ORIGINAL RESEARCH

published: 22 October 2020

doi: 10.3389/fphys.2020.580711

Proposal of a Conditioning Activity

Model on Sprint Swimming
Performance
Tarine Botta de Arruda 1* , Ricardo Augusto Barbieri 1,2 , Vitor Luiz de Andrade 3 ,
Jônatas Augusto Cursiol 1 , Carlos Augusto Kalva-Filho 4 , Danilo Rodrigues Bertucci 3 and
Marcelo Papoti 1,3
1
Laboratory of Aquatic Activities, School of Physical Education and Sport of Ribeirão Preto, University of São Paulo,
EEFERP-USP, São Paulo, Brazil, 2 Estácio University Center of Ribeirão Preto, Ribeirão Preto, Brazil, 3 Bioscience Institute,
Physical Education Department, São Paulo State University “Júlio de Mesquita Filho”, São Paulo, Brazil, 4 Human Movement
Research Laboratory, Post-graduate Program in Movement Sciences, São Paulo State University, Bauru, Brazil

This study aimed to propose a conditioning activity (CA) model to stimulate improvement
on neuromuscular responses, mechanical parameters and for the 50-m freestyle
swimming. Thirteen male swimmers (19 ± 3 years and performances of 77% in relation
to World Championship records) performed four CA protocols followed by a maximum
performance in the 50-m freestyle. In the first protocol (P1) swimmers performed a
standard warm-up (∼15 min); in the second protocol (P2) lunges (3 × 85% of the
one-repetition maximum); in the third (P3) pull-ups (3 maximum repetitions) and box
Edited by:
Juan Manuel Murias,
jumps 40 cm high and 60 cm deep (1 × 5 with 10% of the corporal weight); and in the
University of Calgary, Canada fourth protocol (P4) a combination of exercises from the second and third protocols.
Reviewed by: CA protocols had no effect on the standard warm-up. However, P2 performance
Jerome Koral,
(27.01 ± 1.25 s) was similar to P1 (27.01 ± 1.18 s) and presented higher positive
Université Jean Monnet, France
Fernando Diefenthaeler, effects in mechanical parameters for the swim start performance in comparison to other
Federal University of Santa Catarina, protocols, contributing to improvements in the 50-m freestyle. In addition, turnaround
Brazil
time also had a negative effect, mainly in P3 (3.12 ± 0.28 s), signaling the improvement
*Correspondence:
Tarine Botta de Arruda
of this variable in all protocols (P1: 3.30 ± 0.38 s; P2: 3.17 ± 0.30 s; P4: 3.17 ± 0.34 s).
tarine.arruda@alumni.usp.br P2 (after: 80 ± 11%; before: 82.7 ± 9.9%) and P3 (after: 82.7 ± 9.9%; before:
85.1 ± 9.7%) presented a possible positive effect on the percentage of voluntary
Specialty section:
This article was submitted to
activation in relation to P1 (after: 79.3 ± 10.7%; before: 76.3 ± 12%). In conclusion, the
Exercise Physiology, proposed conditioning activity protocols were not efficient for performance improvement
a section of the journal
in the 50-m freestyle compared to the standard model and seem to specifically influence
Frontiers in Physiology
each phase of the event.
Received: 06 July 2020
Accepted: 29 September 2020 Keywords: training, competition, fatigue, Twitch, post-activation potentiation, sports science
Published: 22 October 2020
Citation:
de Arruda TB, Barbieri RA,
de Andrade VL, Cursiol JA, Abbreviations: 1RM, one-maximum repetition test; 3RM, three maximum repetitions; AE, angle of entry; AT, angle of
take-off; BT, block exit time; CA, conditioning activity; DD, distance of the dive; FT, flight time; ITT, Interpolation Twitch
Kalva-Filho CA, Bertucci DR and
Technique; IMVC, Isometric Maximal Voluntary Contraction; NS, number of strokes; P1, protocol 1; P2, protocol 2; P3,
Papoti M (2020) Proposal of a
protocol 3; P4, protocol 4; PAP, post-activation potentiation; PFE , Peak force of elbow extension musculature; PFK , Peak
Conditioning Activity Model on Sprint force of knee extension musculature; PTE , Peak Twitch of the elbow extension musculature; PTK , Peak Twitch of the knee
Swimming Performance. extension musculature; SF, stroke frequency; SI, stroke index; SITK , Superimposed Twitch of the knee extension musculature;
Front. Physiol. 11:580711. SL, stroke length; T, total time; T15 , Time in 15-m; T25 , Time in 25-m; T5 , Time in 5-m; TA, turnaround time; V X H, Mean
doi: 10.3389/fphys.2020.580711 of the horizontal hip speed; VA, voluntary activation; VωK, Mean angular velocity of knee extension.

Frontiers in Physiology | www.frontiersin.org 1 October 2020 | Volume 11 | Article 580711

