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More Kinesiology: DL Safety Studies?

In response to a question on another forum, I’m scouring the internet for research studies proving the safety of a properly executed deadlift. Unfortunately, everything I’ve found so far has been anecdotal.

Andy Bolton took up powerlifting after a back injury during rugby, and I know of many individuals online who used light deadlifts to slowly rehabilitate their back injuries, but nothing scientific.

Anybody have anything concrete?

I think the research detailed in “Low Back Disorders: Evidence-Based Prevention and REhabilitation” would say the opposite. I don’t think deadlifts, light or otherwise, are part of the prevention or rehab protocols. In fact, McGill observed an experienced powerlifter blow a disc while deadlifting, when one little muscle (out of the 40 or so involved in stabilizing the spine) failed to fire sufficiently during the movement.

Furthermore, strength of low back muscles does not protect against injury.

Anecdotally, I blew out a disc while deadlifting.

Back injuries do tend to heal over a period of 6 months or so on average, no matter what one does. But if one wants to follow the best EVIDENCE-based rehab protocol, go straight for the above-mentioned book.

I don’t know of any studys. But I know Lamar Gant had scoliosis (crooked spine). And I don’t remember her name but there was a female powerlifter who started for the same reason, scoliosis.

Both my mom and my grandpa have it, and as such, so do I. about 20 degrees in the lumber spine. My grandpa has a metal rod in his back, and my mom can’t lift 10lbs.

So yeah, I worried about that for a while, and after throwing my back out twice at the age of 20, I decided to take care of shit.

So here I am, 60lbs heavier, pulling 450 and I haven’t had any back problems since. Still crooked but the surrounding musculature is strong enough to keep it protected. Not to mention just knowing how to lift, keep tight, getting your air, etc.
aah, memories

[quote]andersons wrote:
I think the research detailed in “Low Back Disorders: Evidence-Based Prevention and REhabilitation” would say the opposite. I don’t think deadlifts, light or otherwise, are part of the prevention or rehab protocols. In fact, McGill observed an experienced powerlifter blow a disc while deadlifting, when one little muscle (out of the 40 or so involved in stabilizing the spine) failed to fire sufficiently during the movement.

Furthermore, strength of low back muscles does not protect against injury.

Anecdotally, I blew out a disc while deadlifting.

Back injuries do tend to heal over a period of 6 months or so on average, no matter what one does. But if one wants to follow the best EVIDENCE-based rehab protocol, go straight for the above-mentioned book. [/quote]

So the powerlifter with the blown disc, he lifted a maximal load, had a technique breakdown, and got injured. This happens everyday, to all different bodyparts. Bicep tears, hamstring tears… When someone screws up and tears a hamstring while deadlifting, then by your logic, deadlifts aren’t a good way to build strong hamstrings.

And odds are, whether you realized it or not, when you hurt yourself it was probably because your technique was shit.

deadlifts help build a strong “core”, which could prevent back injuries, if you have a decent pull beltless you probablly arent going to hurt yourself picking up a box of books or dresser like so many people do.

[quote]evansmi wrote:
I don’t know of any studys. But I know Lamar Gant had scoliosis (crooked spine). And I don’t remember her name but there was a female powerlifter who started for the same reason, scoliosis.

Both my mom and my grandpa have it, and as such, so do I. about 20 degrees in the lumber spine. My grandpa has a metal rod in his back, and my mom can’t lift 10lbs.

So yeah, I worried about that for a while, and after throwing my back out twice at the age of 20, I decided to take care of shit.

So here I am, 60lbs heavier, pulling 450 and I haven’t had any back problems since. Still crooked but the surrounding musculature is strong enough to keep it protected. Not to mention just knowing how to lift, keep tight, getting your air, etc.
aah, memories [/quote]

On this point, my girlfriend also suffers from it. One side of her back was much more developed than the other as a result, you could feel the muscular imabalance with your hands. This used to cause her terrible pains and she couldn’t carry a heavy bag for too long or it would cause pain.

She started deadlifting and other general back exercises 8 or so months ago, and since then not only has her back developed more evenly, but she’s pain free and I don’t have to carry her bags anymore!

