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An Examination Of Muscle Activation And Power Characteristics While Performing The Deadlift Exercise With Straight And Hexagonal Barbells

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The deadlift exercise is commonly performed to develop strength and power, and to train the lower body and erector spinae muscle groups. However, little is known about the acute training effects of a hexagonal barbell vs. a straight barbell when performing deadlifts. Therefore, the purpose of this study was to examine the hexagonal barbell in comparison to the straight barbell by analyzing electromyography (EMG) from the vastus lateralis, biceps femoris, and erector spinae, as well as peak force, peak power, and peak velocity using a force plate. Twenty men, with deadlifting experience volunteered to participate in the study. All participants completed a one-repetition maximum (1RM) test with each barbell on two separate occasions. Three repetitions at 65% and 85% 1RM were performed with each barbell on a third visit. The results revealed there was no significant difference for 1RM values between the straight and hexagonal barbells (mean ± SD in kg = 181.4 ± 27.3 vs. 181.1 ± 27.6, respectively) (p > 0.05). Significantly greater normalized EMG values were found from the vastus lateralis for both the concentric (1.199 ± 0.22) and eccentric (0.879 ± 0.31) phases of the hexagonal barbell compared to the straight barbell deadlift (0.968 ± 0.22 and 0.559 ± 1.26), while the straight barbell deadlift led to significantly greater EMG values from the bicep femoris during the concentric phase (0.835 ± 0.19) and the erector spinae (0.753 ± 0.28) during the eccentric phase compared to the corresponding values for the hexagonal barbell deadlift (0.723 ± 0.20 and 0.614 ± 0.21) (p ≤ 0.05). In addition, the hexagonal barbell deadlift demonstrated significantly greater peak force (2,553.20 ± 371.52 N), peak power (1,871.15 ± 451.61 W), and peak velocity (0.805 ± 0.165) compared to the straight barbell deadlift values (2,509.90 ± 364.95 N, 1,639.70 ± 361.94 W, and 0.725 ± 0.138 m/s) (p ≤ 0.05). These results suggest that the barbells led to different patterns of muscle activation, and that the hexagonal barbell maybe more effective at developing maximal force, power, and velocity.
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ANEXAMINATION OF MUSCLE ACTIVATION AND POWER
CHARACTERISTICS WHILE PERFORMING THE DEADLIFT
EXERCISE WITH STRAIGHT AND HEXAGONAL BARBELLS
KEVIN D. CAMARA,JARED W. COBURN,DUSTIN D. DUNNICK,LEE E. BROWN,ANDREW J. GALPIN,
AND PABLO B. COSTA
Department of Kinesiology, Center for Sport Performance, California State University, Fullerton, California
ABSTRACT
Camara, KD, Coburn, JW, Dunnick, DD, Brown, LE, Galpin, AJ,
and Costa, PB. An examination of muscle activation and power
characteristics while performing the deadlift exercise with
straight and hexagonal barbells. J Strength Cond Res 30(5):
1183–1188, 2016—The deadlift exercise is commonly per-
formed to develop strength and power, and to train the
lower-body and erector spinae muscle groups. However, little
is known about the acute training effects of a hexagonal barbell
vs. a straight barbell when performing deadlifts. Therefore, the
purpose of this study was to examine the hexagonal barbell in
comparison with the straight barbell by analyzing electromyog-
raphy (EMG) from the vastus lateralis, biceps femoris, and
erector spinae, as well as peak force, peak power, and peak
velocity using a force plate. Twenty men with deadlifting expe-
rience volunteered to participate in the study. All participants
completed a 1 repetition maximum (1RM) test with each bar-
bell on 2 separate occasions. Three repetitions at 65 and 85%
1RM were performed with each barbell on a third visit. The
results revealed that there was no significant difference for
1RM values between the straight and hexagonal barbells
(mean 6SD in kg = 181.4 627.3 vs. 181.1 627.6, respec-
tively) (p.0.05). Significantly greater normalized EMG values
were found from the vastus lateralis for both the concentric
(1.199 60.22) and eccentric (0.879 60.31) phases of the
hexagonal-barbell deadlift than those of the straight-barbell
deadlift (0.968 60.22 and 0.559 61.26), whereas the
straight-barbell deadlift led to significantly greater EMG values
from the bicep femoris during the concentric phase (0.835 6
0.19) and the erector spinae (0.753 60.28) during the eccen-
tric phase than the corresponding values for the hexagonal-
barbell deadlift (0.723 60.20 and 0.614 60.21) (p#
0.05). In addition, the hexagonal-barbell deadlift demonstrated
significantly greater peak force (2,553.20 6371.52 N), peak
power (1,871.15 6451.61 W), and peak velocity (0.805 6
0.165) values than those of the straight-barbell deadlift
(2,509.90 6364.95 N, 1,639.70 6361.94 W, and 0.725
60.138 m$s
21
, respectively) (p#0.05). These results sug-
gest that the barbells led to different patterns of muscle acti-
vation and that the hexagonal barbell may be more effective at
developing maximal force, power, and velocity.
KEY WORDS electromyography, vastus lateralis, biceps
femoris, erector spinae, peak power, peak force, peak velocity
INTRODUCTION
The deadlift exercise is widely used by athletes of
many sports, as well as recreational lifters, to
enhance power and strength (20). The exercise
is a multijoint movement that activates several
large muscle groups. Research has shown that, compared
to other free weight exercises, the deadlift involves the lifting
of heavier loads (1,10). The ability to lift heavier loads elicits
a larger stimulus to adapt, making it ideal for enhancing
muscular strength, which contributes to power (20). The
movement requires grasping a barbell while in a squatting
position and then elevating the barbell by extending the hips,
knees, and ankles. When the hips are fully extended the
concentric portion of the movement has ended. The barbell
traveling downward until it reaches the floor or starting
position completes the eccentric portion of the deadlift.
The movement begins with the barbell starting at the midleg
level and should remain close to the leg, thighs, and hips as
the barbell elevates (1). It is vital that the barbell remain close
to the lower extremities throughout the lift to reduce the
moment arm of the barbell at the individual joints, decreas-
ing the resistance of the external load (7).
In comparison with other strength exercises, such as the
squat, the deadlift has received comparatively little research
interest (2,4,5,9,11,13,19). A common belief is that the dead-
lift and back squat have similar movement patterns and that
it is acceptable to relate theories and new findings between
the 2 exercises. However, this was shown to be false through
Address correspondence to Jared W. Coburn, jcoburn@fullerton.edu.
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a kinematic analysis showing different movement patterns
between the 2 exercises (8). Clearly, further research is
needed to better understand the deadlift and optimize its
use in training.
