A Simplified Method for Determination of Critical Swimming Velocity
as a Swimming Fatigue Index for Freestyle Sprinters and Distance
Swimmers
Shigehiro T AKAHASHI, Kohji W AKA YOSHI, Seigo NAGASA WA, Yuko SAKAGUCHI, Kaoru
KITAGAWA
Chukyo University,
Toyota, Japan
Shigehirot@aol. corn
Abstract
Critical swimming velocity (Veri) is recognized to be the swimming speed corresponding to the
maximal lactate steady state (MLSS), and it is expressed as the slope of a regression line between
swimming distances and their sustained times. The purpose of this study was to confirm that V cri
estimated by the swimming velocity for a distance of 300 m at maximal effort (Vcn-pred) shows
the MLSS. Eight sprinters (50 m and 100 m freestyle) and eight distance swimmers (400 m and
1500 m freestyle) participated in this study. In the MLSS, the subjects were instructed to swim
2500m (5 x 500 m) freestyle at three constant velocities (98.0 %, 100 %, 102% of Vcri·pred)
interrupted by four short rest periods of 30 to 40 s used for blood sampling. As a result, 100 %
ofVcri-pred showed a higher steady state than 98% ofVcri-pred. but 102% ofVcri-pred did not show
the steady state for sprinters and distance swimmers. In conclusion, one timed 300m maximal
effort swimming test is believed to be a simpler, more rational method to determine Vcri for both
sprinters and distance swimmers.
Key words: V cri• MLSS, Sprinters, Distance swimmers.
Introduction
Critical swimming velocity (V cri) has been utilized as an index for determining training speed
and evaluating endurance capacity in the field of competitive swimming. Veri has its origin in
critical power (Pen), which was defined by Monad and Scherrer (1965) as the intensity of
exercise which can be theoretically maintained and continued without exhaustion. They found a
linear relation between the total work done at each work rate and its duration for local muscular
exercise. Pcri was determined by the slope of the regression line based on the total work
performed and the corresponding time until exhaustion. Moritani et al. (1981) extended the
concept of Pcri to total body work performed on a cycle ergometer and found a significant
relationship between Pen and the ventilatory threshold. Wakayoshi et al. (1993) then applied the
concept of Pcri to the field of competitive swimming as the critical swimming velocity (V cri), and
showed that Veri corresponds to the maximal lactate steady state (MLSS). Moreover, Wakayoshi
et al. (1993) developed a two-trial test for the determination of Veri· This method, however,
requires the swimmer to swim a distance of 200 m and 400 m twice. In a previous study, we
investigated a simpler method using one timed swimming test to determine the Yen of freestyle
sprinters and distance swimmers, and both sprinters and distance swimmers showed significant
relationships between Veri and swimming velocities at distances over 300 m (V 300 ). The Veri of
sprinters and distance swimmers corresponded to 88.8 % and 91.3 %, respectively, of the
421
Shigehiro TAKAHASHI
velocity at maximal effort swimming at 300 m [Takahashi et al. (2002)]. The purpose of the
present study was to confirm that Veri estimated by V300 (Veri-prect) reflects the MLSS.
Methods
Subjects:
The subjects were eight male sprinters (50 m and 100 m freestyle specialists) and eight male
distance swimmers (400 m and 1500 m freestyle specialists). All subjects had more than six
years experience as competitive swimmers.
Determination of critical swimming velocity CVen):
The subjects were instructed to swim the distance of 300 m at maximal effort to determine Veri·
Another 2000 m swimming test at maximum effort (V 2ooo) which could be the swimming
velocity to be sustained at a MLSS was performed for comparison of V2000 with V eri-pred· The
time taken to swim each distance was measured.
Maximal lactate steady state test:
The swimmers were instructed to swim 2500 m (5 x 500 m) freestyle at three constant velocities
(98 %, 100%, 102% ofVeri-pred) interrupted by four short rest periods of30 to 40 s used for
blood sampling. Blood lactate concentration was determined in 20J.1l samples of capillary blood
taken from the fingertip before each trial, during the four rest periods, and immediately after,
and 3 and 5 min after each trial. Blood lactate was analyzed using an enzymatic membrane
analyzer [YSI, 1500 Sports, USA], which had been calibrated against a standard lactate
concentration. In order to swim 2500 m at three constant velocities, the subjects swam with a
swimming pace maker system [Takagi Co. PM3-103], which can lead subjects by signal lights
at a predetermined velocity.
