A key ingredient in ones ability to press efficiently, thus heavy, is the concept known as rooting.
Meaning, during the overhead press, the athlete should not only push the kettlebell up, but also push his body away from the resistance.
If done correctly, the athlete will be able to feel it in his feet and the feeling that you are pushing back against the weight with your feet should become obvious. The power to press a heavy kettlebell overhead literally should come from the ground up.
Why this happens can be explained by Newtons third law which states that for every action, there is an equal and opposite reaction.
When we press, if we don’t push back with our feet, some of our power will bleed out. Pushing back with our feet sends the energy back up through the kettlebell.
Now, lets take this concept one step further. In addition to pushing down into the floor with our feet, visualize that you are cork screwing your feet into the ground.
This corkscrew effect will amplify the power you generate in the legs and create a greater degree of tension which moves it’s way up through the thighs, into your core and up through the kettlebell.
I like to plant my feet while twisting my heals in slightly and gripping the ground with my toes. The affect is much greater if you press with bare feet.
I first learned of this concept while deadlifting.
I would set my feet and screw them into the ground. This technique allowed me to create a great deal of tension before I even lifted the bar off the floor. I have also employed this technique to my bench press where I would attempt to twist my arms inward during the press.
The amount of weight I could handle in both the deadlift and the bench press increased significantly by just employing this one technique.I later experienced similar results while performing the military press.
Oh, and if you are having trouble trying to complete a pistol or a one arm push up, this technique is almost guaranteed to get you over the hump.