de Arruda et al. Conditioning Activity on Sprint Swimming

INTRODUCTION pull-ups and box jumps and demonstrated a decrease in the

50-m freestyle time when compared to the performance after
The warm-up period preceding swimming events aims to prepare solely implementing a standard warm-up. Nevertheless, Kilduff
the body for the upcoming effort and aid in injury prevention et al. (2011) compared a CA model with a standard warm-up
(Woods et al., 2007), increase blood flow and oxygen delivery protocol and detected no significant differences in the swim start
in active muscles (McCutcheon et al., 1999; Pearson et al., 2010; performance until the initial 15-m in international swimmers.
Burnley et al., 2011), elevate body temperature (Bishop, 2003) as Furthermore, Abbes et al. (2018) found no improvements in the
well as increase joint mobility and improve motor coordination 50-m freestyle performance after testing the execution of squats
(Smith, 1994). Different warm-up models have been adopted and push ups for 30 s for potentiation. Therefore, it is not yet
for the physiological, psychological and mechanical preparation clear whether the adoption of conditioning activities is indeed
of swimmers (Bishop, 2003; Girold et al., 2007), since these effective for improving performance in swimming sprint events
variables seem to be determining factors for improvement in in “real-life” context, mainly due to the lack of standardization of
sports performance (Bishop, 2003; Girold et al., 2007; Cuenca- the protocols currently used.
Fernández et al., 2015; Hancock et al., 2015). Despite evidence showing improvements in the swim start
Traditionally, swimmers warm-up is composed of moderate- (Cuenca-Fernández et al., 2015) and reduced time in the 50-m
intensity stimuli and short stimuli at high intensity, not exceeding freestyle (Sarramian et al., 2015), knowledge about the possible
1,500-m and usually the competition styles are used (Kilduff effects of CA on clean swimming, i.e., without the influence of
et al., 2011). Nonetheless, conditioning activity (CA) of high- the swim start and turnaround phases, as well as the effects of
intensity and short-duration has been the focus of attention warm-up strategies on the performance of turns are still limited.
in swimming, especially in sprint events (Hancock et al., 2015; Although the use of CA is, theoretically, an interesting strategy
Sarramian et al., 2015; Barbosa et al., 2016; Cuenca-Fernández for improving the performance of swimmers in “real life” sprint
et al., 2017; Sanchez-Sanchez et al., 2018). CA is characterized events, a warm-up protocol that allows swimmers to improve the
by previous voluntary contractions of the requested musculature stages that determine success in a sprint event, such as swim start,
in the task of interest from complex exercises with maximum clean swimming and turning, is still unknown. In that manner,
or close to maximum loads (Hodgson et al., 2005; Batista et al., the hypothesis of the present study is that a CA protocol is likely
2007; Cuenca-Fernández et al., 2015). Previously, it was believed to improve swimming performance in sprint events in all of its
that CA aimed to stimulate short-term neuromuscular and phases. Hence, this study aimed to investigate the influence of
physiological changes generating an initial stress where muscles different CA models on mechanical, neuromuscular and swim
enter into a brief state of “fatigue,” followed by a later potentiation performance parameters.
(Rassier and Macintosh, 2000; Hodgson et al., 2008). The main
mechanism justifying this process is related to the increase of
actin-myosin sensitivity to Ca2 + released by the sarcoplasmic
reticulum resulting in the activation of the myosin light chain MATERIALS AND METHODS
kinase, which favors its phosphorylation (Metzger et al., 1989;
Sale, 2003; Hodgson et al., 2005). Participants
Currently, the scientific community has deepened several Through the G∗ Power software (version 3.1.1.9 – Universitat
reflections on this mechanism, and it is believed that it is Kiel, Germany), using the mean difference in the performance
linked to post-activation potentiation (PAP) which explains the of the 50-m freestyle between the best and the worst protocols
increase in torque caused by an electrical stimulus after a proposed by Sarramian et al. (2015), it was possible to identify
maximum voluntary contraction (Blazevich and Babault, 2019; that 13 participants were necessary for the present study to obtain
Prieske et al., 2020; Zimmermann et al., 2020). Other factors a significant statistical power (sample power of 95%, effect size
(i.e., temperature, muscle activation, muscle and cellular water of 0.898 and t-critical = 1,782). Initially, 18 swimmers were
content) seem to determine whether the stimulus of the CA recruited, but three of them were unable to adapt to the proposed
will sustain an improvement in performance or an improvement exercises, one of the selection criteria, and two suffered injuries
in voluntary strength (Blazevich and Babault, 2019). When over the data collection period. Therefore, we concluded the
there is a positive presence of this behavior, this model has study with a total of thirteen male swimmers (19.46 ± 3.45 years,
been called post-activation performance enhancement (PAPE) 72.02 ± 7.61 kg, and 177.85 ± 5.40 cm). All participants had
(Cuenca-Fernández et al., 2017). a minimum of 3 years of systemized training experience and a
Several studies have shown the efficiency and benefits of using mean performance in the 50-m freestyle of 77% in relation to
CA in swimming. Cuenca-Fernández et al. (2015) verified an World Championship records (Fina, 2015). All participants had
improvement in the performance of the 50-m freestyle by testing a training frequency of at least 5 days a week and were in the
two proposed CA protocols, where protocol 1 was composed specific period of the training season. They received the necessary
of three repetitions at 85% of the one-maximum repetition information about the study, and they confirmed participation
(1RM) for lunges and 4 maximum repetitions of the Yoyo after signing the free and informed consent approved by the
Squat performed on the flywheel, in the comparison with the local Human Research Ethics Committee (School of Physical
standard warm-up. Sarramian et al. (2015) proposed a CA model Education and Sport, Ribeirão Preto, Brazil; protocol number:
that encompassed a combination of maximum repetitions for 60154516.1.0000.5659).

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de Arruda et al. Conditioning Activity on Sprint Swimming

Experimental Design maximum repetitions of pull-ups in the fixed bar and five and box
The study was conducted in the same semi-Olympic swimming jumps 40 cm high and 60 cm deep wearing a vest with 10% of the
pool where the participants trained daily with water temperature body weight. The last protocol (P4), corresponding to the model
maintained at 27◦ C. The whole experiment was carried out in proposed, was the combination of P2 and P3. It is important
the specific preparatory period and lasted 2 weeks involving the to point out that in the 2 months preceding the evaluations,
four protocols, one consisted of a standard warm-up whereas the coaches and physical trainers were instructed to include in the
other three added different conditioning activities for PAP. The training routines of swimmers the exercises that were used as
first week was designed to perform the one-maximum repetition conditioning activity.
test (1RM) according to the model proposed by Brown and Weir
(2001) and three maximal repetitions (3RM) according to the Determination of Neuromuscular
model used by Sarramian et al. (2015) for the lunge exercise Parameters
and pull up, respectively. If it was impossible to determine the The technique defined by Merton (1954) and Allen et al. (1995),
maximum repetition for any participant, the test was repeated on Interpolation Twitch Technique (ITT), was used to evaluate
a different day. In the second week, the swimmers were randomly neuromuscular parameters of the elbow extension musculature
submitted to the four proposed protocols. The evaluation routine (triceps brachii) and knee extensor musculature (rectus femoris).
followed the same principle.
Firstly, the Interpolation Twitch Technique (ITT) was used to Acquisition and Analysis of Strength Levels
determine the neuromuscular parameters followed by a warm- Levels of muscle strength and evoked strength were determined.
up in the swimming pool for 30 min or CA respective to All measurements were performed on the participants’ right limb.
the protocol. Swimmers performed a maximum 50-m freestyle For this purpose, a specific chair was built containing an iron
effort at the individual interval time, ending with a further bar attached to a 200 kg load cell and a velcro strap attached
intervention using the ITT. The individual interval for each at the ankle. For the upper limb, an iron bar on the back of
participant at before the CA of protocols, immediately after 4, the chair allowed a perpendicular extension, also made of iron,
8, and 12 min was determined in another situation through with an adjustable rod containing a 50 kg load cell with velcro
medicine ball throwing, horizontal jump and peak force at strap connecting the handle to the load cell. The participant was
Isometric Maximum Voluntary Contraction (IMVC) in the placed seated, so that the knee, hip and elbow joints were in a
elbow extension musculature and knee extension musculature, 90◦ angle and very well stabilized with reinforced straps on the
enabling the comparison of assessment tools with greater hip, thighs and torso. The force was produced against load cells
muscle activation. The individual interval was considered when (CSR-200 kg; CSR-50 kg, MK Controle , São Paulo – Brazil) to
R

