fphys-12-600668 February 16, 2021 Time: 19:13 # 1
published: 22 February 2021
Anthony C. Hackney,
University of North Carolina at Chapel
Hill, United States
Hessische Hochschule für Polizei und
Xanne Janse de Jonge,
The University of Newcastle, Australia
This article was submitted to
a section of the journal
Frontiers in Physiology
Received: 30 August 2020
Accepted: 29 January 2021
Published: 22 February 2021
Dasa MS, Kristoffersen M,
Ersvær E, Bovim LP, Bjørkhaug L,
Moe-Nilssen R, Sagen JV and
Haukenes I (2021) The Female
Menstrual Cycles Effect on Strength
and Power Parameters in High-Level
Female Team Athletes.
Front. Physiol. 12:600668.
The Female Menstrual Cycles Effect
on Strength and Power Parameters
in High-Level Female Team Athletes
Marcus S. Dasa1, Morten Kristoffersen2, Elisabeth Ersvær3, Lars Peder Bovim4,
Lise Bjørkhaug3, Rolf Moe-Nilssen1, Jørn V. Sagen5,6 and Inger Haukenes1,7*
1Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway, 2Department of Sport, Food,
and Natural Sciences, Western Norway University of Applied Sciences, Bergen, Norway, 3Department of Safety, Chemistry,
and Biomedical Laboratory Sciences, Western Norway University of Applied Sciences, Bergen, Norway, 4Department
of Health and Functioning, Western Norway University of Applied Sciences, Bergen, Norway, 5Department of Clinical
Science, University of Bergen, Bergen, Norway, 6Department of Medical Biochemistry and Pharmacology, Haukeland
University Hospital, Bergen, Norway, 7Research Unit for General Practice, NORCE Norwegian Research Centre, Bergen,
Purpose: The female menstrual cycle (MC) is characterized by hormonal ﬂuctuations
throughout its different phases. However, research regarding its effect on athletic
performance in high level athletes is sparse. The aim of this study was to (i) investigate
the female MCs effect on strength and power performance in highly trained female team
athletes throughout the MC and (ii) examine whether eumenorrheic participants with
natural hormonal ﬂuctuations displayed enhanced performance in the follicular phase
(FP) versus the luteal phase (LP), compared to controls using hormonal contraceptives.
Materials and Methods: A total of 29 athletes (Age 21.2 ±3.3 years; weight
65.6 ±8.7 kg; height 170.2 ±8.0 cm; and fat free mass 52.7 ±7.1) completed
the study after a 6-week testing period (8 eumenorrheic participants and 21 hormonal
contraceptive controls). Participants were recruited from the team sports soccer,
handball and volleyball. Testing protocol consisted of maximal voluntary isometric grip
strength, 20-m sprint, countermovement jump and pneumatic leg-press. Based on self-
reported use of hormonal contraceptives, participants were divided into non-hormonal
contraceptive group and hormonal contraceptive group, the latter working as a control
group. Differences in performance between the FP and LP were investigated. MC
phase was conﬁrmed by serum hormonal levels through venous blood samples in the
non-hormonal contraceptive group.
Results: There were no statistically signiﬁcant changes for the two different phases of
the MC, in terms of physical performance for the whole group. Further, there was no
signiﬁcant difference between groups during the MC for any of the outcome variables,
maximal voluntary isometric grip strength F(3.29) = 0.362; 20-m sprint F(3.24) = 0.710;
countermovement jump F(3.26) = 2.361; and leg-press F(3.26) = 1.746.
Conclusion: In high level female team athletes, no difference in performance was
observed based on hormonal contraceptive status. This suggests that the MC does not
alter acute strength and power performance on a group level in high level team athletes.
Keywords: menstrual cycle, female athletes, strength, power, hormones
Frontiers in Physiology | www.frontiersin.org 1February 2021 | Volume 12 | Article 600668
fphys-12-600668 February 16, 2021 Time: 19:13 # 2
Dasa et al. Strength Performance in Female Athletes
Modern intermittent team sports require a wide range of
physiological attributes in order to meet the demands
of the given sport. Strength and power are important
characteristics in intermittent team sports, hence, compelling
attributes to research in relation to physical performance
(Drust et al., 2007;Lidor and Ziv, 2010;Póvoas et al.,
2014). Although gender equality has been more in focus
in recent years, related to exposure, conditions and
professionalism in sport, females are underrepresented in
the scientiﬁc literature. Findings from studies investigating
male physiology and performance does not necessarily
translate to females, as the female menstrual cycle (MC)
cause monthly changes in serum hormone levels (Reilly, 2000)
that may aﬀect strength, power, and endurance (Hansen, 2018;
Thompson et al., 2020).
The role of the sex hormones (estradiol and progesterone)
in addition to the pituitary hormones regulating the gonadal
axis [i.e., lutenizing hormone (LH)- and follicle stimulating
hormone (FSH)], in developing strength and power, is not
fully understood. Studies suggest that estradiol, one of the
primary sex hormone during the reproductive MC, induce
anabolic, and muscle building processes in females (Lowe
et al., 2010;Hansen et al., 2012). Furthermore, hormone
replacement therapy using exogenous estrogen seem to attenuate
loss of muscle strength in peri and post-menopausal women
(Carter et al., 2001;Minahan et al., 2015). The impact of
estradiol on muscle strength is not necessarily accomplished
by increased muscle size through hypertrophy, but rather
by aﬀecting the intrinsic quality of skeletal muscle, enabling
muscle ﬁbers to generate greater force (Lowe et al., 2010).
However, the role of estradiol during acute hormonal changes,
as seen amid the MC is not fully understood (Chidi-Ogbolu
and Baar, 2019). A second hormone playing an important
role during the female MC is progesterone. A decline in
progesterone levels (and estradiol levels) signals shedding of
the endometrium resulting in menstrual bleeding. Related to
sports, progesterone has been associated with protein catabolism,
conceivably attenuating muscle strength (Oosthuyse and Bosch,
2010). Indeed, studies have demonstrated ameliorated strength
levels during both the follicular phase (FP) and luteal phase
(LP) (Phillips et al., 1996;Birch and Reilly, 2002). These
conﬂicting ﬁnding makes understanding of potential superior
performance allocated to a speciﬁc MC phase speculative.
