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Objectives This study aimed to determine whether looped resistance bands affect knee kinematics and lower body muscle activation during the barbell back squat. Methods Twenty-six healthy participants (13 female, 13 male) calculated their one repetition maximum (RM) prior to data collection. Each participant performed three squats at both 80% and 40% 1RM wearing a light resistance band, an extra-heavy resistance band and no resistance band. Vicon 3D motion analysis cameras were used to collect the kinematic data, and Delsys Trigno Lab wireless electromyography (EMG) system was used to measure vastus medialis, vastus lateralis, gluteus maximus, gluteus medius and biceps femoris muscle activity. Peak knee flexion angle, peak knee valgus angle and maximum tibial rotation values were examined. Peak EMG values were also analysed after being normalised and expressed as a percentage of maximum voluntary contraction (MVC). Results Gluteus maximus (GM) activity is significantly increased when a resistance band is used during squatting. However, squatting with a resistance band is detrimental to knee kinematics as it leads to an increase in knee valgus angle and maximum tibial rotation angle. A direct correlation is recorded between an increase in resistance and an increase in these two angles. Conclusions Squatting with resistance bands is likely to increase the risk of knee injury. Coaches and clinicians who already implement this technique are advised to remove resistance band squats from training and rehabilitation programmes. Further research evaluating the long-term effects of using resistance bands during the barbell back squat should be considered.
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ReeceMB, etal. BMJ Open Sp Ex Med 2020;6:e000610. doi:10.1136/bmjsem-2019-000610 1
Open access Original research
Barbell back squat: how do resistance
bands affect muscle activation and
knee kinematics?
Madeleine B Reece,1 Graham P Arnold,1 Sadiq Nasir,1 Weijie W Wang,1
Rami Abboud 2
To cite: ReeceMB, ArnoldGP,
NasirS, etal. Barbell back
squat: how do resistance bands
affect muscle activation and
knee kinematics? BMJ Open
Sport & Exercise Medicine
2020;6:e000610. doi:10.1136/
bmjsem-2019-000610
Accepted 8 January 2020
1nstitute of Motion Analysis &
Research (IMAR), University of
Dundee, Dundee, UK
2Dean’s Ofce, University
of Balamand Faculty of
Engineering, El- Koura, Lebanon
Correspondence to
Dr Graham P Arnold;
g. p. arnold@ dundee. ac. uk
Professor Rami Abboud;
rjabboud@ balamand. edu. lb
© Author(s) (or their
employer(s)) 2020. Re- use
permitted under CC BY- NC. No
commercial re- use. See rights
and permissions. Published by
BMJ.
ABSTRACT
Objectives This study aimed to determine whether
looped resistance bands affect knee kinematics and lower
body muscle activation during the barbell back squat.
Methods Twenty- six healthy participants (13 female, 13
male) calculated their one repetition maximum (RM) prior
to data collection. Each participant performed three squats
at both 80% and 40% 1RM wearing a light resistance
band, an extra- heavy resistance band and no resistance
band.
Vicon 3D motion analysis cameras were used to collect
the kinematic data, and Delsys Trigno Lab wireless
electromyography (EMG) system was used to measure
vastus medialis, vastus lateralis, gluteus maximus, gluteus
medius and biceps femoris muscle activity. Peak knee
exion angle, peak knee valgus angle and maximum tibial
rotation values were examined. Peak EMG values were
also analysed after being normalised and expressed as a
percentage of maximum voluntary contraction (MVC).
Results Gluteus maximus (GM) activity is signicantly
increased when a resistance band is used during
squatting. However, squatting with a resistance band is
detrimental to knee kinematics as it leads to an increase
in knee valgus angle and maximum tibial rotation angle.
A direct correlation is recorded between an increase in
resistance and an increase in these two angles.
Conclusions Squatting with resistance bands is likely
to increase the risk of knee injury. Coaches and clinicians
who already implement this technique are advised
to remove resistance band squats from training and
rehabilitation programmes. Further research evaluating
the long- term effects of using resistance bands during the
barbell back squat should be considered.
