Wednesday, February 26, 2014

Weight belt basics

I have spent time in dozens of gyms in the past year. I have seen the inside of fancy health clubs, chalk covered boxes and everything in between. And in almost every gym I have seen some degree of weight belt use. Some people use it for squats and deadlifts, some use it for heavy pressing, some seem to have it on when they leave the car and head for the gym's front door. It's something I'm asked about a lot as a coach.



So how do you decide as an athlete or a trainer when this tool is necessary and how best to implement it?

Origins

It is commonly believed that weight belt use (like many fitness trends) originated by mimicking medical or rehabilitative fields. Corsets and back braces have been used to help in the treatment of lower back pain for hundreds of years. The logic goes that if someone with back pain can alleviate symptoms with a belt then perhaps the belt can help to prevent the first onset of pain as well.

Not only have weight belts become popular in the gym settings but also in the workforce. Many lifting intensive professions (movers, factory workers etc.) have gone so far as to require their employees to use a weight belt while on the job, under the impression that it will decrease incidence of injury.

Belt Function

The proposed mechanism of the weightlifting belt is to provide additional intra-abdominal pressure in the attempt to stabilize the spine, specifically the lumbar spine. Increased pressure reduces the likelihood of flexion or other undesired movement under load, thereby decreasing injury risk. Additionally, increased pressure can allow for the lifting of greater loads.

Interestingly some studies have shown that weight belt use actually increases the compressive load on the spine but decreases the shear stress. Thankfully our spines can handle high compressive loads compared to shear forces so this isn't especially problematic.



In weightlifters pressure is increased by forcefully pushing the abdomen into the front of the belt to maximize tension between the lifter and the belt. In an occupational setting or during exercise that does not maximally stress the spine the mechanism of increased tension is simply due to a tightening effect, or hoop tension, provided by the belt. Workers can't be expected to push their abdomen into the belt all day.

Anatomy

Well, what stabilizes my spine if I am not wearing a weightlifting belt? Your body is actually quite well equipped to provide a good deal of spinal stabilization on its own without the use of any additional equipment. This is the role of the oh so popular "core" muscles. The core muscles are composed of both an inner and outer unit with different roles in the body.

The outer unit muscles are very important for stability and include the rectus abdominus (the abs) the erector spinae, and the external oblique, with some people including the lats and glutes as well because of their pull on the spine and influence on spinal and pelvic position. These muscles work in unison to keep the spine and pelvis in a neutral position by generating or resisting force. The inner unit does not push and pull or move the spine a great deal, but exerts a large influence on stability by increasing IAP (intra abdominal pressure) and therefore maintaining a stable environment for the spine, particularly under heavy load.

The inner unit can be thought of as a pliable box in the middle of the body. The multiple faces of the box are the transverse abdominus (front of the box), diaphragm (top), multifidus (back), pelvic floor (bottom) and internal obliques (sides). In a properly functioning system these muscles (both inner and outer unit) all work together to create tension around the spine to help resist unwanted movement.

Does the belt work?

So the weight belt increases pressure in the abdomen, improves the amount of weight that can be lifted and was adopted from use in the rehabilitation community so it must be safe. Perfect right?


The anti-belt crowd will argue that wearing a belt causes dependence and an over-reliance on external forces to provide a safe environment for lifting, as well as altering core muscle firing patterns. I would agree to a certain point. Studies performed on workers moving heavy loads (furniture delivery men etc.) examined the injury occurrence in belted and not belted employees. In the study, healthy workers were either given, or not given, a belt to wear during work for several months. Injury rates were similar for both groups (fairly low). Interestingly, following the study injury rate rose significantly in the group that had been using the belts and had them taken away at the completion of the test.

That study was performed on people who wear a weight belt all day and therefore the outcome is situation specific. No such study has been conducted on weightlifters (that I know of), nor is their any information regarding exactly what dose or volume of belt use has to occur in order to cause negative adaptations. But clearly there is a point of diminishing returns.

It has been clearly proven that constant or excessive use of the weight belt can cause reliance on the belt for stability and long term decrease in natural core function (belts are bad!). Additionally it has been shown that more weight can be lifted with than without a belt and it can be assumed that greater IAP will reduce the likelihood of acute injury (belts are good!). So how do we combine this information? My recommendation would be as follows:

If you compete in a sport where the maximum load you can lift determines your outcome in the sport you should wear a belt during competition and during training when loads approach competition intensity (anything above 90% of your maximum is a reasonable cutoff point) This will be a low enough volume to not have negative outcomes on your normal trunk muscle recruitment patterns.

In athletes whose weightlifting performance doesn't directly correlate to sporting success I typically forego weight belt use entirely. Most people I train have poor trunk stability and my goal as a coach is to enhance their core function, not mask it with equipment. The weight belt will not be worn on the field/court or anywhere outside the gym and I want to encourage stability in a belt free environment. Similarly, I don't use elevated heel weight-lifting shoes for athletes that do not compete in weightlifting based sports. The goal is to prepare the body for the environment it will face in competition. For your non athlete client that entails all of the activities of daily living, most of which are done belt free. 

With all that said, if you or a client have been using a weight belt for a long time and you are trying to switch to unbelted lifting do not make the transition suddenly. This is what happened in the aforementioned study and they had a high incidence of back injury. Lifting without a belt needs to be slowly re-introduced to a program. Start by removing the belt for the warmup up sets while also incorporating a lot of belt free stability exercises (basic plank and bridge variations should do to start). Each week increase the intensity of belt free exercises slightly until the belt is no longer necessary.





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