Sung et al. (2014) demonstrated increased muscle strength
and muscle diameter through strength training periodized to
the FP, compared to LP (Sung et al., 2014). Wikström-Frisén
et al. (2017) conﬁrmed this ﬁnding and reported increased
power and strength gains through FP periodized training
(Wikström-Frisén et al., 2017). Despite this, several studies
within this ﬁeld of research are hampered with insuﬃcient
methodology, by lacking biological documentation of the MC
phase, which is seen as the gold standard (Allen et al.,
2016;Janse et al., 2019;Thompson et al., 2020). Studies with
unsatisfactory biological methodology also report increased
muscular performance through changes in serum hormonal
levels during and shortly prior to menstrual bleeding (Sarwar
et al., 1996;Bambaeichi et al., 2004).
A recently published systematic review investigating the eﬀect
of MC and oral contraceptives on acute responses and chronic
adaptations to resistance training, concluded that the eﬀects of
both the MC and oral contraceptive use on acute responses
to resistance training remain unclear (Thompson et al., 2020).
To summarize some ﬁndings of this review: (i) One of the 17
studies found no signiﬁcant diﬀerences in acute responses to a
resistance training session over the natural MC, while four studies
did ﬁnd changes (Thompson et al., 2020). (ii) For the responses
to a resistance training program, three studies reported FP -
based training to be superior to LP -based training or regular
training, while one study reported no diﬀerences (Thompson
et al., 2020). Finally, (iii) when assessing the diﬀerences in
acute responses between the oral contraceptive and MC groups,
two studies reported oral contraceptives to have a positive
inﬂuence, whilst four studies reported that oral contraceptive
users had a delayed recovery, higher levels of markers of
muscle damage, or both (Thompson et al., 2020). Some of the
conclusions made by this review is that FP -based resistance
training programs appear to result in better responses than LP
based and regular training programs. Furthermore, this review
highlights the need for further experimental research in this area
(Thompson et al., 2020).
We argue that more research is needed to investigate whether
hormonal ﬂuctuations during the MC may alter performance
and in such have implications for periodic training and
competition. Furthermore, no studies have investigated the
eﬀect of female sex hormone ﬂuctuations on performance in
high-level team athletes, a sub-group where small changes
may have major impact. The aim of the study was therefore
(i) to examine potential changes in performance in high
level female team athletes during diﬀerent phases of the MC
and (ii) to examine whether eumenorrheic participants, with
natural hormonal ﬂuctuations during the MC display enhanced
performance during the FP versus the LP (due to higher relative
concentrations of circulating estradiol), compared to participants
using hormonal contraceptives.
MATERIALS AND METHODS
Women from six high-level teams from the Hordaland County
of western Norway, Norway, were invited to participate in the
study. Team sports invited were soccer, handball and volleyball,
competing at the top two national levels. Twelve players were
currently representing their national team. Five teams accepted
the invitation; one team declined due to logistics. Inclusion
criteria were (i) ≥18 years of age, (ii) competing at a national
level in their respective team sport, and (iii) free of any injury
or disease prohibiting testing. All participants satisfying inclusion
criteria (n= 55) received a baseline questionnaire via email
before the start of the intervention period. Of these, nine
team-members dropped out before testing, leaving the ﬁnal
participant number at 46.
Frontiers in Physiology | www.frontiersin.org 2February 2021 | Volume 12 | Article 600668
fphys-12-600668 February 16, 2021 Time: 19:13 # 3
Dasa et al. Strength Performance in Female Athletes
During the testing period, additional ﬁve participants were
lost to follow up due to time commitment, school, or injury.
Four participants were excluded post hoc as they did not self-
report onset of menstruation during the 6-week testing period.
Additionally, eight participants were excluded as they did not
provide at least two test weeks from both FP and LP. Thus, the
total number of participants completing the study was Figure 1
(Age 21.2 ±3.3 years; weight 65.6 ±8.7 kg; height 170.2 ±8.0 cm;
and fat free mass 52.7 ±7.1). Group speciﬁc descriptive data are
presented in the section “Results.”
This study was approved by the Regional Ethics Committee
A prospective cohort study with repeated measures over 6-
weeks was executed. Exposure was hormonal contraceptive
(HC) status. Hormonal contraceptive group (HCG) and non-
hormonal contraceptive group (NHCG) were deﬁned post hoc
(the participants HC status was unknown during the 6-week
testing period). The MC phases (FP and LP) were conﬁrmed
through serum hormonal levels in blood samples taken at every
visit during the 6-week testing period, in the NHCG, to ensure
correct group assignment and validity of self-reported menstrual
phase. This validation procedure (hormonal values in serum
samples) was not performed in the HCG, as conﬁrmation of
MC phase through blood samples is not possible due to a
steady ﬂow of contraceptive speciﬁc exogenous sex hormones
throughout the MC (Allen et al., 2016). Self-reported onset of
menstruation was used in this group for assignment of FP and
LP phases. Guidelines provided by Sims and Heather (2018)
were used to choose test weeks included in the statistical analysis
for the HCG (Sims and Heather, 2018). More speciﬁcally, we
strived to test participants in the HCG using monophasic oral
contraceptives in the active pill phase. Blood samples of subjects
in the HCG were, however, drawn, but for other analytical
purposes (parallel study). HC types were recorded at baseline in
the HCG (Supplementary Table 3). Weekly outcome measures
(see testing procedure) were compared between the HCG and
NHCG. For this, four out of six testing weeks were selected
for statistical analysis to represent the FP and LP phases (FP
week 1/2 and LP week 3/4). Six weeks of consecutive testing
was performed to secure a minimum of two measurements in
both FP and LP, thus minimizing exclusion based on failure
to fulﬁll this requirement (e.g., week 1-4 and week 5-2 etc.).
