Biomechanics and Medicine in Swimming XI

Fastskin suit, a real sprinter does not have to stack his action to reach
his highest speed. Similar to the findings in the global population, the
propulsive phases were significantly reduced when wearing a Fastskin
suit (46.40±4.03 vs. 51.26±3.88 %). Moreover, the SLZR had a specific
influence on the stroke length/stroke rate ratio and also on coordination
and the propulsive phases. In fact, it appeared that the effect of wearing
this suit was the opposite of the effects of the two other Fastskins. It
thus seems that the morphologic characteristics of the swimmer and the
technical characteristics of the swimsuit have combined and specific effects.
Passive torque measurement also indicated these differences. Each
swimmer being unique, the same swimsuit could have a different effect
for another swimmer. This case study also showed that the same swimmer
wearing different swimsuits was affected differently.
conclusIon
The new generation Fastskin suit, which does not improve buoyancy,
had the effect of improving glide and reducing drag. Because of these
effects, swimmers have fewer constraints, can therefore swim higher in
the water, and do not need to stack their actions. Coordination when
wearing a Fastskin suit corresponds at a given speed to coordination at a
slower speed without a Fastskin suit.
reFerences
Benjanuvatra, N., Dawson, G., Blanksby, B. A. & Elliott, B. C. (2002).
Comparison of buoyancy, passive and net active drag forces between
Fastskin and standard swimsuits. Journal of Science and Medicine in
Sport, 5(2), 115-123.
Chatard, J. C., Senegas, X., Selles, M., Dreanot, P. & Geyssant, A.
(1995). Wet suit effect: a comparison between competitive swimmers
and triathletes. Medicine and Science in Sports and Exercise, 27(4), 580-
586.
Chatard, J. C. & Wilson, B. (2008). Effect of Fastskin Suits on performance,
drag and energy cost of performance. Medicine and Science in
Sports and Exercise, 40(6),1149-1154.
Chollet, D., Chalies, S. & Chatard, J. C. (2000). A new index of coordination
for the crawl: description and usefulness. International Journal
of Sports Medicine, 21(1), 54-59.
Hue, O., Benavente, H. & Chollet, D. (2003). The effect of wet suit use
by triathletes: an analysis of the different phases of arm movement.
Journal of Sport Sciences, 21, 1025-1030.
Naemi, R. & Sanders, R. H. (2008). A “hydrokinematic method of measuring
the glide efficiency of a human swimmer. Journal of Biomechanical
Engineering, 130(6), 061016.
McLean, S. P. & Hinrichs, R. N. (1998). Sex differences in the center of
buoyancy location of competitive swimmers. Journal of Sports Sciences,
16(4), 373-383.
Millet, G. P., Chollet, D., Chalies, S. & Chatard, J. C. (2002). Coordination
in front crawl in elite triathletes and elite swimmers. International
Journal of Sports Medicine, 23, 99-104.
Mollendorf, J. C., Termin, A. C. 2nd., Oppenheim, E. & Pendergaast,
D. R. (2004). Effect of swim suit design on passive drag. Medicine and
Science in Sports and Exercise, 36(6), 1029-1035.
Roberts, B. S., Kamel, K. S., Hedrick, C. E., McLean, S. P., Sharp, R. L.
(2003). Effect of a FastSkin suit on submaximal freestyle swimming.
Medicine and Science in Sports and Exercise, 35(3), 519-524.
Seifert, L., Chollet, D. & Rouard, A. (2007). Swimming constraints and
arm coordination. Human Movement Science, 26, 68-86.
Toussaint, H. M., Truijens, M., Elzinga, M. J., Van den Ven, A., De Best,
H., Snabel, B., et al. (2002). Effects of a Fast-skin “body” suit on drag
during front crawl swimming. Sports Biomechanics, 1(1), 1-10.
chaPter2.Biomechanics
The Effect of Wearing a Synthetic Rubber Suit on
Hydrostatic Lift and Lung Volume
Cortesi, M. 1 , Zamparo, P. 2 , Tam, E. 1, Da Boit, M. 1 , Gatta, G. 1
1 Faculty of Exercise and Sport Science, University of Bologna, Italy
2 Faculty of Exercise and Sport Science, University of Verona, Italy
Buoyancy improvement is the result of the use of a technical suit to
increase swimming speed. Hydrostatic lift and lung volumes were measured
in 9 competitive swimmers while wearing a “standard” swimsuit
(S) or a full body synthetic rubber suit (Xg). The average values of the
hydrostatic lift were 14.51 ± 4.53 N with S and 14.33 ± 3.99 N with
Xg. The average values of lung volumes when wearing S and XG were
VC 6.31/6.14 L, ERV 2.12/1.79 L, VT 0.94/0.88 L, IRV 3.26/3.47 L,
respectively. A strong thoracic and/or abdominal compression caused
by the technical suits may be related to the observed reduction in the
chest and abdominal circumferences during maximal inspiration and
expiration, as well as to the reduction in the lung volumes and in the
hydrostatic lift. The improvement in performance obtained by wearing
Xg is not related to better static buoyancy.
KeYWords: hydrostatic lift, buoyancy, bodysuit, swimming, lung
volume
IntroductIon
In the last World Championships, held in Rome in 2009, swimmers utilized
suits produced partially or entirely with industrial polymers and 43
world records were broken. Even if the effect of these technical suits in
determining the increase in swimming speed is still not fully understood,
their advantage may be related to the increase of buoyancy. Benjanuvatra
et al. (2002) did not find any improvement in buoyancy when wearing
technical (cloth) suits. However, according to Technical Commission of
F.I.N.A., the possible air-trapping effect, i.e. “air sacks” between the suit
and the swimmers body, has to be taken into account for suits entirely
made in polyurethane/neoprene. Indeed, the hydrostatic weight of these
suits should be less than 1 N according to F.I.N.A. rules (Dubai Charter
on F.I.N.A. requirements for swimwear approval 2009).
The aim of this work was to evaluate the differences in hydrostatic
lift in swimmers wearing (or not wearing) a suit made of polyurethane/
neoprene and to relate these findings with possible variations in lung
volume.
Methods
Nine male swimmers (23.25 ± 3.01 years of age; 1.80 ± 0.03 m of stature;
75.45 ± 6.96 kg of body mass) were asked to perform two different
tests. In the first test their hydrostatic lift was measured in a swimming
pool (water temperature: 27.5°C) while wearing a “standard” textile
brief swimming-suit (S) or a full body shoulder-to-ankle technical suit
(X-glide Power-skin Arena Italy, not modified: Xg). Before the measurements
the subjects were asked to warm-up for about 10 minutes. After the
warm-up, the subject wore the swimming suit required for the test. Particular
attention was paid to reproduce the pre-race situation asking the
subjects not to perform any “not conventional” manoeuvre of “adaptation”
of the swimsuit. After the warm up phase, the subjects were kept for 10
s under the water surface. They were held in position throughout a cable,
connected to a pulley system positioned on the swimming pool floor and
fastened to the subject waist (Figure 1). The cable was also connected to a
load cell (Tesys 400, Globus, Italy) positioned on the pool's edge that allowed
to measure the subject’s hydrostatic lift (the force with which their
body tended to rise towards the water surface). Ten measurements were
collected in both conditions (with S and Xg swimming suits). During
these tests the subjects were required to hold their breath after a forced
maximum inspiration and not to exhale for the entire duration of the test.
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