Find a plank position with hands on the box underneath the shoulders and feet together on the platform. Bring the carriage in using your midsection by bending knees to one elbow, then alternate to the other side.
1B.
Down or up.
Short Box.
Inhale in plank, exhale to rotate towards one knee, and repeat.
Develop strength of the core, internal and external obliques, and scapular stabilisers.
Progression: Fewer springs.
Regression: Kneeling on platform, try one side at a time. Use foam protector.