_VO2 kinetics and tethered
strength inﬂuence the 200-m
front crawl stroke kinematics and
speed in young male swimmers
Kamil Sokołowski1*, Raul Filipe Bartolomeu2,3,4,
Tiago Manuel Barbosa2,3 and Marek Strzała1
1Department of Water Sports, Faculty of Physical Education and Sport, University of Physical Education,
Kraków, Poland, 2Department of Sport Sciences and Physical Education, Instituto Politécnico de
Bragança, Bragança, Portugal, 3Department of Sports Sciences, Polytechnic of Guarda, Guarda,
Portugal, 4Research Center in Sports Sciences, Health and Human Development (CIDESD), Vila Real,
Portugal
Background: The aim of this research was to examine the relationship between
the fast component of oxygen consumption developed in 1-min _VO2 and force
indices both measured in tethered swimming test and to assess the inﬂuence of
the gathered indices on speed and swimming kinematics in 200-m front
crawl race.
Methods: Forty-eight male swimmers (aged 13.5 ± 0.9 years old) participated in
this study. Testing included 1) 1-min all-out front crawl tethered swimming
while oxygen consumption (breath by breath) and tethered forces were
measured, 2) 200-m front crawl race-like swimming featuring kinematic
analysis, and 3) biological age (BA) examination.
Results: During the 1-min all-out tethered swimming test, a linear increase in
oxygen consumption was observed. There were moderate to high partial
correlations between particular periods of seconds in the 1-min
_VO2:
31–60, 41–60, and 51–60 and Fmax, Fave, and Iave of tethered swimming,
while 41–60 and 51–60 _VO2 were moderately to highly interrelated with all
the swimming speed indices and SI. The swimming speed indices signiﬁcantly
interplayed with SL, SI, Fmax, Fave, and Iave. Partial correlations were computed
with BA control.
Conclusion: The ability of reaching a high level of _VO2 fast is essential for a
swimmer’s energy production at short- and middle-distance events. Reaching a
high level of _VO2 signiﬁcantly determines tethered strength and swimming
kinematics. The level of _VO2 inﬂuences the maintenance of a proper pulling
force and the stroke technique of front crawl swimming in young male
swimmers.
KEYWORDS
adolescent swimming, oxygen uptake, tethered swimming, front crawl, biological age,
kinematic indices
OPEN ACCESS
EDITED BY
Philippe Hellard,
Ministry of Education and Sport, Albania
REVIEWED BY
Sebastian Weber,
INSCYD, Switzerland
Santiago Veiga,
Universidad Politécnica de Madrid,
Spain
*CORRESPONDENCE
Kamil Sokołowski,
kamil.sokolowski@awf.krakow.pl
SPECIALTY SECTION
This article was submitted to Exercise
Physiology, a section of the journal
Frontiers in Physiology
RECEIVED 15 September 2022
ACCEPTED 07 November 2022
PUBLISHED 24 November 2022
CITATION
Sokołowski K, Bartolomeu RF,
Barbosa TM and Strzała M (2022), _VO2
kinetics and tethered strength inﬂuence
the 200-m front crawl stroke kinematics
and speed in young male swimmers.
Front. Physiol. 13:1045178.
doi: 10.3389/fphys.2022.1045178
COPYRIGHT
© 2022 Sokołowski, Bartolomeu,
Barbosa and Strzała. This is an open-
access article distributed under the
terms of the Creative Commons
Attribution License (CC BY). The use,
distribution or reproduction in other
forums is permitted, provided the
original author(s) and the copyright
owner(s) are credited and that the
original publication in this journal is
cited, in accordance with accepted
academic practice. No use, distribution
or reproduction is permitted which does
not comply with these terms.
Frontiers in Physiology
frontiersin.org
01
TYPE Original Research
PUBLISHED 24 November 2022
DOI 10.3389/fphys.2022.1045178
Introduction
The ability to increase energy production is considered
crucial in various sports, even in swimming where high
velocities cause relatively high energy cost of movement.
Thus, it is necessary among athletes of different age groups to
develop either aerobic or anaerobic metabolic pathways of energy
production. This begins with proper and adequate training from
early prepubertal age and continues further with aging, while
controlling the maturation level of the swimmer (Balyi and Way,
2009; Lätt et al., 2009). The contribution of energy pathways in
swimming events is varied and depends on the duration of the
race (Olbrecht, 2000). The 200-m front crawl, for example, is a
race which requires a high involvement of aerobic and anaerobic
pathways of energy production (Gastin, 2001).
