Biomechanics and Medicine in Swimming XI

0-m
*
A: adult
5
Horton, 2001). A reduced carbohydrate utilisation may decrease the
[La] levels in females compared to males exercising at the same relative
intensity (Deschenes et al., 2006). The relative intensity in the present
study (96% of 400 m velocity) was similar to previous studies calculating
the CV with the same combination of distances in males (Filipatou
et al., 2006). It is also important to note that the time to complete each
distance is shorter in male swimmers than female swimmers while using
the same distances for CV calculation. This may underestimate the
slope of the distance vs. time relationship, while the lower [La] may
overestimate the boundary between moderate and severe exercise intensity
domains for females. Thus, it may be easier for female swimmers
to complete a series of repetitions at this velocity since they swim with
decreased metabolic stress. As a consequence, a steady [La] during the
5x400 or 5x300 m repetitions was evident.
Blood lactate (mmol*L -1 )
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
C: children Y: young A: adult
rest 1 2 3 4 5
Repetitions of 300 or 400-m
Figure 2. Blood lactate responses of each group during the 5x300 or
5x400 m repetitions.
RPE
RPE / La ratio
10
9
8
7
6
5
4
3
2
1
0
6
5
4
3
2
1
0
3B
3A
*
*
C: chlildren Y: young A: adult
1 2 3 4 5
Repetitions of 300 or 400-m
*
1 2 3 4 5
Repetitions of 300 or 400-m
*
*
*
C: chlildren
Y: young
A: adult
*
RPE / La ratio
Figure 3. The RPE changes (3A) and RPE to [La] ratio (3B) during the
5x300 or 5x400 m repetitions. * p8 in the 10-point scale). It is interesting to note that eight
of the swimmers (four in the C group) reached “maximal” values in the
RPE scale. Increased RPE to [La] ratio after the third repetition may
be a sign of fatigue caused by the exercise duration when the intensity
remains constant.
conclusIon
Critical velocity calculated by slope of the distance vs. time relationship
using distances of 50, 100, 200, 400 m, can be sustained during intermittent
swimming for 28 to 31 minutes in female swimmers of eleven to
nineteen years of age. Irrespective of the age-group, female swimmers
display steady-state and similar blood lactate responses during intermittent
swimming at a velocity corresponding to critical velocity, and this is
in contrast to previous findings in male swimmers.
301