Re: Spinal flexion during lifting?

[Guest guest]

Ian, this is why you find strong advocates against any form of

spinal flexion when performing lift such as squats, deadlifts etc.

Your voluntary self sees yourself using 40kgs. Your involuntary

self sees what you are really lifting using in the following formula

Force of resistance x effective resistance arm = Force of effort x

effective effort arm.

Using above formula let us say you spine is in flexed position

where the 40 kgs is infront of the L5 Sacral joint 12 inches. The

effective lever arm that the extensor muscle in your lower back

across the L5 sacral joint is 2 inches.

Using the above formulae

40kgs x 12 = muscle effort x 2 = 240kgs

You not lifting 40kgs but actually 240 kgs.

It is not the weight but the how the weight effectively is

impacting your joints that you have to worry about.

Scherger chiropractor

Washington State USA

>

> Hi

> Most information I come across strongly advocates against any form

of

> spinal flexion when performing lift such as squats, deadlifts etc.

But

> when doing back extensions many people use a full ROM of flexion

into

> extension (I normally do). But what about when you start to load

this

> exercise, I currently use 40kgs but I can see this increasing. I

would

> like to get some opinions on whether a gradual progresive increase

in

> this exercise is putting myself or anybody else doing similar at

high

> risk of a spinal injury?

>

> I also came across this site

> http://www.exrx.net/ExInfo/DangerousExercises.html

> which seems to promote some flexion in certain lifts see the

section on

> cable rows and stiff legged deadlifts

>

> Thanks for your feedback

> B.App.Sc (Hons)

> Adelaide Australia

>

[Guest guest]

Yes I did mean loaded hyperextensions using the standard hyper bench

seen in most gyms and holding a dumbell to my chest. From what you

stated you think I should be using the valsalver maneuver to raise

IAP during this movement even with the spine flexed (and its not to

a great degree).

B.App.Sc (Hons)

Adelaide Australia

>

> Most information I come across strongly advocates against any form

of

> spinal flexion when performing lift such as squats, deadlifts etc.

But

> when doing back extensions many people use a full ROM of flexion

into

> extension (I normally do). But what about when you start to load

this

> exercise, I currently use 40kgs but I can see this increasing. I

would

> like to get some opinions on whether a gradual progresive increase

in

> this exercise is putting myself or anybody else doing similar at

high

> risk of a spinal injury?

>

> I also came across this site

> http://www.exrx.net/ExInfo/DangerousExercises.html

> which seems to promote some flexion in certain lifts see the

section on

> cable rows and stiff legged deadlifts

>

> Casler writes:

>

> Hi Ian,

>

> Axial loading of the spine (or similar conditions) that cause

significant

> loads to be seen at the anterior disc body, while decreasing the

compression

> of the posterior disc body can be a problem.

>

> That said, each and every loading need be looked at as to its

complete

> myriad of forces, and how they are managed during the dynamic load

phases.

>

> For example, your stiff legged deadlift may have less danger than

one might

> expect from a simple stick drawing only looking at the " main "

force vectors

> to the spine.

>

> Elements of the Torso Stabilization Mechanism, such as the load

transmitted

> via arms > lats > lumbar spine, can stabilize the lumbar spine and

reduce

> the danger. (This will not happen to the same degree during a Good

Morning

> for obvious reasons)

>

> So between the actions of the spinal extensors, which are

compressive, and

> the lats, in conjunction with the gluteals, you are creating a

compressive

> and stabilizing force relationship to the posterior disc body. If

this is

> coupled with anti-compression activity of the Anterior Torso

muscles, and

> IAP, you have significant support for reasonable loads, as long as

the

> " stabilization processes " remain active, and one does not go

to " too great "

> ROM's.

>

> That said, I cannot encourage one to perform Stiff Legged DL's

without

> significant understanding of what I just wrote.

>

> But the key is analyzing and evaluating each portion of the ROM,

and how

> each of the forces of the TSM (Torso Stabilization Mechanism) acts

to manage

> the force load to the spinal discs.

>

> When you post of " Back Extensions " , are you asking about a

specific

> exercise, like loaded hyperextensions?

>

> Regards,

>

> Casler

> TRI-VECTOR 3-D Force Systems

> Century City, CA

>