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Eur J Appl Physiol (1992) 64:153-157 
European um,= App l ied 
Phys io logy 
and Occupational Physiology 
@ Spdnger-Verlag 1992 
Determination and validity of critical velocity 
as an index of swimming performance in the competitive swimmer 
Kohji Wakayoshi 1, Komei Ikuta ~, Takayoshi Yoshida 2, Masao Udo 2, Toshio Moritani 3, Yoshiteru _N'hltoh 4, and 
Mitsumasa Miyashita 4 
Laboratory of Motor Behavioral Education, and 
2 Laboratory of Exercise Physiology, Faculty of Health and Sport Sciences, Osaka University, Toyonaka, Osaka 560, Japan 
3 Laboratory of Applied Physiology, College of Liberal Arts and Sciences, Kyoto University, Kyoto 606, Japan 
4 Laboratory for Exercise Physiology, Biomechanics and Sports Sciences, University of Tokyo, Tokyo 113, Japan 
Accepted September 16, 1991 
Summary. The purpose of this investigation was to test 
whether the concept of critical power used in previous 
studies could be applied to the field of competitive 
swimming as critical swimming velocity (V~rit). The Vor~t, 
defined as the swimming velocity over a very long pe- 
riod of time without exhaustion, was expressed as the 
slope of a straight line between swimming distance 
(dlim) at each speed (with six predetermined speeds) 
and the duration (him). Nine trained college swimmers 
underwent tests in a swimming flume to measure/)crit at 
those velocities until the onset of fatigue. A regression 
analysis of d~m on t~.~ calculated for each swimmer 
showed linear relationships (r 2 > 0.998, P< 0.01), and 
the slope coefficient signifying v=it ranged from 1.062 
to 1.262 m.s -a with a mean of 1.166 (SD 0.052) 
m. s -a. Maximal oxygen consumption (1202max), oxy- 
gen consumption (VO2) at anaerobic threshold, and the 
swimming also velocity at the onset of blood lactate ac- 
cumulation (VoBLA) were also determined during the in- 
cremental swimming test. The Vor~t showed significant 
positive correlations with 1202 at anaerobic threshold 
(r = 0.818, P< 0.01), VOBLA (r= 0.949, P< 0.01) and mean 
velocity of 400m freestyle (r=0.864, P<0.01). These 
data suggested that Ucrit could be adopted as an index of 
endurance performance in competitive swimmers. 
Key words: Competitive swimming--Critical swim- 
ming velocity -- Onset of blood lactate accumulation -- 
Maximal oxygen consumption 
Introduction 
Performance capacity has separate aerobic and anae- 
robic components which can be evaluated by measure- 
ment of maximal oxygen uptake (1202 max) and maximal 
oxygen debt, respectively. In competitive swimming, 
race distances range from 50 m to 1,500 m, the former 
primarily dependent on anaerobic, and the latter on 
Offprint requests to: K. Wakayoshi 
aerobic capacity. Therefore each swimmer has to de- 
velop his performance by a programme which optim- 
ises the combination of aerobic and anaerobic training 
to correspond to his race distance and time. 
Recently numerous studies have revealed a high cor- 
relation between swimming or running velocity at anae- 
robic threshold (AT) and endurance performance 
(Allen et al. 1985; Arabas et al. 1987; Farrell et al. 1979; 
Kumagai et al. 1983; Olbrecht et al. 1985; Sawka et al. 
1979; Tanaka et al. 1984, 1985; Yoshida et al. 1987). 
Furthermore, swimming velocity at 4 retool-1-1 of 
blood lactate concentration has been used as an impor- 
tant criterion of training intensity for competitive swim- 
ming (Madsen and Lohberg 1987; Maglischo et al. 
1982; Skinner 1987). 
Monod and Sherrer (1965) have found linear rela- 
tionship between the total work done at each rate and 
its duration during local muscular exercise. They de- 
fined critical power (Worit) as the intensity of exercise 
which could be maintained for a very long time without 
exhaustion. The Wcrit was equivalent to the slope of the 
regression of total work and time until exhaustion. Mo- 
ritani et al. (1981) applied the concept of Wcrit to total 
body work performing cycle ergometry and found a 
strong relationship between Wcrit at AT as determined 
by the gas exchange method (r= 0.928, P< 0.01). 
