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OPINION
published: 07 July 2020
doi: 10.3389/fphys.2020.00859
Frontiers in Physiology | www.frontiersin.org 1July 2020 | Volume 11 | Article 859
Edited by:
Hassane Zouhal,
University of Rennes 2 - Upper
Brittany, France
Reviewed by:
Antonio Dello Iacono,
University of the West of Scotland,
United Kingdom
Pantelis Theodoros Nikolaidis,
University of West Attica, Greece
*Correspondence:
Paulo Gentil
paulogentil@hotmail.com
Specialty section:
This article was submitted to
Exercise Physiology,
a section of the journal
Frontiers in Physiology
Received: 24 May 2020
Accepted: 26 June 2020
Published: 07 July 2020
Citation:
Gentil P, Ramirez-Campillo R and
Souza D (2020) Resistance Training in
Face of the Coronavirus Outbreak:
Time to Think Outside the Box.
Front. Physiol. 11:859.
doi: 10.3389/fphys.2020.00859
Resistance Training in Face of the
Coronavirus Outbreak: Time to Think
Outside the Box
Paulo Gentil 1,2
*, Rodrigo Ramirez-Campillo 3and Daniel Souza 1
1College of Physical Education and Dance, Federal University of Goiás, Goiânia, Brazil, 2Hypertension League, Federal
University of Goias, Goiânia, Brazil, 3Laboratory of Human Performance, Quality of Life and Wellness Research Group,
Department of Physical Activity Sciences, Universidad de Los Lagos, Osorno, Chile
Keywords: COVID19, human physical conditioning, virus infection, exercise is medicine, barbell, dumbbell, muscle
strength, weightlifting
THE PROBLEM
Resistance training (RT) is an exercise type commonly associated with the performance of
muscle contractions against external resistance. This training model is very popular and has been
recommended as an essential part of an exercise program by several important associations (ACSM,
2009; Garber et al., 2011). Its benefits are commonly associated with muscle strength and mass gains
and expand to several areas such as blood pressure control (MacDonald et al., 2016), improved
bone mineral density (Zhao et al., 2015), depression management (Gordon et al., 2018), cancer
treatment (Fuller et al., 2018), controlling blood glucose (Codella et al., 2018), weight management
(Paoli et al., 2014), among others. Such benefits, largely mediated by strength gains, culminate in
reductions in mortality rates in different populations (Ruiz et al., 2008; Artero et al., 2011; Ortega
et al., 2012; Hardee et al., 2014; Dankel et al., 2016). Many of the problems that RT has been
shown to counteract are related to increased mortality and morbidity associated with COVID,
like hypertension, diabetes, coronary diseases, overweight (Muniyappa and Gubbi, 2020; Salerno
et al., 2020; Shahid et al., 2020; Singh et al., 2020; Zhou et al., 2020). Although it is not possible to
attribute a direct cause-effect relationship between RT and mortality risk during COVID, it might
be important to perform RT to improve general health and help in a better prognostic in case
of contamination.
Notwithstanding, in the face of the coronavirus or COVID-19 outbreak, the practice of
RT has been strongly threatened. Considering that this virus is highly contagious and may
be transmitted by close contact among people and by sharing subjects, public health policies
generally recommend distance from other people, avoidance of tight spaces and agglomeration
as preventive measures (Adhikari et al., 2020). Therefore, RT practice faces new challenges and
these should be addressed in the near future, for practical and logistical reasons. However,
this might not be an inherent problem to RT, but rather in the way that it is commonly
understood and applied. Although it originally involved exercises with body weight or objects
obtained from the nature itself, RT began to be increasingly associated with sophisticated
equipment and facilities, and with time-consuming, and complicated routines. As a result,
RT is being mainly performed in facilities such as gyms, health clubs, fitness centers, and
with high-cost specialized machines. Such conceptions regarding RT imposes a barrier for its
implementation in the current scenario, since its performance would involve agglomeration,
climatized environments, sharing of materials, and other characteristics that may favor an increased
risk of infection. However, is it important to note that RT does not necessarily involve the
need of conventional equipment and facilities which allows it to be performed in a range of
alternative situations.
Gentil et al. Resistance Training and the Coronavirus Outbreak
When analyzing current scientific evidence, it seems that
RT can safely, time-efficient and easily be implemented, in
almost anywhere and with minimal resources, which makes it
fully feasible within measures adopted to control coronavirus
dissemination. Therefore, this opinion aimed to discuss practical
and uncomplicated evidence-based RT alternatives to overcome
the restrictions measures adopted during COVID-19 outbreak.