INTRODUCTION
The barbell back squat is a strengthening
training exercise that is continuing to grow
in popularity. As a compound exercise, it
develops the most powerful muscles in the
human body. The exercise attracts both
professional athletes and recreational gym
goers as well as playing an important role
in rehabilitation situations.1 2 As the feet
remain in a fixed position throughout the
squat movement, the exercise is classified
as a closed kinetic chain exercise. It is often
prescribed with regard to the rehabilitation
of anterior cruciate ligament (ACL) injuries,
as the forces on the ACL are lower than other
exercises such as knee extension.2
If the squat is not performed in alignment
with the recommended technique, the risk of
injury occurring increases. Movement of the
knee in the frontal plane is one factor that
increases the risk of injury sustained to the
knee when squatting.3 Medial knee displace-
ment (MKD) is particularly abundant among
inexperienced squatters and is described
as the movement of the knees towards the
midline, resulting in a knee position medial
to the great toe (figure 1).4–7 It is thought to
originate from an inability of the hip muscles
to support the femur resulting in excessive
adduction and internal rotation.4 The ACL
directly resists internal tibial rotation as well
as opposing knee valgus, making this struc-
ture susceptible to injury if MKD occurs
during squatting.2
The use of a looped resistance band as a
proprioceptive aid when squatting is a tech-
nique already implemented by clinicians and
coaches to maintain a neutral knee alignment.
Despite this, recent studies have disagreed
that resistance bands are capable of achieving
this result.3 8 However, it has been shown that
resistance bands can increase the activation
of certain lower limb muscles during the
movement, which may work to prevent knee
valgus.9 The focus in many of these studies
was not on weighted squats alone, but rather
on a combination of bodyweight squats and/
or jumping squats, rendering the results less
relevant to athletes and gym goers. Only one
Summary box
Looped resistance bands placed around the distal
thigh during the barbell back squat:
increases gluteus maximus muscle activation,
increases peak knee valgus angle and maximum
tibial rotation angle.
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Open access
Figure 1 Normal knee alignment in the squat (A) and valgus knee alignment in the squat (B).
study, conducted by Foley et al (2017), investigated both
EMG amplitudes of lower limb muscles and medial knee
collapse during a banded barbell back squat. Their paper
was methodologically limited as neither the internal
tibial rotation nor knee valgus angles were calculated.8
Foley et al study also excluded women, despite ACL inju-
ries in women being 4–6 times higher than their male
counterparts.10
Therefore, the primary aim of this study was to supply
more conclusive evidence to support whether looped
resistance bands reduce peak knee valgus and internal
tibial rotation and therefore ACL strain. A secondary aim
was to investigate the effect resistance bands have on the
muscle activation of vastus lateralis (VL), vastus medialis
(VM), biceps femoris (BF), gluteus medius and gluteus
maximus (GM) during the barbell squat.
METHODS
Study design
A repeated measures design was employed to examine
the effect of using resistance bands on frontal plane knee
mechanics and lower limb muscle activation during the
barbell back squat.
Patient and public involvement
A convenience sample of 26 healthy (13 male, 13 female)
participants volunteered for the study. This is the largest
number of participants of any study in this field to date
and the only study to investigate females using resistance
bands during the barbell back squat to our knowledge.
Participant requirements included: at least 6 months
experience of squatting, novice user of looped resistance
bands, over the age of 18 and be in good general health
at the time of the study. The mean height, mass and
age of participants was 172.3 cm ±6.9, 73.3 kg ±9.6 and
21.7years±1.3, respectively. Participants were verbally
informed of all procedures and signed a written consent
form. Ethical approval was gained from the University
Medical Research Ethics Committee. No patients were
involved in this study.
Instrumentation
The collection of motion data was synchronous with
EMG data.
Delsys Trigno Lab wireless EMG system was used for
data collection of muscle activity. Nine 37 mm × 26 mm ×
15 mm EMG sensors were attached, after hair removal and
skin cleaning with NuPrep gel, over the muscle bellies of
VM, VL, BF, GM bilaterally and the right gluteus medius.
EMG data were captured at 1000 Hz with the bandwidth
of 10–850 Hz and a CMRR of <–80dB.
