Biomechanics and Medicine in Swimming XI

BiomechanicsandmedicineinswimmingXi
dIscussIon
Usually swimmers breathe out from the nose while the face is in the water.
We detected that nasal pressure adapted to water depth pressure automatically
(Hara H., et al., 1998). To study effects on nasal pressure, the
nostrils were covered with film while subjects did the breaststroke. In this
case, of shutting down the nose, a person might not be able to feel pressure
changes in that area (Hara H, et al., 2006). This disturbed the inhalation
timing and resulted in swimming apnea. Experimentation in this form of
nose-blocking has been carried out earlier (Hara H., et al., 2002).
In the present study, the airway changes from nose to mouth were
defined, when four trained subjects were swimming simulated breaststroke.
The nose pressure suddenly decreased when the nose broke the
surface of the water. We think such a change of nasal pressure stopped
exhalation from the nose. This also brings about a large blow-out from
the mouth. The strong exhalation from the mouth needs a closing of
the airways to the nose. Pronouncing “Mnn” facilitates exhaling from
the nose, while pronouncing “Pa” or “Pha” will shut the nasal airways
leading to exhalation from the mouth. Trained swimmers breathe out of
the nose while their faces are in the water. In the case of instruction for
beginners, to prevent swimming apnea it is effective if the instructor has
the learner pronounce “Mnn” with the nose, then once that is completed,
pronounce “Pha” or “Pa” from the mouth to blow out.
The ventilation volume from the nose is smaller than from the mouth.
However, the flow volume sensor in the nose is more sensitive than that
in the mouth (Thubone H. 1990). Moreover, because the diameter of
the nasal airways is smaller than the mouth’s, flow volume and pressure
might be useful for providing information for breath control. This is the
reason for using the nasal passages while swimming (Wheatly, JR., et
al., 1991).
In the case of sleep apnea, airway condition is very important for
breathing (Amal MO, et al., 2004). Airway conditions are controlled
by the autonomic nervous system. When attempting to pronounce a
word, one controls the palate movement, intentionally. To prevent swimming
apnea it is important for novice swimmers to acquire appropriate
breathing skills in their swimming skill progression.
conclusIon
In conclusion, it was verified that trained swimmers vary the amount
of air blown out of the nose and mouth, independently. In swimming,
to protect from apnea, blow out from nose and stop breathing, then
feel non water pressure in nostrils. After that, change the airway to the
mouth for large volume exhalation. This process is developed through
palate control. We find that to acquire this intentional airway control,
word pronouncing is appropriate.
reFerences
Amal MO, et al. (2004). Posthypoxic ventilatory decline during NREM
sleep: Influence of sleep apnea. J. Appl. Physiol., 96, 2220-2225
Hara H., et al. (1999). The development of measuring nasal pressure in
water, In Keskinen K., Komi P. & Hollander A.P. Biomechanics and
Medicine in Swimming VIII, 135-139
Hara H., Watanabe R, et al. (2003). A study on nasal pressure influenced
by swimming speed in breaststroke. In Chatard, J.C. Biomechanics and
Medicine in Swimming IX, 63-67
Hara H, et al. (2006). The function of nasal pressure for breathing in the
breaststroke. In Vilas-Boas J.P. Alves F. & Marques A. Biomechanics
and Medicine in Swimming X, 137-139
Thubone H., (1990). Nasal ‘pressure’ receptors. Jpn J Vet Sci, 52(2), 225-
232
Wheatly, JR., et al. (1991). Relationship between alae nasi activation
and breathing route during exercise in humans. J Appl Physiol, 71(1),
118-124
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AcKnoWledGeMents
The study was supported in part by Kokugakuin University, Specially
Promoted Research, 2007. We acknowledge the students at Kokugakuin
University and Kawasaki University of Medical Welfare for their participation
in this study.