what i am a little confused about, though .. @ miaou:
why are supermans bad for your back, or bad if you have lower back issues?
Dont hyperextensions have a smiliar movement .. ?
Explain please. I'm believe in the S&P style...but how would supermans increase the risk of injury in a healthy person.
The ROM of the supermans exercise is from neutral to hyper-extender lumbar spine position. There are two specific problems with this.
Hyper-extension of the spine results in a mechanically unfavorable alignment of the vertebrae (meaning there is an uneven distribution of force in the intervertebral discs). It is the same thing that happens with spinal flexion, and they will both put uneven pressure on the spine, increasing the risk of injury.
The proper function of the spinal erectors (as well as the rest of the core muscles in relation to the lumbar spine) is not to create motion in the lumbar spine, it is to create stability, so that force can be
transfered through the spine in a safe way.
For instance, when you are squatting, motion is generated by your lower-body, your spinal erectors (and the rest of your core muscles) function in an isometric way in order to keep your lumbar spine in proper alignment for the force to be safely transfered to the upper back and through the upper back to the barbell. So in the kinetic chain, the function of the lumbar erectors is not to generate motion, it is to provide/generate stability. If the lumbar spine stays in proper alignment then the force can be transfered both with greater efficiency as well as with greater safety.
The above is just one example, but the same principle follows for all movements. In rotational movements (the TS mentioned practicing MT, which is full of those) the spinal erectors will still want to stabilize the lumbar spine, not provide motion (which needs to be provided by movement on the hips instead). Rotation while the spine is in hyper-extension is a great way to increase the risk of suffering a spondylolysis injury. The general idea is that in any normal function of the body there needs to be stability, not mobility, in the lumbar spine. Any exercises that reinforce lumbar spine mobility can reinforce an improper function to the spinal erectors.
The second problem is that the majority of people with lower-back issues tend to have some degree of anterior pelvic tilt (APT). APT increases the risk of injury because it constantly places the lumbar spine in an unsafe position (extension/hyper-extension). This condition can be worsened by using "supermans" as a main tool for lower-back strengthening, because due to it's ROM (from neutral to hyper-extension) it will contribute to the spinal erectors getting shorter/stiffer. Which is a symptom and contributing factor to APT. Doing a lot of situps can also worsen this condition btw, by contributing to hip flexor shortening/stiffening.
When "back hypers" (hyperextensions) or "45