The Vicon Nexus system V.2.7.1 was used for collection
of motion analysis data. Fourteen MXF40 cameras were
used, each recording at 200 Hz at 4 megapixel resolution.
Twenty 14 mm diameter, retroreflective markers were
placed on each participant in alignment with the plug- in
gait model (figure 2).
Two resistance bands were tested, the light and extra
heavy Corezone resistance bands. The elastic rate of the
light band was 0.21 N/mm, whereas the elastic rate of the
extra heavy band was 0.68 N/mm.11
Procedures
All data were collected during one single session at
IMAR's gait laboratory. Before attending the session,
participants were asked to determine their 1RM.
First, the height (cm), weight (kg), knee width (mm),
ankle width (mm), inter- ASIS distance (mm) and leg
length (mm) of each participant were recorded. Partic-
ipants warmed up in whichever way they felt most
comfortable, in order to accommodate the different
levels of ability between participants. Retro- reflective
markers and EMG sensors were attached to the relevant
locations on the body and a standard T frame was used
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ReeceMB, etal. BMJ Open Sp Ex Med 2020;6:e000610. doi:10.1136/bmjsem-2019-000610
Open access
Figure 2 Retroreective marker and EMG sensor placement.
to statically and dynamically calibrate the Vicon Nexus
system.
The MVC value of each muscle tested was required for
normalisation of the data. The dynamic normalisation task
used was recommend by Balshaw and Hunter (2012).12
First, the participant’s 3RM was calculated, by multiplying
their 1RM by 0.92,13 which was summed with 88.6% of
their body mass, resulting in their 3RM system mass. The
normalisation task required 80% of this load to be squatted
five times. Peak muscle activity over the five repetitions for
each muscle was taken as the MVC value.
Before data collection, the Vicon 3D motion system
required further static and dynamic calibration which
involved the participant standing in a T- pose for three
seconds and then walking up and down the lab. During
data collection, each participant completed three repe-
titions of the barbell back squat, lifting 80% 1RM and
40% 1RM (separately), under the following conditions:
no band, light band and extra heavy band. The order of
completion was randomised. A number of factors were
controlled: squat width was set to be slightly wider than
shoulder width, all participants squatted barefoot and
adopted a high bar placement, resistance bands were
placed just above the lateral epicondyle of the femur,
speed was standardised at 5 s to complete the full move-
ment. A 5 min rest period was provided between each
set and participants were continually instructed to push
their knees out as much as possible against the resistance
of the band in order to maintain knee alignment over the
great toe throughout the movement.
Data analysis
Each trial was labelled using Vicon software and three
events were added: the start of the squat, the deepest
point of the squat and the end point of the ascent phase.
The deepest point of the squat was identified as the point
of greatest vertical displacement of the ASIS markers.
Once labelled, a CSV file from the Nexus software for
each trial was uploaded to a custom written extraction
programme, producing an Excel file which indicated the
peak knee angles during both the concentric (ascent)
and eccentric (descent) phases of the squat.
EMG data for each muscle from each trial were
exported from Nexus as CVS files and was uploaded to
the Nexus 2 EMG analyser programme, producing an
Excel file which indicated (as a % of the MVC) the peak
EMG muscle contraction for each muscle investigated
during the eccentric and concentric phases of the squat.
Statistical analysis
Statistical analyses were carried out using Statistical
Package for Social Sciences (SPSS) V.22.0. Statistical
significance was determined at p<0.05.
Kinematic and EMG data were analysed using the General
Linear Model Repeated Measures to calculate means and
SE of means. Each subject has three trials per condition and
the number of trials is balanced for all subjects; therefore,
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Open access
we did not consider that we needed corrections. Means, SE
of means and p values were taken from estimates and pair-
wise comparisons tables which is posthoc.
During both the eccentric and concentric phase of the
squat for 40% 1RM and 80% 1RM, two lower body kine-
matic parameters were analysed. These parameters are
comprised of knee valgus angle and maximum tibial rota-
tion, for both the left and right knee. EMG data were also
analysed for the five chosen muscles during the concen-
tric phase of the squat for 40% 1RM and 80% 1RM.
RESULTS
Knee kinematics
Table 1 shows the results for peak knee valgus angle and
maximum tibial rotation value during both the 40%
and 80% 1RM squats, while pairwise comparisons are
displayed in table 2.