Moreover, W~rit calculated by the same method as 
that of Moritani et al. (1981) was highly correlated with 
fatigue threshold as estimated from electromyographic 
data and AT, respectively (de Vries et al. 1982; Nagata 
et al. 1983). Recently, Jenkins and Quigley (1990) have 
shown that Worit calculated using cycle ergometry pro- 
vided a simple and inexpensive means for assessing the 
exercise intensity which can be maintained continuous- 
ly, while avoiding the methodological difficulties asso- 
ciated with ventilatory and lactate thresholds. From 
this it could follow that the concept of W~rit may be 
used to assess the aerobic capacity in competitive swim- 
mers. However, no study has as yet shown the validity 
of Worst in competitive swimming. 
In the present study, critical velocity (VCrit) has been 
defined, based upon W~r~t, as the speed which could 
154 
theoret i ca l l y be mainta ined w i thout exhaust ion dur ing 
runn ing or sw imming . The purpose o f this invest igat ion 
was to eva luate whether Ucrit cou ld prov ice a non inva- 
sive method for es t imat ing sw imming per fo rmance in 
compet i t i ve sw immers . 
Methods 
Subjects. Nine male trained college swimmers (18-21 years) vo- 
lunteered for this study. Seven subjects specialised in freestyle 
(short and middle distance: n=3, and long distance: n=l ) and 
two subjects specialised in the individual medley. Each subject 
signed a statement of informed consent. 
Swimming flume and protocol. All swimming tests were performed 
in a specially designed swimming flume similar to that of Astrand 
and Englesson (1972) and Nomura (1982) in which water could be 
circulated in a deep loop by a motor-driven propeller providing a 
velocity from 0 to 3.0 m • s -1 with increments of 0.01 m - s-1 (Iga- 
rashi Co., Ltd, Tokyo, Japan). The dimensions of the swimming 
area were 6.0 m long, 2.5 m wide and 1.5 m deep. The water and 
the indoor ambient temperatures were 25-26 ° C and 24-25 ° C, re- 
spectively. 
The swimming speed of the incremental exercise test started at 
0.75 m • s - i and, increased thereafter by 0.05 m • s- ~ every minute 
until the limit of the subject's tolerance was reached. 
A T and 1202 max" During the incremental exercise test, the subjects 
breathed through a low resistance valve assembly. Expired gas 
was analysed every 30 s with Mijnhardt Oxycon System (Type 
OX-4) for measurements of oxygen uptake (VO2), carbon dioxide 
output (I?CO2) and minute ventilation (IRE). 
The determination of AT was made during the incremental ex- 
ercise test using gas exchange parameters (Davis et al. 1976; 
Wasserman et al. 1973) summarized as follows: 
1. The po!nt of departure from linearity in the relationship be- 
tween VE and VCO2 
2. Abrupt increase of fractional concentration of expired oxygen 
3. Abrupt increase in respiratory exchange ratio (R) 
4. A systematic increase in the 12z/1202 without any increase in 
VE : VCO 2 . 
The highest I;'O2 value obtained during the incremental exercise 
test was recorded as I202 . . . . 
Protocol for Ocrit determination. Figure 1 illustrates the determina- 
tion (subject 6) of v¢~it based upon the concept of Wcrit (Monod 
and Scherrer 1965; Moritani et al. 1981). In the present paper, v¢~t 
has been defined as the swimming speed which could theoreti- 
cally be maintained without fatigue. 
When a subject swims at a steady speed in the swimming 
flume, exercise usually ceases at a fairly well-defined point, i.e. 
the subject can no longer keep up the predetermined swimming 
speed. The steady swimming speeds employed in the present 
study were six steps of 1.2, 1.3, 1.4, 1.5, 1.6 and 1.7 m • s -1 (one 
subject used only from 1.1 to 1.6 m • s-l). The lowest swimming 
speed was
set as the exercise intensity at which each subject could 
continue to swim longer than 5 min. The end-point was marked 
by a line placed 90 ° to the water flow, 3 m behind the head posi- 
tion at which the subject began to swim. Rest periods of at least 
30 rain between the test periods were allowed. 