the participant reached the highest activation value and the obtain the data using the LabView 2015 and further analysis in
R

moment with most repetition in the tests in relation to the pre the LabChart 8 software.
R

values. In addition, there was no separation of groups for the

protocols, since all participants performed the four protocols Electrical Stimuli for Knee Extension and Elbow
in a randomized manner. The tests were performed in the Extension
afternoon and evening, according to the participants’ usual At the beginning of each session, the electrical stimulation
training schedule for both stages of the experiment. In addition, intensity was determined in each participant through incremental
an interval of 24-h between the tests was respected for each stimuli. The double electrical stimuli lasted 1 ms with 10 ms
participant, who included a fixed schedule in all assessments. The intervals between them, using a prototype electro stimulator
evaluation of neuromuscular parameters lasted less than 2 min developed specifically for this purpose (Biostimulator, Insight , R

both before and after the 50-m performance. The total duration Ribeirão Preto – Brazil). In the lower limbs, self-adhesive
of each assessment was approximately 1 h for each participant electrodes (5 × 5 cm, Valutrode, Arkts, Santa Tereza, Paraná,
(Figure 1A). BR) were placed on the femoral nerve (cathode) and gluteal fold
(anode) to receive stimulation. The increase in the intensity of
the stimuli occurred until the participant manifested a sensation
Conditioning Activity Protocols of discomfort or attained an intensity in which there is no
Protocol 1 (P1) consisted of a standardized warm-up for 30 min increase in the torque produced by the relaxed muscle. In the
in the water, followed by a 10-min interval and a 50-m freestyle upper limbs, self-adhesive electrodes (5 × 5 cm, Valutrode, Arkts,
maximum performance. The other protocols had the same Santa Tereza, Paraná, Brazil) were positioned on the belly of
logistics, but the warm-up in the pool lasted only 15 min the long head of the triceps brachii (cathode) and the distal
followed by the conditioning activity. This warm-up was at light tendon of the triceps brachii (anode) to receive the electrical
to moderate intensities, with short-term efforts and technical stimulus charge. In contrast, the stimulation threshold assumed
exercises, characteristics of a typical swimming warm-up. The for this musculature was the intensity corresponding to the
stimuli were similar to the P1 warm-up, but only a half of the highest torque produced without apparently influencing the
series were performed. Protocol 2 (P2) used as a conditioning contraction of the biceps brachii (Norberto et al., 2020). Once
activity three repetitions with 85% 1RM for the lunge exercise the stimulation thresholds were determined, the intensity of the
(Cuenca-Fernández et al., 2015). The protocol 3 (P3) followed the electrical stimulus was assumed for both limbs. The maximal
model proposed by Sarramian et al. (2015), composed by three electrical current achieved in the knee extension was assumed

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de Arruda et al. Conditioning Activity on Sprint Swimming

FIGURE 1 | (A) Experimental design and the timeline of the evaluations. (B) Scheme of the positioning of the cameras and markings for analysing the variables
coming from the block exit (C1), clean swimming (C2) and turns (C3). 1RM: one-maximum repetition test; 3RM: three maximal repetitions. Protocol 1: standard
warm-up in the pool (30 m); Protocol 2: 15 m warm-up in the pool and 1 × 3 repetitions at 85% 1RM for the lunge exercise; Protocol 3: 15 m warm-up in the poll
and three maximum repetitions of pull-ups in the fixed bar and five box jumps 40 cm high and 60 cm deep wearing a vest with 10% of the body weight; Protocol 4:
model proposed combining Protocol 2 and Protocol 3; Lightning symbol: Interpolation Twitch Technique.

FIGURE 2 | Swimmer used markers produced with 2 × 2 cm elastic bandages on the ankle, knee, hip and shoulder axes for tracking during locomotion. Points
marked on the joints of interest to determine the mechanical parameters at the time of the block exit using Dvideo R software was used by the Direct Linear
Transformation (DLT) method.

and supramaximal stimulation was ensured by increasing the of knee extension musculature (PFK ) consisted of an electric
final intensity by 20%, whereas for elbow extension the maximum stimulus applied during IMVC for the determination of the
amperage that generated the highest peak strength in the upper Superimposed Twitch of the knee extension musculature (SITK ),
limb was applied. calculated by the difference between the IMVC mean force and
the force evoked by the electrical stimulation during contraction.
Protocol for the Evaluation of Neuromuscular Another electrical stimulus was applied after IMVC, with the
Parameters muscles relaxed, for the determination of the Peak Twitch of
Swimmers performed an IMVC with a duration of 5 s for both the knee extension musculature (PTK ). Both parameters enable
the lower and upper limbs. The determination of Peak Force the determination of the percentage of voluntary activation

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de Arruda et al. Conditioning Activity on Sprint Swimming

TABLE 1 | Comparison of statistical methods (ANOVA, Effect Size and Magnitude Based Inferences) used for analysis and conclusions of the main results.

ANOVA Effect Size/MBI Conclusions

PFE Protocol 1 was different than P2, P1 produced a negative effect in relation to the other Values increased in P2, P3, and P4 and decrease in P1
P3, and P4 protocols
PTE No differences P1, P2, and P3: negative effect. P4 remained trivial Values decreased in P1, P2, and P3
PFK No differences All protocols trivial No differences
PTK No differences All protocols produced a negative effect Values decreased, but without differences
SITK P1 different from P3 Protocol 3 produced a negative effect P3 was the only protocol that had a drop in these values.
The others were greater than P1
VA Protocol 1 different from P3 P2 and P3: probable positive P1 values tend to decrease, and P2 and P3 had an
increase in voluntary activation
VXH P1 was different from P2 and P3 Probable negative for P2, P3 and P4 All protocols values decreased in relation to P1
FT P1 was different from P2 and P3 Most likely positive for P2 and likely positive for P3 The swimmers maintained more time in the air compared to
protocol 1

PFE , Peak Force of elbow extension; PTE , Peak Twitch of the elbow extension musculature; PFK , Peak Force of knee extension; PTK , Peak Twitch of knee extension;
SITK , Superimposed Twitch of the knee extension musculature; VA, voluntary activation; V X H, Mean of the horizontal hip speed; FT, Flight Time.