[quote]Hanley wrote:
evansmi wrote:
I don’t know of any studys. But I know Lamar Gant had scoliosis (crooked spine). And I don’t remember her name but there was a female powerlifter who started for the same reason, scoliosis.

Both my mom and my grandpa have it, and as such, so do I. about 20 degrees in the lumber spine. My grandpa has a metal rod in his back, and my mom can’t lift 10lbs.

So yeah, I worried about that for a while, and after throwing my back out twice at the age of 20, I decided to take care of shit.

So here I am, 60lbs heavier, pulling 450 and I haven’t had any back problems since. Still crooked but the surrounding musculature is strong enough to keep it protected. Not to mention just knowing how to lift, keep tight, getting your air, etc.
aah, memories

On this point, my girlfriend also suffers from it. One side of her back was much more developed than the other as a result, you could feel the muscular imabalance with your hands. This used to cause her terrible pains and she couldn’t carry a heavy bag for too long or it would cause pain.

She started deadlifting and other general back exercises 8 or so months ago, and since then not only has her back developed more evenly, but she’s pain free and I don’t have to carry her bags anymore![/quote]

Clearly we will need picture of your girlfriends backside as evidence :wink:

[quote]evansmi wrote:

So the powerlifter with the blown disc, he lifted a maximal load, had a technique breakdown, and got injured. This happens everyday, to all different bodyparts. Bicep tears, hamstring tears… [/quote]

Right. So by definition, these movements aren’t “safe” and they don’t help you “prevent injuries.”

BTW the powerlifter wasn’t lifting maximal load. He didn’t have a “technique breakdown” that anyone could have identified visually. Because he was hooked up to all the muscle measuring equipment at the time, it was identified that one little muscle failed to fire. So it was a motor control error, but not one that could have been consciously prevented through “technique.”

Also, damaging discs, ligaments, and tendons is a much bigger deal than a muscle tear.

No that’s not my logic and that’s not what I said.

Deadlifts may be a great way to build strong hamstrings and a strong back (depending on technique and an individual’s leverages and motor patterns during the lift).

The original poster didn’t ask whether DLs are a good exercise for building strong hams; he asked about safety.

Safety and efficacy are two different things.

First of all, who deadlifts with 100% impeccable technique 100% of the time.

Second, even such a rare individual MAY injure himself while deadlifting.

[quote]andersons wrote:

[/quote]

There is no sport that doesn’t involve some risk of injury. People get hurt playing golf, that doesn’t make golf dangerous.

One powerlifter slipping a disc does not mean that deadlifting causes slipped disks. There could be confounding variables. Drawing conclusions based on one individual is irresponsible.

Stating that that one individual is evidence, and that all other individuals who have benifited from deadlifts are anectodal… it just doesn’t work like that. If your scared to deadlift, don’t bring others down with you.

[quote]andersons wrote:

Because he was hooked up to all the muscle measuring equipment at the time, it was identified that one little muscle failed to fire.
[/quote]

Speaking of confounding variables, I wonder what effect having a bunch of equipment hooked up to him had on his ability to concentrate. What effect could the electromagnetic feild coming of the wire pressed against the skin could have on a tiny little muscle, being that muscles fire off of electrical impulses. Could any of the wires tugged a little, throwing off the lifters balance.

The point is there are a million possibilities, which is why one individual proves nothing.

Interesting discussion guys.

Anyone have any studies dealing with deadlift safety/compressive forces tho?

[quote]IronAbrams wrote:
Interesting discussion guys.

Anyone have any studies dealing with deadlift safety/compressive forces tho?[/quote]

Stuart McGill is supposed to be an expert in spine related things and he talks about loads on the spine affecting it and the like. You could check him out.

My athletic training professor brought his name up in lecture a couple weeks ago, sounds I’ll have to pick up some of his material.

