Rev Bras Fisiol exerc 2020;19(5):377-85
doi: 10.33233/rbfex.v19i5.3893
ORIGINAL
ARTICLE
Muscular
strength and aerobic resistance: are there differences of physical performance
during the stages of two menstrual cycles?
Força muscular e
resistência aeróbia: existem diferenças de desempenho físico durante as fases
de dois ciclos menstruais?
Isadora Cristina
Ribeiro1, Leonardo Henrique Fernandes Carvalho2, Anderson Souza Oliveira3, Carlos Roberto Padovani4,
João Paulo Borin5
1School of Medical Sciences, University of Campinas, Campinas, SP,
Brazil
2School of Physical Education, University of Campinas, Campinas, SP,
Brazil
3Aalborg University, Aalborg, Denmark
4São Paulo University Júlio de Mesquita Filho, Botucatu, SP, Brazil
5University of Campinas, Campinas, SP, Brazil
Received
on: January 9, 2020; Accepted on: August 21, 2020.
Corresponding author: Isadora Cristina
Ribeiro, Rua Tessália Vieria de Camargo, 126 Cidade
Universitária Zeferino Vaz 13083-887 Campinas SP, Brazil
Isadora Cristina
Ribeiro: isadora.cr@hotmail.com
Leonardo Henrique
Fernandes Carvalho: leo_carvalho_1994@hotmail.com
Anderson Souza Oliveira:
oliveira@mp.aau.dk
Carlos Roberto Padovani:
cr.padovani@unesp.br
João Paulo Borin: borinjp@fef.unicamp.br
Abstract
Introduction: The
menstrual cycle has been pointed as a possible factor of interference in the
physical training, but the relation between its different phases and the
physical performance has been recent target of investigation. Aim: To verify the physical performance in the motor capacities of
aerobic resistance and muscular strength during the menstrual cycle phases.
Methods: During two complete menstrual cycles, 12 healthy, active and oral contraceptive
women underwent a training protocol. During training were evaluated for
physical performance in each phase of each cycle through the tests: Yo Yo Test 1 and one repetition
maximum test (1RM) for exercises in the leg extension, bench press, leg curl
and rower machine. Results: We point to a reduction of the resistance
performance in the follicular phase for both menstrual cycles evaluated. The
behavior of muscle strength was significantly higher in the second cycle for
the bench press and leg curl exercises. Conclusion: The performance on
resistance capacity in active women, when evaluated in two menstrual cycles, is
lower in the follicular phase, while the muscular strength performance was not
influenced by the menstrual cycle phases.
Keywords: physical fitness; exercise; women.
Resumo
Introdução: O ciclo menstrual tem
sido apontado como um possível fator de interferência no treinamento físico,
porém a relação entre suas diferentes fases e o desempenho físico tem sido alvo
recente de investigação. Objetivo: Verificar o
desempenho físico nas capacidades biomotoras de
resistência aeróbia e força muscular durante as fases do ciclo menstrual.
Métodos: Durante dois ciclos menstruais, 12 mulheres saudáveis, ativas e usuárias de
contraceptivos orais foram submetidas a um protocolo de treinamento e foram
avaliadas quanto ao desempenho físico em cada fase de cada ciclo menstrual por
meio dos testes: Yo Yo Test
1 e teste de uma repetição máxima (1RM) para os exercícios: cadeira extensora,
supino reto, cadeira flexora e remada. Resultados: Houve uma redução
do desempenho no teste de resistência na fase folicular para ambos os ciclos
menstruais avaliados. Já o comportamento da força muscular apresentou-se significativamente
maior (p<0,05) no segundo ciclo para os exercícios supino reto e cadeira
flexora. Conclusão: O desempenho na capacidade de resistência em mulheres
ativas, quando avaliado em dois ciclos menstruais, é menor na fase folicular, e
que o desempenho de força muscular não foi influenciado pelas fases do ciclo
menstrual.
Palavras-chave: aptidão física;
exercício; mulheres.
In recent years, the possible influence of the menstrual cycle (MC) on
physical performance (PP) has been a concern for athletes, health professionals
and researchers. Hormonal fluctuations, common during this process, produce
physiological responses according to MC phases and can lead to changes in the
performance of physical exercises [1]. The MC is the result of events
coordinated by the hypothalamic-pituitary-ovarian axis and it is divided into
the phases: Follicular, Ovulatory and Luteal. During the follicular phase,
blood concentrations of estrogen and progesterone are low and in the luteal
phase they are high, in the ovulatory phase the concentration of estrogen is
high, and progesterone is low. Hormonal fluctuations cause bodily responses
such as psychological, renal, body weight, substrate metabolism changes, and
they affect the cardiovascular system, bones, brain, thermoregulation and
ventilation [1,2].