For each test, the swimming velocity (v) of the swimming 
flume multiplied by swimming time (tli~) until the subject could 
no longer maintain his speed equalled the swimming distance 
(d t im) : 
d l im = t3 X t l im (1 ) 
'03 
0 
0 
1.7 
1.6 
1.5 
1.4 
1.3 
~ 1.2 ~"Critical velocity 
1.1 . . . . . 
0 200 
1000 
- - - - o 
i , , i , , _ _ 
400 300 800 
y = 17.503+1.1808x 
800 r 2= 1.000 
£ p < 0 
o 600 
0 
400 
rq 
0 200 400 600 800 
Time (s) 
Fig. 1. Relationship between predetermined swimming velocity 
and time for which that velocity could be maintained (him) and 
between swimming distance and tlim plotted from the data of sub- 
ject 6 
In the lower part of Fig. 1, dum obtained from five different 
swimming speeds was plotted as a function of hi~. Those points 
were accurately situated on a line defining the relationship be- 
tween dlim and tlim. 
The equation of the regression line could be expressed as fol- 
lows: 
dlim = a + b × tli m (2) 
dlim can be substituted by v x tlim from Eq. 1, giving: 
v x him = a + b x tu~ (3) 
v = a/him + b (4) 
Theoretically, if we were to set v at a level which could be 
performed indefinitely (tUm~ ~), a/h~m would approach zero and 
v would approach b. 
Therefore, vcrit could be expressed as the slope of the regres- 
sion line: 
vorit=b (5) 
Blood lactate tests and determination of the onset of blood lactate 
accumulation. The onset of blood lactate accumulation (OBLA) 
has been selected as an index for blood lactate accumulation and 
used for evaluating endurance (Heck et aL 1985). In the present 
study, OBLA was calculated as the swimming velocity at which 
the blood lactate concentration reached a value of 4 mmol - 1-1 
(VOBLA, Karlsson et al. 1984; Olbrecht et al. 1985; Yoshida et al. 
1987, 1989, 1990). 
For this purpose, the venous blood samples were taken at the 
end of each of the five stages of the incremental swimming test to 
determine the OBLA of each individual and the corresponding 
swimming speed (VoBLA). The subjects swam for 4 min at speeds 
of 95%, 97.5%, 100%, 102.5% and 105% of v~r~t. Rest periods longer 
than 20 rain were provided between test periods. Arterialized ca- 
pillary blood was taken from the finger tip before, immediately 
after, and 3 and 5 min after each test period. Blood lactate con- 
Table 1. Physical characteristics, performance and test results for each subject 
No. Subject Age Height Mass Speci- 400 m l?O2~,x VO2,AT /)OBLA /)crit r2 
(years) (cm) (kg) ality (m.s -1) (ml.lg-l-min -1) (ml.kg-l'min -1 (m.s -1) (m's -1) (dlim vs tlim) 
155 
1 MU 20 173.5 74.3 FR-S 1.368 53.5 33.3 1.092 1.062 0.999 
2 TT 20 173.5 66.4 FR-S 1.533 52.5 38.0 1.140 1.140 0.999 
3 YF 21 180.6 73.2 FR-S 1.556 55.3 37.5 1.144 1.156 1.000 
4 SH 19 174.5 71.9 FR-M 1.615 68.1 40.9 1.158 1.174 0.999 
5 TS 21 175.1 77.2 FR-M 1.547 49.4 36.3 1.175 1.170 1.000 
6 ET 20 171.0 58.5 FR-M 1.554 68.4 41.9 1.160 1.181 1.000 
7 TS 19 175.0 63.3 FR-L 1.609 58.3 44.7 1.227 1.262 0.999 
8 YT 20 174.0 67.9 IM 1.543 58.2 39.3 1.174 1.176 0.999 
9 SY 21 173.1 71.1 IM 1.540 56.2 35.0 1.191 1.173 1.000 
Mean 20.1 174.5 69.3 1.541 57.8 38.5 1.162 1.166 0.999 
SD 0.8 2.6 5.9 0.071 6.6 3.6 0.037 0.052 0.001 
FR, Freestyle (S, 50 m and 100 m; M, 200 m and 400 m; L, 400 m 
and 1,500 .m); IM, individual medley; 400 m,. velocity of 400 m 
freestyle; VO2 .... maximal oxygen uptake; VO2.AT, oxygen up- 
take at anaerobic threshold; /)OBLA, swimming velocity at 4 
mmol• 1 - ~ of blood lactate accumulation; v~t, critical velocity 
centrations were determined by an enzymatic membrane method 
(HER-100, Toyobo Co., Ltd., Tokyo, Japan), which had been 
calibrated against a standard concentration of lactate solu- 
tion. 
