Spinal flexion during lifting?

[Guest guest]

wrote:

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