This variation of included test weeks reduced the chance of a
systematic learning eﬀect.
At baseline, all participants completed the LEAF-Q
questionnaire: a screening tool for the identiﬁcation of female
athletes at risk for the female athlete triad. The questionnaire
comprises questions of age, height, weight, and BMI, as well
as more comprehensive information (sleep, nutrition, and
metabolism) for purposes beyond the scope of this study
(Melin et al., 2014).
On the day of testing, participants were encouraged to
eat approximately the same type and amount of food and
liquid throughout the testing period. They were also instructed
to avoid any caﬀeine consumption 12 h preceding testing,
due to the possible ergogenic eﬀects related to physical
performance (Goldstein et al., 2010;Grgic et al., 2019a).
When arriving at the facility for testing, participants were
asked to complete a self-administered questionnaire regarding
MC, nutrition, training, injuries/pain, and test-day form
(expectations on test inﬂuence). Weight and body composition
were measured using multi-frequency bioelectrical impedance
(IN-body 720, Biospace, Tokyo, Japan), along with venous blood
samples for determination of menstrual phase. Before physical
testing, participants performed a 15-min standardized warm
up (100 watts) using the Wattbike ergometer (Wattbike Ltd.,
FIGURE 1 | Flow chart displaying the drop-out rate and exclusion during the study. N, number of participants; HC, hormonal contraceptive user; NHC, non-hormonal
contraceptive user. HC status for drop out prior to the start of the study is not included, due to incomplete questionnaires from some of the participants.
Frontiers in Physiology | www.frontiersin.org 3February 2021 | Volume 12 | Article 600668
fphys-12-600668 February 16, 2021 Time: 19:13 # 4
Dasa et al. Strength Performance in Female Athletes
Nottingham, United Kingdom). The weekly testing protocol
consisted of maximal voluntary isometric grip strength (MVIGS),
20-m sprint, Counter movement jump (CMJ) and leg-press.
Testing was completed once a week, at approximately the
same time each weekday to control for circadian variations
(±2 days/±2 h on the testing day). To minimize potential
bias through a learning eﬀect, participants were given two
experimental attempts for every test, before recording started.
Maximal Voluntary Isometric Grip
Isometric grip strength of the dominant hand was measured
using a digital pinch/grip analyzer (MIE, Medical research
Ltd, Leeds, United Kingdom). Standard instructions before and
during the test: (i) to be seated with a slight forward bend of
the trunk, elbow resting on the thigh with 90◦elbow ﬂexion,
(ii) exert maximal force for 3–5 s, (iii) two attempts with a 30 s
break between. If deviation from the instructions the attempt was
disallowed. If the force production in their last attempt exceeded
the previous with >5%, a new attempt was performed. The best
recording was used for statistical analysis. MVIGS is shown to
be a repetitive measure, with ICC-scores classiﬁed as very good
Sprint performance was assessed over a 20-m track, made
from portable non-slipping surface (Hitashita international, ON,
Canada). Times were recorded at 5, 10, and 20-m using single
beam photocells (Brower timing systems, Utah, United States).
Photocells were ﬁxed at 120 cm height, apart from the ﬁrst pair,
which were ﬁxed at 10 cm height to ensure similar photocell
interception. participants were instructed to a stationary start
with the dominant leg behind and a slight forward bend of
the trunk. Participants decided when to start their eﬀort, with
recording being initiated by interception of the ﬁrst photocell
beam. Each subject carried out two attempts, separated by 2 min
of rest. If the second attempt was >5% faster than the previous,
a new attempt was performed. The best total 20-m sprint time
was used for statistical analysis. 20-m sprint is shown to be a
repetitive measurement, with ICC-scores classiﬁed as very good
(Shalfawi et al., 2012). This method is also reviewed as reliable
in a comprehensive review of sprint performance monitoring
(Haugen and Buchheit, 2016).
Counter movement jump performance started from an upright
position and the participants were instructed to descend to
a self-chosen depth, followed by a maximal vertical jump
eﬀort. Participants were instructed to use a hand on hips
position throughout the entire movement. Maximum jump
height (cm) was calculated using Kistler Measurement, Analysis
and Reporting Software (MARS, 2015, S2P, Ljubljana, Slovenia).
Participants performed at least two attempts or continued
until performance declined. The best attempt was selected for
statistical analysis. CMJ is shown to be a repetitive measure, with
ICC-scores classiﬁed as very good (Slinde et al., 2008).
Relative peak power (RPP) was estimated using a progressive
maximal pneumatic resistance seated leg press test on a Keiser
A420 (Keiser, Fresno, CA, United States). An estimated 1-
Repetition maximum (1 RM) was chosen based on participants
self-reported training history, bodyweight, sport and previous
internal testing. Participants completed a 10-repetition
incremental step test toward peak of 1 RM on last repetition. The
test protocol is well established and described in detail elsewhere
(Redden, 2019). RPP was estimated using all 10 repetitions, and
each participant was to use the same protocol at every test point.
RPP measured and estimated with pneumatic leg press is shown
to be a repetitive measure, with ICC-scores classiﬁed as good
(Redden et al., 2018).
Serum Hormone Analysis
To provide hormonal conﬁrmation of MC phase, participants
provided non-fasted venous blood samples before testing at every
visit, in order to avoid eﬀect of physical strain on hormonal
levels. Blood was collected using eclipse blood collection needles
(BD vacutainer, Franklin Lakes, NJ, United States) in EDTA-
vials by qualiﬁed biomedical laboratory scientists. After 30 min,
blood samples were centrifuged at 2000×gfor 10 min (Thermo
Fisher Scientiﬁc SL1R centrifuge, Thermo Fisher Scientiﬁc,
Waltham, MA, United States). Serum was isolated and stored
at −80◦C until all samples were collected during the 6-week
testing period prior to hormonal analysis. Serum samples were
analyzed for progesterone, estradiol, FSH, LH, and Sex hormone-
binding globin (SHBG). Analysis of progesterone and estradiol
levels were performed using Liquid Chromatography-Mass
Spectrometry (LC-MS/MS) (progesterone by the LC-system by
Agilent (Santa Clara, CA, United States) and MS-system: SICX,
while estradiol by LC-MS/MS by Waters). FSH, LH and SHBG
was analyzed by chemical luminescence on the Immulite 2000
XPi (Siemens, Erlangen, Germany). All hormone analyses were
performed at the Hormone Laboratory, Department of medical
biochemistry and pharmacology, Haukeland University Hospital.