Despite the possible physiological changes regarding physical exercise,
Lebrun [1] found no significant differences in the literature regarding
aerobic, anaerobic or muscle strength capacity between MC phases. On the other
hand, studies suggest that the hormonal variation of this period favors PP in
exercises during the ovulatory phase and leads to a lower DF during the luteal
phase, one of the justifications being the catabolic aspect of progesterone and
anabolic estrogen [3-5]. Studies that
assess PP in aerobic resistance argue that hormonal fluctuations during the MC
do not significantly affect PP [1,6-8]. However, there are reports that during
the luteal phase there is a reduction in the PP [9] or an improvement in the
recovery of oxygen consumption [10].
As for muscle strength, Thompson [11] suggests that hormonal changes in
MC may influence PP, since estrogen and progesterone receptors are identified
in skeletal muscles. Greater muscle strength performance is documented during
the luteal phase of the MC by Loureiro [12] and during the follicular phase by
Wikström-Frisén [13]. On the other hand, there are
reports of decreased muscle strength during the follicular phase [11,14,15],
and studies that found no significant differences in muscle strength
performance between MC phases [6,12,15--20].
The divergences found regarding the PP in the different MC phases may be
related to the methodological differences between the studies. In addition,
most studies evaluate PP during just one MC, limiting the understanding of the
phases of this cycle in extended periods. Therefore, studies that approach the
MC as a periodic process regarding multiple cycles are relevant to demonstrate
potential fluctuations in PP in biomotor capacities
between cycles. Thus, this study investigated the influence of MC phases on the
performance of motor skills: aerobic resistance and muscular strength of lower
limbs and upper limbs, in a period of two menstrual cycles.
This is a prospective cross-sectional study, approved by the Research
Ethics Committee of the State University of Campinas (CEP - UNICAMP) under
approval number 2,678,716, CAAE: 87128617.2.0000.5404.
Sample
Twelve healthy university women participated in this study, with an
average age of 26 ± 3.7 years and physically active, practicing dance. In
addition, they had been using oral contraceptives (of various brands) for at
least six months, 21-day ingestion pattern and a 7-day break, or 24-day
ingestion pattern and a 4-day break, or continuous daily intake.
The level of physical activity was determined via simple self-report on
the practice of weekly physical activities and the following inclusion criteria
were considered through self-report: making use of oral contraceptives with the
purpose of regulating and manipulating the MC [21], as well as being physically
active (exercising at least twice a week). The following exclusion criteria
were considered: having a cardiovascular, neuromuscular disease or pathology
under treatment.
After selecting the volunteers, the participants were informed about the
research and were only included in the project after reading and signing the
Free and Informed Consent Form.
Experimental
protocol
During two weeks prior to the data collection, a familiarization was
made including the performance tests and exercises proposed for training, a
weekly meeting being conducted for each and following the data collection
protocols likewise. In addition, the current MC phase the volunteers were in
was determined.
Over the course of eight weeks completing a period of two consecutive
MCs, in two weekly 60-minute meetings, the volunteers underwent motor skills
training (aerobic endurance and muscle strength) and were evaluated in
performance tests at the end of each MC phase. Therefore, the performance test
included a third weekly meeting for the weeks when the MC phase changed.
During this period, the volunteers did only the exercises proposed by
the project, avoiding the influence of other physical practices on the
performance results. All meetings took place in the morning, maintaining the
same schedule per volunteer. The order of data collection procedures for
capacity training and performance tests are shown in Figures 1A and 1B.
Biomotor
skills training: For resistance training, continuous running in open space was
prescribed. Then, for strength, large muscle group exercises were prescribed,
with an interval of one minute between sets and between exercises. In addition,
the load used was based on the maximum repetition percentage (1RM) of the last
test done by the volunteer. The first time, the load was estimated based on the
last test performed during familiarization (Figure 1A).
Physical performance tests (Figure 1B): The first day of tests occurred
in the follicular phase, between the third and the fifth day of the MC (in the
first cycle called follicular phase 1 (FOL1) and in the second cycle follicular
phase 2 (FOL2). The second day of tests, on the other hand, occurred during the
ovulatory phase, between the ninth and the 10th day of the MC, (OVU1 and OVU2
respectively). Lastly, the third day of testing took place during the luteal
phase, between the 17th and the 21st day of the MC (LUT1 and LUT2) [12]. During
the performance tests, the volunteers did not make any other intense physical
effort.