The aerobic energy system participates in the overall energy
production right from the beginning of the all-out effort, and the
oxygen uptake almost reaches its maximum level within 60 s of
exercising (Gastin and Lawson, 1994; Serresse et al., 1988; Strzała
and Tyka 2009). It has been stated that the maximal oxygen
uptake ( _VO2 max) assesses the ability in developing and
maintaining high speed of sprint swimmers in efforts lasting
about 60 s (Ribeiro et al., 2015; Hellard et al., 2018). According to
the data presented by Figueiredo et al. (2011), even in 200-m
front crawl race, the aerobic pathway engages fast in providing
energy for muscle work within half of the race, while at the third
(long course) lap, aerobic metabolism provides for around 80% of
all energy production. Among swimmers of different age groups,
in the 200-m event, the aerobic contribution has been estimated
to be 72% (Zamparo et al., 2000) or even 78.6% (Sousa et al.,
2011). However, the contribution of the aerobic pathway of
energy production in swimming at short and middle distances
seems to have been underestimated over the past years
(Peyrebrune et al., 2014). Rodriguez et al. (2003) have
reported that swimmers not only reached 92.3% of their
_VO2 max in the 100-m events but also exhibited _VO2 kinetics
that was signiﬁcantly faster in the 100-m race than in the 400-m
one. Their results highlight the signiﬁcance of fast oxygen
kinetics especially while competing in short races, such as the
100-m ones. Despite the existence of research on the relationship
between oxygen consumption and swimming performance, there
is a need to refresh (Costill et al., 1985) and further investigate the
fast component of _VO2 kinetics, i.e., the abrupt oxygen delivery
to the body in short- to medium-term exercising periods.
Moreover, there is a knowledge gap on the inﬂuence and
dependence of this type of cardiorespiratory efﬁcacy, present
in most swimming races, on the ability to generate propulsion
force and stroke kinematics.
In swimming, the examination of speciﬁc strength abilities is
deemed as a key factor when performing an evaluation. For this
purpose, swimming tethered tests are often conducted in adults
(Kjendlie and Thorsvald, 2006) and swimmers of other age
groups (Amaro et al., 2014). Several studies have conﬁrmed a
strong relationship between tethered swimming tests (30–120 s)
and
short-to-middle
distance
swimming
performances
(Morouço et al., 2012; Santos et al., 2016).
Biomechanical indices such as stroke length (SL), stroke rate
(SR), and stroke index (SI) are signiﬁcant predictors of young
swimmers’ performance (Lätt et al., 2009) and are directly related
to swimming efﬁciency (Geladas et al., 2005). The literature
reports that strength preparation and a well-developed oxygen
system should cause better stroke kinematics in terms of the
ability to maintain proper SR and SL along the race (Costill et al.,
1985; Sokołowski et al., 2021). Given these premises, the aim of
this research was threefold: 1) to examine the relationship
between the fast component of oxygen consumption and
tethered swimming force production, 2) to examine the
relationship
between
the
fast
component
of
oxygen
consumption and 200-m front crawl race kinematics, and 3)
to assess the relationship between 200-m front crawl race
swimming kinematics and performance. It is hypothesized
that there would be a signiﬁcant relationship between oxygen
uptake, tethered swimming force, stroke kinematics, and the
performance indices.
Materials and methods
Participants
Forty-eight young male swimmers [13.5 ± 0.9 years old;
14.55 ± 1.66 years of biological age (BA)] participated in this
study. They were recruited as swimmers with the highest
performance level in their age category from the Polish
region of Krakow and were at the ﬁfth threshold in the
Ruiz-Navarro et al. (2022) classiﬁcation of competitive
level.
Participants
presented
swimming
levels
which
resulted in a mean value of 350.32 ± 60.22 FINA points for
the 200-m front crawl race. All participants were clinically
healthy and held a license from the Polish Swimming
Federation. All swimmers had been through 4–5 years of
systematic
swimming
at
the
time
of
conducting
this
research, encompassing at least 10 sessions per week and
had taken part in national-level competitions and national
swimming championships for their age group.
