EFFECT OF DEADLIFT TRAINING ON CORE STRENGTH IN PREVIOUSLY-UNTRAINED MALES

Abstract

The purpose of this study was to examine the effect of the deadlift, a heavy compound exercise, on core strength as determined through the 1-RM deadlift and the Bunkie tests. The deadlift is a multi-joint movement that involves picking up a barbell from the floor and standing up to an upright position. This movement includes plenty of muscle activation, mainly the lower back, upper back, quadriceps, hamstrings and abdominals. The core is a collection of muscles in the abdominal and lower back areas although it is commonly mistaken as simply the abdominal muscles. This study investigated the effect of deadlift training on core strength through a pretest-posttest comparison in the 1-RM deadlift to assess maximum muscular strength and the Bunkie test for core strength. 21 previously-untrained male college students participated in a 5-week deadlift strength program using progressive overload with no direct core training involved. The 5-week deadlift program resulted in significant increases in both the 1-RM deadlift, derived from the Brzycki formula, and Bunkie test scores most notably in the posterior stabilizing line and the medial stabilizing line. Deadlift strength training, even without direct core training, was able to produce significant improvements in core strength in previously-untrained male college students.

Full text

Correspondence: Christian Wisdom Magtajas Valleser (M.S.), Assistant
Professor, Department of Sports Science, College of Human Kinetics, University
of the Philippines Diliman, Quezon City, PHILIPPINES. Tel: +63-9150029678,
Email: cmvalleser@up.edu.ph
EFFECT OF DEADLIFT TRAINING ON CORE STRENGTH IN
PREVIOUSLY-UNTRAINED MALES
CHRISTIAN WISDOM MAGTAJAS VALLESER*, GARIZALDY S.
SANTOS
Department of Sports Science, College of Human Kinetics, University of the Philippines Diliman,
Quezon City, PHILIPPINES.
*Email: cmvalleser@up.edu.ph
How to cite this article: Valleser, C.W.M., & Santos, G.S. (March, 2017). Effect
of deadlift training on core strength in previously-untrained males. Journal of
Physical Education Research, Volume 4, Issue I, 10-18.
Received: January 07, 2017 Accepted: March 23, 2017
ABSTRACT
The purpose of this study was to examine the effect of the deadlift, a heavy compound
exercise, on core strength as determined through the 1-RM deadlift and the Bunkie
tests. The deadlift is a multi-joint movement that involves picking up a barbell from the
floor and standing up to an upright position. This movement includes plenty of muscle
activation, mainly the lower back, upper back, quadriceps, hamstrings and abdominals.
The core is a collection of muscles in the abdominal and lower back areas although it is
commonly mistaken as simply the abdominal muscles. This study investigated the effect
of deadlift training on core strength through a pretest-posttest comparison in the 1-RM
deadlift to assess maximum muscular strength and the Bunkie test for core strength. 21
previously-untrained male college students participated in a 5-week deadlift strength
program using progressive overload with no direct core training involved. The 5-week
deadlift program resulted in significant increases in both the 1-RM deadlift, derived
from the Brzycki formula, and Bunkie test scores most notably in the posterior
stabilizing line and the medial stabilizing line. Deadlift strength training, even without
direct core training, was able to produce significant improvements in core strength in
previously-untrained male college students.
Keywords: Deadlift, core, strength, repetition maximum.
1. INTRODUCTION
The deadlift is a resistance training exercise in which a loaded barbell is lifted off
the floor by extending the hips and knees until the body reaches a fully erect torso
position (Earle & Baechle, 2008). This barbell deadlift is one of the three lifts in
the sport of powerlifting and is a part of many resistance training programs. The
Journal of Physical Education Research, Volume 4, Issue I, March 2017, pp.10-18
ISSN: Print-2394 4048, Online-2394 4056, Impact Factor: 0.519, IBI Factor: 4.29, GIF: 0.765