(VA) (Gandevia, 2001). For the elbow extension musculature, Angle of Take-off (AT): angle referring to the horizontal line
it was possible to determine the Peak Force of elbow extension and the line of body mass center, at the moment of the last contact
musculature (PFE ) through 5 s IMVC followed by an electric of the foot with the block at the swim start (Seifert et al., 2010);
stimulation in the relaxed muscle (Peak Twitch of the elbow Angle of Entry (AE): angle referring to the horizontal line and
extension musculature – PTE ). the line of body mass center, at the moment of the swimmer’s first
contact with the water (Seifert et al., 2010);
Block Exit Time (BT): time between the moment of the signal
Determination of Mechanical Parameters to exit the block until the moment the swimmer leaves the block
and Performance at the swim start;
Swimmers were submitted to the maximum effort in the 50-m Mean angular velocity of knee extension (VωK): angular
freestyle, filmed by three camcorders to determine biomechanical difference between the moment of maximum extension of the
parameters (Figure 1B). The first camera was positioned for the knees by the moment of knee flexion, divided by the time of this
analysis of the swim start (CASIO Exilim FH-25), the second
R
action;
for all course and clean swimming (GoPro HERO3 +), and R
Time in 5-m (T5 ): time from the signal to exit the block until
the third was exclusive for the turns (GoPro HERO3 +). All R
the swimmer’s head reaches the 5-m line;
of them were configured with a sampling frequency of 30 Hz. Time in 15-m (T15 ): time from the signal to exit the block until
In addition, a light signal was used as a reference to the starting the swimmer’s head reaches the 15-m line.
signal in the video. Time in 25-m (T25 ): time from the signal to exit the block until
the swimmer touches the wall at the turn.
Swim Start Time in 50-m (T50 ): time from the swimmer’s touch on the
Elastic band markers with 2 × 2 cm size were used at wall at the turn until the swimmer finishes the effort.
points related to the lateral axis of the ankle, knee, hip, and Total Time (T): time from the signal to exit the block until the
shoulder joints for tracking during locomotion. To obtain the swimmer finish the effort.
two-dimensional kinematic variables of the block exit, the
Dvideo software was utilized to perform the Direct Linear
R Clean Swim
Transformation (DLT) method (Figure 2). Later, through a In relation to the determination of the kinematic parameters of
routine developed in MatLab 2014 environment, it was possible
R the stroke, markers were placed at 7 meters from each edge of the
to determine the values of the following variables coming from swimming pool, for analysis of the 11 meters referring to the clean
the block at the swim start (Cuenca-Fernández et al., 2015): swim. Within this segment, from the number of strokes (NS), we
Distance of the Dive (DD) in meters: distance from the block analyzed: stroke frequency (SF) – the ratio of stroke number by
at the swim start to the first contact of the swimmer with the water time; stroke length (SL) – the ratio of stroke number by distance
(Jorgić et al., 2010); traveled; stroke index (SI) – product of velocity by stroke length,
Flight Time (FT) in seconds: time between the last contact variables in the first half of the sprint (NS25 , SF25 , and SL25 ) and
of the feet in the block and the entry of the fingers in the water second half of the sprint (NS50 , SF50 , and SL50 ). These variables
(Jorgić et al., 2010); were analyzed using Kinovea software (version 0.8.15).
Mean of the horizontal hip speed (V X H) in meters/second: it
is the ratio of the distance between the last contact of the feet with Turns
the exit block to the entry of the fingers in the water by the time The turn segment was understood as the moment when the
elapsed for that action; swimmer performs the last stroke (approximation) until the end

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de Arruda et al. Conditioning Activity on Sprint Swimming

FIGURE 3 | Mean ± standard deviation of the variables obtained in the elbow and knee extension musculature before and after the effort of 50-m. PFE : Peak Force
of elbow extension musculature; PTE : Peak Twitch of elbow extension musculature; PFK : Peak Force of knee extension musculature; PTK : Peak Twitch of knee
extension musculature; SITK : Superimposed Twitch of knee extension musculature; VA: Voluntary Activity.

of the slide and starts the clean swim (Hay, 1978). Markers the spreadsheets proposed by Hopkins et al. (2009). The effects
were placed at 7 meters from each edge of the swimming on neuromuscular, biomechanical and performance parameters
pool for analysis of the turnaround time (TA), calculated from were classified qualitatively as an increase effect, trivial effect
the approximation to the demarcated distance by utilizing the or decrease effect. For this, the differences from baseline values
swimmer’s head traced as a reference. The analyses were also were expressed as standardized differences (Cohen’s d) and the
conducted using the Kinovea software (version 0.8.15). smallest standardized change was assumed to be 0.20 (Cohen,
1988). Qualitative inferences were classified as most unlikely
Statistical Analysis (<1%), very unlikely (1–5%), unlikely (5–25%), possibly (25–
The normality of the data was confirmed using the Shapiro– 75%), likely (75–95%), very likely (95–99%), and most likely
Wilk test, which allowed the description of the variables using (>99%). The inference was Unclear when both the increase and
mean ± standard deviation. The values observed were compared the decrease effects were >5%. Conventional statistical methods
with baseline values using the Magnitude Based Inferences using were also carried out for this analysis. A paired t-test was used

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de Arruda et al. Conditioning Activity on Sprint Swimming

FIGURE 4 | Effect size ± IC90% values used for Magnitude Based Inferences of differences between pre and post moments for the variables obtained in the elbow
and knee extension musculature in all protocols. The area in grey represents the trivial differences. PFE : Peak Force of elbow extension musculature; PTE : Peak
Twitch of elbow extension musculature; PFK : Peak Force of knee extension musculature; PTK : Peak Twitch of knee extension musculature; SITK : Superimposed
Twitch of knee extension musculature; VA: Voluntary Activity; Protocol 1: standard warm-up in the pool (30 m); Protocol 2: 15 m warm-up in the pool and 1 × 3
repetitions at 85% 1RM for the lunge exercise; Protocol 3: 15 m warm-up in the poll and three maximum repetitions of pull-ups in the fixed bar and five box jumps
40 cm high and 60 cm deep wearing a vest with 10% of the body weight; Protocol 4: model proposed combining Protocol 2 and Protocol 3. M.L.Trivial: most likely
trivial; L.Trivial: likely trivial; L. +ive: likely positive; L. -ive: likely negative; L. Trivial : likely trivial; P. +ive: possibly positive; P. Trivial: possibly trivial.