All analyses are accredited according to NS-EN ISO 15189:2012.
Reference values used by the laboratory are presented in
Supplementary Table 4.
We performed a dichotomous division for FP and LP,
respectively. A progesterone value <0.5 nmol/L was considered
true FP whereas a value >5.5 nmol/L was considered true LP. In
some instances, we identiﬁed progesterone levels between 0.5 and
5.5 nmol/L. For these cases we evaluated the preceding and the
following weeks progesterone values. If the week prior presented
a progesterone value of >5.5 nmol/L, both weeks were considered
to be LP. In other cases, a low but measurable progesterone
value appeared, followed by a spike in progesterone. These cases
were labelled mid-cycle and were not included in the statistical
analysis, since it is diﬃcult to conclude whether the value is
actually late FP or early LP.
Descriptive statistics were used to examine the distribution of
subject characteristics across exposure groups. We calculated
Frontiers in Physiology | www.frontiersin.org 4February 2021 | Volume 12 | Article 600668
fphys-12-600668 February 16, 2021 Time: 19:13 # 5
Dasa et al. Strength Performance in Female Athletes
interclass correlation coeﬃcients (ICC, random model) as
measures of reliability, based upon the four weekly measurements
chosen for analysis of performance during the MC. The results
are presented as mean ±standard deviation (SD). One-way
repeated measures analysis of variance (ANOVA) were used
to analyze for between group diﬀerences, between the average
results of two FP measures and two LP measures. ANOVA
was also conducted separately for the HCG and NHCG to
investigate potential within group chances between the FP and
LP. Bonferroni correction was conducted post hoc to reduce
the chance of type one error with signiﬁcant ANOVA’s. An
alpha level of P<0.05 was set a priori. Participants with
incomplete hormonal or performance data were excluded from
the statistical analysis. Between groups comparison is based on
the interaction between hormonal status∗menstrual cycle (time).
Statistical analysis was performed using IBM SPSS 25 (IBM,
Armonk, NY, United States).
A total of 29 participants were included in the study, 21 and
8 individuals in the HCG and NHCG, respectively. Mean age,
height, weight, fat free mass, and monthly training volume are
presented in Table 1. There was no statistical diﬀerence between
the two groups for any of these measures.
Self-reported onset of menstruation was registered in the
NHCG (n= 8) and compared with hormonal analyses to
investigate the accuracy of self-reported onset of menstruation.
We found deviating results in the self-reported data in two
individual cases (ID: D16, H3). Range of analyses in the diﬀerent
phases of MC are presented in Supplementary Table 1. Reference
values for FP and LP are presented in Supplementary Table 4.
Repeated measures reliability was assessed as satisfactory
to excellent, with the following ICC vales; 0.75 for
countermovement jump, 0.80 for leg press, 0.88 for MVIGS, and
0.91 for 20-m sprint performance.
There were no statistically signiﬁcant changes for the two
diﬀerent phases of the MC, in terms of physical performance
for the whole group. Further, the interaction eﬀect between
contraceptive status and time (MC phase) were compared. There
were no statistically signiﬁcant group diﬀerences between the
HCG and NHCG for any outcome measures throughout the
TABLE 1 | Descriptive data showing mean values ±standard deviation of subject
characteristics in the hormonal contraceptive group and non-hormonal
Total HCG NHCG
N29 21 8
Age 21.2±3.3 20.48 ±2.5 22.5±4.2
Weight (kg) 65.6±8.7 66.9±8.3 63.1±9.3
Height (cm) 170.2±8.0 170 ±7.6 168.8±8.9
Fat free mass (FFM) 52.7±7.1 53.4±6.7 52.3±7.9
Training volume (monthly hours) 52.8±14.2 52.7±14.9 52.9±13.7
N, number of participants.
4 weeks chosen for analysis, although both groups showed
variation in performance (Figure 2 and Supplementary Table 2).
Additionally, no signiﬁcant changes were observed when
investigating the MC cycle in both groups separately.
Despite non-signiﬁcant ﬁndings, In terms of maximal
isometric grip strength both groups demonstrated weekly
variations in MVIGS, displaying the highest isometric grip
strength values for both groups in the LP with a mean of
31.3 ±5.6 kg in the HCG and 28.7 ±3.6 in the NHCG,
respectively (Figure 2 and Supplementary Table 2). Further,
both groups showed consistent measures for sprint performance
throughout the 4 weeks of the MC, with results ranging
from 3.194 ±0.132 s to 3.209 ±0.123 s in the HCG and
3.165 ±0.121 s to 3.191 ±0.116 s in the NHCG, respectively
(Figure 2 and Supplementary Table 2). With respect to counter
movement jump the CMJ displayed a greater between group
diﬀerence compared to the other tests, with means ranging from
32.9 ±6.3 cm to 30.7 ±4.3 cm in the HCG and 33.5 ±4.7 cm
to 30.7 ±2.7 cm in the NHCG, respectively (Figure 2 and
Supplementary Table 2). Finally, the NHCG displayed greater
variation between weeks in leg press compared to the HCG; means
ranging from 24.4 ±2.9 W/kg to 23.3 ±2.0 W/kg in the NHCG
compared to 23.6 ±2.6 W/kg to 23.2 ±2.8 W/kg in the HCG
(Figure 2 and Supplementary Table 2).