Statistics:
Data are reported as mean values and standard deviation (SD). The relationships between
variables were examined by linear regression analysis. For all statistical analyses, the
significance level was set at p < 0.05.
Results
Table I shows the physical characteristics of subjects and the data obtained from the tests. The
V2000 and V 300 of sprinters were from 1.327 to 1.452 m.s- 1 and from 1.481 to 1.622 m.s- 1, with
mean values of 1.407±0.041 m.s- 1 and 1.566±0.039 m.s_I. These values for distance swimmers
were from 1.444 to 1.585 m.s- 1 and from 1.581 to 1.668 m.s-\ with mean of 1.507±0.046 m.s- 1
and 1.621±0.034 m.s- 1• These data showed that distance swimmers were faster than sprinters,
although the difference was not significant.
422
A simplified method for determination of critical swimming velocity
Table 1: The physical characteristics and test results for each subject.
m
~
liil
E-l
~
r:..
m
l":r;liJ'J.
C)~
~~
~~
t:IIJ'J.
Subjects
Age
(year)
S-1
S-2
S-3
S-4
S-5
S-6
S-7
S-8
Mean
SD
D-1
D-2
D-3
D-4
D-5
D-6
D-7
D-8
Mean
SD
20
20
20
20
20
19
19
19
19.6
0.5
22
20
20
19
19
19
19
19
19.6
1.1
Height
(cm)
180.5
179.0
177.2
169.2
165.2
182.0
173.0
171.9
174.8
5.9
173.8
178.1
178.0
178.0
175.5
171.5
178.0
171.0
175.5
3.0
Weight
(kg)
V2000
(m.s_l)
66.7
74.5
74.0
64.5
61.9
73.2
71.3
71.5
69.7
4.7
70.1
66.3
67.8
77.4
69.6
71.0
61.5
68.5
69.0
4.5
1.441
1.407
1.372
1.414
1.327
1.452
1.440
1.401
1.407
0.041
1.534
1.481
1.452
1.585
1.522
1.517
1.518
1.444
1.507
0.046
V300
(m.s-1)
1.573
1.575
1.559
1.580
1.481
1.622
1.574
1.565
1.566
0.039
1.668
1.590
1.582
1.657
1.622
1.627
1.643
1.581
1.621
0.034
Figure 1 illustrates the relationship between V2000 and Vcn-pred for sprinters and distance
swimmers. Both sprinters and distance swimmers showed significant relationships between
V2ooo and V cri-pred·
Figure 2 illustrates the changes in blood lactate concentration every 500 m at three constant
swimming velocities (98 %, I 00 %, 102 % of Vcri-pred)· At 100% of Vcri-pred for sprinters, blood
lactate concentration measured after 500 m showed an increase of0.6 mmol!l up to 2500 m. At
the low velocity (98% ofVcri·pred), blood lactate concentration remained at a steady level from
500 m to 2500 m.
423
Shigehiro TAKAHASHI
D JSTANCE SW :MMERS
SPR:NTERS
1<i5
~
OJ
Ill
......
.El.
1115
~
111
>
1<15
'g
•
.,
b
0
1<i
0
1<i
0
(1J
Ill
/:
1<3
1<30
"'~
"'"'. ""
111
>
y
1<35
1<3
1<35
11\[]
v2000
1~5
1<i0
1<iS
= 0 601x + 0 574
r= 0805 (p<005)
n=8
·~
= 0801 (p<OOSl
n=8
•
11!5
~--~~~~--~--~--~
1<10 1<35
160
On/sec}
1ll0 1ll5 HO 1<i5 160
V 2000
On
I sec)
Fig 1: The relationship between V 2000 and V cri-pred for sprinters and distance swimmers.
SPR:NTERS
DlSTANCE SW:MMERS
8
A'
~
7
a
b
0
.El.