It should be noted that females had higher maximum
tibial rotation means and lower peak knee valgus means
compared with males across all conditions studied. This
indicates that males may be at a higher risk of injury when
squatting compared with females, regardless of whether
a band is used or not. However, the effect that each resis-
tance band had on knee kinematics during a squat was
very similar between both males and females. Therefore,
the results are discussed without referring to gender.
Peak knee valgus angle was highest in both the eccentric
and concentric phases of the squat when an extra heavy
band was used, and lowest when no band was used to squat.
This was true for both the high intensity and low intensity
squats. Similar findings were found in the left and right
knee.
The extra heavy resistance band showed significantly
higher peak knee valgus angles when compared with
using no resistance band in the concentric phase (an
increase of 28% was seen during the 80% 1RM squat and
an increase of 37% was seen during the 40% 1RM squat)
and the eccentric phase (an increase of 32% in peak
knee valgus was seen during the 80% 1RM squat and an
increase of 27% was seen during the 40% 1RM squat).
The light resistance band also showed significantly
greater peak knee valgus angles than the no resistance
band condition in both the concentric (14% increase
during the 80% 1RM squat and 27.2% increase during
the 40% 1RM squat) and eccentric (19% increase during
the 80% 1RM squat and 18% during the 40% 1RM squat)
phases of the squat.
Notable significant differences were recorded between
the different squatting conditions with regard to tibial
rotation. The extra heavy band resulted in the highest
maximum tibial rotation value, while the no band condi-
tion resulted in the lowest value. One exception to this
was in the left limb of the low intensity squat where
the light resistance band condition elicited the highest
maximum tibial rotation value.
The extra heavy band condition significantly increased
maximum tibial rotation values by an average of 1.78°
compared with the no band condition during the 80%
1RM squat. The same was true during the 40% 1RM squat
where the extra heavy band produced an average increase
in maximum tibial rotation of 1.75°. The pattern of results
when comparing the light resistance band to the no band
condition mirrored that of the extra heavy resistance band
compared with the no band condition. The light band
caused an increase in maximum tibial rotation of 1.55°
during the 80% 1RM squat and 1.93° during the 40% 1RM
squat, compared with the no band condition.
Muscle activity
Muscle activity results for the concentric phase will be
studied as this phase of the squat generated the largest
muscle activation values (figure 3). The extra heavy resis-
tance band generated a significantly larger mean peak
EMG value in GM than the light resistance band (80%
1RM left: p<0.001; 80% 1RM right: p<0.001; 40% 1RM left:
p<0.001; 40% 1RM right: p<0.001) and the no band condi-
tion (80% 1RM left: p=0.009; 80% 1RM right: p=0.005;
40% 1RM left: p<0.001; 40% 1RM right: p<0.001). Quan-
tifying this, the heaviest resistance band elicited a mean
GM EMG value 13.25% higher than the no band condition
during the high intensity squat and 23.15% higher during
the low intensity squat. Significant difference was found
in the activity of the right VL where the no band condi-
tion produced much higher activity than the extra heavy
band (80% 1RM: p=0.028) and the light band (80% 1RM:
p=0.018; 40% 1RM: p=0.005). However, peak EMG value
in the left VL during low intensity squats was significantly
lower in the extra heavy band condition than no band
(p=0.007) and the light band condition (p=0.031). During
the low intensity squats for left VM, the no band condition
also produced the highest peak EMG value and the extra
heavy band was found to achieve significantly lesser muscle
activity than both the no band condition (p=0.008) and the
light band condition (p=0.008).
No other significant differences with regard to muscle
activity were found.
DISCUSSION
The aim of this study was to determine whether looped
resistance bands reduce peak knee valgus and internal
tibial rotation, as well as their effect on lower body muscle
activation during the barbell back squat. If resistance
bands can successfully achieve what has been suggested
then they will be beneficial in ACL rehabilitation situa-
tions, as stress on the ACL will be reduced. They will also
be a useful piece of equipment for athletes as the resis-
tance band could reduce the incidence of knee injuries
within squatting, particularly injuries to the ACL, which
are extremely debilitating to athletes. Hence two hypoth-
eses to test: first, performing a barbell back squat with a
resistance band will cause a decrease in peak knee valgus
angle and a decrease in maximum tibial rotation angle.