Results 
Table 1 shows the physical characteristics, style special- 
ity, performance and data obtained from the tests in the 
present study. As will be seen the subjects in the pres- 
ent study were relatively homogeneous with regard to 
their swimming performance, having a coefficient var- 
iation of 3.8% for a mean velocity of 400 m (V4oo), al- 
though that of 1.368 m. s -1 (subject 1) was somewhat 
less than the others. 
The l?Ozm~x for these nine subjects ranged from 49.4 
to 68.4 ml • kg -1 • min -a with a mean of 57.8 (SD 6.6) 
ml . kg -1 . min-1. The I?O2 achieved by these subjects 
at AT (I?O~,AT) ranged from 33.3 to 44.7 
ml .kg -a .min -1 with a mean of 38.5 (SD 3.6) 
ml • kg - ~ • min - 1. 
Figure 2 illustrates the relationship between blood 
lactate concentration and VOBLA. Four out of nine sub- 
8.0 
E 
E 6.0 
4.0 
-0 
0 
0 
m 2.0 
I 
, i , f , i I 
1.10 1,20 1.30 
Swimming velocity (m. s 1) 
Fig. 2. Relationship between blood lactate concentration and 
swimming velocity at 95%, 97.5%, 100%, 102.5% and 105% critical 
swimming velocity with each swimmer expressed by a different 
symbol 
jects could not continue to swim at the highest exercise 
intensity over the full 4 rain. This may have led to an 
underestimation of lactate concentrations at the highest 
exercise intensity. The VOBLA ranged from 1.092 to 1.227 
m- s -a with a mean of 1.162 (SD 0.037) m. s -1. 
The experimental plots used to determine Ucrit oF 
subject 6 are shown in Fig. 1 as an example, The regres- 
sion equations relating dlim with him were expressed in 
the general form, dlim = a + b x tlim, with r 2 value (good- 
ness of fit) above 0.999 (P< 0.01). The results indicated 
extremely good linearity regardless of time spent until 
exhaustion. The slope coefficient (b) signifying vorit (see 
Fig. 1) ranged from 1.062 to 1.262 m. s - I with a mean 
of 1.166 (SD 0.052) m-s -1. The average him ranged 
from 26.0 (SD 4.0) s for the highest speed to 497.2 (SD 
141.9) s for the lowest. This range of fiim was similar to 
Worit data measured by Moritani et al. (1981). Subject 7 
who was a specialist in 1,500 m freestyle was able to 
continue to swim at a speed of 1.2 m • s - I for longer 
than 30 min without exhaustion, and had to be in- 
structed to stop. Therefore, his vcrit was calculated from 
tlim at five speeds higher than 1.2 m • s - ] 
Results presented in F!g. 3 show the relationship be- 
tween v~tit and VO2 . . . . VO2,AT , UOBLA and/)400. Signifi- 
cant positive correlations were found between VO~oAT 
and v~it (r=0.818, P<0.01), VOBLA and v~rit (r=0.949, 
P< 0.01) and/)4oo and Vcrit ( r= 0.865, P< 0.01). However, 
there was no significant correlation between VOzmax 
and V4oo (r=0.437, P>0.05), and l?O2m,x and v~rit 
(r = 0.318, P> 0.05). On the other hand, the relationship 
between V4oo and VO2,AT, and that between /)400 and 
VOBLA (not shown in the figure, and the table in this pa- 
per) were significant (/)4oo) vs VOz.AT; r= 0.750, P< 0.05, 
V4oo vs VOBLA; r----0.763, P<0.05). 
