The Upa, or Bridge & Roll
The Upa is an incredibly powerful and useful technique. Sometimes it feels like we need all our strength to escape a mounted opponent. If we break down the mechanics, we will see that one little movement will make a big difference. The major movement of the Upa is the rotation of the the upper torso. The problem is, the shoulders are working against you in this symmetrical setup below:
Now we take a look at the forces at work. The Glute muscles contract, forcing the left foot down into the mat. The (equal and opposite) reaction is for the left side of the hips to move up. This begins the clockwise rotation of the hips.
In this “normal” position, the hip and torso rotation is impeded by the position of the shoulder. Imagine trying to roll a freshly cut tree on the ground. The branches act as a lever and work against your efforts to roll it. My shoulders are roughly 50cm wide, so there is a moment arm of about 25cm working against me.
The same effect is here with the torso as the tree and branches as shoulders. How do we make this technique more efficient? Trim the branches.
By contracting my left abdomen, I move my shoulders to the left. My right shoulder has now moved closer to the axis of rotation. This reduces the lever working against my left leg.
Now when I complete my Upa, the rotation is much easier. This allows me to move even larger opponents using the same amount of strength in my leg. Notice that the more vertical my shoulder line is, the more weight I am able to support in this extended position.