1-min Tethered swimming test
A tethered swimming test (Figure 1) in a laboratory-
controlled environment (temperature and humidity) was
conducted. The test consisted of a single bout of 1-min
duration of all-out freestyle tethered swimming and was
performed in a ﬂume in still water. With due advance
notice, the swimmers were asked to rest the day before the
test and maintain their daily diet. Before entering the pool,
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10.3389/fphys.2022.1045178
they were informed about the testing procedure and then
underwent a 1000-m in-water warm-up, as before any
competition. After the warm-up and before the test, they
swam for 1 min in the ﬂume at a slow pace, fully equipped
with the testing apparatus for adjusting to the testing
conditions.
At
this
time,
they
got
the
possibility
to
familiarize with the speciﬁc environment of the ﬂume and
potential inconveniences of using the breathing apparatus and
tethered swimming. After the initial 1 min of familiarization,
the scientist conducting the test received feedback from the
participant. To signal the beginning and ending of the test, a
whistle was used. For the last minutes of warm-up and the test
itself, the swimmers were asked to breathe only through the
mouthpiece and avoid losing their nose clip. This procedure is
similar to their training sessions done using a snorkel. The
swimmers were equipped with a respiratory valve system that
featured an ergospirometer (Start 2000 MES, Poland). The
valve system was attached to a rod-like construction just above
the swimmer’s head. During the duration of the test, the
expired air was analyzed continuously (breath by breath)
(Ergo 2000M software MES, Poland) and data were saved
for further analysis. This has been proved to be a reliable
method of calculating oxygen uptake in swimming (Neiva
et al., 2017; Ribeiro et al., 2015; Sousa et al., 2011).
From the collected
data, the following
indices were
computed: 1) average oxygen consumption from the ﬁrst 30 s
of the test (1–30 _VO2, l·min−1), 2) average oxygen consumption
from the last 30 s of the test (31–60 _VO2, l·min−1), 3) average
oxygen consumption from the last 20 s of the test (41–60 _VO2,
l·min−1), 4) average oxygen consumption from the last 10 s of the
test (51–60 _VO2, l·min−1), and 5) oxygen consumption from the
total test duration (1–60 _VO2, l·min−1).
Additionally, the participants wore a nylon waist belt,
connected by a 3.7 m steel cable to a load cell (ZPS5-BTU-
1kN, Poland) which was ﬁxed on a steel pole (the ﬁxing point
is 0.49 m above the water surface). Data were recorded by the
load cell at 100 Hz and transferred to a computer software
program for further analysis (MAX6v0M software, Poland).
Three parameters were calculated over a 60-s recording time:
1) maximum value of force (Fmax, N); 2) average value of force
in the entire test (Fave, N) and in the ﬁrst and second 30-s
parts: Fave 0-30, Fave 30-60, N; and 3) average impulse per single
cycle (Iave, N·s−1) which is deﬁned as the integral of force over
a period of time containing all full cycles divided by the
number of completed cycles:
Iave 

t1
t0Fdt
n
(1)
where t0 is the beginning of the ﬁrst full cycle and t1 is the ending
of the last full cycle in the 60-s period. Tethered swimming has
been described as a reliable method to assess swimming force
production (Kjendlie and Thorsvald, 2006; Psycharakis et al.,
2011; Amaro et al., 2014).
200-m Front crawl race
The 200-m all-out test was carried out in a 25-m swimming
pool that meets the International Swimming Federation (FINA)
requirements. Before the race, the swimmers completed a 1000-
m warm-up just like in competitions. Each trial was performed by
three to four swimmers in order to mimic competition
conditions. The ﬁnal and split times of each trial were
measured
with
an
automatic
timing
device
(Omega,
Switzerland; OCP5, StartTime V). All trials were recorded
with a camera at 50 Hz framing (GC-PX100BE, JVC, Japan).
The velocity of the part of the race containing the ﬁrst 10-m
start zone as well as start, turn, and ﬁnish (which resulted in
115 m) was calculated as VSTF (m·s−1). The surface swimming
velocity, i.e., the velocity over the effective clean swimming
distance (85 m) was deemed Vsurf (m·s−1). The times for
separate sectors were measured when the swimmer’s head
crosses the imaginary line linking the markers at both sides of
the pool. The 200-m front crawl velocity (Vtotal200, m·s−1) was
deﬁned as 200 divided by the ﬁnal time of the race. The video
footage, placement of the cameras and markers, video analysis,
and computation of the basic kinematic parameters were
performed analogically to the ones described in the literature
(Sokołowski et al., 2021), but in this study, a swimming distance
twice as long was considered.
