The aim of this study was: (1) to assess the energy cost of swimming (Cs, kJ km-1) in a group of male (n=5) and female (n=5) elite swimmers specialised in long-distance competitions; (2) to evaluate the possible effect of a 2-km trial on the absolute value of Cs. Cs was assessed during three consecutive 400-m trials covered in a 50-m pool at increasing speeds (v1, v2, v3). After these experiments the subjects swam a 2-km trial at the 10-km race speed (v2km) after which the three 400-m trials were repeated at the same speed as before (v5=v1, v6=v2, v7=v3). Cs was calculated by dividing the net oxygen uptake at steady state ðV_ O2ssÞ by the corresponding average speed (v, m s1). V_ O2ss was estimated by using back extrapolation technique from breath-to-breath VO2 recorded during the first 30 s of recovery after each test. Cs increased (from 0.69 kJ m1 to 1.27 kJ m1) as a function of v (from 1.29 m s1 to 1.50 m s1), its values being comparable to those measured in elite short distance swimmers at similar speeds. In both groups of subjects the speed maintained during the 2-km trial (v2km) was on the average only 1.2% faster than of v2 and v6 (P>0.05), whereas Cs assessed at the end of the 2-km trial (v2km) turned out to be 21±26% larger than that assessed at v2 and v6 (P<0.05); the average stroke frequency (SF, cycles min1) during the 2-km trial turned to be about 6% (P<0.05) faster than that assessed at v2 and v6. At v5, Cs turned out to be 19±9% (P<0.05) and 22±27% (0.1<P=0.05) larger than at v1 in male and female subjects (respectively). SF was significantly faster (P<0.05, in male subjects) and the distance per stroke (Ds=v/SF) significantly shorter (P<0.05) in female subjects at v5 and v6 than at v1 and v2. These data suggest that the increase of Cs found after the 2-km trial was likely related to a decrease in propelling efficiency, since the latter is related to the distance per stroke.

Zamparo, P., Bonifazi, M., Faina, M., Milan, F., Sardella, F., Schena, F., et al. (2005). The energy cost of swimming of élite long distance swimmers. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 94, 697-704 [10.1007/s00421-005-1337-0].

The energy cost of swimming of élite long distance swimmers

BONIFAZI, MARCO;
2005

Abstract

The aim of this study was: (1) to assess the energy cost of swimming (Cs, kJ km-1) in a group of male (n=5) and female (n=5) elite swimmers specialised in long-distance competitions; (2) to evaluate the possible effect of a 2-km trial on the absolute value of Cs. Cs was assessed during three consecutive 400-m trials covered in a 50-m pool at increasing speeds (v1, v2, v3). After these experiments the subjects swam a 2-km trial at the 10-km race speed (v2km) after which the three 400-m trials were repeated at the same speed as before (v5=v1, v6=v2, v7=v3). Cs was calculated by dividing the net oxygen uptake at steady state ðV_ O2ssÞ by the corresponding average speed (v, m s1). V_ O2ss was estimated by using back extrapolation technique from breath-to-breath VO2 recorded during the first 30 s of recovery after each test. Cs increased (from 0.69 kJ m1 to 1.27 kJ m1) as a function of v (from 1.29 m s1 to 1.50 m s1), its values being comparable to those measured in elite short distance swimmers at similar speeds. In both groups of subjects the speed maintained during the 2-km trial (v2km) was on the average only 1.2% faster than of v2 and v6 (P>0.05), whereas Cs assessed at the end of the 2-km trial (v2km) turned out to be 21±26% larger than that assessed at v2 and v6 (P<0.05); the average stroke frequency (SF, cycles min1) during the 2-km trial turned to be about 6% (P<0.05) faster than that assessed at v2 and v6. At v5, Cs turned out to be 19±9% (P<0.05) and 22±27% (0.1
Zamparo, P., Bonifazi, M., Faina, M., Milan, F., Sardella, F., Schena, F., et al. (2005). The energy cost of swimming of élite long distance swimmers. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 94, 697-704 [10.1007/s00421-005-1337-0].
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11365/28696
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