Valleser, C.W.M., & Santos, G.S. (March, 2017). Effect of deadlift training on core strength in
previously-untrained males. Journal of Physical Education Research, Volume 4, Issue I, 10-18.
JOPER® www.joper.org JOPER 11
deadlift entails plenty of muscle activation mainly the gluteal muscles, hamstring,
quadriceps and lower back as well as numerous synergist muscles in the upper
body (Blanchard, Berning, Adams, & DeBeliso, 2016). Certain exercises like the
squat and lunges require the same prime movers as the deadlift. However, the
emphasis of the deadlift lies on the powerful activation of the gluteal and
hamstring muscles to straighten the hips as well as highly involved synergistic
role of the upper body. Such is the fundamental appeal of the deadlift in terms of
physical enhancement that it and its variations have been the subject of many
reviews (Farley, 1995; Gardner & Cole, 1999; Frounfelter, 2000; Graham, 2000;
Piper & Waller, 2001; Graham, 2001; Hales, 2010; Bird & Barrington-Higgs,
2010). The practical application of the deadlift is simple and can be used in daily
life like picking items off the floor or moving heavy objects like furniture.
Among the lifts that are widely beneficial for an individual, the deadlift is
one of the most underrated and underappreciated. The reason for its unpopularity
probably stems from the deep rooted idea that it is hazardous to the lumbar tract
of the spine or the vertebral column (Casillo, 2008). Although assuming that the
deadlift is completely safe and harmless is false, certain precautions can be done
to minimize and even prevent injuries while training (Thibaudeau, 2008). The
core can be broadly defined as the torso, an area of the human body that is
essential for movement capacity such that a lack of muscular development may
predispose one to injury (Karageanes, 2004). It can be further described as a
collection of muscles in the abdominal and lower back areas. This includes all the
abdominal muscles (rectus abdominus, internal and external obliques, transverse
abdominus and intercostals) as well as the muscles associated with the spine (the
erector spinae group) and the hip flexors (iliacus and psoas, collectively known as
the iliopsoas. Having a strong core brings about many functions, one of which is
to stabilize and protect the spine by creating stiffness that limits excessive
movement in any direction- most notably extension, flexion, lateral flexion and
rotation (Bumgardner, 2015). That being said, it is assumed that a strong core
equates to better overall stability and balance. Core stability is an important
attribute of the body and is vital to athletes and non-athletes alike (Hamilton,
Berning, Sevene, Adams, & DeBeliso, 2016). The core has become a household
term in the fitness industry. People seem to equate the core with abdominal
training which explains why various websites, commercials, advertisements and
even trainers use the phrase to attract misinformed potential clients vying to get a
“ripped” abdominal area (Springall, Larson, & DeBeliso, 2016). In truth, the core
exists for a reason much more than the aesthetic value that lean abdominal
muscles give and needs to be treated as such. The interaction of the overloading
capacity of deadlift training and its inherent benefits to core strength and stability
has logic behind it but is yet to be objectively investigated. Thus, the aim of this

Valleser, C.W.M., & Santos, G.S. (March, 2017). Effect of deadlift training on core strength in
previously-untrained males. Journal of Physical Education Research, Volume 4, Issue I, 10-18.
JOPER® www.joper.org JOPER 12
study is to determine if there will be a significant change in the core strength of
previously-untrained individuals after a deadlift training program. Specifically,
whether a purely deadlift strength training program may illicit changes in one’s
core strength even without direct core training.
Muscular strength testing is an integral aspect of muscular fitness
assessment and this principle can be applied to the deadlift. The absolute strength
of a muscle is defined as the greatest amount of weight the muscle can lift in a
single time - called the One-Repetition Max (1-RM) – in this case the 1-RM
deadlift. Many strength tests are performed using free weights so proper form and
control are important to maintain safety. Studies on 1-RM testing have reported
them to have high validity and test-retest reliability (English, Loehr, Laughlin,
Lee, & Hagan, 2008; Bezerra, Simão, Fleck, Paz, Maia, Costa, & Serrão, 2013)
making them an ideal method of measuring an individual’s absolute strength.
Used to assess core strength, the Bunkie test is primarily a functional
performance test consisting of five positions performed on the left and right side
of the body totaling 10 positions of evaluation. The Bunkie test was first
introduced by de Witt and Venter (2009) to evaluate fascia mobility and athletic
performance. The name Bunkie was derived from the Afrikaans word “bankie”
which means “little bench”. The results of the test depend on the participants'
ability to hold each of the five positions. The test prescribes participants to hold
each position for a specified amount or duration and would stop if pain or
deviation from the standard form occurs. The test identifies performance in the
anterior, posterior, medial and lateral aspects of the core. Identifying weak areas
is essential to determine how the core can be strengthened through training thus
even rehabilitation professionals can utilize this test (Brumitt, 2011).
A study that assessed the relationship of the Bunkie test and athletic
performance was done by Van Pletzen and Venter (2012) on professional rugby
players using the Bunkie test along with other tests for athletic performance. The
results were groundbreaking as the participants who scored high in the Bunkie test
(those who were able to hold the positions for the prescribed duration) exhibited
positive significant relationships with the results for the other tests – agility,
speed, anaerobic endurance, leg power and upper-body strength. Furthermore, the
participants were familiar with all of the tests aside from the Bunkie test and
therefore would not have been able to prepare for the Bunkie test in any way
possible. When tested on a general, healthy population, Brumit (2015) reported a
high test-retest reliability for the five testing positions with intraclass correlation
coefficients going as high as 0.95. Furthermore, the Bunkie test may also be a
useful tool for diagnosing muscular asymmetry as the tests are done unilaterally
or as a means of tracking muscular function progress for patients undergoing
rehabilitation (Brumitt, 2011).