to verify the differences between neuromuscular parameters in Nevertheless, in the Table 1, a simple comparison between the
the moments before and after each 50-m effort for each protocol. statistical models follows.
To verify the differences between the protocols based on the
parameters of interest, ANOVA was performed for repeated Neuromuscular Variables
measures. Eta squared (η2 ) was interpreted as trivial (effect size Figures 3, 4 present the values observed and analyses of
<0.1), small (effect size >0.1), medium (effect size >0.25) or neuromuscular variables obtained in the elbow extension
large (effect size >0.37). Significance level assumed was p < 0.05, musculature and knee extension musculature after the 50-m
followed by the Bonferroni post hoc when necessary. All analyses freestyle effort.
were performed using SPSS version 20.0 (SPSS Inc., Chicago, IL). The PFE presented lower values after the 50-m effort
performed with P1 (Likely negative: 01/07/92; ES: small), whereas,
their values were higher in the comparison with P4 (Likely
RESULTS positive: 83/17/00; ES: small). When P2 and P3 were applied,
PFE presented Trivial differences (00/100/00; ES: small, for both)
Statistical Models in relation to resting values. The PTE presented lower values
From the results found, we can conclude that both statistical after P1 (Likely negative: 01/10/89; ES: small), P2 (Likely negative:
models presented practically the same results, without altering 01/10/89; ES: small) and P3 (Likely negative: 01/09/90; ES: small).
the idea, context and conclusions of the manuscript and therefore P4 seems to have maintained the values of PTE (Likely negative:
Magnitude Based Inferences were adopted to present the results. 00/96/4; ES: negligible).
We believe it is valid to present only the effects of the protocols The PFK was not altered after the 50-m effort by performing
on the variables, since for sports, minimal changes can determine P1, P2, P4 (Most Likely Trivial: 00/100/00; ES: negligible, for all)
success in performance. This type of analysis has been discussed and P3 (Possibly Trivial: 00/53/47; ES: negligible). Differently,
in the scientific community (Bernards et al., 2017; Marcelino PTK presented values Likely negative with P2 (00/44/36; ES:
et al., 2019) and is often accepted for publication of the negligible) and Likely negative with P1 (00/08/92; ES: small), P3
results. In fact, the proposed protocol was not efficient to (00/20/80; ES: negligible) and P4 (01/07/92; ES: small). SITK was
generate improvements in the maximum 50-m freestyle effort. not modified with P1 (Likely Trivial: 20/80/00; ES: negligible) and

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de Arruda et al. Conditioning Activity on Sprint Swimming

with P4 (Most Likely Trivial: 00/100/00; ES: negligible). However, ES: negligible) and T (Likely of Trivial: 00/100/00; ES: negligible).
SITK was higher with P2 (Likely positive: 82/18/00; ES: small) and In addition, the TA presented higher values with P4 in relation to
lower with P3 (Possibly Trivial: 00/12/88; ES: small). The VA was the values observed with P1 (Likely positive: 86/14/00; ES: small).
not altered with P4 after the 50-m effort (Most Likely Trivial:
00/100/00; ES: negligible), but presented higher values after the
50-m effort with P2 (Likely positive: 69/31/00; ES: negligible) DISCUSSION
and P3 (Likely positive: 64/36/00; ES: negligible). Differently,
VA presented lower values with P1 after the 50-m effort (Likely The present study aimed to investigate the influence of
negative: 00/31/69; ES: negligible). different conditioning activity protocols on mechanical and
neuromuscular parameters of the 50-m freestyle swimming. We
Kinematic Variables hypothesized it would be possible to propose a conditioning
The kinematic variables observed at the swim start and during activity model that could improve the performance of the 50-m
clean swim in each protocol are presented in Table 2. Analyses freestyle in all phases (swim start, clean swim and turns), and not
on the magnitude of the differences between P1 and CA protocols only in specific segments. The main finding of the study was the
are presented in Table 3. DD presented higher values in P1 than proposed model of conditioning activity was not superior than
those observed in P2 (ES: negligible) and P4 (ES: negligible) the standard warm-up. In addition, protocol 2 presented a trend
protocols, which did not occur with P3 (ES: negligible). V X H toward improvement in most of the variables analyzed and the
was lower with all CA protocols applied (ES: between negligible closest to generating results similar to the standard warm-up.
and moderate). AE was lower with P2 (ES: small), which did Regarding the neuromuscular parameters, the protocols
not occur with P3 (ES: negligible) and P4 (ES: negligible). No promoted a decrease in PTE and PTK , except for P2 that remained
effect of the CA protocols was evidenced for AE (ES: negligible). trivial. These results evidence the occurrence of peripheral fatigue
VωK was higher with P3, but did not change with P2 and P4 after the 50-m freestyle effort. Xenofondos et al. (2015) evaluated
(ES: negligible). the possible influences of neural mechanisms in relation to
No effect of the CA protocols was observed for the parameters PAP using maximal voluntary contraction with duration of 10 s
obtained in the first 25-m of effort (ES: negligible, for all). Similar and did not observe an increase in the excitability of motor
results were observed in the parameters obtained in the 50-m neurons, a characteristic that may limit the occurrence of PAP.
effort, with P2 and P4 (ES: negligible). However, the NS50 and They also concluded that the occurrence of PAP may be more
SL50 presented higher values with P3 in relation to P1 (ES: small), related to peripheral factors, which may cause decrease in muscle
which did not occur for SF50 and SI50 (ES: negligible). contractile activity (Fitts, 1994) due to several factors such as
accumulation of H+ ions and decrease in blood pH, leading to
Performance deficiency of calcium transport into the muscle (Sahlin, 1986), an
Table 3 shows the performance values obtained during the effort extremely important mechanism for triggering PAP (Sale, 2003;
of the 50-m freestyle after each CA protocol. Analyses of the Hodgson et al., 2008).
magnitude of the differences between P1 and the CA protocols In addition, PTE and PTK are related to type II fibers
are presented in Tables 2 and Tables 3. (Vandervoort and McComas, 1983), the main fiber type recruited
Time was lower in P2 for BT (Likely negative: 00/19/81; ES: in short-term events (Hamada et al., 2000), which may also
small), TS (Likely negative: 01/05/94; ES: moderate), T5 (Likely explain the decrease in strength values for these variables. It was
negative: 91; ES: small) and TA (Likely negative: 00/15/84; ES: evidenced a rise in VA in protocols P2 and P3 in comparison
small). However, with P2, FT was higher than P1 (Likely positive: to P1. This increase is not only related to the peripheral
95/04/01; ES: moderate) and no effect was observed for T15 (Most factors, especially if there is a decrease in SITK strength values,
Likely Trivial: 00/100/00; ES: negligible), T25 (Most Likely Trivial: but also indicates the occurrence of central fatigue, as it was
00/100/00; ES: negligible) and T (Most Likely Trivial: 00/100/00; the case with P3. This effect can also be explained by the
ES: negligible). relationship of exercise complexity and increased intramuscular
Although P3 did not decrease BT (Most Likely Trivial: and intermuscular coordination (Zhi et al., 2005; Tillin and
00/100/00; ES: negligible), lower times were observed in the Bishop, 2009), especially for pull ups, since high loads are
comparison with P1 for TS (Likely negative: 01/09/90; ES: small), required for this exercise as a conditioning activity to achieve
T5 (Likely negative: 00/15/85; ES: small) and TA (Likely negative: PAP. Nonetheless, some participants were unable to perform
00/09/91; ES: small). However, time increased in T15 (Likely the three maximum repetitions of pull ups beyond their body
positive: 63/37/00; ES: negligible), T25 (Likely positive: 65/35/00; weight and others were aided by an elastic with medium strength
ES: negligible), T50 (Likely positive: 86/14/00; ES: small) and T intensity, which may have negatively influenced the results of
(Likely positive: 82/18/00; ES: small). neuromuscular parameters for this protocol.
Despite the fact that P4 had decreased TS (Likely negative: The phases of the swim start and turn in the 50-m freestyle
01/11/88; ES: small), T5 (Likely negative: 01/06/93; ES: small) and event in a semi-Olympic swimming pool seem to be determinant
TA (Likely negative: 00/16/84; ES: small), no effect on P1 was for a satisfactory result (Hay, 1978; Miyashita, 1996). Cuenca-
observed for BT (Most Likely Trivial: 00/100/00; ES: negligible), Fernández et al. (2015) corroborated these results, where they
T15 (Likely Trivial: 00/79/21; ES: negligible), T25 (Most Likely observed an improvement in the swim start by using a CA
Trivial: 00/100/00, ES: negligible), T50 (Likely Trivial: 33/67/00; protocol in relation to a standard warm-up and therefore, we