Discussion 
The primary goal of this study was to apply the concept 
of Wcr i t formulated by Monod and Scherrer (1965) and 
Moritani et al. (1981) to vcrit, i.e. the velocity that swim- 
156 
~ 70 "7 c- 
"7 60 
U~ 
E 
~ 50 
E 
.> 40 
c- 44 
c~ 40 
E ~ 36 
© 32 .> 
A 
y = 10.68+40.38x r 2 = 0.101 
NS 
1.1 1.2 1.3 
Critical velocity (m. s -1) 
y = -27.48 + 56.62x .~ 
B r2= 0.670 J 
p < 0.05 . / ~ 
, f 
1.1 1.2 1.3 
Critical velocity (m. s -1) 
1.3 
'03 1.2 
E 
v 
.< 
d 1.1 
o 
> 
1.0 
1.7 
~ 1.6 
O3 
E 1.5 v 
8 
>~ 1.4 
1.3 
C 
+ 0.686x 
J r2= 0.901 
p < 0.0I 
q i 
1.1 1.2 
Criticat velocity (m.
s -1) 
° 
e~ry2~= 0.3475 + 1.195x 
0.749 
p < 0.01 
, t 
1.1 1.2 
Critical velocity (m-s -1) 
.3 
Fig. 3. Relationship between 
maximal oxygen consumption 
(12OEm,x) (A), oxygen consump- 
tion at anaerobic threshold 
(I?O2,AT) (B), swimming velocity 
at onset of blood accumulation 
(VoaLg) (C), a mean velocity of 
400 m (v400) (D) and critical 
swimming velocity 
mers can maintain without exhaustion. We used six 
swimming speeds to calculate vcrit for each subject in 
the flume. A strong correlation between dlim and tlirn 
(r 2 > 0.998) was found for every subject, so that the rela- 
tionship d~m = a+b x tlim, was remarkably linear (Fig. 
1). Thus, it was possible to apply the concept of/)crit to 
swimming by substituting d~m and tlim in the equation 
(Wli m ~---a+ b x tlim) which was used to measure Wcrit in 
cycle ergometry (Moritani et al. 1981; Jenkins and 
Quigley 1990). 
The concept of AT rests on the notion that during 
sufficiently heavy exercise, the ability of the circulation 
to supply 02 may not be adequate to meet the meta- 
bolic 02 requirement of the muscles and, as a conse- 
quence, the aerobic energy supply is supplemented 
from the energy reserves available via anaerobic glyco- 
lysis with subsequent lactate accumulation (Davis et al. 
1976). Moritani et al. (1981) have reported that the 
physiological significance of AT and Wcrit may well be 
similar since there was no signfiicant difference be- 
tween 1202,AT and Wcrit" 1202 and a high correlation 
between these two variables. Furthermore, Jenkins and 
Quigley (1990) have recently demonstrated that Wcrit 
was equivalent (with an error of only a few percent) to 
the maximal exercise intensity which can be maintained 
for up to 30 min. These data, together with the present 
finding of significant positive correlations between v~r~t 
and VO2.A-r, /3crit and VOBLA, and Pcrit and V4oo, seems to 
support the assumption that v~rit in the present study 
could be adopted as an index indicating swimming per- 
formance. 
Recently, numerous studies have found that blood 
lactate variables such as lactate threshold or OBLA ac- 
count for a large part of the variation in endurance per- 
formance. In fact, VOBLA calculated mathematically for 
each swimmer has been found to appraise performance 
and to establish training intensities (Maglischo et al. 
1982; Skinner 1987). Furthermore, Olbrecht et al. 
(1985) have reported that the relationship between 
blood lactate concentration and v could be understood 
better if it were based on the results from the two-speed 
test (Mader et al. 1980). In the previous studies re- 
ported by Costill et al. (1985) and Ribeiro et al. (1990), 
there was little correlation between 1202max and per- 
formance in front crawl swimming over 365.8 m and 
400 m. In the present study, an insignificant correlation 
between V4oo and VO2 . . . . and a significant correlation 
between V40o and VOBLA support their results. Further- 
more, a significant correlation was found between V4oo 
and VOz, Aa" as this parameter has a close physiological 
link with OBLA, suggesting that muscle respiratory ca- 
pacity is of primary importance in determining the ex- 
ercise intensity at which blood lactate begins to in- 
crease rapidly (Ivy et al. 1980). 
