At what weight should I start to use a belt? When I deadlift, doing reps of 315 or 340 I feel pressure in my stomach etc which leads me to believe I should use a belt? Am I right or should I just let my body adapt?
I would say let the body adapt. You will gain a ton of strenght in yopur core if you simply keep form good and dont use a belt.
Now if you are planning on competeing etc thats a different story as you might want to use the equipment to get used to it on occasion say for maximum lifst etc.
All in all though if you can largely keep your form in check you will get more bang for the buck going beltless.
Hope that helps,
Phil is right. Also, bear in mind that the belt does nothing that properly trained abs and low back cannot.
If you're training for competition, belt at around 80-85% of max is a good general rule. I actually wear a loose one often when the gym's a little chilly just to keep the midsection warm, though.
Since I started Westside a couple months ago, I've begun using my belt again. I only use it on the last few sets of my ME exercise (90% > of my 1RM). Otherwise, I don't use the belt or need it.
I'd like to know additionaly, and this might seem a stupid question, what is a belt good for?
I mean I know that it protects the back and it protects the belly, it increasses the intraabdominal pressure e.t.c. but I'd like to read a really scientific explanation on this matter.
Squat rack curls and heavy deadlifts.
This is just not true...if a belt didn't do anything, no one would use one. A belt will help you no matter how strong your abs are.
80-85% is a good rule, though. I would even suggest though, using it on your lighter warmups to get form, and then around 75-80, taking it off to build core strength, then putting it back on for max lifts, of course.
When to use a belt?
When you think your pants are gonna fall down!
I'm very careful with movements like deadlifts, there's a lot of pressure on the lower back there and I can see how a belt would help you feel more stable.
I still think it's better to do without though. Concentrate on technique and go for small increases in weight or reps and it should be fine.
If I'm going for a PR on squats I always wear one now. A couple years ago I went for a max and stalled at the bottom, instead of spotting me from below my chest he tried to push up on the bar from behind which resulted in the bar going forward and my back curving with it, needless to say it was not a good thing.
It was my fault for not ensuring he knew what he was doing, and for not having a belt on, but I didn't squat for a couple months afterwards, and my back still doesn't like me for that one.
I started realizing the benefits of not using a belt about a year ago, so I gradually stopped when doing lighter sets of deads and squats.
There is a trade-off though. By putting pressure on the belt with your stomach, you will be able to use more weight with squats and deadlifts, even if your core is already strong.
The problem I had when I first started not using a belt was that my core wasn't as strong as it should be for the amount of weight I was using for squats and deads. I lightened up on the weight, but that of course affects the benefits that my posterior chain and legs would have gotten with heavier weights (with the same rep scheme).
I think of it sort of the same way I think of deadlifting from a deficit compared to Romanian deads. One has a longer range of motion but you have to use less weight, the other has a shorter ROM but you can use more weight.
With a belt you can add a little more weight and that's one way to change things up; just remember that your lower back and stabilizing ab muscles aren't getting worked as hard so when you use a belt you can add core work (like standing military presses without a belt).
You can even rotate which exercises you use a belt with so you get more weight with some, and more core work with others.
All in all, I'd say that most gym-goers use their belt too often at the expense of core strength.