Valleser, C.W.M., & Santos, G.S. (March, 2017). Effect of deadlift training on core strength in
previously-untrained males. Journal of Physical Education Research, Volume 4, Issue I, 10-18.
JOPER® www.joper.org JOPER 13
2. METHODS AND MATERIALS
This study is a pretest-posttest comparison specifically in the 1-RM deadlift and
the Bunkie tests. The intervention was a 5-week, twice a week frequency (with
rest days in between sessions) deadlift strength program using progressive
overload. The conventional deadlift style was used in this study. The conventional
deadlift uses a narrower stance (feet about 32 to 35 cm apart) with hand/grip
placement outside the stance feet compared to the sumo style (Escamilla,
Francisco, Fleisig, Barrentine, Welch, Kayes, & Andrews, 2000; Escamilla
Francisco, Kayes, Speer, & Moorman, 2002) which involves a placement of the
hands outside the stance feet. Aside from the 5-week training program, separate
days were provided each for the (1) Orientation and practice session of the
deadlift, (2) pretesting of the 1-RM deadlift, (3) pretesting of the Bunkie test, (4)
post testing of the 1-RM deadlift and (5) post testing of the Bunkie test.
2.1 Subjects
21 previously-untrained but healthy male college students with a mean age of
20.6 (± 2.6 yrs) novices with no background in weight training participated in the
study. The diet, sleeping habits, fatigue management strategies, pre- and post-
workout nutrition of the participants were not monitored.
2.2 Procedure
Since novices are typically incapable of handling heavy free weights due to their
lack of familiarity and experience, a derivative of the 1-RM was employed using
predicted 1-RM testing through a conversion table. The Brzycki (1993) formula is
one of the commonly used 1-RM prediction methods and is calculated using the
formula “weight lifted/(1.0278-(0.0278*repetitions))”. It provides a fairly
accurate estimation of the 1-RM especially in performances of less than 10
repetitions and was thus applied in the pretest and posttest of the 1-RM deadlift.
As introduced earlier, the Bunkie test is a method for assessing core
strength and was applied in this study to determine the pretest and posttest core
strength of the participants. The test involves five testing positions namely the (1)
posterior power line (PPL), (2) anterior power line (APL), (3) posterior stabilizing
line (PSL), (4) anterior stabilizing line (ASL) and (5) medial stabilizing line
(MSL). Each position is to be held with the feet on a 30-cm bench and the upper
extremities (palms and forearms) supporting the upper body. Once ready, the
individual would raise one leg or foot (depending on the test) a few inches off the
bench. Although it is suggested that athletes are to hold the position for 20 to 40

Valleser, C.W.M., & Santos, G.S. (March, 2017). Effect of deadlift training on core strength in
previously-untrained males. Journal of Physical Education Research, Volume 4, Issue I, 10-18.
JOPER® www.joper.org JOPER 14
seconds, the participants were novices and were just tested on how long they
could hold the position as suggested by de Witt and Venter (2009). Aside from
the five scores that would be derived from each testing position, an overall score
was also obtained by summing all five scores in the Bunkie test.
2.3 Statistical Analysis
Normality was assessed using the Shapiro-Wilk (1965) test and showed that data
was normally distributed meeting the assumptions of a parametric test. Two t-tests
for dependent means were used for comparison of the pretest and posttest scores.
When applicable, significant differences were evaluated for effect size using
Cohen’s d to measure the magnitude of mean differences (Cohen, 1988).
Significance was tested at α = 0.05.
3. RESULTS
As expected due to training specifically for deadlifts, there was a significant
increase in the 1-RM deadlift at 21% and was significant (p<0.000) with a large
effect size (d=1.13194). This result was not surprising since the participants
underwent a 5-week deadlift strengthening program with progressive overload.
Throughout the 5-week program, there was no direct core training and the
participants were not subjected to the Bunkie test at any point in the training
period. As implied by the specificity principle, this should not illicit any changes
in core strength unless otherwise affected by other factors. The researchers
observed a 28.6% increase in overall the Bunkie test scores (p<0.000) with a very
large effect (d=1.6810). As can be observed in figure 1 below, post test scores in
both the 1-RM deadlift and Bunkie test were considerably much higher than the
pretest scores:
Figure 1: Pretest vs. posttest 1-RM deadlift and Bunkie test scores
*p<0.05