Wow talk about good timing, an article published today on elitefts sites an abstract from a study. Not sure where to find the study itself buy here ya go.

http://www.elitefts.com/documents/pilates_magic.htm

�??A weight-bearing exercise is known to improve bone mineral density. However, excessive forces exerted on the lumbar spine can be pathologic. Cadaveric studies have calculated a hypothetical �??critical compression force�?? at which the lumbar spine would suffer collapse. In addition, recent studies have suggested that bone density correlates with strength. Thus far, studies have failed to examine elite power athletes to determine the possible upper range for bone mineral density and critical compression force. Therefore, we recruited the current world record holder in the squat lift with a record squat lift > 469 kg for an examination of lumbar spine bone mineral density. The subject had dual energy x-ray absorptometry (DEXA) and magnetic resonance imaging (MRI) performed on the lumbar spine. The subject also had serum chemistries, cell blood count, and testosterone levels performed. The DEXA scan revealed the highest bone mineral density reported to date. The MRI revealed normal alignment, no evidence of disc herniation, or compressive disc disease. There was no frank or neural foraminal canal stenosis. The estimated compressive force generated on his lumbar spine during the squat lift of > 469 kg doubles the previously reported critical compression force. This case study supports the previously described relationship between strength and bone density and redefines the upper limits of bone density in strength athletes.�?? (Reference: Dickerson RD, Pertusi R, Smith GH (2000) The upper range of lumbar spine bone mineral density: An examination of the current world record holder in the squat lift. Int J Sports Med 21:469�??70.)

Saw that study today, a great example. I just wish they’d done it on a larger sample aka more than one powerlifter.

[quote]IronAbrams wrote:
Saw that study today, a great example. I just wish they’d done it on a larger sample aka more than one powerlifter.[/quote]

Yeah, I’d be interested to find out what the average bone density is of elite powerlifters in multi ply feds.

[quote]evansmi wrote:
IronAbrams wrote:
Saw that study today, a great example. I just wish they’d done it on a larger sample aka more than one powerlifter.

Yeah, I’d be interested to find out what the average bone density is of elite powerlifters in multi ply feds. [/quote]

It’s been done with olympic weightlifters…

[quote]Hanley wrote:
evansmi wrote:
IronAbrams wrote:
Saw that study today, a great example. I just wish they’d done it on a larger sample aka more than one powerlifter.

Yeah, I’d be interested to find out what the average bone density is of elite powerlifters in multi ply feds.

It’s been done with olympic weightlifters…[/quote]

And powerlifters:

The Upper Range of Lumbar Spine Bone Mineral Density? An Examination of the Current World Record Holder in the Squat Lift

R. D. Dickerman1, R. Pertusi2, G. H. Smith2
1 Surgical Neurology Branch, national Institutes of Health, Bethesda, MD, USA
2 Department of Surgery, University of North Texas Health Science Center, Fort Worth, TX, USA

Weight-bearing exercise is known to improve bone mineral density, however, excessive forces exerted on the lumbar spine can be pathologic. Cadaveric studies have calculated a hypothetical �??critical compression force�?? at which the lumbar spine would suffer collapse.

In addition, recent studies have suggested that bone density correlates with strength. Thus far studies have failed to examine elite power athletes to determine the possible upper range for bone mineral density and critical compression force. Therefore, we recruited the current world record holder in the squat lift, with a record squat lift > 469 kg, for an examination of lumbar spine bone mineral density.

The subject had dual energy x-ray absorptometry (DEXA) and magnetic resonance imaging (MRI) performed of the lumbar spine. The subject also had serum chemistries, cell blood count and testosterone levels performed.

DEXA scan revealed the highest bone mineral density reported to date.

MRI revealed normal alignment, no evidence of disc herniation or compressive disc disease.

There was no frank or neural foraminal canal stenosis.

The estimated compressive force generated on his lumbar spine during the squat lift of > 469 kg doubles the previously reported critical compression force.

This case study supports the previously described relationship between strength and bone density and redefines the upper limits of bone density in strength athletes.

Makes you think don’t it?
As the SQ record is mentioned as 469kg (~1034lb) it not the heaviest from multiply feds, anymore at least.

Look 4 posts above you :stuck_out_tongue:

Seriously tho, this is great info guys. I mean, I respect physical therapists, doctors and chiros for their education and all that they’ve went through, but when one just blatantly singles outs deadlifts as inherently unsafe and inevitably destroying backs I like to see a little research.