The aim of this study was to examine potential changes in
performance due to hormonal changes during the MC. This was
done by comparing test results from FP and LP between a NHCG
and HCG, the latter serving as controls over a 6-week period.
When comparing eumenorrheic participants with controls using
HC, we found no statistically signiﬁcant diﬀerences for the MC
overall. Further, no statistically signiﬁcant diﬀerences were found
for the FP when comparing the two groups. These ﬁndings
suggest that HC status does not alter strength and power
performance on a group level in high-level female team athletes,
when tested in a controlled environment throughout one MC.
Our ﬁndings are in line with several studies reporting no
diﬀerence in strength or power performance throughout the
diﬀerent phases of the MC (Lebrun et al., 1995;Jonge et al.,
2001;Fridén et al., 2003;Bushman et al., 2006;Abt et al., 2007;
Julian et al., 2017;Romero-Moraleda et al., 2019). However,
there are studies reporting altering eﬀects on strength and power
performance following periodized training regiments, adjusting
for hormonal ﬂuctuations in the diﬀerent MC phases (Thompson
et al., 2020). For instance, Sung et al. (2014) reported increased
muscle strength in participants following a FP periodized training
regimen, compared to a LP periodized training regiment, over a
total of three MC’s (Sung et al., 2014). Possibly, this procedure,
in contrast to acute performance as investigated in our study,
could better utilize the proposed mechanisms behind estradiol’s
ameliorating eﬀects in muscle strength (Lowe et al., 2010). Our
study was cross-sectional, and we did not follow any speciﬁc
strength intervention and only provided data for one MC. This
might explain why the NHCG did not display any signiﬁcant
Frontiers in Physiology | www.frontiersin.org 5February 2021 | Volume 12 | Article 600668
fphys-12-600668 February 16, 2021 Time: 19:13 # 6
Dasa et al. Strength Performance in Female Athletes
FIGURE 2 | Mean values through the menstrual cycle with 95% conﬁdence intervals for (A) maximal voluntary grip strength, (B) 20-m sprint, (C) leg press, and (D)
countermovement jump. Week 1–4 (week 1/2 FP; week 3/4 LP) are based on serum hormonal levels.
alterations in their performance relative to the HCG. Further,
Phillips et al. (1996) reported up to 10% increase in maximal
voluntary force of the adductor pollicis during the FP of the
MC (Phillips et al., 1996). These ﬁndings contradict our result,
although we used MVIGS with a handheld dynamometer, which
is comparable with maximal voluntary force of the adductor
pollicis. Although not signiﬁcant, in the current study, MVIGS
demonstrated small weekly variations in performance for both
groups with the greatest variations between FP and LP for both
groups. As the weeks are based on self-reported menstruation and
conﬁrmation with hormonal analyses, representing the biological
week of the MC and not chronological test week, a systematic
learning eﬀect can be ruled out. The fact that both groups showed
similar variations in their results, suggests that the MC was not
the impacting factor in the NHCG.
Counter movement jump displayed slight weekly non-
signiﬁcant variations in the NHCG throughout the MC. In
contrast, the HCG showed a substantial deviation with a mean
diﬀerence of 2.2 cm between week two and four, which is a
6.9% diﬀerence. This manifested itself with a FP peak before
declining in the LP and can be viewed as a meaningful diﬀerence,
considering the marginal diﬀerences in high level sport. If
estradiol indeed does ameliorate muscle strength and power,
this increase in performance would be plausible. However, with
HC agents providing a steady supply of exogenous hormones
throughout the MC, minimizing the hormonal ﬂuctuations, this
weekly diﬀerence in the HCG was unexpected. As highlighted
by Myllyaho et al. (2018), diﬀerent HC agents may exert varying
eﬀects of performance (Myllyaho et al., 2018). Hence, this might
be a line of investigation interesting to follow in future studies, by
separating groups of diﬀerent HC agents.
Relative peak power showed weekly variations, with the
NHCG displaying the greatest change between week one and two,
with a mean diﬀerence of 1.1 w/kg. For this outcome, the greatest
value manifested itself in the FP. This is in line with previous
research, demonstrating superior performance in the FP (Phillips
et al., 1996;Greeves et al., 1997). However, the outcome measures
of both these studies are quite reductionistic. Further, MC phase
was not necessarily veriﬁed through serum blood samples, giving
these results low validity (Allen et al., 2016).
A total of 20-m sprint displayed the least variation in
both groups. Since repeated measures ICC was high for sprint
measures, these results cannot be explained as uncertainty of
the measurement method to detect small changes, but rather
demonstrates stable performance across the testing period.
Further, it is possible 20-m was too short of a distance to measure
any meaningful diﬀerence, as results were very marginal.
Although no signiﬁcant ﬁndings were detected between
groups, several variables showed substantial weekly variations in
performance in both the HCG and NHCG. As small changes
in performance may impact results in high level sport, our
ﬁndings indicate that the time of testing could yield diﬀerent
results for high level female athletes in general. However,
these variations cannot directly be contributed to hormonal
ﬂuctuations occurring during the MC. One plausible explanation
for the weekly variations observed in this study is individual
physiological load. Indeed, Andersson et al. (2008) demonstrated
that full match recovery in female soccer players can last up
Frontiers in Physiology | www.frontiersin.org 6February 2021 | Volume 12 | Article 600668
fphys-12-600668 February 16, 2021 Time: 19:13 # 7
Dasa et al. Strength Performance in Female Athletes
to 72 h. The recovery time from handball is also proven to be
substantial (Ronglan et al., 2006;Andersson et al., 2008).