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de Arruda et al. Conditioning Activity on Sprint Swimming

TABLE 2 | Description of the kinematic variables in the swim start, clean swim, turns and performance observed in the different protocols.

P1 P2 P3 P4

Swim Start
DD (cm) 375.95 ± 25.91 383.56 ± 24.73 380.80 ± 28.46 382.38 ± 30.29
V X H (m.s−1 ) 4.39 ± 0.84 3.22 ± 1.70 4.05 ± 0.80 4.09 ± 0.95
AT (◦) 36.15 ± 14.93 28.18 ± 18.43 35.57 ± 15.55 33.77 ± 17.38
AE (◦) 31.97 ± 13.13 29.61 ± 10.45 30.10 ± 10.91 30.41 ± 12.86
VωK (◦.s−1 ) 40.77 ± 26.42 41.12 ± 32.76 48.15 ± 29.60 44.57 ± 21.40
Clean swim
NS25 9.92 ± 1.68 9.82 ± 1.83 10.17 ± 1.75 10.17 ± 1.53
NS50 11.42 ± 1.83 11.69 ± 1.65 12.17 ± 2.04 11.67 ± 1.23
SF25 (Hz) 1.16 ± 0.15 1.51 ± 0.31 1.52 ± 0.24 1.53 ± 0.26
SF50 (Hz) 1.43 ± 0.15 1.75 ± 0.22 1.76 ± 0.26 1.74 ± 0.19
SL25 (m) 0.90 ± 0.15 0.89 ± 0.17 0.92 ± 0.16 0.92 ± 0.14
SL50 (m) 1.04 ± 0.17 1.06 ± 0.15 1.11 ± 0.19 1.06 ± 0.11
SI25 (m2 .s) 1.53 ± 0.21 1.51 ± 0.31 1.52 ± 0.24 1.53 ± 0.26
SI50 (m2 .s) 1.73 ± 0.21 1.75 ± 0.22 1.76 ± 0.26 1.74 ± 0.19
Turns
TA (s) 3.30 ± 0.38 3.17 ± 0.30 3.12 ± 0.28 3.17 ± 0.34
Performance
BT (s) 1.00 ± 1.06 0.88 ± 0.26 1.01 ± 0.53 1.01 ± 0.48
FT (s) 0.89 ± 0.21 1.92 ± 1.74 0.97 ± 0.20 0.99 ± 0.29
TS (s) 3.01 ± 0.12 2.44 ± 1.15 2.93 ± 0.16 2.93 ± 0.20
T5 (s) 1.57 ± 0.40 1.39 ± 0.19 1.46 ± 0.16 1.37 ± 0.10
T15 (s) 7.59 ± 0.35 7.58 ± 0.50 7.69 ± 0.47 7.53 ± 0.47
T25 (s) 13.31 ± 0.61 13.26 ± 0.74 13.47 ± 0.66 13.31 ± 0.82
T50 (s) 13.69 ± 0.71 13.83 ± 0.66 13.98 ± 0.67 13.81 ± 0.71
T (s) 27.01 ± 1.18 27.01 ± 1.25 27.44 ± 1.26 27.12 ± 1.44

P1, standard warm-up; P2, lunge exercise; P3, pull-up and box jump exercise; P4, model proposed; DD, distance of the dive; V X H, Mean of the horizontal hip speed;
BT, block exit time; FT, flight time; TS, time submersed; AT, angle of take-off; AE, angle of entry; VωK, Mean angular velocity of knee extension; T5 , time in five meters; T15 ,
time in fifteen meters; T25 , time in twenty-five meters; T50 , time in the second half of the sprint; NS25 , number of strokes in 25 m; NS50 , number of strokes in the second
half of the sprint; SF25 , stroke frequency in 25 m; SF50 , stroke frequency in the second half of the sprint; SL25 , stroke length in 25 m; SL50 , stroke length in the second
half of the sprint; SI25 , stroke index in 25 m; SI50 , stroke index in the second half of the sprint; TA, turnaround time; T, total time (time from the signal to exit the block until
the swimmer finish the effort).

