The Knee is the Key ( Part 2)
A big issue that beginning students have with the knee is that, as they start, they bend it to achieve a good looking stance, but in transition as they move forwards, they straighten their legs, and then bend the knee once they've finished moving. Suddenly, their energy is directed in an up and down manner instead of forwards towards their opponent. You can tell that you are doing this as you move forwards because you will actually witness the wall across from you moving up and down. I can still remember my first Sensei walking calmly up to one of the dojo walls, placing his hands on it, and calling back at us "It's o.k. now.. I'm holding it steady for you." This was his humourous way of telling us that we are standing up, and going back down as we were moving in stance.
Not only does this up and down movement waste energy, direct power in the wrong way, cause more joint stress than necessary, but it also makes your body movement become more noticable to the eyes of your opponent. Why? Because your body is not staying in the same place coming forwards, instead it's visibly moving up, and down which activates the targeting system in the eyes. You only need to think about how difficult it is to track a ball that is coming straight at you, and to gauge it's distance in order to catch it, and compared that to catching a ball that is coming at you in a downwards arc.
"When an object of interest appears in the peripheral vision the eyes are rapidly turned towards it. The same ocular motor response may be provoked by a sudden noise or painful stimulus applied to the body’s surface. This sudden fast eye movement is called a saccade from the French word meaning the flick of a sail in the wind or the jerking of a horse’s head by a tug on the reins....... When a target is moving, the saccadic system can initially capture it but soon loses it as the image tends to slide off the fovea (termed retinal slip), necessitating another saccade. The smooth pursuit (SP) system overcomes this deficiency by enabling a target to be tracked smoothly rather than with a series of jerks, thereby keeping its image steadily centred on the fovea. To prevent blurring, movement of the retinal image has to be kept less than 5º/s. For the SP system to be effective, the target’s velocity has to be relatively slow, i.e. less than about 50º/s. If the target moves too fast for SP, the saccadic system is activated to recapture it. The latency period for a pursuit movement is usually 100–130 ms. ........Normally SP is triggered by movement of the target’s image off the fovea (retinal slip). During the latency period and from the retinal input, the brain first plots the direction of the target’s movement. The eyes then begin to turn in that direction and rotation accelerates to match the speed of the target. The accuracy of SP is reduced and its latency period prolonged when attention is distracted by a simultaneous second target.24 " To learn more about how your eyes target, and see movement click here.
Keeping the knees bent as one moves forwards: Whether in fighting stance, or in formal Traditional stance creates the least amount of body movement and contributes towards an illusion that you haven't moved as far as you have, nor as quickly as you have since the eyes have more difficulty registering horizontal movement. One minute the opponent is over there, and then almost like magic he/she is closed in. That's one kind of optical illusion that I would like to take advantage of when sparring!