Second, performing a barbell back squat with a resis-
tance band will cause an increase in muscle activation of
all lower limb muscles tested.
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Table 1 Knee parameters for 40% and 80% 1RM squats
Extra heavy resistance band No resistance band Light resistance band
Mean±SE
95% CI
Mean±SE
95% CI
Mean±SE
95% CI
Lower bound Upper bound Lower bound Upper bound Lower bound Upper bound
40% 1RM
Concentric
phase
Peak knee valgus (°) Left 3.98±0.70 2.60 5.37 2.85±0.61 1.63 4.07 3.83±0.75 2.33 5.33
Right 3.98±0.72 2.54 5.41 2.95±0.70 1.56 4.34 3.54±0.66 2.22 4.87
Max. tibial rotation (°) Left −0.55±0.86 −2.26 1.17 −2.33±0.75 −3.82 −0.83 −0.15±0.76 −1.67 1.37
Right −3.78±0.85 −5.47 −2.10 −5.69±0.75 −7.18 −4.21 −3.86±0.91 −5.66 −2.05
40% 1RM
Eccentric
phase
Peak knee valgus (°) Left 3.64±0.70 2.26 5.02 2.76±0.66 1.44 4.09 3.46±0.75 1.97 4.96
Right 3.98±0.71 2.56 5.40 3.24±0.75 1.74 4.73 3.55±0.70 2.15 4.96
Max. tibial rotation (°) Left −0.43±0.84 −2.10 1.24 −1.88±0.71 −3.29 −0.46 0.12±0.75 −1.37 1.60
Right −3.75±0.85 −5.44 −2.05 −5.58±0.69 −6.94 −4.21 −3.86±0.85 −5.54 −2.17
80% 1RM
Concentric
phase
Peak knee valgus (°) Left 3.44±0.82 1.80 5.08 2.60±0.85 0.90 4.30 3.08±0.84 1.42 4.74
Right 4.75±0.75 3.26 6.24 3.81±0.79 2.24 5.38 4.18±0.76 2.67 5.69
Max. tibial rotation (°) Left −0.92±0.90 −2.72 0.87 −2.99±0.83 −4.64 −1.34 −1.07±0.78 −2.63 0.49
Right −4.58±0.99 −6.54 −2.61 −6.18±0.75 −7.68 −4.68 −4.74±0.82 −6.37 −3.12
80% 1RM
Eccentric
phase
Peak knee valgus (°) Left 2.98±0.79 1.40 4.56 2.13±0.89 0.36 3.90 2.75±0.83 1.10 4.40
Right 4.63±0.78 3.08 6.19 3.70±0.83 2.05 5.34 4.05±0.78 2.48 5.60
Max. tibial rotation (°) Left −0.39±0.96 −2.30 1.53 −2.56±0.74 −4.04 −1.08 −0.95±0.75 −2.44 0.55
Right −4.49±0.92 −6.32 −2.65 −5.73±0.67 −7.06 −4.40 −4.52±0.76 −6.04 −3.00
Mean±SE and CIs are displayed.
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Table 2 Pairwise comparisons for 40% and 80% 1RM
squats with p values displayed
Condition
40% 1RM
Squat
80% 1RM
Squat
Sig. Sig.
Concentric phase
Peak knee valgus (°) Left 1 2 0.000* 0.023*
2 3 0.001* 0.045*
3 1 0.555 0.309
Right 1 2 0.000* 0.001*
2 3 0.018* 0.169
3 1 0.056 0.007*
Max. tibial rotation (°) Left 1 2 0.000* 0.000*
2 3 0.000* 0.000*
3 1 0.286 0.747
Right 1 2 0.000* 0.002*
2 3 0.000* 0.000*
3 1 0.829 0.624
Eccentric phase
Peak knee valgus (°) Left 1 2 0.001* 0.026*
2 3 0.017* 0.033*
3 1 0.521 0.495
Right 1 2 0.004* 0.001*
2 3 0.160 0.156
3 1 0.067 0.003*
Max. tibial rotation (°) Left 1 2 0.001* 0.003*
2 3 0.000* 0.000*
3 1 0.160 0.383
Right 1 2 0.001* 0.012*
2 3 0.000* 0.000*
3 1 0.761 0.926
1=Extra heavy resistance band. 2=No resistance band. 3=Light
resistance band.
