I did two months of beltless barbell training, and I am back to pushing my numbers a bit, so on with the belt,...
Belt Misconceptions
Putting on a belt for lifting does not mean your abs take a nap during the exercise set and wake up when the set is over.
The abs are engaged with or without a belt. Wearing a belt employ the ab differently.
"Compared with the no-belt condition, the
belt condition produced significantly greater rectus abdominis activity and significantly less external oblique activity."
An electromyographic analysis of sumo and conventional... : Medicine & Science in Sports & Exercise
As per William, " I get more abdominal work, having...to push my abs against" it.
In pushing against the belt, William is performing an Isometric Action, contracting the abs against an immovable object.
Essentially, William is performing a Vertical "Abdominal Plank".
Facts And Fallacies of Fitness
Dr Mel Siff
As Siff's research noted in this book, pushing on the weight belt with your abs, increases stability in the back via Intra-Abdominal Pressure.
The more stability you have, especially in the core, the more force you can produce.
The greater your stability the more Limit Strength and Power you are able to display; the more weight you move.
"Leakage", Staying Tight
Dr Stuart McGill
In a heavy Squat, the bridge between you legs in driving the weight up and the bar on your shoulders is your core.
If you are unable to maintain a ridig, stiff core, a "Leakage" of strength and power occur in driving the weight up. That means you are going to lift less.
Early Powerlifters and The Belt
The early Powerlifter used Olympic Lifting Belts; narrow in the front, wide in the back
Powerlifting Belts were not around; belts about 4 inches all the way around, front to back.
Powerlifter would turn the Olympic Lifting Belt around backward. The narrow part of the belt in the back, the wide part of the belt in the front. They knew that worked better but not why.
As it turn out, placing the wider part of the belt in front allowed the abdominal muscles have a larger area to push against, increasing stability in the lower back, producing Intra-Abdominal Pressure.
This allowed them to Squat more. Thus, the evolution of the Powerlifting Belt.
When To Wear The Belt
It does not make much different if you wear the belt or don't wear the belt for your light sets. It is not going to dramatically weaken or increase your ab strength.
Increasing your ab strength occurs with dedicate ab training.
Kenny Croxdale