Our finding, i.e. significant correlation between 
VOBLA and V40o, is consistent with previous studies of 
male distance runners, indicating the importance of 
blood lactate variables in achieving success (Allen et al. 
1985; Farrell et al. 1979; Kumagai et al. 1983; Tanaka 
et al. 1984, 1985). Moreover, using untrained women, 
Yoshida (1986) and Yoshida et al. (1987) have sug- 
gested that lactate variables may be more useful indices 
for endurance performance than other variables such as 
I202 . . . . the step test score, and predicted physical 
work capacity at a heart rate of 170 beats • min -1. 
Blood lactate concentration at a v of 100% vcrit for 
4min in the lactate test ranged from 3.4 to 5.1 
mmol-1-1 with a mean of 4.23 (SD 0.67) mmol. 1-1. 
This value agrees with the previous report by Heck et 
al. (1985), who have described that a maximal lactate 
steady-state, which has been defined as a maximal 
value of blood lactate without a sustained increase dur- 
ing exercise, was found at a lactate concentration value 
of 4.02 (SD 0.7) mmol. 1-1. However, it has been diffi- 
cult to determine blood lactate concentration after peri- 
ods of swimming training, because the athletes and 
157 
coaches have tended to refuse to allow blood to be 
sampled. The /)crit of this noninvasive method for esti- 
mating aerobic performance could therefore be used as 
a practical and useful measurement. 
In conclusion, it was found that the concept o f Wcrit 
could be appl ied to competitive swimming, and Ucrit ob- 
tained by this simple and inexpensive method could be 
adopted as an index for indicating swimming perform- 
ance. This investigation, however, has been done using 
a swimming flume. I f the concept of v~it could be ad- 
opted by using not only a swimming flume, but also a 
normal swimming pool, coaches and the swimmers 
could easily f ind a valuable index for assessing aerobic 
performance without employing highly expensive 
equipment. 
Acknowledgement: This work has been supported in part by a 
Grant-in-Aid from the Japanese Ministry of Education, Science 
and Culture (no. 02780110). 
References 
Allen WK, Seals DR, Hurley B, Ehsani AA, Hagberg JM (1985) 
Lactate threshold and distance running performance in young 
and old endurance athletes. J Appl Physiol 58:1281-1284 
Arabas C, Mayhew L, Hudgins PM, Bond GH (1987) Relation- 
ships among work rates, heart rates, and blood lactate levels in 
female swimmers. J Sports Med 27:291-295 
,~strand PO, Englesson B (1972) A swimming flume. J Appl Phy- 
siol 33:514 
Costill DL, Kovaleski D, Porter D, Kirwan J, Fielding R, King D 
(1985) Energy expenditure during front crawl swimming: pre- 
dicting success in middle-distance events. Int J Sports Med 
6: 266-270 
Davis JA, Vodak P, Wilmore JH, Vodak J, Kurtz P (1976) Anae- 
robic threshold and maximal aerobic power for three modes of 
exercise. J Appl Physiol 4t:544-550 
de Vries HA, Moritani T, Nagata A, Magnussen K (1982) The re- 
lation between critical power and neuromuscular fatigue as es- 
timated from electromyographic data. Ergonomics 25:783- 
791 
Farrell PA, Wilmore JH, Coyle EF, Billing JE, Costill DL (1979) 
Plasma lactate accumulation and distance running. Med Sci 
Sports Exerc 11:338-344 
Heck H, Mader A, Hess G, Mucke S, Muller R, Hollmann W 
(1985) Justification of the 4-retool/1 lactate threshold. Int J 
Sports Med 6:117-130 
Ivy JL, Withers RT, Van Handel PJ, Elger DH, Costilt DL (1980) 
Muscle respiratory capacity and fiber type as determinants of 
the lactate threshold. J Appl Physiol 48:523-527 
