BOSU back crunch is a simple exercise to work your spinal erectors.
Strengthening your lower back is always because it assists the core to stabilize
your spine during functional movements such as dead lifts, squats and activities
of daily living. The back crunch can be performed on the floor if desired but
the BOSU balance trainer is softer and rounder which may be more comfortable and
allow you to perform the back crunch more efficiently.