LOADS, EQUIPMENT AND IMPLEMENTS
Most conventional approaches suggest that RT should be
performed with moderate to high loads, with specific number of
repetitions and using specific equipment, like machines and free
weights (Kraemer et al., 2002; ACSM, 2009). However, according
to the muscle effort principle (i.e., effort-based paradigm; Steele
et al., 2017a), when effort is high, RT performed in different ways,
such as using different loads, different types of equipment and in
different environments, can bring gains in muscle size and fitness
similar to the most conventional approaches (Fisher et al., 2017b;
Steele et al., 2017b, 2019).
With regard to load, it is commonly recommended that, for
optimal gains in strength and muscle mass, it is necessary to
use moderate- to high-loads [≥60% of one repetition maximum
(1RM)] (McDonagh and Davies, 1984; ACSM, 2009), which
would make it difficult to perform RT without specialized
equipment. However, studies have shown that, regardless of
training level, gains in muscle strength, and mass may be related
to muscle effort (i.e., physiological stimulus), and not necessarily
to the load being used (Fisher et al., 2017b).
Studies in untrained (Mitchell et al., 2012; Assunção et al.,
2016) and trained people (Morton et al., 2016) reveal that
training with low-external loads (LEL) promote similar gains
in muscle mass and strength compared to high-external loads,
especially when the strength tests are not specific (Fisher et al.,
2017b). In fact, relevant gains in strength and muscle mass are
feasible with LEL (40% of 1RM) and a high number (>100) of
repetitions (Farup et al., 2015), something that was previously
unimaginable for RT. Although the studies with LEL involved the
precise quantification of the load, which might not be feasible
during the social distance measures, the results suggested that
RT benefits might be associated with effort and not with the
number of repetitions or loads used. Therefore, it brought the
insight that muscles do not “see” the load being lifted or count
repetitions performed, but it seems to interpret physiological
signaling associated with effort (Steele et al., 2017a, 2019). With
this in mind, it might be expected that training with affordable
implements (elastic bands, light dumbbells, and barbells) without
the need of specialized resources or facilities could be a feasible
option for RT.
Indeed, similar physiological stimulus can be induced with
elastic bands when compared to traditional methods, including
muscle activation and micro-structural damage (Aboodarda
et al., 2011, 2016), strength gains (Martins et al., 2013), and
functional improvements (Colado et al., 2010; Souza et al., 2019).
Moreover, some training models traditionally associated with
aerobic activities such as stationary cycling may promote muscle
hypertrophy and strength gains (Ozaki et al., 2015, 2016; Steele
et al., 2019). Such a proposal has already been presented and
tested, with promising results (Steele et al., 2019). Therefore,
effective RT programs can be performed using implements easily
obtained in standard commercial facilities at low cost, and that
might be stored at home.
Moreover, significant peripheral physiological stimulus can be
induced even without external-load (NEL), involving maximal
or near-maximal voluntary muscle contraction. For example,
acute studies verified high levels of motor units recruitment
when performing NEL muscle contractions with the intention
to maximally contract the muscles (Gentil et al., 2017a). Some
studies showed muscle strength and mass gains after NEL-RT
programs (Counts et al., 2016; Barbalho et al., 2019). In young
men and women, after a contralateral training design, equivalent
gains in the arm muscle size was observed after traditional RT
and NEL-RT (Counts et al., 2016). This hypothesis was also
confirmed in rehabilitation setting, with positive outcomes in
terms of hypertrophy and functionality (Barbalho et al., 2019).
Therefore, evidence points toward the need of inducing
significant muscle physiological stimulus and this can be
achieved with LEL, or even with NEL. Therefore, the need for
equipment and implements should not be viewed as a barrier to
implement RT programs during current pandemic times. On the
other hand, due the high levels of perceived effort and discomfort
during NEL and LEL (Fisher and Steele, 2017; Gentil et al.,
2017a), as well as the high cardiovascular stress induced by LEL
(Vale et al., 2018), is reasonable to suggest that these training
methods might not be suitable for special population, such as
sedentary aging people and heart disease patients.
Finally, RT has been usually monitored by external load
parameters, which might not be feasible in absence of specialized
equipment. However, it has been suggested that that monitoring
internal load might be also important to understand exercise
response (Impellizzeri et al., 2019). In this regard, session rate
of perceived effort and training impulse (repetitions x session
rate of perceived exertion) might be useful tools for this purpose
(Martorelli et al., 2020). According to (Martorelli et al., 2020),
session rating of perceived exertion might be more indicated
when training to or close to muscle failure, while training impulse
might be indicated when avoiding muscle failure.
