Haha, I have actually used this tool. When I was a yellow belt, and had just began to practice Heian Shodan, I have having the hardest problems going into and holding back stance for the shuto-uke techniques at the end, and an even worse time with back stance in Heian Nidan. This tool is nothing more than a fancy rip cord that you wrap around your legs and arms, so that when you attempt techniques, it makes it increasingly harder to do so. The concept is supposed to be that when you take the ripcord off, since your muscles are so accustomed to the increased pressure, it'll be easier to perform the stance/technique. Well, it works, but not because it's a revolutionary product. You can acheive the same effect with your standard ripcord available where boxing supplies are sold. If you've ever tried the exercise where you tie a ripcord to a post, wrapped it around your foot, and attempted to practice kicks, you'll understand what this thing does.