Kinematic parameters
For the kinematic analysis, the stroke rate (SR), stroke length
(SL), and stroke index were calculated. The SR was deﬁned as the
number of full stroke cycles performed within a unit of time (in
FIGURE 1
1-min tethered swimming test.
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10.3389/fphys.2022.1045178
cycles per minute) and was calculated by video analysis of three
consecutive stroke cycles (intraclass correlation of 0.99, 95% CI =
0.960–0.997). The SL was deﬁned as the horizontal distance that
the body travels during a full stroke cycle and was calculated as
SL  v
SR
(2)
where SL (in m) is the stroke length, v is the swimming velocity,
and SR is the stroke rate. Finally, the SI was deemed as an overall
swimming efﬁciency estimator and computed as
SI  SL · v
(3)
where SI (in m2·s−1) is the stroke index, SL is the stroke length,
and v is the swimming velocity.
Biological age
Examination of the participants in terms of BA was
conducted by an experienced anthropologist and calculated as
BA  BHage + BMage
2
(4)
where BHage is the age obtained from the percentile charts based
on the participant’s body height and BMage is the age obtained
from the percentile charts based on the participant’s body mass.
The growth charts by the Children’s Memorial Health Institute,
which are standardized and validated for the Polish population,
were used (the 50th percentile was used to align the height and
mass with age). Additionally, pubertal development was assessed.
The Tanner stages based on pubic hair scale were estimated
(Bornstein, 2018). The great variety of biological maturation
levels in the adolescent groups at the same calendar age causes
great differences in muscle mass and aerobic and anaerobic
capacities of swimmers. Because of differences in maturation
speciﬁc water abilities of swimmers and speciﬁc testing could be
less correlated with swimming performance than simple general
tests as isometric force or counter movement jump (Garrido
et al., 2012; Strzała et al., 2019). BA may cause bias in the
statistical
analysis
and
conclusions.
The
use
of
partial
correlation statistics with age control helps limit the strong
inﬂuence of BA in the effects of statistical calculations. The
data used in biological age calculation are presented in Figure 2.
Statistical analysis
The values are presented as mean ± standard deviation. The
normality
of
the
data
was
checked
with
the
Kolmogorov–Smirnov test. In oxygen consumption averaged
per 10-s periods, the trend that was most suitable for the
gathered data (Figure 3) was identiﬁed. The paired-sample
t-test was used to compare the values of the average tethered
swimming force of the ﬁrst and second parts of the 1-min
tethered swimming test. To identify the relationship between
all the variables and swimming velocities in the 200-m front
crawl, partial correlations controlled for BA were computed for
1) oxygen consumption and force indices;
2) oxygen
consumption,
swimming
speed
variables,
and
kinematic indices; and
FIGURE 2
Average data of BHage, BMage, and BA.
FIGURE 3
Average oxygen consumption of all participants, in 10-s
periods, during the 1-min tethered swimming test.
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3) swimming speed variables and kinematic and force indices.
The magnitude of the correlations was determined using the
modiﬁed scale by Hopkins (2000)—trivial: r ≤ 0.1; low: 0.1 < r ≤
0.3; moderate: 0.3 < r ≤ 0.5; high: 0.5 < r ≤ 0.7; very high: 0.7 < r ≤
0.9; nearly perfect: r > 0.9; and perfect: r = 1.
Results
The data shown in Figure 3 represent the increase in oxygen
consumption in the 1-min all-out tethered swimming test, in 10-s
periods. The analysis of variance revealed signiﬁcant differences
between values measured every 10 s (F = 164,9, p < 0.01). Further
trend analysis indicates the linear trend as the best adjusted to the
collected data (F = 289,44, p < 0.01).