Our study contradicts the suggestion that estradiol acutely
ameliorates muscle strength and power, supporting the ﬁndings
of Jonge et al. (2001), showing no correlation between estradiol
serum hormonal levels and muscle strength, fatiguability, and
contractile properties (Jonge et al., 2001). Serum estradiol levels
varied in the range from 35 pmol/L to 1122 pmol/L. As
highlighted by Jonge et al. (2001), the large variations seen in
serum estradiol levels is partly caused by secretory pulses of
these hormones. In addition, the MC is highly individual in their
length, thus, the participants may have been in diﬀerent stages of
their respective cycles. This is in line with Greeves et al. (1997)
who demonstrated that supraphysiological doses of estradiol
did not signiﬁcantly increase muscle strength, questioning the
ﬁndings of Phillips et al. (1996), and Sarwar et al. (1996),
suggesting that acute changes in estradiol ameliorates muscular
strength (Phillips et al., 1996;Sarwar et al., 1996).
Indeed, several studies have shown estradiol hormone
replacement therapy to be beneﬁcial in decreasing attenuation
of muscle strength in peri and post-menopausal women, as
summarized by Chidi-Ogbolu & Baar (Chidi-Ogbolu and Baar,
2019). Lowe et al. (2010) hypothesize that estradiol alters myosin
function during muscle contractions through estradiol receptors
in a typical steroid manner (Lowe et al., 2010). As described
by the aforementioned authors, skeletal muscle is an estradiol
receptive tissue, working through the estradiol receptor. This may
help explain why studies adopting periodized training protocols,
utilizing elevated circulating estradiol levels over time have
demonstrated increased muscle strength, as opposed to more
modest results displayed when measuring acute performance.
Exploiting a preferable milieu may promote strength gains over
time, as adaptations in skeletal muscle may need time to manifest
themselves, even if estradiol alone also improves the intrinsic
quality of contractile ﬁbers. Individual estrogen receptor content
may therefore be partly indicative of muscle strength gains
As highlighted by Sims and Heather (2018), HC users are
proposed as suitable controls when measuring the eﬀects of
the MC (Sims and Heather, 2018). However, several types
of contraceptive agents, with diﬀerent active ingredients and
exogenous hormones were administered in the HCG. Thus, the
impact on performance may vary, depending on the type of
contraceptive agent being used. To our knowledge, there is no
study investigating the eﬀect on diﬀerent type of HC’s related
to athletic performance in high level athletes. Considering the
current lack of knowledge related to diﬀerent HC agents and
performance, we would like to re-emphasize the need for future
research regarding this manner.
Methodological Considerations and
This study highlights the possibility of conducting prospective
research on female athletes, which is often considered
problematic due to training and competition schedule,
paired with female physiology. A further strength is the
prospective study design, were we measured 6 weeks and
chose 4 weeks, representing the MC based on self-reported
onset of menstruation and hormonal conﬁrmation. However,
measurements over several MC’s would have provided increased
validity, due to individual variation in MC length and onset.
Comparing self-reported onset of menstruation to hormonal
analysis, revealed deviating results in four participants.
Although some of these variations may be contributed to
survey misunderstandings, the results indicate that some
caution should be made when interpreting studies exclusively
applying this method for MC phase determination. Although
no statistical diﬀerence was observed between the two groups,
some interindividual variability was present in both groups.
With a relatively small sample size, it is possible that the results
would approach being statistically signiﬁcant with a larger
population. Further, a potential limitation is small variations
in test procedures. Testing was originally scheduled for the
same day (±2 days) and time (±2 h) throughout the study
period to account for circadian variations. However, due to
national team obligations and training/competition schedules
being ﬂuctuant in pre-season, some participants were tested
outside these frames at one or several time points. This could
have impacted the results, as circadian rhythm has been shown
to aﬀect performance in strength and power endeavors (Grgic
et al., 2019b). Grgic et al. (2019b) reported that expression of
strength is greater in the evening, versus the morning. On the
other hand, the circadian eﬀects on test results also depend on
athletes normal training schedule (Grgic et al., 2019b). Thus, the
impact of variation in test procedures on the ﬁnal results is not
fully known. Indeed, the relatively low sample size limits external
validity. On the other hand, the participants were selected based
on stringent criteria’s before entering the study, increasing the
likelihood of being representative for high level female team
athletes within the relevant sports. As described earlier, HCG
testing weeks was selected based on self-reported menstruation.
Although we strived to follow guidelines presented by Sims and
Heather (2018), this method of validation should be interpreted
with caution (Sims and Heather, 2018). Finally, we chose to limit
testing to FP and LP exclusively. Ideally, hormonal validation
of MC phase should have included ovulation. Further, FP and
LP could have been divided to include early and late FP and LP.
Due to time and ﬁnancial reasons, this was not done. Hence, this
limits our result, due to variations in serum hormonal levels in
diﬀerent parts of FP and LP, respectively.
In this study, there was no statistically signiﬁcant changes
for the two diﬀerent phases of the MC, in terms of
physical performance in high level female team athletes.
Further, testing of strength and power performance
parameters were not signiﬁcantly aﬀected by HC status
when comparing an HCG and NHCG during the MC. These
ﬁndings suggest that MC phase should not be of major
consideration for athletic testing or competition, emphasizing
strength and power performance. However, interindividual
Frontiers in Physiology | www.frontiersin.org 7February 2021 | Volume 12 | Article 600668
fphys-12-600668 February 16, 2021 Time: 19:13 # 8
Dasa et al. Strength Performance in Female Athletes
variability in results and hormonal levels, together with a
small sample size makes ﬁrm guidelines arduous. Based on
our study and the current literature, possible alterations to
strength and power performance elicited by the MC are
more likely to occur during long term MC phase dependent
training interventions, rather than acute testing of performance.
Our ﬁndings should be interpreted with caution, due to the
limitations of the study.
DATA AVAILABILITY STATEMENT
The raw data supporting the conclusions of this article will be
made available by the authors, without undue reservation.
The studies involving human participants were reviewed and
approved by Regional Committees for medical and health
research ethics (2018/1529). The patients/participants provided
their written informed consent to participate in this study.
MD: planning, data collection, statistical analysis, and writing.
MK and LPB: planning and data collection. EE: planning and
writing. LB: planning, data collection, and writing. RM-N:
statistical analysis. JS: writing and hormonal data analysis. IH:
planning, statistical analysis, and writing. All authors contributed
to the article and approved the submitted version.
