this product is used at times for injuries or ligament/tendon rehabilitation. Thats why in very lazy, sedentary individuals there may be a posistive gain from this product. However, just like unltrasound, once you reach a certain point of strength, it can no longer have an advantageous effect. That's why its used in areas like physical therapy, but not areas like personal training. They say after 5-12 uses, it has no effect. And it will only have an effect if you've been REAL lazy, otherwise you're just kidding yourself.