NSCA CORNER: Use of Lifting Belt

[Guest guest]

Here are some extracts from another article from an NSCA publication on the

controversial topic of belt wearing during training. Some of the

discussion of findings and conclusions warrant comment from list members, so

over to you all for your views.

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J of Strength & Conditioning Research: 1999, Vol. 13, No. 4, pp. 384-388.

The Use of Lumbar-Supporting Weight Belts While Performing Squats: Erector

Spinae Electromyographic Activity

A Bauer, Cory , Fry

ABSTRACT

This study sought to analyze the effects of subjects' wearing weightlifting

lumbar support belts on surface electromyographic recordings of the erector

spinae muscle group while the subject executed parallel squats. Ten healthy

college-age men with weightlifting experience participated in this study.

Participants completed a total of 6 repetitions of high-bar parallel

back-squats at loads equaling 60% of their 1 repetition maximum. Experimental

conditions required subjects to perform 6 squats, 3 while wearing a belt and

3 without. Electromyographic electrodes recorded muscle activity at 800 Hz on

both the right and left erector spinae at the lumbar (L3-L5) and thoracic

(T5-T7) regions during all lifts.

The results indicate that subjects' mean erector spinae activity was greater

in the lumbar region of the spine when wearing weight belts (±258 SD; 69.0

analog-to-digital units) during squatting exercises than the mean activity in

subjects who were not wearing weight belts (±235 SD; 71.3 analog-to-digital

units).

Introduction

It must be stressed that weightlifting is a very safe sport when proper

protocols are followed; however, as with any sport, there are risks involved,

and those risks are magnified when participants consider themselves protected

by their sport equipment. Even today, when most athletes realize that weight

belts may not significantly protect the wearer against lower-back injury in

weightlifting, it is still common to see recreational and competitive athletes

wearing weight belts during lifting activities. In addition, many industries

that require employees to lift heavy objects at work have adopted policies

requiring those employees to wear weight belts while performing their tasks,

in hopes of reducing work-related lifting injuries.

A specific concern arises for the mechanical loading of the spine and the

vulnerability of the mid- to lower-back musculature to injury while

performing squats. Many researchers dispute whether wearing weight belts

during lifting is actually an effective method of reducing the risk of back

injury. It is hypothesized that wearing lifting belts will induce an

increase in intra-abdominal pressure, concomitantly reducing loads on the

lower back, specifically at locations L5-S1. However, one recent report rev

ealed no significant differences in intra-abdominal pressure between

subjects wearing belts and subjects without belts.

However, belts do appear to be effective in reducing asymmetric movements

while performing many types of lifting, including lateral bending and

twisting. Although the use of lifting belts is widespread throughout

competitive, recreational, and industrial lifting situations, research does

not support the general belief that belts increase functional performance

(isometric lumbar muscle strength, isokinetic muscle endurance or fatigue, or

dynamic lifting capacity) and prevent injury

This study was designed to determine whether there were measurable

differences in thoracic and lumbar erector spinae EMG activity between

submaximal lifting tasks for experienced weightlifters with and without

weight belts. Submaximal loads were selected to approximate lifting

requirements experienced by athletes during warm-up and cool-down and

experienced by high-repetition training and industrial settings, where

high-repetition lifting is common but where individuals are rarely required

to perform lifts of greater than 60% of 1 repetition maximum.........

Methods

Scientific studies reporting the physiological effects of wearing weight

belts are limited. Therefore, a greater understanding of the

electrophysiological effects of using weight belts was sought by evaluating

mean and integrated surface EMG signals of the thoracic and lumbar regions of

the erector spinae for lifting conditions in which some subjects wore belts

and others did not. The goal of this study was to determine if weight belts

effectively stabilize the back, reducing the need for erector spinae muscle

activity that would otherwise be required to stabilize the spine while

performing parallel squats without wearing a weight belt.

Subjects

Ten healthy college-age men with weightlifting experience agreed to

participate in the study and signed informed consent forms, as approved by

both the University of Florida and the University of Memphis. For the purpose

of this study, individuals who had a history of supervised weightlifting of

more than twice per week for a minimum of 2.5 years were selected as

subjects. All participants were familiar with and routinely wore weight belts

during moderate to heavy lifting workouts. A summary of participant

demographics is provided in Table 1.

Lifting Protocol

Each participant completed 2 trials, each consisting of 3 repetitions of

high-bar parallel back-squats. One trial condition required subjects to

perform 3 squats while wearing weight belts. All conditions were held

constant for the second set of 3 squats, but in this set, no weight belt was

worn. Lifting loads equaled 60% of each individual's self-reported 1

repetition maximum (1RM). The 60% load was considered safe for repeated lifts

and simulated the weight often used during the warm-up or cool-down phases of

a workout. The 60% 1RM load adequately represents a level of lifting required

in many industrial settings, where workers are required to wear lifting belts

while performing their duties.