For verifying resilience capacity, the Yo-Yo Intermittent Recovery Test
- Level 1 [22] was applied to evaluate the displacement capacity (in meters) at
high intensity repeatedly. This test consists of two courses of 20 meters each
(round trip) in a variation of increasing difficulty. Displacements are
announced by a beep and have a 10-second recovery interval between them. The
volunteers carried out as many rounds and turns as they could. The test ended
when the participant did not reach the 20 meter mark
twice in a row within the requested time, indicating physical wear and tear.
The one repetition maximum test (1RM) was used to assess muscle strength
capacity [23]. Before its execution, eight repetitions were warmed up with 50%
of the 1RM load presented in the previous test, followed by three repetitions
at 70% of 1RM. For the first test, the heating load was stipulated so that the
participant could complete the series with ease. The 1RM test measured the
maximum load at which a single repetition could be performed with the correct
technique, it was not possible to perform a second repetition and for each
attempt an interval of five minutes was maintained.
The PP tests were performed in the same order as the training, but
respecting the minimum pause necessary for the volunteer's recovery, decreasing
the influence of one capacity over the other: after the Yo
Test 1 there was an interval of 10 minutes before the 1RM tests. However, there
is still an influence of one capacity over the other in carrying out the tests
on the same day, since the energy reserve for performing the 1RM test is lower
after the Yo Test 1.
Figure
1 - Description of the order of data collection
procedures. 1A: Description of the skills training protocol. 1B: Description of
the physical performance testing protocol
Statistical
analysis
The dependent variables of the present study are: YoYo-Test
execution time, and maximum strength (1RM) in the leg extension, bench press,
leg curl and rowing exercises. All variables will be presented as mean ±1
standard deviation. The normality of the dependent variables was verified by
the Shapiro-Wilk test. To verify the effects of the menstrual cycle (Cycle 1 vs
Cycle 2) and the MC phase (FOL vs OVU vs LUT), 2-way ANOVA was used for
repeated measurements with use of SPSS (Version 24, SPSS, Inc., Chicago, IL,
USA). In the case of the significant effect of the MC phase, Bonferroni tests
were used for post-hoc analysis. The level of significance was set at p <
0.05, and the values of F and effect size (partial ETA square) were reported
for the 2-way ANOVA in case of significant effects.
A significant effect was found for the phases of the MC in the distance
covered during the Yo Test 1 (F (2.10) = 7.159,
effect-size = 0.394, p < 0.05, Figure 2). The post-hoc analysis showed that
the distance covered is shorter during the FOL phase compared to the OVU (p
< 0.05) and LUT (p < 0.05) phases. There was no significant effect of MC,
nor interaction between MC vs cycle phase for this variable.
Figure
2 - Mean (SD) of the distance covered during the Yo Yo Test 1 in MCs 1 and 2,
subdivided into the follicular (FOL1 and FOL2), ovulatory (OVU1 and OVU2) and
luteal (LUT1 and LUT2) phases. † denotes a significant difference in relation
to the ovulatory and luteal phase (p < 0.05)
There was a significant effect of MC on the maximum bench press load (F
(1.11) = 24.497, effect-size = 0.690, p < 0.0001, Figure 3B), and leg curl (F
(1.11) = 9.158, effect-size = 0.454, p 0.05, Figure 3C). For both variables,
the maximum load was higher in the second MC compared to the first. There was
no effect of the MC phase for the extensor chair exercises (p = 0.08 [Figure
3A], considered a trend), and rowing (p = 0.727, Figure 3D). There was no
significant effect of the MC phase, as well as interaction between MC vs cycle
phase for any muscle strength variable.
Figure
3 - Mean (SD) of the one maximum repetition (1RM)
during the leg extension (A), bench press (B), leg curl (C) and rowing (D)
exercises during MC 1 (gray bars) and MC 2 (black bars), subdivided into
follicular (FOL), ovular (OVU) and luteal (LUT). * denotes a significant
difference in relation to CM 2 (p < 0.05)
This study stands out for evaluating a period longer than a MC,
simultaneously evaluating more than one biomotor
capacity and having a training protocol during the analysis period. Regarding
the resistance capacity, the results presented show a lower performance in the
follicular phase than in the ovulatory and luteal phases in both evaluated MCs.
In addition, there were no significant differences in resistance performance
between cycles, likely due to the applied training, which did not lead to enough
adaptations to generate differences in performance between one cycle and
another.