There were moderate to high correlations between 31–60 _VO2,
41–60 _VO2, and 51–60 _VO2 and all the swimming force indices
(Fmax, Fave, Iave). Low correlations were observed between Fmax, Iave,
and 1–60 _VO2 (Table 1). A signiﬁcantly higher average of tethered
force was noted in the ﬁrst 30-s duration of the test: Fave 0-30 85.41 ±
21.41 N vs Fave 30-60 67.12 ± 15.22 (t = 14.77; df = 47; p ≤ 0.0000).
The 41–60 _VO2 and 51–60 _VO2 were moderately to highly
correlated with all the swimming speed indices and SI. Vsurf was
also signiﬁcantly correlated with 1–30 _VO2 (Table 2). There was a
positive correlation between SL and 51–60 _VO2.
TABLE 1 Partial correlations controlled for BA between oxygen consumption and force indices from the tethered swimming test.
Fmax (N)
Fave (N)
Iave (N·s−1)
250.24 ± 58.39
74.90 ± 20.63
101.93 ± 23.48
1–30 _VO2 (l·min−1)
0.167
0.053
0.134
1.68 ± 0.59
31–60 _VO2 (l·min−1)
0.296*
0.363**
0.372**
3.30 ± 0.76
41–60 _VO2 (l min−1)
0.395**
0.494**
0.502**
3.65 ± 0.81
51–60 _VO2 (l min−1)
0.482**
0.516**
0.559**
3.92 ± 0.97
1–60 _VO2 (l min−1)
0.285*
0.245 p = 0.054
0.290*
2.55 ± 0.59
*p ≤ 0.05; **p ≤ 0.01.
TABLE 2 Partial correlations controlled for BA between oxygen consumption indices from the tethered swimming test, and swimming speed variables
and kinematic indices from the 200-m front crawl race.
Vtotal200
Vsurf
VSTF
S
SL
SI
(m·s−1)
(m·s−1)
(m·s−1)
(cycles·min−1)
(m)
(m2·min−1)
1.40 ± 0.09
1.34 ± 0.09
1.46 ± 0.10
41.68 ± 4.52
1.93 ± 0.24
2.53 ± 0.42
1-30 _VO2 (l·min−1)
0.187
0.299*
0.106
0.080
0.076
0.206
1.68 ± 0.59
31-60 _VO2 (l·min−1)
0.294
0.311
0.288
-0.083
0.206
0.283
3.30 ± 0.76
41-60 _VO2 (l·min−1)
0.463*
0.428*
0.487*
-0.136
0.310
0.412*
3.65 ± 0.81
51-60 _VO2 (l·min−1)
0.640**
0.584**
0.666**
-0.119
0.393*
0.539**
3.92 ± 0.97
1-60 _VO2 (l·min−1)
0.242
0.311
0.201
-0.007
0.155
0.255
2.55 ± 0.59
p = 0.075
*p ≤ 0.05; **p ≤ 0.01.
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Regarding the swimming speed and kinematic variables, the
strongest relationships were observed between SI and Vtotal200
and Vsurf and VSTF. The swimming speed was also moderately
correlated with SL, Fmax, Fave, and Iave (Table 3).
As a supplement to the results, it was decided to present the
level of selected oxygen uptake and strength indicators, measured
in the 1-min test, followed by the kinematics of 200-m front crawl
in relation to BA (Table 4). It could be observed that oxygen
uptake and strength abilities continuously improve with higher
BA. There was also a general increase in values of stroke
kinematics through the years of BA.
Table 5 shows 200-m front crawl kinematics by each 50-
m lap.
Discussion
Regarding the analysis of _VO2 kinetics, an instantaneous and
sudden increase was observed along the 1-min all-out tethered
swimming. Despite the increase in
_VO2 which could be
characterized as a linear increase, the slopes in both initial
and ﬁnal segments of the 1-min consumption were noticeably
lower than the one observed at the middle (Figure 3). Slower
oxygen uptake at the beginning of the test may be associated with
the use of high-energy phosphocreatine resources and yet low
ventilation ( _V E); the ﬁnal slowdown in _VO2 growth is from
reaching a peak and increasing fatigue. This study revealed a
signiﬁcant inﬂuence of _VO2 (mainly 41–60 _VO2 and 51–60 _VO2)
on 200-m front crawl race swimming speed, swimming
kinematic
indices,
and
tethered
force
indices.