*Statistically signicantly (p<0.05).
Knee kinematics
Results illustrate that in both phases of the squat, resis-
tance bands increase peak knee valgus angle and internal
tibial rotation in low intensity and high intensity barbell
squats. This was true for both the light resistance band
and the extra heavy resistance band. It must be noted that,
although there was no significant difference between the
light and extra heavy bands, the trend observed was that
the higher the resistance the greater the two angles inves-
tigated. No other studies are known to have investigated
these angles with regard to squatting with resistance
bands. While Gooyers et al (2012)3 and Foley et al (2017)8
conducted similar investigations and used knee width
index as the primary measure of medial knee collapse,
results from both studies along with the current study
support the notion that resistance bands do not promote
neutral knee alignment during squatting. The current
study expands on this by warning that performing the
barbell back squat with a resistance band, regardless of
strength, increases knee valgus.
A potential explanation for these results may be that,
although the band could have acted as a proprioceptive
aid and participants were continually encouraged to
‘push their knees out against the resistance band’, the
strength of the resistance bands may have been too high
for participants to overcome. This is a plausible assump-
tion, as the majority of participants had never squatted
with resistance bands before, meaning the hip abductor
muscles may not be strong enough to resists the forces
created by the band. This left participants with a peak
knee valgus angle and tibial rotation value, in both the
eccentric and concentric phases, higher than when no
band was used. Therefore, resistance bands increase
medial knee collapse which consequently raises the risk
of injury to the knee. It would be interesting to see if
the same results would be generated in individuals who
have used resistance bands during the barbell squat exer-
cise over a prolonged period of time, as they may have
developed the necessary muscle activation patterns to
overcome the forces produced.
Muscle activity
Gluteus maximus and gluteus medius
In agreement with previous literature,8 9 the present study
found that all participants experienced an overall signif-
icant increase in GM activity when using either the light
resistance band or the extra heavy resistance band in the
high intensity or low intensity squat, compared with the
no band condition. Figure 4 illustrates raw EMG data of
the GM muscle during the three squat conditions for
one participant. The heavier band produced the largest
increase, allowing us to conclude that, by increasing the
strength of the resistance band, GM activity exponentially
increases. This is in agreement with the results demon-
strated by Spracklin et al (2017).9
This result can be explained as the forces produced by
the resistance bands must be opposed by the hip abductor
muscles, with the likely aim of resisting internal hip rota-
tion.9 Therefore, individuals who aim to target the GM
during squatting should achieve this goal through squat-
ting with looped resistance bands.
Although the highest GM EMG value was achieved in
the high intensity squat, it should be noted that a larger
percentage increase in GM activity was achieved in the
low intensity squat. Individuals who focus on low intensity
squats could increase GM activation by a staggering 25%
if a heavy resistance band is implemented.
The current study found no significant difference in
the activity of the gluteus medius muscle with and without
looped band intervention. This differs from the results
found in previous research.8 9
Biceps femoris
There was no difference in the activity of BF when squat-
ting with and without a resistance band, regardless of
strength or squat intensity. This is in agreement with
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ReeceMB, etal. BMJ Open Sp Ex Med 2020;6:e000610. doi:10.1136/bmjsem-2019-000610
Open access
Figure 3 Mean peak EMG values as a % of MVC during the concentric phase of 80% 1RM (top) and 40% 1RM (bottom).
results from Spracklin et al (2017).9 The hamstrings are
unlikely to contribute to resisting the forces produced by
the resistance band, explaining the result.
Vastus lateralis and vastus medialis
Many individuals who squat aim to target the quadri-
ceps; thus; any insight into how to gain increased muscle
activity in the quadriceps is beneficial.