Strength and conditioning professionals typically
include the deadlift in their programs to strengthen the
legs, hips, back, and torso musculature (1,20). Variations
of the deadlift are also often performed to alter the move-
ment patterns and muscular requirements of the exercise.
One popular variation is the hexagonal-barbell deadlift.
The hexagonal design of the barbell is theorized to shift
the stress from the lower back, hips, and hamstrings to
the quadriceps femoris. Theoretically, this would be
a more advantageous position and reduce external forces
and injuries to the lumbar spine. However, little research
exists on performing deadlifts with a hexagonal barbell
(Figure 1) (6,14).
To date, one study has compared the hexagonal barbell
with a straight barbell during the deadlift exercise. The
results indicated that the hexagonal barbell reduced
stress on the lumbar region while enhancing force,
velocity, and power (16). To our knowledge, however,
no previous studies have simultaneously examined mus-
cle activation and power characteristics while performing
the deadlift exercise with a straight vs. hexagonal barbell.
Therefore, the purpose of this study was to further inves-
tigate the hexagonal barbell in comparison with a straight
barbell while performing the deadlift, through an analysis
of electromyography (EMG), force, velocity, and power
characteristics.
METHODS
Experimental Approach to the Problem
A repeated-measures design was used to compare the effects
of deadlifting with 2 different barbells on EMG (vastus
lateralis, bicep femoris, and erector spinae) and force plate
data (peak force, power, and velocity). Participants visited
the laboratory for 3 testing sessions. Each session began with
a dynamic warm-up consisting of knee pulls, walking lunges,
and alternating leg swings. The first 2 sessions consisted of 1
repetition maximum (1RM) testing with each barbell in
a randomized order. The third session consisted of 3
repetitions with submaximal loads of 65 and 85% 1RM for
each barbell, with the order of barbells randomized for each
participant. We chose these 2 loads to determine whether
the 2 barbells had different effects when using loads
associated with power (65% 1RM) vs. strength development
(85% 1RM).
Subjects
Twenty men, 19 to 27 y, (mean 6SD age = 23.3 62.1 y,
height = 176.8 67.6 cm, body mass = 89.9 618.3 kg,)
who performed three days per week of resistance training,
including deadlifting once per week for the past year,
volunteered to participate in the study. Participants were
disqualified from the study if they were not capable of
lifting one and one half times their body weight with
either bar. All procedures were approved by the Univer-
sity Institutional Review Board for Human Subjects and
the participants signed informed consent forms before
any testing. Participants were also instructed to avoid
anylower-bodyresistancetraining48hoursbeforeeach
session.
One Repetition Maximum Testing
For deadlift 1RM testing, subjects were required to warm
up for 10 repetitions at 50%, 5 repetitions at 70%, 3
repetitions at 80%, and 1 repetition at 90% of their
predicted 1RM (1). Three minutes of rest were given
between warm-up sets. During 1RM attempts, the weight
was increased in increments of 5–20 pounds until the sub-
jects were able to only complete 1 repetition successfully.
If the subjects were not able to execute the lift success-
fully, the weight was reduced
by 5–10 pounds. Subjects
weregivenupto5single-
repetition sets to determine
their 1RM. All deadlifts were
performed using a conven-
tional stance. A lift was
deemed successful if at the
end of the ascent phase the
participant stood erect with
knees and hips extended, the
torso upright, and the shoul-
der girdle retracted. During
each condition, participants
were allowed normal deadlift-
ing shoes and chalk; however,
these remained consistent for
all conditions. No belts or
straps were used.
Figure 1. Deadlift performed with straight (left) and hexagonal (right) barbells.
Straight vs. Hexagonal Barbell Deadlifts
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Experimental Trials Testing Procedure
This testing session was separated by a minimum of 48 hours
from the previous session. Data collection then consisted of
3 repetitions at 65% and 3 repetitions at 85% with each
barbell. Participants were instructed to perform each repe-
tition with maximal velocity during the concentric phase of
the lifts, then to lower the bar under control during the
eccentric phase. The order of bars was randomized. All
repetitions were performed with 3 minutes of rest, and
5 minutes of rest was given between lifts with each bar.
Electromyography
Electromyography data were collected during each visit.
Before collection, each participant’s skin was prepared for
EMG electrode placement by shaving the hair on the skin,
mild abrasion, and cleaning with isopropyl alcohol. Electro-
myography data were collected and stored on a personal
computer (Dell Latitude D610; Dell, Round Rock, TX,
USA). Three separate bipolar (3.5-cm center-to-center)
surface electrode (BIOPAC EL500 silver-silver chloride;
BIOPAC Systems, Inc., Goleta, CA, USA) arrangements
were placed over the biceps femoris, vastus lateralis, and
erector spinae (longissimus) muscles, with the reference elec-
trodes placed over the iliac crest. The biceps femoris electro-
des were placed at 50% of the distance along the line
between the ischial tuberosity and the lateral epicondyle of
the tibia. Electrodes for the vastus lateralis were placed 2/3
of the distance on the line from the anterior superior iliac
spine to the lateral side of the patella. For the erector spinae
(longissimus), 2 electrodes were placed at a width of 2 fin-
gers, lateral from the spinous process of L1. All measure-
ments were taken on the left side of the participant’s body.
The EMG signals were preamplified (gain 1,0003) using
a differential amplifier (EMG 100C, bandwidth = 1–500
Hz; BIOPAC Systems, Inc., Santa Barbara, CA, USA).
The EMG signals were band-pass filtered (fourth-order
Butterworth) at 10–500 Hz. The amplitudes of the signals
were expressed as root mean square values. All analyses were
performed with custom programs written with LabVIEW
software (version 7.1; National Instruments, Austin, TX,
USA). The EMG values for the experimental condition rep-
etitions were normalized to the EMG values achieved during
the concentric phase of the straight-barbell 1RM tests. These
normalized EMG values for the 3 repetitions performed with
each load (65 and 85% 1RM) were then averaged before data
analysis. Intraclass reliability values exceeding 0.9 were
found for EMG amplitude values.
Force and Velocity
A velocity transducer (Model V-80-L7M; UniMeasure, Inc.,
Corvallis, OR, USA) was attached to the end of each barbell.
An AMTI force plate (Watertown, MA, USA) was used to
collect force data. Both the linear velocity transducer and the
AMTI force plate were connected to a desktop computer
running custom LabVIEW data collection and analysis
software (version 2013; National Instruments Corporation).
As with the EMG data, the 3 repetitions performed with
each load (65 and 85% 1RM) were averaged before data
analysis. Intraclass values between 0.8 and 0.9 for force plate
measures have previously been reported from our lab.
