Resistance stretching is rooted in knowledge of the organic nature of muscular flexibility. It is based on the principle that muscles stretch best if they are intentionally contracted while lengthening them. This active contraction is called resistance and is the key to producing rapid increases in flexibility.
The simplicity that muscles only truly stretch by using resistance is the power behind Resistance Flexibility Training. This new kind of fitness training tells you to maximally contract your muscles while lengthening them. Placing yourself in over-extended positions is not stretching. Pulling and yanking on your muscles is not stretching. True flexibility increases only occur when you maximally contract muscles while stretching.
Resisting while stretching is natural. Animals do it all the time. Most people start resistance stretching for physical reasons, but in time they continue to stretch because they learn that predictable upgrades in their physiological and psychological health can occur by doing certain stretches. The Meridian Flexibility System is the knowledge base that describes how specific physical stretches can create specific improvements in organ and body functions and specific changes in mental health. So stretching is not only good for your muscles and joints, it's good for your physical and mental well being.