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European Journal of Applied Sciences – Vol. 11, No. 2

Publication Date: April 25, 2023

DOI:10.14738/aivp.112.14137.

Williams, B., Horschig, A., Lock, A., & Redmon, S. (2023). The Measured Effects of Barbell Loading in a Flexed vs Neutral Lumbar

Spinal Position: A Case Study. European Journal of Applied Sciences, Vol - 11(2). 13-21.

Services for Science and Education – United Kingdom

The Measured Effects of Barbell Loading in a Flexed vs Neutral

Lumbar Spinal Position

Brogan Williams

College of Functional Movement Clinicians, New Zealand

Aaron Horschig

Squat University, United States of America

Andrew Lock

College of Functional Movement Clinicians, Australia

Stephen Redmon

Private Practice, United States of America

Abstract

This case study examines the physical and psychological effects of placing the

lumbar spine under heavy loads while in a macro-flexion (65°) or relative-neutral

(29°) position for up to 25 seconds during an isometric 45° hip hinge. A

150kg/330lb weighted barbell used by a powerlifter was taken through 1 set of

macro-flexion and relative-neutral. Tightness, discomfort, and pain were

measured. The examiner documented a time stamp for each symptom once

verbalized by the participant. For set 1, symptoms became present at 2 seconds

(tightness), 5 seconds (discomfort), and 14 seconds (pain), with the set ending at 21

seconds due to 7/10 pain and extreme discomfort reported. There was then a 10-

minute pause for the participant to recover and prepare for the next lift. For set 2,

only one symptom became present at 20 seconds (tightness), with no discomfort

and no pain. This study demonstrates that loaded flexion can potentially provoke

lumbar tissues faster than a loaded neutral position.

Keywords: Barbell, Lumbar flexion; biomechanics; spine; pain.

INTRODUCTION

Loaded lumbar flexion has been documented to be problematic and provocative towards injury

and pain throughout many peer-reviewed published research articles [1-11]. The

recommendation to minimize loaded lumbar flexion during exercise and functional tasks is

supported by decades worth of in-vitro studies as well biomechanical modeling, imaging, sEMG

and epidemiological studies [16-19]. Maintaining the lumbar spine in a relatively neutral

lordosis posture allows the extensor muscles that span the lumbar spine to bear the majority

of the responsibility for offsetting the moment forces created by the load rather than the

ligaments or discs. Conversely, the more the spine is flexed, the more force is transferred to the

passive structures. Biomechanically speaking, lumbar flexion will dictate the amount of force

required by the active muscular system and the passive sub-structures (ligaments, facets, discs)

to meet the extensor-moment demand of the lift [18-19].

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European Journal of Applied Sciences (EJAS) Vol. 11, Issue 2, April-2023

Services for Science and Education – United Kingdom

This mechanism was documented first in ‘Changes in lumbar lordosis modify the role of the

extensor muscles’ [6]. Investigators showed, via high-resolution ultrasound, various changes to

lower back muscles and their fiber orientation or direction when in different lumbar positions.

In a relatively neutral lumbar spinal posture, the iliocostalis lumborum pars lumborum, and

longissimus thoracis pars lumborum form a 25-45° angle between the sacrum/iliac crest and

the lumbar vertebrae through their attachment sites. This alignment allows these muscles to

aid in the ability to resist shear forces through the lumbar spine, more specifically, resist the

anterior shear of the superior vertebra on its inferior counterpart. The study reported that as

the spine was flexed, the oblique angle of these muscles was reduced to 10°, which in turn

greatly diminished the back-extensor muscles’ leverage to resist shear force [8]. Increased

lumbar flexion not only elongates the iliocostalis lumborum pars lumborum and longissimus

thoracis pars lumborum, altering the force-length-tension relationship but also reduces muscle

function, therefore, increasing force as well as stress on the passive lumbar spinal structures

and tissues [15]. This can be problematic as studies have shown tissues under load over time

in high degrees of lumbar flexion have not only high levels of creep but also inflammatory

cytokines, which can directly impact pain [5]. Although it is understood that one cannot

completely avoid spinal flexion while bending over or lifting, various studies show we can

change, control, and alter our spinal position. In fact, According to Boocock et al. (2019),

participants were able to modify their lumbosacral flexion with the help of postural

biofeedback, lowering their risk of low back injury when repeatedly lifting [13-14], [20], [25].

