15.2 - 0 - 29.9 - 0 91.4
103.0
12.7
92.1
103.0
11.8
♀ (n = 46)
40.9 - 0 - 90
43.8 - 0 - 90
7.1 - 0 - 0
41.7 - 0 - 90
44.8 - 0 - 90
7.4 - 0 - 0
♂ (n = 10)
38.3 - 0 - 90
43.5 - 0 - 90
13.6 - 0 - 0 37.2 - 0 - 90
41.5 - 0 - 90
11.5 - 0 - 0
♀ (n = 46)
45.2 - 0 - 90
49.5 - 0 - 90
9.5 - 0 - 0
46.7 - 0 - 90
50.9 - 0 - 90
9.0 - 0 - 0
♂ (n = 10)
42.4 - 0 - 90
48.5 - 0 - 90
14.4 - 0 - 0 39.8 - 0 - 90
46.2 - 0 - 90
16.0 - 0 - 0
Glenohumeral
joint
Move
correction/
bend
-motoricity
practicing
-motoricity
passive
Discussion
Universally
a
fact
that
the
physical
activity
does
good
is
familiar
to physiological properties of the organism - irrespective of the age, preventing or limiting
limiting elderly people (Godges et al. 1993; Roach, Miles, 1991).
273
Planting the strategy of a healthy lifestyle one should plan and carry action overtaking
illness out, but more than anything else assisting health (Drabik, 2006).
The test results of tests presented in the present article shows that the 3-month's
training program can already bring expected effects in the form of increasing the scope of the
movement in ponds, leading to the improvement of quality of life and of improving the
physical fitness. Morini et al. (2004) present similar effects, proposing the training about
endurance character. For a statistical analysis big ponds which are most involved were chosen
during Nordic Walking march. Here movements in the fibular plain were included. All values
were defeated by favorable changes under the influence of the applied program. The scope of
straightening out women in the right glenohumeral joint examined grew on average about
over the 7.1% (practicing) and 9.6% (passive), however at men appropriately by the 13.6%
and the 14.4%. They are these are values almost twice as bigger amongst men, however angle
sizes achieved an almost identical result at both of sex. We observe the smaller difference
within the left glenohumeral joint, where men while straightening out got the percentage good
result by the 4.1%, however the angle size is lower about 3.3 ° in the active movement and
appropriately 7% more and 4.7 ° less in the passive movement. Both at the beginning and at
the end the practicing extension of the glenohumeral joint classifies the cycle examined
women to and of an age bracket i.e. 18-40 years, although all examined qualify to the III
range i.e. 61-85 years, however passive movement to the II period - 41-60 years. Angle sizes
in the practicing extension of the glenohumeral joint qualify men for the II period (41-60
years), however after the completion they promote the cycle to norms right for persons at the
age of 18-40. The scope passive in the first measurement of the movement qualifies men for
the III period (61-85 years), however after the completion of cycle - of the II range (41-60
years). In bending in the glenohumeral joint all achieved results are correct achieving 90 °
(the maximum value for all age brackets). Towards the glenohumeral joint an extension
presents the opposite situation in the hip joint, where men got values greater than women.
Bigger however in percentage values women got the improvement in the practicing move
about less than 4%, however the passive scope of the movement differed about close the 12%.
Bending the hip joint is a difference about nearly 10 ° to the benefit of women both at
the beginning as well as end of the training cycle, at least at both the scope of the movement
in this direction improved the sex oneself on average about over the 10% in the second
measurement.
Conclusions
274
The improvement in the result of angle bending the hip joint at examined women
causes their promotion from the III age bracket to II. the similar improvement at men doesn't
affect the change of the range. They stay in the upper limit of the norm in their age group.
In case of the extension of the hip joint both examined women and men are promoted
from the II age bracket to 1st century of 18-40 years). Presented findings of chosen scopes of
movements in ponds attest to the high level of the suppleness of examined seniors at the
beginning and at the end of the training cycle, writing them down into norms for considerably
younger persons. Moreover the improvement shows Nordic Walking sizes of all parameters to
the effectiveness of the suggested health training in the form.
References
1. Cieślicka M, Stankiewicz B, Napierała M, Żukow W, Brzeziński M., Aktywność fizyczna
osób starszych.[w:] (Red.) Maik W, Napierała M, Żukow W., wybrane problemy turystyki,
rekreacji, fizjoterapii ochrony zdrowia człowieka. Bydgoszcz 2011 s.28- 37.
2. Drabik J. (2006) Pedagogiczna kontrola pozytywnych mierników zdrowia fizycznego.
Wydawnictwo Uczelniane AWFiS. Gdańsk.
3. Drozdowski Z. (1987) Antropometria w wychowaniu fizycznym. AWF Poznań, 92.
4. Duda K. (2012) Proces starzenia się. [W]: Fizjologia starzenia się - profilaktyka
i rehabilitacja (red. Marchewka A., Dąbrowski Z., Żołądź J.A.) Wydawnictwo Naukowe
PWN, Warszawa.
