Flexibility and Strength

It is important to get in touch with your body and feel by actually touching or simply sensing the muscles (kinesthenics) as they tighten or relax. It is also important to know which muscles are involved in any action. By knowing this it is possible to deliberately relax a muscle through mental control where the natural reaction is for the muscle to tighten especially when being stretched. This is a natural protection mechanism and must be offset by training. It is fundamental to stretching and improved flexibility. The difference between an isometric stretch of 5-30 or so seconds and a sustained relaxed stretch (static passive) of 15-30 seconds or more must be understood. The former is a deliberate and hard contraction at the full muscle length.
   The muscle cannot shorten under this contraction as the limb is prevented from moving. The latter is a completely relaxed muscle but at full length working against the natural tendency to contract. It is difficult to learn this control but is the key to effective stretching. It is the same kind of mental control necessary to relax while fighting yet retain fast and smooth movements. One parameter to increase power is to increase speed over a fixed distance.
   Power is related to the square of the speed of the fist or foot (tool) and the kinetic energy (KE) is one-half the mass x the square of the velocity: 1/2 x m x v x v. So doubling the speed gives four times the power. Three times the speed results in 9 times power and so on. As an example consider the focus of punching power and the speed/distance relationship. The chest and back muscles can be prestretched much in the same way as an elastic band if pulled apart. They will contract very powerfully. Stretched muscles are elastic. The added energy can be utilised during a concentric (positive) contraction immediately following the stretch. This would lead to a stronger contraction. The main muscle groups involved in punching are at the side of the back below the arm (latissimus dorsi) and chest (pectoralis major). The punching arm is brought back with the hand to the hip and elbow to the rear.
   The chest muscles and the large muscles of the back between the rear of the shoulder and waist all tighten - if the elbow moves out to the side the tension between the chest and shoulder is lost as is that down the back on the side of the punching arm. The punch is delivered and the chest muscles contract more powerfully as the arm straightens. At the same time as the punch is prepared the opposite side of the body is also prestretched across the chest and back by raising the reaction arm outwards and to the centre in front. The combination of left and right prestretched muscles enhances even more the punching power by the increased speed of contraction. Prestretching the shoulder and chest muscles increases the energy available for a punch. Now, if the muscles are lengthened by stretching not only is the distance between the fist and target increased but also the contraction power of the lengthened muscles. The hand can travel a greater distance in the same time assisted by this prestretching. A stretched muscles results in more potential power through prestretching than does an inflexible one. The greater the length of the muscle and the resultant increase in contraction by stretching, then the greater the potential speed. The punching power is increased. This is simply in regard of stretching. If the muscles are increased in size and strength then the increase in power is even more. The same applies to any technique. The greater the length of a muscle the contraction power is increased as is the prestretching potential.