Biomechanics and Medicine in Swimming XI

BiomechanicsandmedicineinswimmingXi
were reached (Table 1.). Something similar was observed with maximal
heart rate values (Table 3.). Additionally, kinetics of HR frequency was
similar at 110% intensity to that at 100% intensity (Figure 4.). From our
results it could be concluded that the aerobic energy supply to working
muscles could be limited by the cardiovascular system at supra-maximal
intensities (no further increase of maximal heart rate and kinetic responses
of heart rate). However at the beginning of the swimming, swimmers
were able to compensate the insufficient energy supply by aerobic processes
with increased energy production by anaerobic lactic processes, since
increased lactate production per unit of time was found with increasing
intensity of swimming (Figure 3.). However when the level of acidosis
and lactate concentration at 110% intensity was similar to that at 100%
intensity swimmers were no longer able to swim at that intensity (Table
2.). From the results it was not possible to demonstrate that insufficient
energy supply is the limiting factor of maximal performance in front crawl
swimming. However, when certain levels of V E , Vo 2 , HR, pH and lactate
concentration were reached, similar to those at maximal intensity, swimmers
were no longer able to swim at selected supra-maximal intensity.
conclusIon
The energy cost of swimming increases as a function of the speed. With
increase of swimming speed the sum of energy supply during swimming
should increase from either alactic (AnAl), lactic (AnL) and aerobic
(Aer) processes. It is concluded that insufficient energy supply because
limitations in aerobic and anaerobic lactic processes occur, could limit
the maximal speed of swimmers for 200 m front crawl.
However there is still the open question as to whether the swimmers
studied need more aerobic training or do they need more anaerobic
training to better their performances in the 200 m front crawl or do they
need to improve their swimming technique.
reFerences
Capelli C., Pendergast D.R., Termin B. (2005). Energetics of swimming
at maximal speeds in humans. Eur J Appl Physiol 78,385-393.
Holmer I. (1974). Physiology of swimming man. Acta Physiologica Scandinavica
supplementum 407, 1 – 55.
Monpetit R., Lavoie J.M., Cazorla G. (1988). Energy expenditure during
front crawl swimming: a comparision between males and females.
In: Ungerechts BE, Wilke K, Reisschee K. Swimming Science V. Human
Kinetics, Champaign III., pp 229-236.
Prampero P.E. di. (1986). The energy cost of human locomotion on land
and in water. Int J Sports Med 7,55-72.
Toussaint H.M., Beelen A., Rodenburg A., Sargeant A.J., de Groot G.,
Holander P., Ingen Schenau AG van (1988). Propelling efficenciy of
front crawl swimming. J Appl Physiol 65, 2506-2512.
Toussaint H.M., Meulemans A., De Groot G., Hollander A.P., Schreurs
W., & Vervoorn K. (1987). Respiratory valve for oxygene uptake
measurments during swimming. Eur J Appl Physio. 56, 363-366.
Zamparo P., Capelli C., Cautero M., Di Nino A. (2000). Energy cost
of front crawl swimming at supra-maximal speeds and underwater
torque in young swimmers. Eur J Appl Physiol 83,487-491.
Zamparo P., Pendergast D.R., Mollendorf J., Termin A., Minetti E.A.
(2005). An energy balance of front crawl. Eur J Appl Physiol 94,134-
144.
230
Lactate Comparison Between 100m Freestyle and
Tethered Swimming of Equal Duration
Thanopoulos, V., rozi, G., Platanou, t.
Faculty of Physical Education and Sports Science, University of Athens,
Greece
The purpose of the present study was to compare the blood lactate
concentrations after two tests of maximal intensity: a) 100m freestyle
swimming and b) tethered swimming of equal duration with the test of
100m freestyle. Furthermore, the force produced in tethered swimming
was measured. Twelve male competitive swimmers participated in this
study. Capillary blood samples were obtained 3 o , 5 o and 7 o min after
the end of each test. Analysis of the results showed that there was no
statistically significant difference between the lactate concentration in
the tethered swimming test and the test of 100m freestyle swimming.
Moreover, there was correlation between performance in 100 m and
force in tethered swimming (r= -0.63). The results indicate that when
tethered swimming is used for sprinters, it seems more adequate to
analyze the values of mean force because as a mechanical characteristic,
it better describes sprinters achievements.
Keywords: blood lactate, pulling force, freestyle sprinters, swimming
performance
IntroductIon
Maximal swimming velocity, especially at sprint distances, except for technical
ability depends on pulling force characteristics and maximal anaerobic
lactic capacity that is proportional with maximum production of lactic
acid. In order to determine maximum lactate accumulation, several middle
distance tests are used as well as resistance swimming. The most common
test for anaerobic capacity is 100m freestyle. Several researchers have also
used tethered swimming. The test most widely used to measure pulling
force realized in swimming is the tethered swimming test (Keskinen et
al., 1989; Sidney et al., 1996; Maglischo, 2003). Furthermore, tethered
swimming is one of the most famous types of training for swimmers and
aims at increasing maximum speed and strength (Maglishco, 2003). The
subject wears a special belt and swims at the same point (tethered swimming
Bonen et al., 1980). Viewed kinematically, swimming is a series of
cyclic movements performed by alternation of arm and leg strokes. Each
stroke results in a characteristic force, which pulls the swimmer forward
and is realized by contracting the muscles involved.
Many researchers suggested this mean of training that helps in increasing
maximum speed and improving strength for better preparation
of swimmers. (Colwin; 1993; Counsilman, 1979; Hannula, 1995; Smith,
2002; Maglischo, 2003).
Some other reviewers found positive correlation between swimming
performance and muscular strength that can be measured in several
ways (Sharp et al., 1982; Costill et al., 1983; Hawley & Williams, 1991;
Crowe et al., 1999). Previous research has focused only on the relationship
between the maximal pulling force or the average of maximal pulling
forces (Fmax or avgFmax) of a single stroke realized in a time interval
of 10 seconds, and the swimming velocity achieved mainly at sprint
distances (Sidney et al., 1996, Dopsaj, 2000).
In terms of measurements, Fmax or avgFmax contains information
solely about the force peak point or the average of such points achieved
for the given single strokes realized by tethered swimming. On the other
hand, force as a measurable value which is a product of muscle contraction
is defined by at least two more dimensions, i.e., by its increment
gradient/ its increment in time (RFD – rate of force development) and
by the impulse of force (ImpF) (Zatsiorsky, 1995), the realization of
which can be reliably measured in water during tethered swimming
(Dopsaj, 2000).