I got another great question across my desk the other day:
Question:
"I read a quote from you on the improper use of a weight vest. The quote indicated that using too much weight with the vest could cause injury to the invertebral discs.

A young man was given a 40 lb weight vest to wear during a team sport practice. He weighed just under 200 lbs at the time, and as a result of improper us of the vest, herniated two discs. What are your thoughts?"


Answer:
OUCH! The weight vest is a very good tool used properly. Miss use or over use can ruin a career (sports or firefighting).

I blew part of a disc training with an Olympic bar on my shoulders. I assumed part of it was altered posture due to the mechanics. This injury you mention is the first injury I have heard of like this. Truth is, if the person is not strong enough muscularly to carry such a loud- from gradually building up to it, this type of thing might happen. I would think that stature, and proper training would have a lot to do with whether or not an injury might happen. He might not have gradually worked up to it- sounds like that, huh?

I start my people with 20 lbs, and use a NON pounding exercise for 3 minutes to start with. Posture is key in the use of the vest. They build up slowly from there. A whole practice, right off, with 40 pounds from nothing sounds like trouble.

I searched, and found nothing on the internet about such an injury. So, I'll take some time and tell you (in brief?) what I know.

The disc is like a jelly donut. The center (nucleus pulposous) is gelatinous, and is surrounded by concentric rings of fibrocartiledge- I could draw you a great picture. These rings look like a spiral when you look at a disk from the top. But, from the side, if you telescoped it out, you'd see the real picture. Each ring has diagonal running fibers, each alternating ring goes diagonally opposite from the one just inside and the one just outside. They attach top and bottom, to the vertebral bodies above and below.

The pressure inside that disk is significantly increased with torsional forces (twisting). Think about it, as you twist one way, half the fibers or forced to be longer, and half of them would be relaxed and shorter. Twist the other way, and the alternating fibers are subject to exactly the opposite forces. I would imagine that some of those rings could tear with each twist, wouldn't you?

Imagine grabbing a wet sponge top and bottom and twisting it. The water comes out, right? Well, so does the gelatinous center of that disk- even a little at a time! Again, I'd love to be able to draw you a picture and show you what I mean.

The pressure inside a disc is also increased significantly when one bends forward. This pushes the contents of the disc backward- toward the posterior part- toward the area of less pressure. This tears the annular fibers too (the rings). The inside rings would tear first, and then, as the nucleus migrated back, each ring would tear, until the pulposous came out as a central lesion- probably visible on an MRI. This could compress the cord centrally, or the spinal nerves on one side or the other.

Lifting heavy objects also increases the pressure within the disc. Wearing a weight vest is the same. It's direct axial compression would do the same thing. Bouncing, jumping, or running add insult to injury here.

Athletes often bend forward, and twist a lot. Putting those together with axial compression, then adding jumping and running sound ill-advised to me.

I have treated disc bulges for 13 years with a technique called Cox Flexion Distraction. In this technique, the indiviual disc is decompressed (with traction) manually to relieve the bulge; hopefully causing a negative pressure within the disk and "sucking it back in"- as it were. That stands to reason that the opposite would do the exact opposite! Ouch!

When I train people with a weight vest, it is always a very gradual increase in weight and time. There is no forward bending or twisting. It is also not ever with bouncing or jumping. It is in a very stiff upright posture with tight abs and shoulders back. This positioning is more apt to allow the body's core musculature to do their work and allow the spine to carry the increased load.

If a fellow athlete suggested he do this, and he did it, well... I think it was a bad judgment call. If a coach or trainer directly told him to do this, depending on whether he had worked up to it, and how long he wore it, it sounds like really bad advice. I would have to know more of the details to render a complete opinion.

Poor kid.

This injury could ruin this player's college career, and cost him a professional one if that's where he was headed. The same holds true for firefighters. The key thing is: use your noggin! Work up to things!

Some people are just not genetically predisposed to being firefighters.... just like bigger people can't be jockies in the Kentucky Derby. Not everyone is big enough to shoulder the weight vest when full- even used properly. Some small people can handle it, though, trained properly. HOWEVER: If you use it, and ease into it, and it still hurts you, STOP! Please don't hurt yourself as this person did.

This is also a very good case for core work....




Dr. Jen Milus, DC
Author of Fire it Up CPAT Training System
www.fireagility.com
This message was edited by DrJen on 4-4-06 @ 8:38 AM