can confirm the use of the exercise lunge to improve the swim horizontal and vertical jumps and concluded that for the swim
start parameters. V X H is an important variable at the swim start horizontal plyometric exercises are more determinant to
start, since it is dependent on DD and FT. Although there increase the rate of force development in comparison to vertical
was an increase in DD and FT (positive effect), there was no exercises and therefore favor a greater impulse in the block.
increase in V X H. This can be explained by the PFK values Since horizontal plyometric exercises cause a positive effect, P4
that have remained trivial in the different protocols. The increase could present the same results, but this was not evidenced.
in PFK values leads to a greater recruitment of muscle fibers The main explanation may be the influence of the lunge
and electromyographic activity of the muscle and can directly exercise under the plyometric exercise due to the complexity of
influence the force applied at the moment of the impulse to the intramuscular and intermuscular coordination with high loads
exit jump (Breed and Young, 2003). in this exercise.
Possibly, the CA protocols tested were not efficient for Clean swim parameters showed that CA protocols remained
increasing the recruitment of the fibers needed for a rise in PFK trivial in comparison to the standard model. However, P3 had
and other variables. Only P3 presented an increase in VωK, a small negative effect on the NS50 and SL50 with an increase
which is the variable that corresponds to the fastest start swim in these variables, which can be explained by the decrease
and is related to vertical jump improvement (Breed and Young, in swimming speed and the rise of the time in the course,
2003; Rebutini et al., 2016; Cuenca-Fernández et al., 2019). In even with the SF50 values remaining trivial. It is likely that a
the present study, a jump was performed on the box, which peripheral fatigue syndrome was established in this protocol,
may have influenced the improvement or maintenance of since the values were lower in PTE and PTK after maximum effort
the values of this variable. Rebutini et al. (2016) compared in 50-m freestyle.

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de Arruda et al. Conditioning Activity on Sprint Swimming

TABLE 3 | Magnitude of the differences between Protocol 1 and conditioning activity for kinematic variables observed at the swim start, clean swim, turns and
performance in each protocol.

P2 vs. P1 P3 vs. P1 P4 vs. P1

ES ± IC90% + ive./T/-ive Inference ES ± IC90% + ive./T/-ive Inference ES ± IC90% + ive./T/-ive Inference

Swim Start
DD (cm) 0.30 ± 0.30 83/16/0 P. + ive 0.18 ± 0.15 40/60/0 P. Trivial 0.23 ± 0.19 61/39/0 P. + ive
V X H (m.s−1 ) −0.92 ± 0.63 1/6/93 L. − ive −0.41 ± 0.33 0/14/86 L. − ive −0.33 ± 0.27 0/20/80 L. − ive
AT (◦) −0.48 ± 0.32 0/15/85 L. − ive −0.04 ± 0.03 0/100/0 M.L.Trivial −0.15 ± 0.12 0/77/23 L. Trivial
AE (◦) −0.20 ± 0.11 0/88/13 L. Trivial −0.16 ± 0.13 0/73/27 L. Trivial −0.12 ± 0.10 0/91/9 L. Trivial
VωK (◦.s−1 ) 0.01 ± 0.25 0/100/0 M.L. Trivial 0.26 ± 0.22 70/30/0 L. + ive 0.16 ± 0.13 29/71/0 L. Trivial
Clean Swim
NS25 −0.06 ± 0.05 0/100/0 M.L.Trivial 0.15 ± 0.12 22/78/0 L. Trivial 0.16 ± 0.13 28/72/0 P. Trivial
NS50 0.16 ± 0.13 29/71/0 P. Trivial 0.39 ± 0.32 84/15/0 L. + ive 0.16 ± 0.13 32/68/0 P. Trivial
SF25 (Hz) −0.08 ± 0.07 0/100/0 M.L.Trivial −0.06 ± 0.05 0/100/0 M.L.Trivial −0.02 ± 0.01 0/100/0 M.L.Trivial
SF50 (Hz) 0.07 ± 0.06 0/100/0 M.L.Trivial 0.12 ± 0.10 0/91/9 L. Trivial 0.02 ± 0.02 0/100/0 M.L.Trivial
SL25 (m) −0.06 ± 0.05 0/100/0 M.L.Trivial 0.15 ± 0.12 22/78/0 L. Trivial 0.16 ± 0.13 28/72/0 P. Trivial
SL50 (m) 0.16 ± 0.13 37/63/0 P. Trivial 0.39 ± 0.32 84/15/0 L. + ive 0.16 ± 0.13 32/68/0 P. Trivial
SI25 (m2 .s) −0.08 ± 0.07 0/100/0 M.L.Trivial −0.06 ± 0.05 0/100/0 M.L.Trivial −0.02 ± 0.01 0/100/0 M.L.Trivial
SI50 (m2 .s) 0.07 ± 0.06 0/100/0 M.L. Trivial 0.12 ± 0.10 0/91/9 L. Trivial 0.02 ± 0.02 0/100/0 M.L.Trivial
Turns
TA (s) −0.39 ± 0.32 0/15/84 L. − ive −0.55 ± 0.45 1/9/91 L. − ive −0.37 ± 0.31 0/16/84 L. − ive
Performance
BT (s) −0,34 ± 0.28 0/19/81 L. − ive 0.02 ± 0.02 0/100/0 M.L.Trivial 0.03 ± 0.02 0/100/0 L. + ive
FT (s) 1,06 ± 0.86 95/4/1 L. + ive 0.39 ± 0.32 85/15/0 L. + ive 0.41 ± 0.43 86/14/0 L. − ive
TS (s) −0.90 ± 0.73 1/5/94 L. − ive −0.53 ± 0.44 1/9/90 L. − ive −0.47 ± 0.38 0/11/88 L. − ive
T5 (s) −0.59 ± 0.48 1/8/91 L. − ive −0.40 ± 0.32 0/15/85 L. − ive −0.77 ± 0.63 1/6/93 L. − ive
T15 (s) −0.02 ± 0.01 0/100/0 M.L. Trivial 0.24 ± 0.19 63/17/0 P. + ive −0.14 ± 0.12 0/79/21 L. Trivial
T25 (s) −0.08 ± 0.07 0/100/0 M.L. Trivial 0.24 ± 0.20 65/35/0 P. + ive 0 0/100/0 M.L. Trivial
T50 (s) 0.20 ± 0.16 50/50/0 P. + ive 0.41 ± 0.33 86/14/0 L. + ive 0.17 ± 0.14 33/67/0 P. Trivial
T (s) 0 0/100/0 M.L. Trivial 0.36 ± 0.29 82/18/0 L. + ive 0.09 ± 0.07 0/100/0 M.L. Trivial