Jenkins DG, Quigley BM (1990) Blood lactate in trained cyclists 
during cycle ergometry at critical power. Eur J Appl Physiol 
61:278-283 
Karlsson J, Holmgren A, Linnarson D, Astrom H (1984) OBLA 
exercise stress testing in health and disease. In: Lollgan L, 
Mellerowicz H (eds) Progress in ergometry: quality control 
and test criteria. Springer, Berlin Heidelberg New York, pp 
67-91 
Kumagai S, Tanaka K, Matsuura Y, Matsuzaka A, Hirakoba K, 
Asano K (1983) Relationships of anaerobic threshold and the 
onset of blood lactate accumulation with endurance perform- 
ance. Eur J Appl Physiol 52:51-56 
Mader A, Madsen O, Hollmann W (1980) Zur Beurteilung der 
laktaziden Energiebereitstellung f~r Trainings- und Wett- 
kampfleistungen im Sportschwimmen. Leistungssport 10:263- 
268 
Madsen O, Lohberg M (1987) The lowdown on lactates. Swim- 
ming Techn 24:21-26 
Maglischo EW, Maglischo CW, Bishop RA (1982) Lactate testing 
for training pace. Swimming Techn
19:31-37 
Monod H, Scherrer J (1965) The work capacity of a synergic mus- 
cular group. Ergonomics 8:329-337 
Moritani T, Nagata A, de Vries HA, Muro M (1981) Critical 
power as a measure of physical work capacity and anaerobic 
threshold. Ergonomics 24:339-350 
Nagata A, Moritani T, Muro M (1983) Critical power as a meas- 
ure of muscular fatigue and anaerobic threshold. In: Matsui 
H, Kobayashi K (eds) Biomechanics VIIIA. Human Kinetics, 
Champaign, IlL, pp 312-320 
Nomura T (1982) The influence of training and age on l?O2max 
during swimming in Japanese elite age group and olympic 
swimmers. In: Hollander AP, Huijing PA, Groot GD (eds) 
Biomechanics and medicine in swimming 14. Human Kinetics, 
Champaign, Ill., pp 251-257 
Olbrecht J, Madsen O, Mader A, Liesen H, Hollmann W (1985) 
Relationship between swimming velocity and lactic concentra- 
tion during continuous and intermittent training exercises. Int 
J Sports Med 6:74-77 
Ribeiro JP, Cadavid E, Baena J, Monsalvete E, Barna A, De Rose 
EH (1990) Metabolic predictors of middle-distance swimming 
performance. Br J Sports Med 24:196-200 
Sawka MN, Knowlton RG, Miles DS, Critz JB (1979) Postcompe- 
tition blood lactate concentrations in collegiate swimmers. Eur 
J Appl Physiol 41:93-99 
Skinner J (1987) The new, metal-plated assistant coach. Swim- 
ming Technique 24:7-12 
Tanaka K, Matsuura Y, Matsuzaka A, Hirakoba K, Kumagai S, 
Sun-O S, Asano K (1984) A longitudinal assessment of anae- 
robic threshold and distance running performance. Med Sci 
Sports Exerc 16:278-282 
Tanaka K, Nakazawa T, Hazama T, Matsuura Y, Asano K (1985) 
A prediction equation for indirect assessment of anaerobic 
threshold in male distance runners. Eur J Appl Physiol 
54:386-390 
Wasserman K, Whipp BJ, Koyal SN, Beaver ML (1973) Anae- 
robic threshold and respiratory gas exchange during exercise. 
J Appl Physiol 35:236-243 
Yoshida T (1986) Relationship of lactate threshold and onset of 
blood lactate accumulation as determinants of endurance abil- 
ity in untrained females. Ann Physiol Anthropo] 5:205-209 
Yoshida T, Chida M, Ichioka M, Suda Y (1987) Blood lactate pa- 
rameters related to aerobic capacity and endurance perform- 
ance. Eur J Appl Physiol 56:7-11 
Yoshida T, Udo M, Iwai K, Muraoka I, Tamaki K, Yamaguchi T, 
Chida M (1989) Physiological determinants of race walking 
performance on female race walkers. Br J Sports Med 23: 250- 
254 
Yoshida T, Udo M, Iwai K, Chida M, Ichioka M, Nakadomo F, 
Yamaguchi T (1990) Significance of the contribution of aero- 
bic and anaerobic components to several distance running per- 
formances in females athletes. Eur J Appl Physiol 60:249- 
253