I have to say that my breathing training has really helped my boxing and sprinting – as I am nearing 40, I can still spar of 12 rounds, 3 minutes, with 30 seconds rest. I also do the 100m in 11 seconds, and consider myself even fitter now then when I was in the army aged 17. My breath training has, along with my mental outlook, contributed much to my level of fitness and I beleive that I would not be able to out-perform many men 20 years younger than me without it.
..I have just bought the blue Powerlung and find it to be very good. Great in fact. It is much better than my original Powerbreathe. It works smoother and is of much higher quality, …when I cleaned my own PowerBreathe the thing never worked the same again. There always seemed to be water trapped inside it somewhere; I could hear it gurgling (only a tiny amount of water I grant you, but some none-the-less).