A
highly
developed fast _O2 supply to working muscles (represented by
51–60 _VO2) is signiﬁcantly related to strength (0.482 ≤ r ≤ 0.559,
p ≤ 0.01). This strength in swimming is expressed as the ability to
TABLE 3 Partial correlations controlled for BA between swimming speed variables and kinematic indices from the 200-m front crawl race and the
force indices from the tethered swimming test.
SR
SL
SI
Fmax
Fave
Iave
(cycles·min−1)
(m)
(m2·s−1)
(cycles·min−1)
(cycles·min−1)
(cycles·min−1)
Vtotal200
0.168
0.325*
0.680**
0.341**
0.321**
0.406**
Vsurf
0.229
0.301*
0.692**
0.321**
0.408**
0.387**
VSTF
0.103
0.337*
0.644**
0.355**
0.411**
0.407**
*p ≤ 0.05; **p ≤ 0.01.
TABLE 4 Average values of oxygen uptake, tethered swimming, and kinematic indices of 200-m front crawl calculated for biological age.
BA
(years)/number
of participants
(n)
51–60
1–60
Fave
Iave
SR
SL
SI
Vtotal200
_VO2
_VO2
(N)
(N·s−1)
(c·min−1)
(m)
(m2·min−1)
(m·s−1)
(l·min−1)
(l·min−1)
11 (n = 1)
2.03
1.33
61.9
89.41
38.88
2.12
2.89
1.43
12 (n = 5)
3.10
1.95
47.31
74.05
45.81
1.72
2.21
1.36
13 (n = 15)
3.42
2.39
65.18
88.31
42.38
1.87
2.45
1.38
14 (n = 5)
3.47
2.38
70.82
98.14
38.62
1.96
2.34
1.31
15 (n = 9)
4.54
2.77
88.6
117.78
41.70
1.99
2.69
1.45
16 (n = 7)
4.41
3.00
82.73
112.44
40.96
1.93
2.49
1.40
17 (n = 4)
4.75
2.91
96.65
123.83
40.09
2.13
2.94
1.48
18 (n = 2)
5.56
3.13
100.95
137.69
40.82
2.08
2.90
1.51
TABLE 5 Average values of kinematic indices for each 50-m lap of 200-
m front crawl.
I 50
II 50
III 50
IV 50
SR (cycles·min−1)
42.91 ± 5.49
40.44 ± 4.63
39.99 ± 4.89
43.93 ± 4.87
SL (m)
1.97 ± 0.29
1.92 ± 0.24
1.90 ± 0.24
1.85 ± 0.23
SI (m2·min−1)
2.75 ± 0.54
2.46 ± 0.41
2.40 ± 0.41
2.49 ± 0.42
Vsurf (m·s−1)
1.45 ± 0.11
1.29 ± 0.09
1.26 ± 0.10
1.32 ± 0.09
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produce propulsive force, which is later translated into higher
stroke efﬁciency and thus better swimming economy (51–60 _VO2
vs SI, r = 0.539, p ≤ 0.01). Similarly, the higher energy demand
connected with 51–60 _VO2 translated into signiﬁcantly higher
Vsurf (r = 0.584, p ≤ 0.05), which depended on proper swimming
economy, due to the relationship between Vsurf and SI (r = 0.692,
p ≤ 0.01) and Iave (0.387, p ≤ 0.01).
This study noted a relationship between 51–60 _VO2 and
the overall performance in 200-m front crawl (r = 0.640, p ≤
0.01) which is in tandem with the results of Rodriguez et al.
(2003), where a correlation between _VO2 peak values and the
performance at 100 m (r = 0.787, p ≤ 0.05) and 400 m (r =
0.752, p ≤ 0.05) was observed. The reason for a weaker
correlation
in
our
study
could
be
the
longer
period
considered for the mean
_VO2 calculation. We used 10-s
periods, while Rodriguez et al. (2003) used 5-s periods. The
breath-by-breath
acquisition
technique
can
induce
a
signiﬁcant variability on acquired _VO2 values, and different
sampling
periods
might
produce
different
outcomes.
Moreover,
our
quite
restrictive
statistical
calculations
(including BA control) could also play a role in that
difference. In comparison to the results of Sousa et al.