Statistical Analyses
A 2 (barbell: straight and hexagonal) 32 (phase of move-
ment: concentric and eccentric) 32 (load: 65 and 85%
1RM) 33 (muscle: vastus lateralis, biceps femoris, and erec-
tor spinae) repeated-measures analysis of variance (ANOVA)
was used to analyze the normalized EMG amplitude data for
each muscle. Follow-up tests included ANOVAs and paired
t-tests with Bonferroni corrections as appropriate. Three
separate 2 (barbell: straight and hexagonal) 32 (load: 65
and 85% 1RM) repeated-measures ANOVAs were used to
determine differences for peak force, power, and velocity
between barbells. An alpha level of 0.05 was used to deter-
mine statistical significance. IBM SPSS Statistics 21 was used
to perform all statistical analyses.
RESULTS
There was no significant difference in deadlift 1RM values
between the straight and hexagonal barbells (mean 6SD in
kg = 181.4 627.3 vs. 181.1 627.6, respectively). For
TABLE 1. Normalized electromyography (EMG) amplitude values (mean 6SD) for the straight and hexagonal
barbells, collapsed across 65 and 85% 1 repetition maximum loads.*
Straight barbell Hexagonal barbell
Concentric Eccentric Concentric Eccentric
Vastus lateralis 0.968 60.22 0.559 61.26 1.199 60.220.879 60.31
Biceps femoris 0.835 60.19z0.347 60.11 0.723 60.20 0.315 60.10
Erector spinae 0.989 60.26 0.753 60.28z0.880 60.27 0.614 60.21
*All concentric normalized EMG amplitude values exceed corresponding eccentric values.
Significantly greater normalized EMG amplitude value for hexagonal vs. corresponding straight barbell value (p#0.05).
zSignificantly greater normalized EMG amplitude value for straight vs. corresponding hexagonal barbell value (p#0.05).
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normalized EMG amplitude (Table 1), there was no signif-
icant 4-way interaction (p.0.05). There was, however,
a significant 3-way interaction (barbell 3phase 3muscle)
(p#0.05). This was followed up with 2-way ANOVAs:
(phase 3muscle), 1 for each barbell; (barbell 3phase), 1
for each muscle; (barbell 3muscle), 1 for each phase. Sig-
nificant interactions were then followed up with separate
paired t-tests as appropriate. These results revealed that nor-
malized EMG amplitude for the vastus lateralis was signifi-
cantly greater with the hexagonal barbell than with the
straight barbell, regardless of phase, whereas it was greater
for the biceps femoris (concentric phase only) and erector
spinae (eccentric phase only) with the straight bar than with
the hexagonal bar (p#0.05). For all 3 muscles and both
barbells, the concentric phase demonstrated greater EMG
amplitude values than the eccentric phase (p#0.05).
For the force plate data (peak ground reaction force, peak
power, and peak velocity), there were no significant 2-way
(barbell 3load) interactions (p.0.05) (Table 2). There
were, however, significant main effects for the barbell and
load (p#0.05). Peak ground reaction force, peak power, and
peak velocity were all greater for the hexagonal barbell than
for the straight barbell. In addition, peak ground reaction
force was greater for the 85% 1RM load, whereas peak
power and peak velocity were greater for the 65% 1RM load.
DISCUSSION
The purpose of this study was to examine the effects of
performing the deadlift exercise (65 and 85% 1RM) with
a hexagonal barbell vs. straight barbell on 1RM values,
muscle activation, peak ground reaction force, peak power,
and peak velocity. There were no significant differences in
1RM values between the bars. The EMG results revealed
that the normalized EMG amplitude values from the vastus
lateralis were significantly greater for the hexagonal barbell
vs. straight barbell, during both the concentric and eccentric
phases. More specifically, the hexagonal barbell led to a more
quadriceps-dominant movement. Conversely, with greater
normalized EMG amplitude values being evident from the
biceps femoris and erector spinae muscles during the
concentric and eccentric phases, respectively, the straight
barbell seemed to use more of the hamstrings and lower
back. Furthermore, deadlifts with the hexagonal barbell
demonstrated higher peak velocity, peak force, and peak
power than deadlifts with the straight barbell.
To our knowledge, only one previous study has examined
deadlifts with a hexagonal barbell in comparison with
a straight barbell (16). Although no significant difference in
1RM values between the bars were found in the present
study, the participants in the study of Swinton et al. lifted
an average of nearly 20 kg more with the hexagonal barbell
compared than with a straight barbell (265.0 641.8 vs.
244.5 639.5 kg). These differences in findings may be
a result of differences in the training experience of partici-
pants in the 2 studies. The participants of the present study
consisted of resistance-trained men that had deadlifting
experience (once a week for a minimum of 1 year). However,
experience deadlifting with a hexagonal barbell was neither
required nor common. The participants in the study of Swin-
ton et al. consisted of competitive men powerlifters from the
Scottish Powerlifting Association. Although no direct
hexagonal-barbell deadlifting experience was reported, pro-
fessional strength athletes, such as powerlifters and strong-
men competitors, often use several variations of the deadlift,
squat, and bench press to enhance their performance (15,18).
Therefore, it is likely that these athletes had more deadlifting
experience with a hexagonal barbell or other deadlift varia-
tions. Perhaps with more training experience with the hex-
agonal barbell, participants in the present study would have
been able to lift more weight with the hexagonal barbell than
with the straight barbell.
The EMG results of the present study are in agreement
with the kinematic findings of Swinton et al. (16). Swinton
et al. (16) concluded that the hexagonal barbell significantly
increased the peak moment at the knee and reduced the
peak moment at the lumbar spine and hip (16). The
increased moment at the knee demonstrated with the hex-
agonal barbell should theoretically lead to increased muscle
activation of the quadriceps femoris muscle group. This is
precisely what was found in the present study, where nor-
malized EMG amplitude data from the vastus lateralis was
greater for deadlifts performed with the hexagonal barbell
TABLE 2. Peak ground reaction force, power, and velocity for straight and hexagonal barbells, collapsed across 65
and 85% 1 repetition maximum loads.*
Straight barbell Hexagonal barbell
PGRF (N) 2,509.90 6364.95 2,553.20 6371.52
PP (W) 1,639.70 6361.94 1,871.15 6451.61
PV (m$s
21
) 0.725 60.138 0.805 60.165
*PGRF = peak ground reaction force; PP = peak power; PV = peak velocity.
Significantly greater value for hexagonal vs. corresponding straight barbell value (p#0.05).