TIME-EFFICIENCY AND UNCOMPLICATED
TRAINING STRATEGIES
A practical issue that raised with social isolation was the
reduction of free time. Although social isolation may presume
more time available it is also possible that greater involvement
in household activities, family care and children’s education,
for example, might make time more scarce. Thus, the need
for time-efficient RT approaches has become promising and
attractive (Fisher et al., 2017a). If we consider a minimum dose
approach, workouts that last a few minutes can be efficient in
promoting muscle strength and size gains (Souza et al., 2020).
Another important aspect is about exercise selection. It is
commonly believed that a complete routine would require a
Frontiers in Physiology | www.frontiersin.org 2July 2020 | Volume 11 | Article 859
Gentil et al. Resistance Training and the Coronavirus Outbreak
wide variety of exercises, including many isolated exercises
for specific muscles, like gluteus, biceps, and triceps brachii.
However, current evidence shows that the use of basic and
multi-joint exercises is sufficient to promote gains in muscle
strength and size in most muscles involved in movement
(Gentil et al., 2015, 2017b; Paoli et al., 2017; Barbalho et al.,
2020a,b) and the addition of isolated exercises, in general, does
not seem to bring additional benefits (Gentil et al., 2013; de
França et al., 2015; Barbalho et al., 2020b). Furthermore, RT
using body weight promotes similar gains in muscle strength
and thickness in comparison with traditional training, even in
young trained practitioners (Calatayud et al., 2015; Kikuchi and
Nakazato, 2017), as: provides benefits to middle-aged people
with non-alcoholic fat liver disease (Takahashi et al., 2015, 2017)
and improvements on muscle strength and body composition
in elderly people (Tsuzuku et al., 2017). Although the study of
Kikuchi and Nakazato (2017) had a limited sample size and a high
variability in the results, it is possible that body-weight exercises
(such as jumps, dips, push-ups, chin-ups, squats, and lunges)
performed at home, requiring no extra equipment, in a relatively
reduced space, with a low-volume time-efficient approach can be
capable of inducing significant health benefits and increases in
muscle strength, power, and hypertrophy.
A common belief related to RT is the need of constant exercise
variation to guarantee continued results over medium and long-
term. This might lead to the misconception that it would not be
possible to obtain positive results unless several different types
of equipment and loads are available, as in traditional facilities.
However, variation of external load, methods and exercises
do not necessarily translates into greater muscle strength and
hypertrophy gains (Loturco and Nakamura, 2016; Loturco et al.,
2016; De Souza et al., 2018; Baz-Valle et al., 2019; Damas et al.,
2019). In this sense, proper adjustment of RT intensity and
volume in order to provide an adequate muscle physiological
stimulus might be more beneficial to achieve optimum gains in
muscle strength and size, than to vary the RT program per se.
FINAL CONSIDERATIONS
The repercussions of the current pandemic on the health of
economy is a major concern for most countries around the
globe. With people at home, sedentary behavior, and physical
inactivity may increase, posing an even greater burden to the
economy (Ding et al., 2016) and increasing the prevalence
of problems associated with greater mortality and morbidity
associated with COVID-19. Home-based (or public open spaces)
RT programs in the context of current pandemic times are highly
feasible, with an enormous potential impact in counteracting the
detrimental effects of sedentary behavior and physical inactivity
on population health and economic burden.
Several effective, safe, low-cost, time-efficient, and practical
RT approaches can be considered, such as programs with
LEL, NEL, body-weight load, jump-based, elastic bands, among
others. Complicated, highly specialized exercises are not an
essential part of RT programs for most people. RT programs
should be promoted during current pandemic times in order
to promote better health and quality of life (Tasiopoulos et al.,
2018; Nikolaidis et al., 2019). However, it might be necessary
to sacrifice some old-fashioned thoughts rooted in beliefs that
have already been overturned by science. Analyzing the new
perspectives brought in this opinion article, we see that it is
possible to perform RT in a practical and uncomplicated manner,
avoiding the exposure to a potentially infectious environment
and adapting training programs to the new time and logistical
challenges brought by the coronavirus outbreak. These strategies
might allow obtaining continued results in terms of mental and
physical health. These seems be the returning message of to what
Leonardo Da Vinci told us more than 500 years ago: “simplicity
is the ultimate sophistication.”
AUTHOR CONTRIBUTIONS
PG, RR-C, and DS contributed to the conception, drafting the
article, revising it critically, and final approval of the version to
be published. All authors contributed to the article and approved
the submitted version.
FUNDING
This research did not receive any specific grant from funding
agencies in the public, commercial, or not-for-profit sectors. PG
receives a Research Grand from CNPq (304435/2018-0).
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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.
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Frontiers in Physiology | www.frontiersin.org 5July 2020 | Volume 11 | Article 859