(2011), which showed a positive correlation between 200-m
front crawl swimming speed and _VO2 peak (r = 0.69, p = 0.03),
our partial correlation was somewhat slightly lower (r = 0.640,
p ≤ 0.01). Nevertheless, these researchers found high _VO2
values right after the ﬁrst 50 m that swimmers could almost
maintain for the 200-m effort. Researchers have put forward
that the need for oxygen in the muscles triggers an
instantaneous and sudden increase in O2 uptake from the
very beginning of the exercise (Ribeiro et al., 2015; Hellard
et al., 2018). Maybe the highest peak of O2 uptake could be
reached even faster in our study and show faster kinetics in
young athletes, but because it is in swimming, the aim of
racing (also through the test) is to withstand the pace as much
as possible until the end of the race. Nevertheless, in our
research, we recorded a positive distribution of average
tethered swimming force (Fave 0-30 85.41 ± 21.41 N vs Fave
30-60 67.12 ± 15.22 N). The question here is how speedily and
individually for a competitor, should a race be open to young
13-year-old swimmers in order to allow for the proper
engagement of the fast component of oxygen consumption.
It is known that positive pacing, or rather starting a race too
speedily, can cause excessive fatigue, low oxygen distribution,
and lactic acidosis in the skeletal muscles, which slow down
energy production in the aerobic pathway. It may also be due
to fatigue of the chest breathing muscles during the second
part of the 200-m distance (Gastin and Lawson, 1994).
It can be stated that for high aerobic capacity, the fast
development of high level of O2 supply is crucial while
performing middle distance events such as the 200-m front
crawl. For this purpose, the 1-min tethered swimming test
seems to be appropriate in examining the ability to supply O2
to the swimmer’s muscles to produce propulsion. Serresse et al.
(1988) who examined the maximum 90-s ergocycle test observed
that the highest _VO2 values occurred at about 60 s into the test.
Similar to our study, their results have shown a linear increase in
oxygen uptake up to 60 s into the test. Gastin and Lawson (1994)
stated that 30–60 s of maximum effort could be enough to reach
up to 90% of athletes’ _VO2 max. Ribeiro et al. (2015) claimed that
if the majority of the swimming races are 50, 100, and 200 m,
performed at high speeds, examining the
_VO2 max at low
intensities has limited application in the evaluation of the
swimmer’s conditioning. Alves et al. (2011) suggested that
faster kinetics during the initial phase of V _O2 max testing is
directly related to a better performance at middle-distance events
in swimming. Based on this reasoning, one could suggest that
middle-distance swimmers should undergo long, high-intensity
aerobic repeated sprints in training sessions.
Regarding tethered force production, in the present study, a
signiﬁcant positive correlation was found between all indices and
200-m front crawl speed (0.321 ≤ r ≤ 0.411, p ≤ 0.01). Other
authors have reported similar ﬁndings: Santos et al. (2016) have
noted a positive correlation (0.61, p < 0.001) between the peak
force of the 2-min tethered swimming test and clean velocity of
200-m front crawl race, while Morouço et al. (2012) showed a
very strong relationship between average pulling force, peak
force, and 200-m front crawl velocity (r = 0.94 and r = 0.93,
respectively, p < 0.01). Again, controlling for BA and longer test
duration could be the reasons for weaker correlations in our
study.
Our study showed great diversity in BA (Figure 2; Table 4). It
is therefore a practical example of emphasizing the need for each
trainer to adapt their training in relation to the BA of their
swimmers. If this is the case, even the most gifted swimmers with
delays in relation to BA are often frustrated by worse athletic
performance when compared to their calendar peers, and in
consequence, they overtrain trying to catch up to the others, get
disappointed, then quit their swimming training. On the other
hand, swimmers more advanced in relation to BA have the
potential to develop through more individualized, intense
training.