Straight vs. Hexagonal Barbell Deadlifts
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than the deadlifts performed with the straight barbell. Fur-
thermore, it has been demonstrated that there is an increase
in the moment around the hip when deadlifting with
a straight barbell vs. a hexagonal barbell (16). The results
of the present study are in agreement with this finding
because EMG amplitude from the biceps femoris during
the concentric phase was greater for the straight barbell vs.
hexagonal barbell. Finally, Swinton et al. (16) reported that
the straight barbell increased the moment at the lumbar
spine, which is consistent with the present study because
significantly greater normalized EMG values in erector spi-
nae were demonstrated while using the straight barbell dur-
ing the eccentric phase.
As with the present study, the higher force, power, and
velocity demonstrated with a hexagonal-barbell deadlift in
comparison with the straight-barbell deadlift has been
reported previously (16,17). The weighted vertical jump is
a common movement frequently used to enhance power.
The results of a study by Swinton et al. (17) suggested that
the straight-barbell vertical jump method is an inferior
technique to the hexagonal-barbell vertical jump method.
With a 20% load, peak velocity, peak force, peak power,
average power, and rate of force development were all
increased with the hexagonal barbell. The design of the
hexagonal barbell seems to allow the user to maintain
a more advantageous position in the starting phase and
throughout the movement allowing for enhanced velocity,
force, and power. The hexagonal barbell may be a more
effective method for not only enhancing force production
for the deadlift exercise but also increasing explosive power
when performing squat jumps (16,17). It should be noted
that these suggestions are drawn from studies examining
acute effects, whereas long-term training effects are
unknown.
When analyzing the starting phase of the deadlift with
a straight barbell, it has been shown that the hip is flexed
the greatest followed by the knee, torso, and ankle
(5,12,16). In contrast, the starting phase of a deadlift with
a hexagonal barbell demonstrates an increase of knee flex-
ion, with no difference among the hip, torso, or ankle joints
(16). This suggests that the hexagonal barbell is a more
quadriceps-dominant movement and distributes the exter-
nal load more evenly among the hip, ankle, and torso.
When comparing barbell paths between hexagonal and
straight barbells, the findings of Swinton et al. further sup-
port this claim. Swinton et al. (16) concluded that the
design of hexagonal barbell allowed the load to be posi-
tioned closer to the body using the horizontal distance
from the ankle as the point of measurement. As the lift with
the hexagonal barbell progressed, the average horizontal
displacement away from the lifter was reduced by 75%
and increased displacement toward the lifter by 22% (16).
The ability to maintain the load closer to the lifter’s center
of gravity may explain the greater force, power, and veloc-
ity found in the present study.
PRACTICAL APPLICATIONS
The ability to manipulate joint range of motion and muscle
activation through barbell selection is valuable information for
practitioners. The conventional, straight-bar deadlift is a com-
mon exercise that is frequently performed within athletic and
recreational weight rooms. However, when performed with
heavy loads, it can be the most taxing exercise on the lumbar
region (3). For individuals with lower-back injuries or pain, the
results of this study suggest that the hexagonal barbell may be
the better choice for barbell selection because of its ability to
evenly distribute the load among all joints and reduce the
moment at the lumbar spine. Conversely, if the goal of the
training session is to emphasize strengthening of the lumbar
region and hamstrings, the straight barbell seems to be the
appropriate choice. Finally, the hexagonal barbell may be
a more effective method for maximizing force, power, and
velocity during the deadlift.
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... The deadlift exercise and its variations are often prescribed as part of resistance training to develop the muscle strength of the knee extensors and flexors (Camara et al., 2016;Martín-Fuentes et al., 2020;Nigro & Bartolomei, 2020). Several studies have demonstrated its effectiveness in inducing neuromuscular adaptations in various populations (Nigro & Bartolomei, 2020;Thompson et al., 2015). ...
... For example, the conventional deadlift (i.e., straight bar) can be difficult for some individuals to perform, especially those who suffer from lower back pain (Martín-Fuentes et al., 2020;Swinton et al., 2011). In this regard, substantial internal forces, moment arms, and electromyography amplitude were demonstrated in the lumbar spine muscle during the conventional deadlift (Camara et al., 2016;Lockie & Lazar, 2017;Swinton et al., 2011), potentially increasing the likelihood of lower back muscle pain or injury when lifting heavy loads (Lockie & Lazar, 2017). Hence, alternative variations of the conventional deadlift have been proposed to broaden its utilization at resistance training. ...
... The hexagonal bar deadlift (HBD) is a common variation of the deadlift exercise used by strength and conditioning coaches (Camara et al., 2016). The hexagonal bar was designed to improve lifting safety by allowing the practitioners to perform the lifting when the load is positioned closer to their body (Lockie & Lazar, 2017). ...
Article
In this study, we examined the load-velocity relationship in the hexagonal bar deadlift exercise in women. Twenty-seven resistance-trained women were recruited. Participants performed a progressive load test up to the one-repetition maximum (1RM) load for determining the individual load-velocity relationship in the hexagonal bar deadlift exercise. Bar velocity was measured in every repetition through a linear encoder. A very strong and negative relationship was found between the %1RM and bar velocity for the linear (R 2 = .94; standard error of the estimation = 5.43% 1RM) and second-order polynomial (R 2 = .95) regression models. The individual load-velocity relationship provided even better adjustments (R 2 = .98; coefficient of variation = 1.77%) than the general equation. High agreement level and low bias were found between actual and predicted 1RM for the general load-velocity relationship (intraclass correlation coefficient = .97 and 95% confidence interval [0.90, 0.99]; bias = −2.59 kg). In conclusion, bar velocity can be used to predict 1RM with high accuracy during hexagonal bar deadlift exercise in resistance-trained women.
... Part of the reasoning behind these changes is the altered body position when utilizing the hex bar. It has been suggested that the hex bar allows for a lower hip position than a conventional deadlift, which increases the amount of quadriceps activation (6,16) and places the exercise somewhere between a deadlift and a squat in terms of mechanics. In other words, the hex bar allows the user to distribute the load closer to the body, i.e., hands directly below hips vs. hands in front of tibia like during the traditional DL. ...
... To date, two studies have performed an electromyographical (EMG) analysis of the deadlift exercise using a hexagonal (hex) barbell in comparison to the standard straight Olympic style barbell (1,6). Although data indicated a differential EMG pattern, particularly in the quadriceps, hamstrings, and lower back muscles, between the two apparatuses/variations, it cannot be ascertained whether these effects were influenced by technique, such as altered starting phase angles in related joints. ...
