What’s up ? This is THE stephane ANDRE ! I read a Frederic Delavier’s book « Strength Training Anatomy » and I learned good stuff.
This exercise is working on the bench originally planned for lumbar extension.
Put yourself on the side with your hip on the bench and your torso in the void. Your hands are behind your head or on your torso and your feet are wedged under the pads :
Do a lateral flexion of your torso upwards.
This movement works mainly obliques and rectus abdominis on the side of flexion. But obliques and rectus abdominis on the opposite side also works by making static contraction (isometric contraction) to prevent your torso from falling below the horizontal.
During the lateral flexions of your torso, quadratus lumborum muscle works always.
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