Check these:

Partitioning of the L4-L5 dynamic moment into disc, ligamentous, and muscular components during lifting.
McGill SM,
Norman RW.
This work describes a dynamic model of the low back that incorporates extensive anatomical detail of a three-dimensional musculo-ligamentous-skeletal system. The reactive moment about L4-L5, determined from sagittal plane lifts, was partitioned into restorative components provided by the disc in bending, ligament strain, and active muscle contraction. Skeletal kinematics were obtained from cine analysis of markers on the rib cage and pelvis. The musculature was driven from surface EMG collected from six sites.

When compared with past models, features of this model included improved anatomical modeling, improved monitoring of vertebral motion unit kinematics, improved estimation of neural activation of the musculature, and consideration of the effects of muscle length, velocity, cross-sectional area and passive elasticity in force estimation. Estimations of L4-L5 disc compression and shear were, on average, 16.2% and 42.5% lower, respectively, than those calculated from a simple 5 cm erector tissue moment arm length. There was no need to invoke intra-abdominal pressure or other contentious compression-reducing mechanisms.

Muscle activity, particularly that of the sacrospinalis, dominated the generation of the restorative moment. Ligaments played a very minor role in the lifts studied. High muscle loads are consistent with the common clinical observation of muscle strain often produced by load handling.
PMID: 3787338 [PubMed - indexed for MEDLINE]1986

Lumbar posterior ligament involvement during extremely heavy lifts estimated from fluoroscopic measurements.
Cholewicki J,
McGill SM.
Department of Kinesiology, University of Waterloo, Ontario, Canada.
The mechanical role of the lumbar posterior ligaments during lifting tasks remains controversial. This study was designed to assess the ligament and disc contribution in resisting trunk flexion moment during extremely heavy lifts performed by national class powerlifters. Direct measurements of lumbar vertebrae kinematics in sagittal plane were obtained from videofluoroscopy utilizing multiple digitizing, correction for optical distortions and digital filtering.

Four experienced powerlifters executed three trials, resulting in about 72 mA s of total radiation exposure. In the first trial, joint angles were measured when subjects fully flexed their spines to a point where the passive tissues resisted the flexor moment creating myoelectric silence in the extensor musculature. Next, two conventional deadlift style lifts were executed with the barbell load ranging from 183.7 to 210.9 kg. Four vertebral corners were digitized at a sampling rate of 30 Hz.

The relative intervertebral joint angles, distance between the ligament attachment points, shearing and compressive displacements were calculated from a rigid body motion approach. Analysis revealed that except for one trial of one subject, they accomplished their lifts with an amount of lumbar flexion between 1.5 and 13 degrees less than they demonstrated during full flexion. Resultant ligament lengths at the beginning of the lifts ranged from 56.1 to 99.8% of their lengths when the trunk was fully flexed. It was concluded that ligaments did not strain sufficiently to contribute substantial resistance to the trunk flexion moment, relegating this responsibility to the musculature.
PMID: 1733981 [PubMed - indexed for MEDLINE] 1992

Can the lumbar spine be crushed in heavy lifting?
Hutton WC,
Adams MA.
Cadaveric lumbar intervertebral joints were wedged to simulate forward flexion and then compressed to failure. The compressive strengths of the young male specimens tested were compared with the forces calculated to act when average young men perform maximum lifts from the flexed posture. It is concluded that the spine has a considerable margin of safety when such lifts are performed.
PMID: 7167831 [PubMed - indexed for MEDLINE]1982

Trunk muscle and lumbar ligament contributions to dynamic lifts with varying degrees of trunk flexion.
Potvin JR,
McGill SM,
Norman RW.
Department of Kinesiology, University of Waterloo, Ontario, Canada.
This study was done to assess the interplay between muscular and ligamentous sources of extensor moment during dynamic lifting with various loads and flexion angles of the trunk segment for 15 subjects lifting a total of 150 loads. Ligament forces predicted from an anatomically detailed biomechanical model did not generally contribute more than 60 Nm for most of the lifts because the lumbar spine was only flexed to a moderate and constant degree for each load condition. In contrast, additional moment demands associated with increases in hand load were supported by muscle.

Although the compression forces on the L4-5 intervertebral disc were fairly insensitive to the interplay between the recruitment of muscle and ligament, the shear force was significantly higher with a greater degree of lumbar flexion . The risk of injury may be influenced more by the degree of lumbar flexion than the choice of stoop or squat technique.
PMID: 1948399 [PubMed - indexed for MEDLINE] 1992