... Our study is one of three studies (1,6) to examine the EMG profiles of the hexagonal barbell to our knowledge. Camera et al (6) displayed increased quadriceps activity (vastus lateralis) and decreased erector spinae and biceps femoris activity in the hex bar compared to the straight bar International Journal of Exercise Science http://www.intjexersci.com ...
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Variations of the deadlift can be executed using the hexagonal (hex) bar by altering, for instance, the knee and torso angles while maintaining a constant hip angle at the start position. Purpose: To examine muscle activation patterns of the biceps femoris, rectus femoris, and erector spinae during three deadlift variations using the hex bar. Methods: Twenty resistance-trained male and female subjects performed hex bar deadlift variations in three different starting knee flexion positions: 128.4 ± 8.5°, 111.9 ± 8.7°, and 98.3 ± 6.5°. Subjects performed three repetitions at 75% of their three-repetition maximum. Electromyography sensors were placed on the dominant biceps femoris, rectus femoris, and lumbar erector spinae. A one-way repeated measures ANOVA was used to detect differences in mean and peak EMG values normalized to maximum voluntary isometric contraction (MVIC) (p < 0.05). Results: As knee flexion increased at the starting position, mean activation of the rectus femoris increased (24.7 ± 21.5 → 35.5 ± 25.4 → 62.1 ± 31.3% MVIC, p < 0.001), while biceps femoris (40.6 ± 17.9 → 34.0 ± 16.4 → 28.1 ± 14.5% MVIC, p = 0.003) and erector spinae (73.0 ± 27.6 → 65.9 ± 34.4 → 54.9 ± 32.5% MVIC, p = 0.009) activation decreased. Peak activation of the rectus femoris increased (46.9 ± 33.0 → 60.9 ± 38.7 → 99.3 ± 41.6% MVIC, p < 0.001) while decreasing in the erector spinae (118.6 ± 47.1 → 105.9 ± 49.4 → 89.1 ± 40.1% MVIC, p = 0.008). The rectus femoris experienced the greatest mean differences of the three muscles. Conclusions: Practitioners should consider the muscular goals when adjusting the starting position of a hex bar deadlift as posterior chain recruitment diminished and quadriceps activation increased as knee flexion increased.
... For a repetition to be considered valid, subjects had to finish the concentric phase with the knees and hips extended, trunk erect, and shoulder girdle retracted. (6). For standardization purposes, the conventional deadlift style was adopted. ...
... Approximately ten minutes after the 1RM test, muscle endurance was assessed by a 50% 1RM conventional deadlift test, in which subjects were instructed to perform as many repetitions as possible with the appropriate technique (9,28). The individuals were instructed to complete each repetition with the knees and hips fully extended, trunk erect, and shoulder girdle retracted (6). Additionally, the plates had to touch the ground before a new repetition began. ...
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The purpose of this study was to compare a periodized versus a non-periodized protocol of kettlebell (KTB) swings over six weeks on strength, power, and muscular endurance. Twenty-eight high intensity functional training (HIFT) practitioners were assigned to non-periodized (NPG = 11), periodized (PG = 11), or control groups (CG = 6). NPG used the same load (20 kg) throughout the training period while the PG used a step loading progression (with an added four kilograms every two weeks). Measures of strength and muscular endurance in the deadlift exercise, and power in the countermovement jump were assessed before and after six weeks. A two-way ANOVA was used to verify pre-to post-test differences in strength, power, and muscular endurance. An analysis of the effect size was also incorporated. For strength and power, statistical differences from pre-to post-test were found for both the NPG (p < 0.001; 1-RM improvement = 8.7%; jump height improvement = 8.7%) and PG (p < 0.001; 1-RM improvement = 7.8%; jump height improvement = 10.1%), with no difference between groups. For muscular endurance, only the PG showed significant differences from pre-to post-test (p = 0.013; muscular endurance improvement = 23.8%). In conclusion, when the goal is to increase strength and power performances in HIFT practitioners, periodized and non-periodized KTB models appear to be equally effective, and this can simplify the strength coach's practice in programming KTB swing training periods. For muscular endurance, the addition of KTB swing on a periodized basis seems to be a more effective strategy.
... The hexagonal bar deadlift (HBD) is a variation of the deadlift that has been shown to put less stress on the lumbar region (4,5,13,15,22). This is partially because of the fact that when performing the HBD, there is approximately 75% less horizontal displacement compared with the straight bar deadlift (SBD) (22). ...
... These differences result in the lifter moving the load over a shorter distance, which also increases the amount of weight that can be lifted for a single repetition (15). The HBD not only reduces biomechanical stress to the lumbar spine but also elicits greater peak force, velocity, and power outputs when compared with the SBD at similar loads (4,15,22). For these reasons, the HBD may be a more advantageous option than the SBD when training certain populations. ...
Article
The aim of this study was to determine if bar velocity can be used to estimate the one-repetition maximum (1RM) on the hexagonal bar deadlift. Twenty-two NCAA Division I male ice hockey players (age= 21.0 ± 1.5 yrs, height= 182.9 ± 7.3 cm, body mass= 86.2 ± 7.3 kg) completed a progressive loading test using the hexagonal bar deadlift at maximum intended velocity to determine their 1RM. Mean concentric velocity (MV) was measured for each load via a linear position transducer. The a-priori alpha level of significance was set at p = 0.05. MV showed a very strong relationship to %1RM (R2 = 0.85). A non-significant difference and a trivial effect size (ES) were observed between actual and predicted 1RM (p = 0.90, ES = -0.08). Near-perfect correlations were also discovered between actual and predicted 1RM (R = 0.93) with low typical error and coefficient of variation (5.11 kg, 2.53%, respectively). The current study presented results that add the HBD to the list of exercises with established load-velocity relationships. The predictive ability for 1RM HBD indicates that this is a viable means of prediction of 1RM.
... There were no differences between exercises in erector spinae activation. Camara, et al., 2016 The purpose of this study (12) The purpose of this study (57) was to investigate local muscle O2 consumption (muscVo2) and forearm blood flow (FBF) in resting and exercising muscle by near-infrared spectroscopy (NIRS) and to compare results with global muscVo2 and FBF from the Fick method and plethysmography. Twenty-six participants (16 men and 10 women; mean ± SD, 28.8 ± 7.7 yrs, 178.9 ± 10.9 cm, 70.0 ± 11.1 kg) performed a maximum voluntary contraction (MVC) of the flexor digitorum superficialis (FDS) and brachioradialis (BR). ...