Electrode Placement

Surface electrodes recorded electrical activity bilaterally on both the right

and left erector spinae at the lumbar (L3-L5) and thoracic (T5-T7) regions.

These sites were chosen because of the large muscle size at these regions,

relative to the rest of the muscle group, which ensured that electrodes could

be placed over the muscle belly regardless of the size of the individual

tested. The electrodes were placed 3 cm laterally to the right and left of

the spinous processes of the L3-L5 and T5-T7 vertebrae. The weight belts

were made of rigid leather, were approximately 1 cm thick, and were 12 cm

wide in the area which, when worn, extended from the anterior aspect of the

pelvis across the lower back. The same brand and style of belt were used for

all testing. Participants were fitted with the size of belt most appropriate

for their body size and structure........

Discussion

These results were contrary to what was expected, since it is believed that

the use of weight belts provides additional support to the spine and

therefore should result in a decrease in the activity of the back musculature

used to stabilize the spine during lifting tasks. The results of our study

indicate that the erector spinae is statistically more active in the lumbar

region of the spine when wearing a belt during squatting exercises.

A possible explanation for the increase in muscle activity may be found in

considering the physical application of the belt. Generally, it was be

observed that when applying a lifting belt, the lifter pulls the belt

extremely tightly around the waist, presumably to increase support. Although

this act may or may not actually increase intra-abdominal pressure, and

although such a practice may or may not actually provide greater stability of

the spine, it is certainly possible that buckling a belt so tightly around

the waist may create a degree of preload on the spinal extensors.

Essentially, by pulling the belt tightly, an amount of tension may already be

placed on the erector spinae before any flexion of the spine or contraction

of the spinal extensors ever occurs.

It is to be expected that the activity of the erector spinae group will

increase once flexion of the spine begins during the squatting repetitions;

but the added tension created by a preload may actually increase the risk of

muscle overexertion and strain rather than decrease the reliance on these

muscles to stabilize back during lifting. However, it is yet to be determined

if the increases shown in this study are physiologically relevant and

indicate a state of activity of the muscles that might lead to increased

fatigue.

Although this study supports the previously suggested contention that there

is actually a potential for an increased degree of lower-back injury while

wearing lumbar support belts during lifting, the limited number of subjects,

trials, and loads lifted, coupled with the selection of a single lifting

exercise for evaluation of data, makes it inappropriate to state that wearing

lifting belts will increase the likelihood of injury. Certainly, more

research is necessary to fully understand the benefits, detriments, and

associated tradeoffs of wearing a back support belt while performing squats.

However, athletes who practise performing squats while wearing weight belts

must be aware of the data that raises doubts as to whether wearing such belts

decreases or increases their likelihood of being injured during their lifting

workouts.

Practical Applications

When an athlete or coach uses or recommends particular equipment, it is

crucial that the equipment performs as expected. Weight belts are commonly

used in recreational, competitive, and industrial lifting situations.

Although the benefits of wearing belts remains in dispute, until evidence is

presented to the contrary, many lifters will continue to believe that wearing

a weight belt increases the stability of the spine and decreases the

likelihood of injuring the lower back. The general opinion of those who use

the back support lifting belts is that the increased external support offered

by the belt should decrease the need for muscular stabilization and should

elicit a decrease in erector spinae activity during lifting.

This study was designed to determine if a decrease in erector spinae activity

is observed while performing high-bar squats when wearing a weight support

belt when compared to equivalent lifts while not wearing a belt. A noticeable

decrease would indicate that the belt is relieving some of the need for the

erectors to provide as much muscular stabilization of the lumbar spine as

would be necessary in performing the same lifts without the belts. Findings

that would indicate an increase or no difference in erector spinae activity

between the 2 conditions of wearing a weight belt and not wearing a weight

belt would tend to refute the theory that wearing a weight belt helps

maintain proper lower-back mechanics and would likely decrease the chance of

injury to that region during lifting.

In short, if anything less than a decrease in erector spinae activity is

observed in someone who performs a squat while wearing a belt, the belt does

not provide the biomechanical change people expect to help minimize the risk

of lower-back injury. Our findings do not support wearing weight belts during

submaximal lifting as a method of reducing erector spinae muscle activity.

Athletes, coaches, and industry in general must be made aware that weight

belts do not elicit the biomechanical benefits in trunk stabilization and

support that they are commonly thought to provide.

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Dr Mel C Siff

Denver, USA

Supertraining/