P1, standard warm-up; P2, lunge exercise; P3, pull-up and box jump exercise; P4, hybrid model of potentiation; ES, Effect size; IC90%, confidence interval of 90%;
+ ive/T/-neg, the first protocol presents value higher than the second/trivial differences/the first protocol presents values lower than the second. P1, standard warm-up;
P2, lunge exercise; P3, pull-up and box jump exercise; P4, model proposed; DD, distance of the dive; V X H, Mean of the horizontal hip speed; BT, block exit time; FT,
flight time; TS, time submersed; AT, angle of take-off; AE, angle of entry; VωK, Mean angular velocity of knee extension; T5 , time in five meters; T15 , time in fifteen meters;
T25 , time in twenty-five meters; T50 , time in the second half of the sprint; NS25 , number of strokes in 25 m; NS50 , number of strokes in the second half of the sprint;
SF25 , stroke frequency in 25 m; SF50 , stroke frequency in the second half of the sprint; SL25 , stroke length in 25 m; SL50 , stroke length in the second half of the sprint;
SI25 , stroke index in 25 m; SI50 , stroke index in the second half of the sprint; TA, turnaround time; T, total time (time from the signal to exit the block until the swimmer
finish the effort). M.L.Trivial, most likely trivial; L.Trivial, likely trivial; L. + ive, likely positive; L. – ive, likely negative; L. Trivial, likely trivial; P. + ive, possibly positive; P. Trivial,
possibly trivial.

Swim speed showed a decrease throughout the course in conditioning activity used is determinant for the improvement
all protocols. That is already expected in sprint swimming of swimmers’ performance.
events because mechanical stroke parameters may influence
the energy cost of swimmers due to the mechanical work Limitations of the Study
relationship and mechanical efficiency (Barbosa et al., 2008). The main influencing factor was the time interval between
We can assume that P3 improved swimmers efficiency by evaluations. We might have obtained different results if
increasing SL50 and decreasing the energy cost (Keskinen and the interval between evaluations lasted longer than 24 h.
Komi, 1993; Nomura and Shimoyama, 2003), but not necessarily Besides, other stages of the participants’ training, such as
better than the other protocols due to the worsening in time the taper or competition period, could have been taken into
in this segment. In order to achieve a satisfactory maximum consideration. Furthermore, psychological parameters could
performance, the combination of SL and SF must be manipulated, have been monitored, in addition to the arrangements of
since the increase of both can result in higher speeds and physiological variables, because the warm-up is a moment of
shorter times. Nonetheless, we found a positive effect on time concentration and preparation for the event strategy, which may
in the different effort segments, mainly in P2, which remained directly influence performance (Bishop, 2003).
closer to the standard warm-up. P4 also approached P1 values Moreover, the intensity and volume of the warm-up in the
in the time variables, and this shows us that in fact the water may have been insufficient to cause the necessary changes
proposed protocol can be an alternative because it presents for potentiation to occur and prepare the body for the effort
a similar behavior similar to P2 and P1. In addition, the (Neiva et al., 2014). It would be interesting to monitor body

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de Arruda et al. Conditioning Activity on Sprint Swimming

temperature at rest, after performing the conditioning activity residual peripheral fatigue. The different protocols tested
and after the 50-m freestyle, since this variable is one of the warm- influenced specific segments of the swimming phases, confirming
up’s main goals. Sargeant (1987) showed that 1◦ C increase in the importance of the different conditioning activities applied
muscle temperature may induce an improvement of up to 4% in relation to the kinematic and neuromuscular parameters in
in leg muscle strength, as well as maintaining core temperature swimming sprint events. Therefore, it is possible to individualize
and increasing hemoglobin concentrations in the upper body the stimuli during the warm-up and adjust the use of the different
are factors which may show improvement in the 100-m freestyle conditioning activity protocols to improve performance variables
(Mcgowan et al., 2017). Therefore, it is critical to consider the that can be enhanced throughout the competitive period.
most effective strategy for maintaining the athlete’s temperature.
These may be some influencing variables, however, it is
possible that even if the potentiation of the musculature of DATA AVAILABILITY STATEMENT
interest mediated by the conditioning activity occurs, in fact,
performance is unlikely to increase due to difference in stimuli The raw data supporting the conclusions of this article will be
between those caused by CA and those from the swimming event, made available by the authors, without undue reservation.
even if they are similar to the mechanics of the sport (Young
et al., 1998; Duthie et al., 2002). Moreover, filming the evaluations
at the swimming pool was very challenging, especially the block ETHICS STATEMENT
exit. It limited us to adopt a low acquisition frequency for further
analysis, even with cameras that support the higher frequencies. The studies involving human participants were reviewed and
The swimming pool in which we carried out the evaluations is approved by School of Physical Education and Sport, Ribeirão
covered and even though all the spotlights were on or with the Preto, Brazil; protocol number: 60154516.1.0000.5659. Written
help of sunlight, there was significant reflection and low lighting. informed consent to participate in this study was provided by the
Some tests were performed, and the most desirable acquisition participants’ legal guardian/next of kin.
was obtained at 30 Hz. Hence, we built a calibration panel made
of PVC pipes and plastic canvas, 2.5 × 3 meters in size, containing
42 reference points with a fixed distance of 50 cm between them. AUTHOR CONTRIBUTIONS
This apparatus was positioned next to the exit block, supported
by two inextensible commercial cords so that it could face the The original study designer was made by TA and RB. VA and
camera (Figure 2). At each evaluation, a stick was passed with CK-F contributed to the data collect and analysis. All authors
two markers with a distance of 50 cm between them so that it was contributed to the drafting and revising the manuscript.
possible to determine the accuracy (2.30 ± 0.29 cm) and precision
(0.74 ± 0.08 cm) of the measurement. These events were recorded
utilizing the camera (CASIO Exilim FH-25) attached to the side
R FUNDING
of the swimming pool with a focus on the block exit. In that
manner, we achieved good results in these variables and close to This work was supported by a grant from the Fundação de
what is presented in the literature, which allowed for validity for Amparo à Pesquisa do Estado de São Paulo (FAPESP), process
the comparisons made in the present study. no. 2016/10029-4. This work was also supported by FAPESP,
process no. 2016/12781-5 to MP.

CONCLUSION
ACKNOWLEDGMENTS
The proposed conditioning activity protocol was not efficient for
performance improvement at the 50-m freestyle swimming in The authors would like to thank all members of the Group of
relation to the standard warm-up possibly because it presented Studies in Physiological Science and Exercise (GECIFEX).

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et al. (2015). Post-activation potentiation: the neural effects of post—activation absence of any commercial or financial relationships that could be construed as a
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