... There were no differences between exercises in erector spinae activation. Camara, et al., 2016 The purpose of this study (12) The purpose of this study (57) was to investigate local muscle O2 consumption (muscVo2) and forearm blood flow (FBF) in resting and exercising muscle by near-infrared spectroscopy (NIRS) and to compare results with global muscVo2 and FBF from the Fick method and plethysmography. Twenty-six participants (16 men and 10 women; mean ± SD, 28.8 ± 7.7 yrs, 178.9 ± 10.9 cm, 70.0 ± 11.1 kg) performed a maximum voluntary contraction (MVC) of the flexor digitorum superficialis (FDS) and brachioradialis (BR). ...
Thesis
BACKGROUND: The capacity to do work is greatly affected by high altitude exposure. Larger muscle groups of the lower body and exercises primarily aerobic in nature have been well investigated at high altitude. The present study examined acute altitude exposure on the number of repetitions to failure and electromyographic (EMG) repetition duration (Time), EMG root mean square (RMS) and EMG mean power frequency (MPF) during dynamic constant external resistance (DCER) exercise of the biceps brachii. METHODS: Thirteen subjects performed two sets of fatiguing DCER arm curl repetitions to failure at 70% of their one repetition maximum (1RM) obtained at 1067 m, in simulated normobaric elevations of 1067m, 2438m, and 3810m. Electromyography of the biceps brachii was analyzed for EMG Time, EMG RMS, and EMG MPF. Repetitions were selected as 25%, 50%, 75% and 100% of total repetitions completed. RESULTS: There was no significant three-way (altitude x set x percent of repetitions to failure) or two-way (altitude x set or percent of repetitions to failure) interaction for any variable. The number of repetitions to failure significantly decreased from (mean ± SEM) 18.2 ± 1.4 to 9.5 ± 1.0 with each set. In addition, EMG Time increased (25% < 50% < 75% < 100%), EMG RMS decreased (50% > 75% > 100%), and EMG MPF decreased (75% > 100%) as a result of fatiguing exercise. DISCUSSION: The changes in biceps brachii EMG variables indicated exercise caused myoelectric manifestations of fatigue, however, acute altitude exposure had no additional influence on rate of fatigue development or neuromuscular parameters.
... Both classes had 15 female trainees in their cohort. The IAT, BOMBT, and deadlift all require the generation of high external force, whether initiating a change of direction [74], projecting a medicine ball [75], or picking up a heavy resistance [76]. When compared to male firefighters, females tend to demonstrate lesser anaerobic power and maximal strength [3]. ...
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Fire academy training classes may have trainees with a range of different fitness capabilities. Documentation of trainee fitness could indicate the need for flexibility in physical training emphases. Therefore, data from six academy classes (males = 274; females = 31) were analyzed, including: Illinois agility test (IAT), push-ups, pull-ups, leg tucks, multistage fitness test, backwards overhead 4.54 kg medicine ball throw (BOMBT), 10-repetition maximum deadlift, and 18 kg kettlebell farmers carry. A one-way ANOVA, with the Bonferroni post hoc test, calculated between-class fitness differences. Normative fitness test data were produced via percentile ranks. Classes 5 and 6 had the most females (n = 15). Class 1 completed the IAT faster than all classes (p ≤ 0.009). Classes 1 and 4 had a further BOMBT distance than Classes 5 and 6, and Class 3 outperformed Class 6 (p ≤ 0.044). Class 4 completed more leg tucks than Class 5 (p = 0.047). Class 1 had a greater deadlift than Classes 3, 4, and 6, and Class 2 outperformed Classes 3–6 (p ≤ 0.036). Class 3 was slower in the farmers carry compared to all classes (p ≤ 0.002). Percentile rankings showed that most females (48–100%) were in the 0–29% rank. Staff should implement individualized programs where appropriate for trainees as cohort fitness differences exist. Female trainees may need targeted maximal strength and power development.
... These studies focused primarily on young male civilian powerlifters, limiting the generalizability of the results to military populations. [7][8][9][10][11][12] Currently, the ACFT is graded by soldiers who have completed training and validation through the U.S. Army Physical Fitness School, U.S. Army Center for Initial Military Training, or through an ACFT Non-Commissioned Officer in Charge/Officer in Charge at their local installation. There is no requirement for additional or advanced specialty fitness certification. ...
Article
Introduction The U.S. Army is updating the physical fitness assessment for soldiers to the six-event Army Combat Fitness Test (ACFT). A paucity of data regarding the ACFT maximum deadlift (MDL) event, especially in military populations, has increased concern over the objectivity of the test. The reliability of scoring the MDL has not been established. It is unknown if grader professional experience impacts the reliability of scoring, and if so, what level of experience is required for reliable assessment. Performance and assessment of the MDL could impact military occupational selection, promotion, and retention within the Army. The purposes of this study were to determine the inter- and intra-rater reliabilities of raters with varying degrees of professional experience on scoring the MDL and to determine the relationships between load lifted, overall lift success, sex, and body mass index (BMI). Methods The design is a reliability study. Approval was granted by the Naval Medical Center—Portsmouth Institutional Review Board. Fifty-five healthy soldiers and cadets from the U.S. Military Academy were recruited. Participants completed one data collection session, performing one MDL attempt. The attempt was video recorded using three devices: two handheld tablets placed perpendicular to the sagittal and frontal planes recording at 240 Hz and one digital camera positioned at a 45° angle recording at 30 Hz. A reference standard was established through slow-motion analysis of the sagittal and frontal plane recordings. Six raters with varying degrees of professional experience viewed the 45° camera recordings at real-time speed independently, in a random order, on two separate occasions. Lift success was dichotomously assessed as successful or unsuccessful according to the MDL standards. Cohen’s kappa was computed to determine inter- and intra-rater reliabilities among raters. Bivariate correlation was used to assess associations among load lifted, BMI, and sex. A chi-squared test of independence assessed the relationship between sex and overall lift success. Results Inter-rater reliability between the six raters ranged from 0.29 to 0.69. Inter-rater reliability between the raters to the reference standard ranged from 0.28 to 0.61. Intra-rater reliability ranged from 0.51 to 0.84. Inter-rater reliability of raters who had attended a Training and Doctrine Command–approved ACFT certification course ranged from 0.51 to 0.66, while those who had not ranged from 0.34 to 0.46. BMI and sex were associated with load lifted (r = 0.405, P = .002; r = −0.727, P < .001, respectively). Overall lift success was not associated with load lifted (r = −0.047, P = .731). Overall lift success was not related to sex (χ2 = 0.271, P = .602). Conclusion Inter-rater reliability of the six raters ranged from poor to substantial, while intra-rater reliability ranged from moderate to excellent. Compared to a reference standard, inter-rater reliability ranged from poor to substantial. The wide range in consistency demonstrated in this study, both between and within raters, brings into question the current subjective methods used to grade the MDL. More research is needed to understand the most feasible, valid, and reliable way to assess performance standards like the MDL that may affect a soldier’s career progression.
