Weight lifting belts mainly support the abdominal muscles, not the back. The belts are like a second set of abdominal muscles that prepare you to lift heavy loads.
To prepare for these very heavy lifting operations, breathe deeply into the abdomen and hold your breath, a type of “breathing” called the Valsalva maneuver. The Valsalva maneuver helps to create pressure in the abdominal cavity to cushion and support your spine. This is where the weight lifting belt comes into play. With the lift belt, you breathe through your abdomen into the belt and press the abdominal muscles back. This reinforces the effect of the intra-abdominal pressure, which in turn helps to protect your back and allows you to cope better with heavy loads. Weight lifting belts are a safe way to secure the bar and prevent slipping.
Wearing a belt does not automatically increase your strength and lifting capacity. There is a learning curve for lifting with a belt (just as there is a learning curve for lifting with correct intra-abdominal pressure). Of course, some people will reap the rewards immediately, but it will take most of the time to get things right.
According to Greg Nuckols of Strengtheory.com, a well-trained belt user generally gets the same set and quality of use. I have found that I can move 5-15% of my weight in repetitions, push 2 to 3 more repetitions for the same weight, and lift the same weight with less effort for the same number of repetitions. This is quite important.
This can be taken as an indication that a workout with a belt is more likely to make you stronger over time than a workout without a belt. This means that in connection with the ability to do more general “work” (i.e. lift more weight and hit more repetitions) and to continuously improve the body, a process known as progressive overuse takes place. In the long run you will gain in size and muscle strength.
Weight lifting straps can be used for squats, jerks and lifts. Experienced weightlifters wear the belt for near maximum effort and take it off to exercise regularly and warm up. In general, a “near maximum” is defined as a weight that is at least 80% of your maximum lifting volume. Exact percentages are often arbitrary, so wear it if you feel that you need extra support for very large lifts.
How do I wear a weight sling?
1) Inhale (and hold)
2) Put on the belt and support the abdominal wall.
3) Pull the belt strongly enough to slightly limit the position of your constricted abdomen for maximum benefit.
Weightlifting belts will be uncomfortable for a while, especially when you get used to them. However, once you get used to the belt, you can start experimenting with different belt positions. According to strength and performance trainer Omar Isuf, for example, experienced users tend to wear their belts higher up the upper body during a ground lift than they do during knee bends. In particular, it may be more comfortable for you to wear the belt in the middle of the abdomen during a deadlift. For squats, you can wear it above the pelvic bone.
In addition, the belt should be tight enough to stay in the same place during the lift, but not so tight that it interrupts deep and complete breathing and circulation. Depending on the clothes you wear and the amount of water you use, you may also need to pull the belt. As you learn, you can wear it a little looser until you learn to enjoy less gentle cuddling. Finally, remember that your new belt should be broken in the same way as your shoes.