The authors gratefully thank the participants for their time and
eﬀort. The authors would also like to thank the students at
Western Norway University of Applied Science, who participated
in the data collection, making this project possible.
The Supplementary Material for this article can be found
online at: https://www.frontiersin.org/articles/10.3389/fphys.
Abt, J. P., Sell, T. C., Laudner, K. G., McCrory, J. L., Loucks, T. L., Berga, S. L.,
et al. (2007). Neuromuscular and biomechanical characteristics do not vary
across the menstrual cycle. Knee Surg. Sports Traumatol. Arthros. 15, 901–907.
doi: 10.1007/s00167-007- 0302-3
Allen, A. M., McRae-Clark, A. L., Carlson, S., Saladin, M. E., Gray,
K. M., Wetherington, C. L., et al. (2016). Determining menstrual phase
in human biobehavioral research: a review with recommendations.
Exper. Clin. Psychopharmacol. 24, 1–11. doi: 10.1037/pha00
Andersson, H., Raastad, T., Nilsson, J., Paulsen, G., Garthe, I., Kadi, F. et al.
(2008). Neuromuscular fatigue and recovery in elite female soccer: eﬀects
of active recovery. Med. Sci. Sports Exer. 40, 372–380. doi: 10.1249/mss.
Bambaeichi, E., Reilly, T., Cable, N. T., and Giacomoni, M. (2004). The isolated
and combined eﬀects of menstrual cycle phase and time-of-day on muscle
strength of eumenorrheic females. Chronobiol. Int. 21, 645–660. doi: 10.1081/
Birch, K., and Reilly, T. (2002). The diurnal rhythm in isometric muscular
performance diﬀers with eumenorrheic menstrual cycle phase. Chronobiol. Int.
19, 731–742. doi: 10.1081/cbi-120006083
Bushman, B., Masterson, G., and Nelsen, J. (2006). Anaerobic power performance
and the menstrual cycle: eumenorrheic and oral contraceptive users. J. Sports
Med. Phys. Fitness 46, 132–137.
Carter, A., Dobridge, J., and Hackney, A. C. (2001). Inﬂuence of estrogen on
markers of muscle tissue damage following eccentric exercise. Fiziologiia
Cheloveka. 27, 133–137.
Chidi-Ogbolu, N., and Baar, K. (2019). Eﬀect of estrogen on musculoskeletal
performance and injury risk. Front. Physiol. 9:1834. doi: 10.3389/fphys.2018.
Drust, B., Atkinson, G., and Reilly, T. (2007). Future perspectives in the evaluation
of the physiological demands of soccer. Sports Med. 37, 783–805. doi: 10.2165/
Fridén, C., Hirschberg, A. L., and Saartok, T. (2003). Muscle strength and
endurance do not signiﬁcantly vary across 3 phases of the menstrual cycle
in moderately active premenopausal women. Clin. J. Sport Med. 13, 238–241.
doi: 10.1097/00042752-200307000- 00007
Goldstein, E. R., Ziegenfuss, T., Kalman, D., Kreider, R., Campbell, B., Wilborn,
C., et al. (2010). International society of sports nutrition position stand: caﬀeine
and performance. J. Int. Society Sports Nutr. 7:5. doi: 10.1186/1550-2783-7-5
Greeves, J. P., Cable, N. T., Luckas, M. J., Reilly, T., and Biljan, M. M. (1997).
Eﬀects of acute changes in oestrogen on muscle function of the ﬁrst dorsal
interosseus muscle in humans. J. Physiol. 500, 265–270. doi: 10.1113/jphysiol.
Grgic, J., Grgic, I., Pickering, C., Schoenfeld, B. J., Bishop, D. J., Pedisic, Z. et al.
(2019a). Wake up and smell the coﬀee: caﬀeine supplementation and exercise
performance—an umbrella review of 21 published meta-analyses. Br. J. Sports
Med. 54, 681–688. doi: 10.1136/bjsports-2018-100278
Grgic, J., Lazinica, B., Garofolini, A., Schoenfeld, B. J., Saner, N. J., Mikulic, P. et al.
(2019b). The eﬀects of time of day-speciﬁc resistance training on adaptations in
skeletal muscle hypertrophy and muscle strength: a systematic review and meta-
analysis. Chronobiol. Int. 36, 449–460. doi: 10.1080/07420528.2019.1567524
Hansen, M. (2018). Female hormones: do they inﬂuence muscle and
tendon protein metabolism? Proc. Nutr. Society. 77, 32–41. doi:
Hansen, M., Skovgaard, D., Reitelseder, S., Holm, L., Langbjerg, H., Kjaer, M. et al.
(2012). Eﬀects of estrogen replacement and lower androgen status on skeletal
muscle collagen and myoﬁbrillar protein synthesis in postmenopausal women.
J. Gerontol. Series A. 67, 1005–1013. doi: 10.1093/gerona/gls007
Haugen, T., and Buchheit, M. (2016). Sprint running performance monitoring:
methodological and practical considerations. Sports Med. 46, 641–656. doi:
Janse, D. E. J. X., Thompson, B., and Han, A. (2019). Methodological
recommendations for menstrual cycle research in sports and exercise. Med.
Sci.Sports Exer. 51, 2610–2617. doi: 10.1249/mss.0000000000002073
Jonge, X. A. K. J., Boot, C. R. L., Thom, J. M., Ruell, P. A., and Thompson, M. W.
(2001). The inﬂuence of menstrual cycle phase on skeletal muscle contractile
characteristics in humans. J. Physiol. 530, 161–166. doi: 10.1111/j.1469-7793.