This warrants further investigation into the role of loaded lumbar flexion with various

populations and settings. The goal of this case study was to investigate additional parameters

by assessing the risk factor for low back pain (LBP) with loaded lumbar flexion in a gym setting

with a larger load of 150kg/330lbs with an experienced weightlifter.

METHODS

Study Design & Ethics

This was a single-participant case study that included the use of a standard 20kg weightlifting

barbell with 4-25kg and 2-15kg Elite EZI-GRIP High-Quality Cast Iron PVC Dipped Olympic

lifting plates. The total load was 150kg/330 lbs. The participant’s lumbar spine was measured

using a digital inclinometer, covering the two key positions designated “macro-flexion” at 65°

and “relative-neutral” at 29°. These positions were determined based on gross visualization of

the participant excessively flexing the lumbar spine and maintaining spinal neutrality in hip

hinge positions. Quantitative data was gathered via the digital inclinometer readings and the

participant’s feedback based on the three key levels of thresholds “tightness, discomfort, and

pain”, the pain was quantified via a Visual Analog Scale (VAS). The participant was briefed, and

the study design was communicated in detail. The participant understood the risks and dangers

surrounding heavy loads in the lumbar flexion position.

Participant Information

The participant was recruited by the primary investigator due to their experience as a World

Champion Super Heavy Weight (SHW) Powerlifter to ensure that they were well prepared for

exposure to the weighted loads as well as the body awareness necessary to recognize when

their tissue tolerance had been reached. The chosen participant’s anthropometrics were 179

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Williams, B., Horschig, A., Lock, A., & Redmon, S. (2023). The Measured Effects of Barbell Loading in a Flexed vs Neutral Lumbar Spinal Position: A

Case Study. European Journal of Applied Sciences, Vol - 11(2). 13-21.

URL: http://dx.doi.org/10.14738/aivp.112.14137

cm in height and 165 kg in weight. Their powerlifting experience consisted of over a decade of

powerlifting experience, including participation in elite levels, including national and

international competitions.

Examiner Information

In this case study, the lead examiner had 22 years of lifting experience, including ten years as a

doctor of physical therapy and 11 years competing in the sport of weightlifting. The project was

managed by the lead examiner, who also had an examiner's assistant who loaded the barbell.

Interventions

The participant was instructed to maintain an isometric hold while performing a 150kg/330

lbs barbell deadlift (static hip hinge) at a 45-degree angle. The participant completed two sets

on the same day with a 10-minute rest period between sets. Set 1 required the participant to

hold the 45-degree isometric hip hinge with a 150-kg loaded barbell while in lumbar “macro- flexion”. Following the 10-minute rest period, the participant performed set 2. This set was

identical to set 1 in all the procedures, however, now we asked the lifter to make every effort

to load his hips, maintaining hip-centric rotation and keep the lower back “relatively neutral” –

or as neutral as possible.

Outcome Measures

While the participant was holding the isometric position, they were timed, and the participant

was asked to verbalize the onset of tightness, discomfort, and pain - at which point the time was

documented to the corresponding symptom. However, the study would not be stopped until

the participant either reached 25 seconds, or the pain reached a 7/10. Three sets of time

intervals associated with a specific symptom were used to monitor the effects of the load in that

position, specifically on the lower back. Time interval 1: tightness; Time interval 2: discomfort

& Time interval 3: pain.

Visual Analog Scale

A VAS was used to assess the level of pain (Visual Analog Scale). Following a demonstration of

the analog scale and an explanation of its purpose and operation, the participant was instructed

to report to the examiner when their VAS score reached a 7/10.

Other Physical & Psychosocial Measurements

Tightness and discomfort were used to indicate how the lifter perceived their tissue tolerance

leading up to the onset of pain. The tightness was defined for the participant as the feeling of

increased tension and stretch that could happen in and around the lower back. The discomfort

was defined for the participant as the moment stretching and tension became intolerable and

manifested as unpleasantness but with an absence of pain.