Although significant results were often not gained, the
predominant trend was that quadriceps muscle activity
was reduced when a resistance band was used to squat,
compared with no band. This disputes the results found
from previous research.8 The differing results may be
attributed to the fact that squat depth was not controlled.
However, the overall recommendations to squatters who
focus on targeting the quadriceps rather than GM are
consequently advised not to squat with resistance bands.
To summarise, the hypothesis that this study explored,
‘performing a barbell back squat with a resistance band
will cause a decrease in peak knee valgus angle and a
decrease in maximum tibial rotation’, can be rejected.
The hypothesis ‘performing a barbell back squat with a
resistance band will cause an increase in muscle activa-
tion of all lower limb muscles tested’ can also be rejected
as not all muscles were found to increase in activation.
LIMITATIONS
Squat depth was not controlled, meaning differing
depths could have been achieved in the different condi-
tions. This may have affected muscle activation results as
the gluteus and quadricep muscles have been shown to
increase in activation as squat depth increases.2 14
Despite apparent bilateral differences in the data
collected, this study did not compare the left and right
side as this was not included in the aim.
Although participants were experienced in practicing
the exercise, one repetition maximums were self- reported
and this could be considered a limitation. In addition,
squat width was set as ‘slightly wider than shoulder width’
which was standardised between sets for each individual.
However, foot width could have been calculated to ensure
absolute standardisation between participants.
CONCLUSION
Squatting with resistance bands was shown to increase
muscle activation of GM, while making no difference in
the EMG amplitude of the hamstrings. However, overall
results indicate that squatting with a resistance band
reduces peak knee flexion angle, increases peak knee
valgus angle and increases maximum tibial rotation
by copyright. on February 5, 2020 by guest. Protectedhttp://bmjopensem.bmj.com/BMJ Open Sport Exerc Med: first published as 10.1136/bmjsem-2019-000610 on 4 February 2020. Downloaded from
8ReeceMB, etal. BMJ Open Sp Ex Med 2020;6:e000610. doi:10.1136/bmjsem-2019-000610
Open access
Figure 4 Raw EMG data of the GM muscle during the three squat conditions for one participant.
value. This may lead to an increased risk of knee injury
during the barbell back squat.
Despite clinicians and coaches supporting the notion
that resistance bands promote neutral knee alignment
during squatting, the current study disagrees and advises
consideration for the removal of this technique as it may
lead to an increased risk of knee injury.
Although this study focused on the results being appli-
cable to the population as a whole, future research could
investigate if results differ between male and females.
Long- term effects of the use of resistance bands during
squatting is another area which could be explored.
Acknowledgements The authors would like to thank Mr Ian Christie for his
valuable assistance in the production of bespoke images.
Contributors All coauthors are in agreement to be accountable for all aspects of
the work presented in this manuscript. MBR: planning the study, conducting the
study, analysing the data, reporting the study, generating the draft write- up and
responsible for the overall content as guarantor. GPA: data collection for study
and Vicon markers repeatability. SN: data collection for study and Vicon software
reliability. WWW: statistical analysis of data. RA: reporting the study, revising the
original and revision manuscript critically for intellectual content, submitting the
study and responsible for overall content as guarantor.
Funding The study was funded internally by the department.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The study was approved by the Medical School Research Ethics
Committee – ID SMED REC 098/18.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available. Data remains condential until
we publish all relevant information.
Open access This is an open access article distributed in accordance with the
Creative Commons Attribution Non Commercial (CC BY- NC 4.0) license, which
permits others to distribute, remix, adapt, build upon this work non- commercially,
and license their derivative works on different terms, provided the original work is
properly cited, appropriate credit is given, any changes made indicated, and the
use is non- commercial. See:http:// creativecommons. org/ licenses/ by- nc/ 4. 0/.
ORCID iD
RamiAbboud http:// orcid. org/ 0000- 0002- 1753- 9606
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... Looped elastic bands around the lower limbs are often used during weight bearing and free weight squat exercises with the aim of enhancing the recruitment of hip muscles and assist in proprioception [1][2][3]. Previous studies testing the effect of adding a looped elastic band around the thigh segments during squats confirmed an increase in hip myoelectric activity. Specifically, increased activation of gluteus maximus (GMax) and gluteus medius (GMed) were observed with the use of elastic bands around the thigh compared to the squat without elastic resistance [1,3,4]. ...
