Sunday, February 13, 2011

Are You Crushing It? Too Much Back Extension Breaking You Down?

Wonder why the back gets sore?

Did you know sit ups, crunches and back extensions do more harm to the lower back than most people realize. Now jump on your bike and you will realize more what a bad fit can cause an ouch!

Enlightening information protects your spine.

A couple of reasons to avoid these exercises:

1) "The sit-up imposes approximately 3300 N or about 730 pounds of compression on the spine." This means that every time you do a sit-up, knees bent with feet locked under something, sitting up from the ground to vertical, that amount of pressure is crushing your intervertebral discs. "The National Institute of Occupational Safety and Health has set the action limit for low back compression at 3300 N. Repetitive loading about this level is linked with higher injury rates in workers, yet this is imposed on the spine with each repetition of the sit-up!"


2) Back extensions are no better. On the roman chair (this is the piece of equipment that is set at 45 degrees and you can lock your feet and rest your thighs on it so that you can drop and lift your upper body, working the back) performing one back extension, imposes over 4000 N or about 890lbs of compression on the spine These types of exercises impose up to 6000 N or over 1300lbs of spinal load and compression, then add road noise. These exercises are referred to as the "superman". Please avoid these exercises at all bike fitting costs! The deadlift both work the back and spine in the biomechanically correct fashion. There is no isolation of the muscles and the body works as one functional unit.

How does the core function on a bike?

3) The most important aspect of abdominal muscle performance on a bike is obtaining the control that is necessary to A) Appropriately stabilize the spine, B) Maintain optimal alignment and movement relationships between the pelvis and spine to the saddle and C) Prevent excessive stress and motions of the pelvis during movements of the extremities i.e. too low of a saddle.


4) Hopefully Point C above enlightens you? You can see that what we are trying to do is train the core to stabilize the pelvis, and to efficiently transfer force to the arms and legs.

What does this all mean?

5) In cycling, there is obvious risk taken by working out, but if we can make good choices we can do a better job at avoiding injury.

6) In sports it is necessary to have abdominal strength in flexion. avoid too much spinal loading while still working hard. Cycling exercise can be tough and its best to work the abs while minimizing the spinal loading and reps performed.

Avoid any type of back extension where possible and try to work the core as it was meant to function. Lot's of front support, side support, and anti-extension exercises will make a difference.


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