Valleser, C.W.M., & Santos, G.S. (March, 2017). Effect of deadlift training on core strength in
previously-untrained males. Journal of Physical Education Research, Volume 4, Issue I, 10-18.
JOPER® www.joper.org JOPER 15
The outcome of the Bunkie test comparison is promising as it offers initial
insights into the argument that many of the muscles targeted by the deadlift were
similar parts of the core responsible for maintaining and ensuring proper posture
for core strength. In effect, gains in core strength presumably came from the
nature of the deadlift which has high muscle activation not only in the torso, but
in the whole body as well. As stated earlier, movement during the deadlift does
activate the abdominal muscles as well as the muscles associated with the spine
and the hip flexors (Nilsson, 2008).
Further investigation into the individual Bunkie scores showed that there
were significant improvements in all testing positions. The PPL had a 12.4%
increase (p<0.000) with a moderate effect (d=0.7860). The APL increase was
higher at 23.8% (p=0.0002) with a large effect (d=1.1678) as well. The third
position, the lateral stabilizing line LSL was impressive with a 61.7% increase
(p<0.000) with a very large effect (d=1.3450). Much more impressive were the
results from the PSL with an 83.6% increase (p<0.000) and the MSL with an
87.8% increase (p<0.000) with both very large effects (d=1.5927 and d=1.5196,
respectively). These results are better appreciated through figure 2 which
illustrates the marked increase in performance in the test positions.
Figure 2: Pretest vs. posttest mean scores in the individual Bunkie test
positions recorded in seconds
PPL – posterior power line, APL – anterior power line, PSL – posterior stabilizing line, LSL –
lateral stabilizing line, MSL – medial stabilizing line,
*p<0.05
4. DISCUSSION
The purpose of this study was to examine the effect of a heavy compound
exercise training, in this case the deadlift, on core strength as determined through
the 1-RM deadlift and the Bunkie test. The deadlift directly targets all of the

Valleser, C.W.M., & Santos, G.S. (March, 2017). Effect of deadlift training on core strength in
previously-untrained males. Journal of Physical Education Research, Volume 4, Issue I, 10-18.
JOPER® www.joper.org JOPER 16
major muscle groups responsible for correct posture and in turn, core strength.
Correct deadlifting technique enables one to hold their back straight and keep a
correct posture when engaging in daily activities due to its emphasis on
maintaining a straight back throughout the movement. The deadlift also
strengthens all the surrounding supporting muscles of the waist, backside, and
hips and, of course, lower back. This exercise can be an integral part of any
resistance training program because it is very simple but is profound in its
capacity to increase overall strength and can contribute to more strength and size
gains compared to many other exercises (Robson, 2015). This study hopefully
contributed towards linking the positive effect of the deadlift on core strength
through statistical evidence.
5. CONCLUSIONS
Deadlift strength training, even without direct core training, leads to significant
improvements in core strength in previously-untrained, healthy males. The
participants in this study were untrained males. Different groups may be
investigated to find out whether the results would be similar especially among
male and female athletes and/or trained individuals. Different training program
durations may also be used to determine the effect of programs which may be
shorter or longer than the five weeks used in this study. Adjustments in training
volume and/or intensity may also be investigated as well as using different
exercises whether multi-joint or isolation exercises.
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Valleser, C.W.M., & Santos, G.S. (March, 2017). Effect of deadlift training on core strength in
previously-untrained males. Journal of Physical Education Research, Volume 4, Issue I, 10-18.
JOPER® www.joper.org JOPER 17
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Valleser, C.W.M., & Santos, G.S. (March, 2017). Effect of deadlift training on core strength in
previously-untrained males. Journal of Physical Education Research, Volume 4, Issue I, 10-18.
JOPER® www.joper.org JOPER 18
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