Based on the high correlation between 51–60 _VO2 and SI
found in the present study (r = 0.539, p ≤ 0.01), we can state that
peak oxygen consumption determined the rate of transfer from
chemical energy to mechanical energy, thus leveling up the stroke
kinematics of the swimmers. This ﬁnding backs up the results by
Sánchez and Arellano (2002), where the SI was found to be higher
in
international-level
swimmers
than
their
national-level
counterparts in all swim strokes. Barbosa et al. (2013)
proposed a multidisciplinary model of swimming performance
predictors where the SI plays a signiﬁcant role. In a study by
Costill et al. (1985), the predictability of _VO2 max at freestyle was
reported to increase signiﬁcantly when the SI was included in the
multiple regression analysis of an approximate 400-m swim. The
multiple
regression
models
prepared
by
Mezzaroba
and
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10.3389/fphys.2022.1045178
Machado (2013) revealed that in young male swimmers, the SI at
the 200-m front crawl race explained 76% of the performance. In
the study by Nasirzade et al. (2015), 200-m front crawl
performance of young swimmers was strongly related to the
SL and SI (r = −0.79 and r = −0.72, p < 0.01, respectively). The
mentioned studies are in tandem with our results where SI
presented the highest positive correlation with all 200-m front
crawl variables (0.644 < r ≤ 0.692, p ≤ 0.01). This very high
percentage
of
share
of
the
SI
in
performance
in
the
abovementioned
studies
is
also
because
of
its
link
to
performance itself, because the stroke index contains the
speed (according to the formula: SI  SL · v).
The present study, analyzing the relationship between the
aerobic
conditioning
level,
force
production,
and
stroke
kinematics is in accordance with the one study found in the
literature on this matter, where Costill et al. (1985) identiﬁed
interrelationships between oxygen uptake, energy cost of
swimming, and stroking economy (SI). In our study, we
found moderate to high correlations between 31–60
_VO2,
41–60
_VO2, and 51–60
_VO2 and Fmax, Fave, and Iave. Low
correlations were observed between Fmax, Iave, and 1–60 _VO2.
It could be stated that the ability to generate the pulling force is
directly and positively related to the fast O2 supply which is
linked with the endurance of the swimmer in terms of aerobic
energy production and also lactate utilization or turnover to ATP
(Greenwood et al., 2008).
Conclusion
In the 1-min all-out effort, a sudden increase in oxygen
uptake was observed, with swimmers reaching high levels of _VO2
by the end of the tethered test. This fast ability of reaching high
_VO2 and trainability of this physiological variable is essential for
ﬁtting an appropriate pacing in middle-distance racing and must
be an important aspect of 13-year-old swimmers’ conditioning
and of the older age groups too, in relation to their BA.
Furthermore, it is suitable for the physiological preparation
for 200-m front crawl performance and can be useful as a
predictor of the swimmer’s endurance. The high intensity
_VO2 testing used in the present study is appropriate for
predicting sprint (100-m) and middle-distance swimming
events performed at high speeds. There is a relationship
between the fast-developed 1-min high-level oxygen uptake
and the tethered strength abilities and high-speed swimming.
The fast O2 supply is crucial for maintaining a proper pulling
force and stroke technique.
Data availability statement
The raw data supporting the conclusions of this article will be
made available by the authors, without undue reservation.
Ethics statement
The studies involving human participants were reviewed and
approved by the Regional Medical Chamber in Cracow; decision
number:
94/KBL/OIL/2020.
Written
informed
consent
to
participate in this study was provided by the participants’
legal guardian/next of kin.
Author contributions
KS collected data, performed statistical analysis, and wrote
the manuscript. RB cowrote the manuscript. TB reread and
corrected the manuscript. MS cowrote the manuscript and
collected data.
Funding
Article processing charge (open access) was funded within
the framework of the programme of the Ministry of Science and
Higher Education (Poland) under the name “Regional Initiative
for Perfection” within the years 2019–2022, project No. 022/RID/
2018/19 in the total of 11,919,908 PLN.
Conﬂict of interest
The authors declare that the research was conducted in the
absence of any commercial or ﬁnancial relationships that could
be construed as a potential conﬂict of interest.
Publisher’s note
All claims expressed in this article are solely those of the
authors and do not necessarily represent those of their afﬁliated
organizations, or those of the publisher, editors, and reviewers.
Any product that may be evaluated in this article, or claim that
may be made by its manufacturer, is not guaranteed or endorsed
by the publisher.
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<math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow> <msub> <mrow><mover><mi>V</mi> <mo>˙</mo></mover> <mi>O</mi></mrow> <mn>2</mn></msub> </mrow> </math> kinetics and tethered strength influence the 200-m front crawl stroke kinematics and speed in young male swimmers.
Sokołowski, Kamil,Bartolomeu, Raul Filipe,Barbosa, Tiago Manuel,Strzała, Marek