... As during the horizontal jump, movement in the hip joint is more pronounced, this could be the reason for stronger correlations between deadlift performed with hexagonal barbell and horizontal jump. In general, the stress on the lumbar spine is reduced, and it is possible to lift heavier loads and to generate higher levels of velocity, force, and power with the hexagonal barbell than with the traditional straight Olympic barbell (Camara et al., 2016;Swinton et al., 2011). These factors almost certainly contributed to the Note. ...
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Background: It has been suggested that velocity-based training (VBT) improves real-life performance in sports, such as jumping, but studies rarely examined the associations between variables derived during VBT (VBT-variables) and jumping performances. Objective: The aim of this study was to investigate the associations between VBT-variables derived during deadlift exercise executed at different loads and anthropometric variables, and vertical and horizontal jump performance in young athletes. Methods: Seventeen youth soccer players (16–18 years old) were included. Predictors were body height, body mass, body fat percentage, and VBT-variables (force, power, and velocity) measured at different loads (45%, 55%, 65%, 75%, 85%, and 95%) of a one-repetition maximum deadlift (1RM). Criteria included tests of vertical and horizontal jumping performance. Results: The VBT-variables are more strongly correlated with horizontal jumps (Pearson’s r up to .81) than vertical jumps (Pearson’s r up to .75). The VBT-variables for the deadlift recorded at lower loads stronger correlated with jumping performance than the VBT-variables recorded at higher loads. Conclusions: Results of the study suggest that light-to-moderate loads (45%–65% of 1RM) maximize power output and are therefore more strongly related to jumping performance in youth athletes. Further intervention studies aimed at the improvement of jumping performances using the VBT are warranted.
Article
OCCUPATIONAL APPLICATIONSHeavy deadlifting is used as a screening tool or training protocol for recruitment and retention in physically-demanding occupations, especially in the military. Spinal loads experienced during heavy deadlifts, particularly shearing forces, are well above recommended thresholds for lumbar spine injury in occupational settings. Although members of the noted occupation likely have stronger musculoskeletal systems compared to the general population, experiencing shearing forces that are 2 to 4 times larger than the threshold of injury, particularly under repetitive deadlift, may transform a screening tool or training protocol to an occupationally-harmful physical activity.
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It is believed that regional activation within a muscle may lead to greater site-specific muscular adaptations in the activated portion of the muscle. Because the hamstrings are a biarticular muscle, it can be theorized that single-joint exercises where movement originates at the hip versus the knee will result in differential activation of the muscle complex. The purpose of the present study was to assess EMG activity in the proximal and distal aspects of the medial and lateral hamstrings during performance of the stiff- legged deadlift (SLDL), a hip-dominant exercise, and the lying leg curl (LLC), a knee- dominant exercise. Ten young, resistance-trained men were recruited from a university population to participate in the study. Employing a within-subject design, participants performed the SLDL and LLC to muscular failure using a load equating to their 8 repetition maximum for each exercise. The order of performance of exercises was counterbalanced between participants so that approximately half of the subjects performed SLDL first and the other half performed LLC first. Surface electromyography was used to record mean normalized muscle activity of the upper lateral hamstrings, lower lateral hamstrings, upper medial hamstrings, and lower medial hamstrings. Results showed that the LLC elicited significantly greater normalized mean activation of the lower lateral and lower medial hamstrings compared to the SLDL (p < 0.05). These findings support the notion that the hamstrings can be regionally targeted through exercise selection. Further investigations is required to determine whether differences in activation lead to greater muscular adaptations in the muscle complex.
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The purpose of this study was to analyze eletromyographic (EMG) signal of biceps femoris (BF), vastus lateralis (VL), lumbar multifidus (LM), anterior tibialis (AT), and medial gastrocnemius (MG) during the deadlift (DL) and stiff-legged deadlift (SLDL). Fourteen men (26.71 ± 4.99 yrs; body mass 88.42 ± 12.39 kg; 177.71 ± 8.86 cm) voluntarily participated in this study. The data were obtained on three non-consecutive days separated by 48 hrs. In the first day, anthropometric measures and the repetition maximum testing (1 RM) for both exercises were applied in a counter-balanced cross-over design. On the second day, the 1 RM was re-tested. On the third day, both exercises were performed at 70% of 1 RM and the EMG data were collected. Parameters related to the RMS during the movement, temporal activation patterns, and relative times of activation were analyzed for each muscle. The maximum activation level for VL during the DL (128.3 ± 33.9% of the EMG peak average) was significantly different (P = 0.027) from the SLDL (101.1 ± 14% of the EMG peak average). These findings should be useful when emphasizing different muscle groups in a resistance training program.
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This study describes the results of a survey of the strength and conditioning practices of strongman competitors. A 65-item online survey was completed by 167 strongman competitors. The subject group included 83 local, 65 national, and 19 international strongman competitors. The survey comprised 3 main areas of enquiry: (a) exercise selection, (b) training protocols and organization, and (c) strongman event training. The back squat and conventional deadlift were reported as the most commonly used squat and deadlift (65.8 and 88.0%, respectively). Eighty percent of the subjects incorporated some form of periodization in their training. Seventy-four percent of subjects included hypertrophy training, 97% included maximal strength training, and 90% included power training in their training organization. The majority performed speed repetitions with submaximal loads in the squat and deadlift (59.9 and 61.1%, respectively). Fifty-four percent of subjects incorporated lower body plyometrics into their training, and 88% of the strongman competitors reported performing Olympic lifts as part of their strongman training. Seventy-eight percent of subjects reported that the clean was the most performed Olympic lift used in their training. Results revealed that 56 and 38% of the strongman competitors used elastic bands and chains in their training, respectively. The findings demonstrate that strongman competitors incorporate a variety of strength and conditioning practices that are focused on increasing muscular size, and the development of maximal strength and power into their conditioning preparation. The farmers walk, log press, and stones were the most commonly performed strongman exercises used in a general strongman training session by these athletes. These data provide information on the training practices required to compete in the sport of strongman.
