For step two in the Manna progression, the I structions state that one should sit up as far as possible without caving in at the chest. I'm able to perform the move for the prescribed reps, however my ROM is somewhat limited compared to the example video (mostly the straddle leg raise portion).
Is it best to continue performing 5X15 as my flexibility increases, or should I move on to MN/ PE3 if I can perform that reps within the context of my current flexibility?