Abdominal Bracing is a key skill to learn for force production
There are a great many ways to learn to brace, some easier than others, some better than others some good and some plain wrong.
The myth of drawing the belly in still seems to be hanging around, please consign this to the rubbish dump, it's not worth the paper it's written on.
It may work on a world where making pretty shapes is more important to generating, or absorbing force, but that's not my world and it's not the world of 99% of the people I've worked with.
What we need is an abdomen that can:
Brace hard enough to become a solid unit
Brace hard enough to repel an impact
Brace hard enough to mitigate excess movement in any direction
Brace on and then off again in an instant
Those first two points are primary, they are foundational. The second two are a little more context specific.
And for the foundational points I like the Front Squat
In the front squat the weight will sit ON your abs.
If you imagine your abdomen as a bottle we can look at it as follows:
Lid = Diaphragm
Base = Pelvic Floor
Front of bottle = Rectus abdominis (vertical muscles)
Rear of Bottle = Spinal erectors (vertical muscles)
Sides of bottle = Obliques (internal and external which run in opposing diagonals)
The label wrapping around the bottle = Transverse Abdominis (imagine the label is inside the bottle)
That gives us 6 "sides" that all need to be working in harmony. The stronger and faster each muscle can contract, the more endurance these muscles have, the greater the coordination between these muscles, then the the stronger and safer you are. There's also a huge correlation between the muscles of the hip and the core.
The better the core works, the stronger the hips!
When you load weight on the front of the body, as in a front squat, you must:
Inhale and lift the chest (not the shoulders)
Tighten the abs
"Place" the chest on top of that solid abdominal wall
As you squat you should feel how the entire core is bracing to hold that weight up. The further forward that weight is, the greater the loading in the core. So a barbell front squat sits close to our centre of mass, kettlebells sit further forward, a Zercher style grip forward and a sandbag may be even further forward.
The forward placement of the load will also encourage a better torso alignment, stacking the rib cage over the pelvis, allowing the abs their best leverage. At the top of the squat as you stand, there will be massive urge to tuck the pelvis under, move towards a posterior tilt, something we see less with the back squats, but if you want to really get the glutes and abs firing together, this is essential.
Here's' the Kettlebell Front Squat:
In terms of Squatting progression, I like to go in the following sequence with clients:
This isn't set in stone, it is of course an individual process.
But the goblet and front squats come before the back squat in most cases to ensure we have proper core bracing in place.
We don't want the core to fail before the legs, which can be disastrous with the back squat. If the legs are needing more work, we can safely go there with single leg work saving the core and spine.
Now, go grab your bells and get squatting