The lower performance in the follicular phase compared to the other
phases found in both cycles can be justified because it was evaluated at the
beginning of the follicular phase. During this period, women's menstruation
occurs, which can lead to natural discomfort due to blood flow and swelling,
generating less disposition to physical activity [24]. Blood estrogen
concentrations are low, and this being a hormone associated with the production
of serotonin, a neurotransmitter that regulates mood, appetite, sleep and other
physiological variables, the mood and motivation to do physical exercises may
decrease, in addition to the possibility of presenting menstrual cramps that
also influence the practice of physical activities [24,25].
Some studies that evaluate only one CM are contrary to our findings.
Julian et al. [9] investigated the resistance performance in the different MC
phases using the Yo-Yo
Intermittent Endurance Test (Yo-Yo IET) and found less
performance in the luteal phase compared to the follicular phase. In the same
direction Silva et al. [6], using the Yo-Yo Test 1, found no performance
differences between MC phases. Both studies are similar in terms of the
evaluation method, but they differ from our study in terms of analyzed population,
namely soccer athletes (n = 9) and women trained in resistance exercises (n =
11), respectively. Similar results were found by studies that use other methods
of assessing resistance capacity and that evaluate women with different levels
of training [17,8].
Regarding physically active women, Middleton [10] suggests better
recovery of VO2 during the luteal phase, however it differs in its
research objectives, as well as in the methods of evaluating the performance
and division of the MC phases. Our results make the relationship between MC and
aerobic resistance performance in physically active women clearer, as it
evaluates this population that has not yet been investigated, and because it is
a pioneering study in the evaluation of resistance performance in two MCs.
Differently from what was observed in the endurance performance results,
the data obtained on the muscular strength capacity indicate a significant
performance improvement in the second cycle for the bench press and leg curl
exercises, which was not observed for the extension and row chair. The
improvement in strength performance in the exercises from one MC to the other
can be justified by the neural adaptation to training and strength gain,
according to the training protocol adopted [4]. If a period longer than two
cycles were adopted, we would likely report an increase in performance also for
the rowing and leg extension exercises (which showed an increasing trend).
In addition, our results showed no significant differences in
performance in all strength exercises between MC phases, similarly to studies
that evaluate a single MC and women trained in resistance exercises via the
load test [18], and physically active women [16] trained in aerobic exercises
[17], as well as athletes [20] using the isokinetic dynamometer. These
findings, together with our results, indicate that MC phases do not influence
the strength performance assessed by different methods and in women of
different levels of physical fitness.
On the other hand, studies indicate a decrease in the strength
performance of physically active women [11,15] and women trained in resistance
exercises [14] during the follicular phase. However, they use other methods of
strength assessment such as isometric strength assessment, 8RM test and total
volume of load used, respectively. The divergence of results between these
studies can be justified by the methodological differences presented. It is
also noteworthy that the afore mentioned studies evaluate only one MC.
Like the present study, Fridén [19]
investigated the strength performance of physically active women (n=10) during
two MCs. However, handgrip strength and isokinetic muscle strength tests in the
leg extension machine were used, a specific training protocol was not applied
during the period analyzed, and the volunteers did not use oral contraceptives.
As a result, no significant differences were found between MC phases for any
variable in both evaluated MCs, similarly to our findings. Thus, physically active
women, when evaluated by two MCs, regardless of the method used to assess
muscle strength, of oral contraceptives are used, and presence of training
protocol, are suggested to have no influence of MC phases under strength
performance.
We point out as limitations of this study the lack of control over the
intensity of resistance training, which interfered in the progress of physical
performance for this biomotor capacity, in addition
to the low number of participants. New studies are suggested to verify how the
evaluation by different methods could influence the results of strength
performance.
This study demonstrated that physically active women show distinct
changes in aerobic endurance and muscle strength when two menstrual cycles (and
their phases) are compared. The performance of aerobic resistance was lower in
the follicular phase in both evaluated cycles, while muscular strength did not
change significantly between different phases of the menstrual cycle. In
addition, when comparing one menstrual cycle and another, there is a
significant increase in strength performance, but not in aerobic endurance
performance.
Acknowledgments
The authors would like to thank “Espaço da Escrita” - Dean of Research - UNICAMP - for the language
services provided and for the Voluntary Scientific Initiation Program (PICV).
Conflicts
of Interest
There are no conflicts of interest
Authors’
Contribution
Ribeiro IC, Carvalho LHF, Borin JP were
responsible for data collection. Ribeiro IC, Carvalho LHF, Borin
JP, Oliveira AS were responsible for writing the manuscript. Oliveira AS was
responsible for creating figures and tables. Oliveira AS and Padovani CR were responsible for statistical analysis.