The powerbreathe is supposed to make your inspiratory muscles work harder - which I'm guessing is the diaphragm.

I bought one on Ebay.

It is actually really hard! I'm on close to the lowest setting! At the moment I can say I'm not feeling aerobicaly weak running etc either but it is really hard work using this thing! I think I have to get into the habit of using it more because I'm meant to be using it twice a day but I forget. Need to make it part of a stretching routine etc and make time for it.

Apart from that yeah pilates with a good instructor as Missy says is working that i think. One who puts some emphasis on using the right muscles and breathing correctly.

Mine also goes into when to 'imprint' the back into the mat and when to keep a neutral spine etc because she's looked further into it than the original pilates which she says was always keeping the back imprinted.

I'd love to eventually use the power breathe while doing pilates but for the powerbreathe to work you have to inhale through your mouth and wear this nose clip thingy.

However in pilates my instructor tells me to breathe in through my nose and out through my mouth. That feels right somehow - perhaps has me expanding my rib cage sideways more to breathe in deeply instead of raising my shoulders incorrectly and encouraging upper back/neck tightness.

For that reason i'm not sure of how to reconcile the two. Perhaps with more practice at both I can keep my ribs expanding sideways the way they are meant to be while breathing in through my mouth but right now as a beginner it is a little more challenging than would be ideal i think.

Oh and the scarf thing you suggest makes sense Missy. My pilates instructor makes us do it with a stretch band.