Julian, R., Hecksteden, A., Fullagar, H. H., and Meyer, T. (2017). The eﬀects of
menstrual cycle phase on physical performance in female soccer players. PloS
one. 12:e0173951. doi: 10.1371/journal.pone.0173951
Lebrun, C. M., McKenzie, D. C., Prior, J. C., and Taunton, J. E. (1995). Eﬀects
of menstrual cycle phase on athletic performance. Med. Sci. Sports Exer. 27,
Frontiers in Physiology | www.frontiersin.org 8February 2021 | Volume 12 | Article 600668
fphys-12-600668 February 16, 2021 Time: 19:13 # 9
Dasa et al. Strength Performance in Female Athletes
Lidor, R., and Ziv, G. (2010). Physical and physiological attributes of female
volleyball players–a review. J. Strength Cond. Res. 24, 1963–1973. doi: 10.1519/
Lowe, D. A., Baltgalvis, K. A., and Greising, S. M. (2010). Mechanisms behind
estrogen’s beneﬁcial eﬀect on muscle strength in females. Exer. Sport Sci. Rev.
38, 61–67. doi: 10.1097/jes.0b013e3181d496bc
Melin, A., Tornberg, ÅB., Skouby, S., Faber, J., Ritz, C., Sjödin, A., et al. (2014). The
LEAF questionnaire: a screening tool for the identiﬁcation of female athletes at
risk for the female athlete triad. Br. J. Sports Med. 48, 540–545. doi: 10.1136/
Minahan, C., Joyce, S., Bulmer, A. C., Cronin, N., and Sabapathy, S. (2015). The
inﬂuence of estradiol on muscle damage and leg strength after intense eccentric
exercise. Eur. J. Appl. Physiol. 115, 1493–1500. doi: 10.1007/s00421-015- 3133-9
Myllyaho, M. M., Ihalainen, J. K., Hackney, A. C., Valtonen, M., Nummela,
A., Vaara, E., et al. (2018). Hormonal contraceptive use does not aﬀect
strength, endurance, or body composition adaptations to combined strength
and endurance training in women. J. Strength Cond. Res. 35, 449–457. doi:
Oosthuyse, T., and Bosch, A. N. (2010). The eﬀect of the menstrual cycle on exercise
metabolism. Sports Med. 40, 207–227. doi: 10.2165/11317090-000000000-
Phillips, S. K., Sanderson, A. G., Birch, K., Bruce, S. A., and Woledge, R. C.
(1996). Changes in maximal voluntary force of human adductor pollicis muscle
during the menstrual cycle. J. Physiol. 496, 551–557. doi: 10.1113/jphysiol.1996.
Póvoas, S. C. A., Ascensão, A. A. M. R., Magalhães, J., Seabra, A. F., Krustrup, P.,
Soares, J. M. C., et al. (2014). Physiological demands of elite team handball
with special reference to playing position. J. Strength Cond. Res. 28, 430–442.
Redden, J. (2019). Assessing lower limb strength, power and assymetry in elite soccer
players using the keiser air420 seated leg press. PhD. Claverton Down, UK:
University of Bath.
Redden, J., Stokes, K., and Williams, S. (2018). Establishing the reliability and limits
of meaningful change of lower limb strength and power measures during seated
leg press in elite soccer players. J. Sports Sci. Med. 17, 539–546.
Reilly, T. (2000). The menstrual cycle and human performance: an overview. Biol.
Rhythm Res. 31, 29–40. doi: 10.1076/0929-1016(200002)31:1;1-0;ft029
Romero-Moraleda, B., Coso, J. D., Gutiérrez-Hellín, J., Ruiz-Moreno, C., Grgic, J.,
Lara, B. et al. (2019). The inﬂuence of the menstrual cycle on muscle strength
and power performance. J. Hum. Kinetics. 68, 123–133. doi: 10.2478/hukin-
Ronglan, L. T., Raastad, T., and Børgesen, A. (2006). Neuromuscular fatigue and
recovery in elite female handball players. Front. Physiol. 16:267–273. doi: 10.
Sarwar, R., Niclos, B. B., and Rutherford, O. M. (1996). Changes in muscle strength,
relaxation rate and fatiguability during the human menstrual cycle. J. Physiol.
493, 267–272. doi: 10.1113/jphysiol.1996.sp021381
Shalfawi, S. A. I., Enoksen, E., Tønnesen, E., and Ingebrigtsen, J. (2012). Assesing
test-retest reliability of the portable brower speed trap II testing system.
Kinesiology. 44, 24–30.
Sims, S. T., and Heather, A. K. (2018). Myths and methodologies:
reducing scientiﬁc design ambiguity in studies comparing sexes and/or
menstrual cycle phases. Exper. Physiol. 103, 1309–1317. doi: 10.1113/ep0
Slinde, F., Suber, C., Suber, L., Edwén, C. E., and Svantesson, U. (2008).
Test-retest reliability of three diﬀerent countermovement jumping
tests. J. Strength Cond. Res. 22, 640–644. doi: 10.1519/jsc.0b013e31816
Sung, E., Han, A., Hinrichs, T., Vorgerd, M., Manchado, C., and Platen, P. (2014).
Eﬀects of follicular versus luteal phase-based strength training in young women.
SpringerPlus. 3:668. doi: 10.1186/2193-1801-3-668
Thompson, B., Almarjawi, A., Sculley, D., and Janse de Jonge, X. (2020). The eﬀect
of the menstrual cycle and oral contraceptives on acute responses and chronic
adaptations to resistance training: a systematic review of the literature. Sports
Med. 50, 171–185. doi: 10.1007/s40279-019-01219-1
Vassilis, G. (2012). Reliability of handgrip strength test in basketball players.
J. Hum. Kinetics. 31, 25–36. doi: 10.2478/v10078- 012-0003-y
Wikström-Frisén, L., Boraxbekk, C. J., and Henriksson-Larsén, K. (2017). Eﬀects
on power, strength and lean body mass of menstrual/oral contraceptive cycle
based resistance training. J. Sports Med. Phys. Fitness 57, 43–52.
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.
Copyright © 2021 Dasa, Kristoﬀersen, Ersvær, Bovim, Bjørkhaug, Moe-Nilssen,
Sagen and Haukenes. 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 | www.frontiersin.org 9February 2021 | Volume 12 | Article 600668