5. Erdmann W.S., Zieniawa R. (2011) Biomechanika judo. Wydawnictwo Uczelniane
AWFiS. Gdańsk, 52.
6. Godges J.J., MacRae P.G., Engelke K.A. (1993) Effects of exercise on hip range of
motion, trunk muscle performance, and gait economy. Phys. Ther. 73: 468-477.
7. Hartvigsen J., Marso L., Bendig T., Manniche C. (2010), Supervised and non-supervised
Nordic Walking in the treatment of chronic low back pain., A single blind randomized clinical
trial. BMC Musculoskeletal Disorders, s. 11-30.
8. Kuński H. (2003) Trening zdrowotny osób dorosłych- poradnik lekarza i trenera. Agencja
Wydawnicza Medsportpress. Warszawa.
9. Malinowski A., Bożiłow W. (1997) Podstawy antropometrii. Metody, techniki, normy.
PWN, Warszawa-Łódź. 408.
10. Marchewka A. (2012) Aktywność fizyczna - oręż przeciw niepełnosprawności osób
w wieku starszym. [W]: Fizjologia starzenia się - profilaktyka i rehabilitacja (red. Marchewka
A., Dąbrowski Z., Żołądź J.A.) Wydawnictwo Naukowe PWN, Warszawa.
11. Marchewka A., Dąbrowski Z., Żołądź J.A. (2012) Fizjologia starzenia się - profilaktyka i
rehabilitacja. Wydawnictwo Naukowe PWN, Warszawa.
12. Morini S., Bassi A., Cerulli C., Marinozzi A., Ripani M. (2004) Hip and knee joint
flexibility In Young and elderly pe ople: effect of physical activity in the elderly. Biology of
Sport, 21 (1): 25-37.
13. Napierała M., Cieślicka M., Szark M., Klimczyk M., Aktywność fizyczna ludzi starszych
– świadomość, nawyki i praktyka, [w]: Wspomaganie rozwoju i edukacji człowieka poprzez
turystykę, sport i rekreację, (red.) Muszkieta R., Napierała M., Skaliy A., Żukow W., WSG,
Bydgoszcz 2009, s.363 - 376.
275
14. Ossowski Z., Prusik K., Kortas J., Wiech M., Prusik K., Słomska H. Bielawa Ł., (2010)
Zmiany poziomu siły kończyn górnych i dolnych pod wpływem treningu Nordic Walking u
kobiet w starszym wieku. Rocznik Naukowy / AWFiS Gdańsk - T. 20, s. 71-78.
15. Ossowski Z., Prusik K., Prusik K. (2009) Rejestracja i analiza obciążeń treningowych w
ukierunkowanym treningu zdrowotnym kobiet w wieku 50-75 lat. [W]: Proces doskonalenia
treningu i walki sportowej (red. A. Kuder, K. Perkowski, D. Śledziewski). Tom VI. Polskie
Towarzystwo Naukowe Kultury Fizycznej. Warszawa.
16. Roach K.E., Miles T.P. (1991) Normal hip and knee active range of motion: the ralation
to age. Phys. Ther. 71:656-665.
17. Sikorski B., Muszkieta R., Brzozowski J. (2010) Nordic Walking jako nowoczesna
i popularna forma treningu zdrowotnego i rekreacyjnego. [W]: Zdrowotne aspekty aktywności
fizycznej-Health
aspects
of
physical
activity
(red.
J.
Łuczak,
St. Bronowicki). Wielkopolska Wyższa Szkoła Turystyki i Zarządzania. Poznań.
18. Sokeliene V., Cesnaitiene V. J. (2011) The influence of nordic Walking on physical
fitness of elderly people. Education Physical Training Sport. Lithuanian Academy of Physical
Education, 3 (82), s. 45-51.
19. Sokołowski M., Kaiser A., Ćepulenas A., Bronowicki S. (2010) Nordic Walking- szansą
zachowania zdrowia. [W]: Zdrowotne aspekty aktywności fizycznej-Health aspects of
physical activity (red. J. Łuczak, St. Bronowicki). Wielkopolska Wyższa Szkoła Turystyki i
Zarządzania. Poznań.
20. Weiss M., Zembaty A. (1983) Fizjoterapia dla medycznych studiów zawodowychwydział fizjoterapii. PZWL Warszawa. 27, 38.
21. Zembaty A. (1989) Pomiary zakresów ruchów w stawach człowieka. AWF, Warszawa. 5,
16,17, 76, 77, 130,131.
22. Zembaty A. (2002) Kinezyterapia. Zarys podstaw teoretycznych i diagnostyka
kinezyterapii. Wydawnictwo "Kasper" Sp. z o.o. 241-243, 424- 425.
This is an open access article licensed under the terms of the Creative Commons Attribution Non
Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non
commercial use, distribution and reproduction in any medium, provided the work is properly cited.
Conflict of interest: None declared.
Received: 23.01.2013.
Revised: 18.04.2013.
Accepted: 07.06.2013.
276