5
~
4
~
3
.Cl
A' 8
7
>0
a
g
~
6
5
4
2
~ 3
'0 2
.Q
0
1
,q
ll\
0
"0
0
In
Rest 500m 1000m 1500m
2000m
2500m
2500m sw:imm.ing (500m x 5)
1
0
Rest SOD m 1000m 150Dm 21JDOm 2500m
2500m sw:imm.ing (,500m x5)
Fig 2: The relationship between blood lactate concentration and the distance of 500 m, 1000
m, 1500 m, 2000 m and 2500 m swam at three constant velocities of 98 %(a), 100 %( •) and
I 02 %( 4.) ofVcri-prect for maximal lactate steady state test of sprinters and distance swimmers.
However, the blood lactate concentration at 98 %of Vcri-pred was obviously lower than that at
100% ofVcri-pred· At the high velocity (102% ofVcri-prect), blood lactate showed a progressive
increase up to 2500 m, and was significantly higher than those at 98 % and 100 % of V cri-prect·
For distance swimmers, at both 98% and 100% ofVcn-prect blood lactate concentration remained
at an approximately steady level from 500 m to 2500 m. Blood lactate concentration at lOO% of
Vcri-pred was, however, higher than that at 98 % of V cri-prect at all times. At the high velocity (1 02
% of V cti-prect), blood lactate did not show a steady state.
424
A simplified method for determination of critical swimming velocity
Discussion
The purpose of this study was to determine whether the Veri estimated by V300 (Vcri-pred) reflects
the MLSS. Olbrecht et al. (1985) reported that the swimming speed at 4 mmol/1 of blood lactate
concentration as determined by the two-speed test was highly correlated with performance in a
30 min swimming event. Wakayoshi et al. (1993) found that blood lactate concentration during
1600 m (4 x 400 m) continuous swimming at Veri showed MLSS. These reports suggest that the
Vcri-pred obtained in this study corresponds to the velocity of MLSS, because a significant
relationship was found between V 2000 and Vcri-pred for sprinters and distance swimmers. To
confirm that Vcri-pred reflects the MLSS, the subjects were instructed to swim 2500 m at the three
constant velocities (98 %, 100 %, 102 % of V cri-preJ). As a result, it was found that 100 % of V cri·
pred showed a higher steady state than 98 % of Vcri-pred, but 102 % of Vcri-pred did not show a
steady state for either sprinters or distance swimmers. The evaluated blood lactate plateau
during exercise at fixed power output indicates the anaerobic threshold and, at such an intensity,
the relationship between lactate production and elimination would be in dynamic equilibrium.
Heck et al. (1985) defmed MLSS as the highest blood lactate concentration increasing by no
more than 1. 0 mmol/1 within the last 20 min of constant workload. Foilowing this definition, an
increase of 0.6 mmol/1 in blood lactate concentration at 100% ofVcri-pred for sptinters would be
accepted as the MLSS. Blood lactate concentrations at MLSS for sprinters and distance
swinuners in this study were 2.7 mmol/1 and 2.9 mmol/1, respectively. These values, however,
are lower than in a previous study. Beneke et al. (1996) concluded that differences in the level of
MLSS between rowing, cycling, and speed skating do not seem to correspond to the testing
procedure, different levels of workload intensity, or the specific metabolic profile of the sports
event. Stegntann et al. (1982) showed that only 4 subjects completed 30 min continuous
exercise at an intensity corresponding to that at 4.0 nm1ol/l. Among swinuners, Martin and
Whyte (2000) showed a MLSS of 3.0 mmol/1 for elite triathletes. Wakayoshi et al. (1993) also
showed a mean MLSS of 3.2 mmol/1 for 8 male swinmiers. These results were similar to the
results of the present study. Therefore, the cause of the difference may be the metabolic profiles
or the motor pattern of swimming. In conclusion, it was found that 100 % of V cri-pred
corresponded to the exercise intensity at MLSS. Thus, the present results suggest that one timed
300 m maximal effort swimming test is a simpler, more efficient method to detemiine Veri for
both sprinters and distance swimmers.
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425
Shigehiro TAKAHASHI
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