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The purpose of the investigation was to compare the kinematics and kinetics of the deadlift performed with 2 distinct barbells across a range of submaximal loads. Nineteen male powerlifters performed the deadlift with a conventional straight barbell and a hexagonal barbell that allowed the lifter to stand within its frame. Subjects performed trials at maximum speed with loads of 10, 20, 30, 40, 50, 60, 70, and 80% of their predetermined 1-repetition maximum (1RM). Inverse dynamics and spatial tracking of the external resistance were used to quantify kinematic and kinetic variables. Subjects were able to lift a heavier 1RM load in the hexagonal barbell deadlift (HBD) than the straight barbell deadlift (SBD) (265 ± 41 kg vs. 245 ± 39 kg, p < 0.05). The design of the hexagonal barbell significantly altered the resistance moment at the joints analyzed (p < 0.05), resulting in lower peak moments at the lumbar spine, hip, and ankle (p < 0.05) and an increased peak moment at the knee (p < 0.05). Maximum peak power values of 4,388 ± 713 and 4,872 ± 636 W were obtained for the SBD and HBD, respectively (p < 0.05). Across the submaximal loads, significantly greater peak force, peak velocity and peak power values were produced during the HBD compared to during the SBD (p < 0.05). The results demonstrate that the choice of barbell used to perform the deadlift has a significant effect on a range of kinematic and kinetic variables. The enhanced mechanical stimulus obtained with the hexagonal barbell suggests that in general the HBD is a more effective exercise than the SBD.
Article
The dorsal muscles of the lower torso and extremities have often been denoted the 'posterior chain.' These muscles are used to support the thoracic and lumbar spine as well as peripheral joints including the hip, knee, and ankle on the dorsal aspect of the body. This study investigated relative muscle activity of the hamstring group and selected surrounding musculature during the leg curl, good morning, glute-ham raise, and Romanian deadlift (RDL). Twelve healthy, weight trained men performed duplicate trials of single repetitions at 85% 1RM for each lift in random order, during which surface electromyography and joint angle data were obtained. Repeated measures analysis of variance (RMANOVA) across the four exercises was performed to compare activity from the erector spinae (ES), gluteus medius (GMed), semitendinosus (ST), biceps femoris (BF), and medial gastrocnemius (MGas). Significant differences (p<0.05) were noted in eccentric muscle activity between exercise for the MGas (p<0.027), ST (p<0.001), BF (p<0.001), and ES (p=0.032), and in concentric muscle activity for the ES (p<0.001), BF (p=0.010), ST (p=0.009), MGas (p<0.001), and the GMed (p=0.018). Bonferroni post hoc analysis revealed significant pairwise differences during eccentric actions for the BF, ST, and MGas. Post hoc analysis also revealed significant pairwise differences during concentric actions for the ES, BF, ST, MGas, and GMed. Each of these showed effect sizes that are large or greater. The main findings of this investigation are that the ST is substantially more active than the BF among all exercises, and hamstring activity was maximized in the RDL and glute-ham raise. Therefore, athletes and coaches who seek to maximize involvement of the hamstring musculature should consider focusing on the glute-ham raise and RDL.
Article
To compare the effectiveness of 3 weight-training movements for the hamstrings, 11 weight-trained men performed 3 repetitions at 75% of 1 repetition maximum of the leg curl (LC), stiff-leg deadlift (SLDL), and back squat. Integrated electromyography (EMG) and peak EMG were analyzed in the biceps femoris and semitendinosus independantly during the concentric (CON) and eccentric (ECC) phase of each exercise. Results were as follows: CON-LC and CON-SLDL elicited the greatest integrated EMG activity, with no significant difference between exercises. The CON-squat showed approximately half as much integrated EMG activity as CON-LC and CON-SLDL. Highest peak EMG was found in the CON-LC and CON-SLDL, with no significant difference in these exercises. The CON-squat produced a peak EMG that was approximately 70% of LC and SLDL. We conclude that LC and SLDL involve the hamstrings to a similar degree; however, the back squat involves only about half as much hamstring integrated EMG activity as LC and SLDL. (C) 1999 National Strength and Conditioning Association
Article
The purpose of this study was to document the differences in kinematics between the Sumo and conventional style deadlift techniques as performed by competitive powerlifters. Videotapes of 19 conventional and 10 Sumo contestants at two regional New Zealand powerlifting championships were analyzed. It was found that the Sumo lifters maintained a more upright posture at liftoff compared to the conventional lifters. The distance required to lift the bar to completion was significantly reduced in the Sumo technique. No significant difference was found between the techniques as to where the sticking point (first decrease in vertical bar velocity) occurred. (C) 1996 National Strength and Conditioning Association
Article
One of the most popular exercises for developing lower-body muscular power is the weighted vertical jump. The present study sought to examine the effect of altering the position of the external load on the kinematics and kinetics of the movement. Twenty-nine resistance-trained rugby union athletes performed maximal effort jumps with 0, 20, 40, and 60% of their squat 1 repetition maximum (1RM) with the load positioned (a) on the posterior aspect of the shoulder using a straight barbell and (b) at arms' length using a hexagonal barbell. Kinematic and kinetic variables were calculated through integration of the vertical ground reaction force data using a forward dynamics approach. Performance of the hexagonal barbell jump resulted in significantly (p < 0.05) greater values for jump height, peak force, peak power, and peak rate of force development compared with the straight barbell jump. Significantly (p < 0.05) greater peak power was produced during the unloaded jump compared with all trials where the external load was positioned on the shoulder. In contrast, significantly (p < 0.05) greater peak power was produced when using the hexagonal barbell combined with a load of 20% 1RM compared with all other conditions investigated. The results suggest that weighted vertical jumps should be performed with the external load positioned at arms' length rather than on the shoulder when attempting to improve lower-body muscular performance.
Article
Many individuals involved in the sport of powerlifting believe that the squat and deadlift have such similar lifting characteristics that the lifts yield comparable training results. The aim of this study was to compare and contrast biomechanical parameters between the conventional style deadlift and the back squat performed by 25 lifters competing in regional powerlifting championship. The 3-dimensional analysis incorporated 4 60 Hz synchronized video cameras for collecting data from 25 participants. Parameters were quantified at the sticking point specific to each lift. Kinematic variables were calculated at the hip, knee, and ankle. Paired (samples) t-tests were used to detect significant differences in the kinematic mean scores for the different lift types. The statistical analysis revealed significant differences exist between the squat (0.09 m/s) and the deadlift (0.20 m/s) vertical bar velocities. Differences were found for angular position of the hip, knee, and ankle between lifts. The sticking point thigh angles were quantified as 32.54 +/- 3.02 and 57.42 +/- 4.57 for the squat and deadlift, respectively. Trunk angles were 40.58 +/- 6.29 (squat) and 58.30 +/- 7.15 (deadlift). The results indicate the back squat represents a synergistic or simultaneous movement, whereas the deadlift demonstrates a sequential or segmented movement. The kinematic analysis of the squat and the conventional deadlift indicate that the individual lifts are markedly different (p < 0.01), implying that no direct or specific cross-over effect exists between the individual lifts.