... Previous studies testing the effect of adding a looped elastic band around the thigh segments during squats confirmed an increase in hip myoelectric activity. Specifically, increased activation of gluteus maximus (GMax) and gluteus medius (GMed) were observed with the use of elastic bands around the thigh compared to the squat without elastic resistance [1,3,4]. ...
... Elastic band positioning other than at the thigh for the squat exercise, such as at the ankles or the feet, have not been investigated in the literature and are typically not explored in clinical practice [1,3,4]. A reason for the lack of clinical use of the elastic band at more distal positions during squats has been the assumption that placing the band close to the floor does not increase the demand of the hip muscles to the extent as when placing around the thigh. ...
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Looped elastic bands around the thigh are commonly used during squats and result in increased hip activation. Due to the closed kinetic chain nature of the squat exercise, one may expect that placing the elastic band on distal segments, close to the floor contact, may not result in the same increase in hip muscle activation as that achieved with a looped band around the thigh. We analyzed the effects of band position (thigh, lower leg, and forefoot) and band stiffness on the myoelectric activity of the tensor fascia latae, gluteus medius, gluteus maximus, biceps femoris, vastus medialis, and vastus lateralis during squats in 35 healthy subjects (18 men and 17 women). The greatest myoelectric activity of hip muscles was observed when the stiffest band was positioned around the forefeet with an increase in 24% for the tensor fascia latae, 83% for the gluteus medius, and 68% for the gluteus maximus compared to free (without resistance band) squatting. Contrary to previous thinking, the use of elastic bands around the forefeet during squats can elicit increased myoelectric activity of hip muscles, with a magnitude often greater than when the band is placed around the thigh segments.
... A pesar de las variaciones de ejecución en cuanto a la técnica de sentadilla, existe un modelo estándar, básico y fundamental que subyace a la técnica biomecánica que sustentará las mejoras progresivas de los atributos físicos y reducirá la vulnerabilidad de lesiones inducidas por el entrenamiento 8,9 . Este modelo comprende algunos aspectos que aportan seguridad y eficacia; como la posición de los pies separados al ancho de los hombros y formando un ángulo de 30º, la respiración contenida al 80% de inspiración máxima para reducir la presión de la columna, a través un aumento de la presión intra-abdominal y finalmente evitar el rebote al finalizar la fase excéntrica del ejercicio 10,11 . ...
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Objective: Review updated information on kinetic and kinematic adaptations that causes squats on the knee joint, including female and male athletes, age range between 18 and 45 years. Methods: Systematic review, based on studies published from January-2010 to December-2020 in Pubmed, Medline, Scopus and SciELO databases. The keywords were used in 3 languages; Spanish, English and Portuguese, Boolean words were distributed in different combinations: squat (AND) knee, knee joint (NOT) genu varum, squat (OR) knee, osteoartrite (AND) lesão. Selection was made through the criteria established by PRISMA. For estime the quality of studies, they´re assessed according to Downs & Black checklist. Results: 22 publications met the established criteria, highlighting three biomechanical topics: i) kinematics; when tibia moves, generates an internal rotation and valgus; ii) kinetics: the maximum moment of knee flexion increases with growth over load of 85% to a 1RM; iii) electromyography: muscles with highest activation are: vastus lateralis, vastus medialis, and rectus femoris. Conclusion: Squat generates different movement patterns, as an internal hip rotation, moving knees medially and generates valgus. This adaptation predisposes loss of stability in the support base, and consequently, the displacement of the center of gravity.
... Furthermore, the findings of yet another study indicate that the use of resistance bands during barbell squatting increases knee valgus and may thus make the individual more prone to injury. Reece et al. assessed kinematic and EMG parameters during squats with a barbell whose weight corresponded to 40% and 80% of 1RM (Reece, Arnold, Nasir, Wang, & Abboud, 2020). The bands used were low-and high-resistance and were placed just above the knee joints, as in our study and the works of Gooyers and Foley (Gooyers, Beach, Frost, & Callaghan, 2012;Foley, Bulbrook, Button, & Holmes, 2017). ...
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