PRACTICE MAKES PERMANENT: SCIENTIFIC TRAINING 
by Harvey Kurland 1985

During the performance of the snake creeps down posture several problems can occur. When the knee is maximally bent, overly flexed, the weight hangs off the knee joint. This is similar to a full deep-knee bend, but with the weight all on one side. The mechanics are such that there is no real muscular action to stabilize the knee, but rather there is a passive stretching of all the structures. This can result is an unstable knee. A more severe problem is when the student has neither the flexibility nor the thigh and hip muscle strength to maintain the proper position. Often what happens is the student cheats leaning over and twisting the knee inward. Rotation plus flexion can result in internal damage to the knee. This causes a strain on the inside of the knee. To prevent problems the student should strengthen the thighs and have sufficient hip flexibility before attempting this posture. Those who don't, should do the 90 degree squatting single whip variation. Trying for an over dramatic posture can also lead to improper alignment. A similar stance is found in pa-kua chang (bagua zhang) and several Chinese and Okinawan styles.

Many native born and raised Asians seem to get away with the deep knee bend position as well as twisting knees. This might be because their knees are looser. This may be genetic a la the elite athlete. They may have used squatting or kneeling as a resting or functional position all their lives, or it could be that they started training so early in life that their knees and hips adapted to these positions. Though it should be noted, some masters do end up with bad knees and hips. Also, those people who are lighter weight can attain this position much easier. But an adult who is just starting out, maybe at age 40, overweight, without the above type of life long adaptation, may have problems with improper position. Teachers should teach the ideal position only, and not tolerate cheating, e.g. twisting the knee. Exercises that over stress these positions such as duck walks, should be avoided as it is too easy to do these improperly. Strengthening exercises done correctly, such as 90 degree lunges and squats, can be used to strengthen the thighs. But I must stress they MUST BE DONE CORRECTLY.

In some arts the Asian sitting positions themselves causes older, life-long, non-squatting people problems. In Aikido and other Japanese martial arts the seiza sitting position is common. This position is where the student kneels with the hips over the heels, sometimes with rotation of the lower leg outward. This position as well as squatting, and sitting cross legged is common in many Asian cultures. This position hyperflexes the knee joint and can cause problems for certain at-risk-students. Performing techniques in this position is common in certain schools as it is part of traditional Japanese training, but for those with knee problems it can cause or aggravate a chronic knee problem. The paradox is that it is lower intensity exercise position than standing throwing for those who are able to do it. Such techniques should be relegated to a historical novelty for most Adult North Americans. What is easy for people who squat all their lives can be injurious to those who haven't. (1,6,8,9)

Aikido has a relatively low serious injury rate. In one study, I observed an injury rate of 16 injuries per 1000 practice hours, with most injuries to the lower extremity. The mat might be the most dangerous to aikidoists. In the study of Aikido injuries, I found certain types of mats seemed to be implicated in injuries. Those that were soft and spongy caught the toes or ankles causing more injuries. Soft mats caught toes and fixed the foot so it could not slide out of harms way. Twisting the knee during a weight bearing turn resulted in two subluxations of the patella in this study. The harder traditional tatami mats had less leg injuries attributed to them. (10)

In contrast in a karate class injury study I found an injury rate of 19 per 1000 practice hours. Most of the karate injuries were sprains of the hand and foot. This is different than I observed in karate tournaments. In tournaments I found that 1787 contestants studied had an overall injury rate of 106 injuries per 1000 matches. Most of those tournament injuries were contusions to the head and torso. Though, what might be considered an unwanted or illegal injury in one tournament, would be considered a winning technique in another. (11, 12, 13)

Shoes and footwear can also result in problems. Shoes are worn in Chinese and some modern eclectic styles. If your footwear is out of balance it puts stress on the knee and hip. For example one student was getting knee pain while practicing. On observation I found his shoes where unevenly worn so that it forced him into a bow-legged position. The outside part of the shoe was worn down and the inside part of the shoe had a built in arch support causing him to roll out on edges of the shoe. By tossing the shoes out, his pain magically disappeared. More often the reverse is found, where the inner, medial, side of the shoe is worn down and the athlete rolls inward, pronating the foot. This also results in improper alignment of the ankle, knee and hip. Constant training in this shoe can result in knee, hip or back pain. These shoes will also throw off the balance of people going into snake creeps down as well as simpler postures. Any student with a true foot problem should see a specialist. Old worn out shoes should be thrown away. Sometimes training barefoot as do Japanese styles, remedies the problem. If it does, check your shoes.

Alignment of the body is important. In t'ai-chi ch'uan there should be a line from the top of the head to the center of the foot. If the body is tilted the line will fall to the front of, rear of or side of the body. This can cause a strain or compression. For example if one tilts forward the strain will be on the low back. While in transitions this is acceptable, depending on stylistic characteristics and applications, long periods of being bent over puts an incredible amount of force on the back. Tilting backward also causes stress on the low back, a lordotic curve should be avoided. At least tilting forward puts you into a biomechanically sound position for power production, i.e. pushing or hitting, but lordosis strains the back and is biomechanically disadvantageous. Bending backward causes the force to go through the body in an arc resulting is wasted effort as well as strain. Proper position is with the head upward, keeping the natural curves of the spine! and no tilting. In t'ai-chi often the lower back is flattened by tucking the hips under to achieve the proper position. (14, 15)

In Aikido, posture is important for movement as well. Just as in t'ai-chi if the body is tilted or bent over you are less able to move circularly, sideways or turn. By standing with the head up and back straight one has better maneuverability. In t'ai-chi the waist can turn like a wheel, in Aikido, "tenkan" turns are more efficient as the student can turn like a top. Any bending over results in a bent axis, like a wheel which is out of alignment.

In t'ai-chi ch'uan it is important for the back to be straight, head held high, with a feeling of energy suspending the head from above. The body should be light and relaxed, but not dead or limp, dead relaxation is not what is meant here by relaxation. All stiffness and strength must be emptied from the upper torso and should sink to the soles of the feet. The body should be alive and full of vigor.

Teachers should strive to minimize injuries and maximize competence through a balance progressive training program.

About the author: Harvey Kurland is an exercise physiologist and certified t'ai-chi ch'uan instructor. He teaches at the University of California Riverside and Loma Linda University. He was a fitness editor for Inside Kung-fu and Inside Karate magazines for several years and Director of Exercise Physiology for the National Athletic Health Institute for seven years. He has performed research into the health benefits and energetics of t'ai-chi ch'uan, as well a mechanisms of Aikido and karate injuries.