This is the machine that has saved my wife's back
While this bloke explains the way it isolates the lumber it also gives one the clue on which exercise is possibly the better to make more inroad into working the smaller muscles in the lumbar area.
It doesn't take much to fatigue the muscles on this machine
Use one 3 times a week
I have found it gives a good carryover to the squat and deadlift - nothing spectacular but it all helps.
The best thing I have found it for is rehab and prehab/recovery. It has really helped my back after dislocating some vertebrae (injury from years ago) and definitely helps recovery from heavy squatting and deadliftiing which in turn helps prevent injury.
If you can get access to one definitely use one whenever you can. Make sure you use it properly though as most people do it incorrectly and don't get the full benefit.
Thanks sumo this is the kind of feedback I need. Looking for exercises to help nurse some back injuries. Stuff to help speed along the rehab when it all falls apart, which is a couple times a year.
No worries mate - the reverse hyper (without trying to sound like an advert) has made a huge difference to me. They are pretty expensive though.
The other argument is that it goes against the McGill school of thought on back injuries, which is the prevailing scientific view at the moment. McGill's research says that we have a limited number flexion/extensions in our spinal columns in our life before our discs degrade. For this reason, he advocates training the supportive muscles of the spine isometrically - ie planks, bird-dogs etc, and to avoid sheering flexion movements, eg reverse hypers and crunches.
Here's a balanced perspective from someone who is actually a Louie Simmons advocate: Re-Building the Reverse Hyper | Robertson Training Systems
FWIW Dr McGill is one of world's leading authorities on spinal injuries.
The cobra yoga position is referred to by back specialists as the McKenzie extensions, which is the standard prescription for a prolapsed disc. It works by exactly the process you describe. Its a form of unloaded lumbar extension - it gaps the verbetrae and takes the pressure of the front of the disc (which is actually what causes a rear prolapse).
A reverse hyper is the exact opposite of a McKenzie extension - it applies eccentric loading to the disc in a flexed position, and is actually putting pressure on the front of the disc potentially leading to further prolapse of the disc's contents. This is the concern. Now I posted a link which shows a variation of the reverse hyper which potentially removes that risk. But that variation basically ends up being a glutes and hams strength building - there are much safer ways of building up the glutes and hams. It's up to you but I'm trying to play devil's advocate here and offer some contrary views.
I think it's worth noting that when Louie Simmons invented the reverse hyper, he didn't have a slipped disc - he actually fractured his 5th verbetrae. Big difference from a slipped disc IMO. Not all back injuries are equal.
I've never used one but general reviews seem to be that it's a good place to rest your beer...
Brick, message rippetoe and ask him about rehab.