January 16, 2008
January 7, 2008
November 14, 2007
Eager for Improvement!
Since the new Dōkōkai has been established, my training spirits is lifted again. Previously I was stuck in sedentary life for more than a month while preparing for final exams followed by 3 weeks holidays away from Melaka (away from training with Adrian Senpai). My fitness level has dropped noticeably, sadly my weight rises noticeably on the contrary. 
Luckily I received a lecture from Senpai regarding my discipline. It seriously wakes me up. Guilt and worries have become the restart elements of my training.
The dōkōkai is very near to my house, a bicycle ride takes less than 3 minutes to reach there. Training is conducted on weekdays 7 to 9pm, usually I’m there before 7 to do some warm-ups and stretching. I enjoy the way to be taught and corrected by Senpai individually as it makes me more aware of mistakes under his full attention. I expect feedback from him each time after I perform a kata. Sometimes it’s a positive one, sometimes neutral and sometimes negative. Like a small kid, a “very good!” from him is like being rewarded a candy after you’ve done something good; but sometimes corrections will upset me, especially when I’m still repeating the same mistake and I thought I’ve corrected it.
For that I really appreciate Senpai’s dedication in guiding me (and also others) to improve time to time, though sometimes he’s kinda impatient. In Zankai training 2 claps are done before training starts to indicate you come to the dojo/dōkōkai to “give and take”, meaning to teach and learn. I used to take over Senpai’s classes when he was away for 1 month sabbatical training in Okinawa, I understand being a teacher/instructor is never an easy job. Other than great responsibility, selflessness is a must. Technically, a teacher/instructor has to give more than to take during the training. This isn’t everyone’s cup of tea after all, as lots of time and effort are committed.
Now I’ve got new assignment from Senpai. If everything goes smoothly it will be started next January. For the sake of Zankai’s development and image, as well as for my personal growth, I must train harder than before, but Senpai told me for women they have to train FIVE times harder in order to keep up the standard with men. Umm… a bit daunting…
I want to become stronger than I was yesterday, than I was half a day ago, than I was a minute ago! – Rock Lee in Naruto Shippuuden 28.
October 22, 2007
The Wolff’s Law
I’ve been studying biomechanics these few days, and learned another interesting topic about the bone response to stress.
Wolff’s Law, a widely known bone adaptation theory in the orthopedics, was developed by the German anatomist Julius Wolff in 1892:
The form of a bone being given, the bone elements place or displace themselves in the direction of functional forces and increase or decrease their mass to reflect the amount of the functional forces.
According to Wolff’s Law, bone grows in proportion to mechanical stress. A healthy living bone models and remodels in response to the mechanical stress it experiences so as to produce a minimal weight structure that is adapted to the stresses acted on it.
The changes in bone density, size and shape are the work of two specialized bone cells called osteoblasts and osteoclasts, which respectively form and resorb bone tissue. The bone remodeling occurs throughout life. During the process, resorption precedes formation, so as old bone tissue is replaced by new bone tissue. Remodeling can be in either “conservation mode” with no change in bone mass, or “disuse mode” with a net loss of bone mass characterized by an enlarged marrow cavity and thin cortex. The latter leads to osteoporosis, results from either excessive resorption or inadequate formation. The bone modeling occurs during growth and healing. Unlike remodeling, the osteoblasts predominate the activity (formation) with a net gain in bone mass.
Dynamic mechanical loading causes bones to deform or strain; the larger the loads, the greater the strain. When strain exceeds the remodeling threshold, bone remodeling occurs in conservation mode with balanced resorption and formation. When strain exceeds the higher modeling threshold, the bone modeling occurs, with bone density and mass increased. Disuse mode remodeling is triggered when strain stays below the remodeling threshold, induces a slow loss of bone.
A physically active individual tends to develop denser and more mineralized bones, particularly at the stressed sites. For example, a tennis player has a stronger and denser radius at the racquet-holding arm than the other arm due to the repetitive high stresses exerted on it. Likewise, a trained runner has an increased bone density at the lower extremity due to the high-impact of the running motion. Interesting to note that a competitive swimmer who spends a lot of time in the water however may have less dense bones than a sedentary individual as the buoyant force exerted on the body has counteracted the body weight (gravity).
The law also explains why astronauts suffer from a kind of bone-loss similar to osteoporosis after a long stay in space. Due to the microgravity, the floating human body undergoes a weightless and almost immobile condition. Since no weight is acted on the skeleton and the body do not have to fight the gravity to move about, the bone mass diminishes, hence the strength and the bone mineral density decrease. Bedridden patients and individuals who lead a sedentary or inactive lifestyle tend to have a decrease in bone mass too as a result of reduced mechanical stress and weightbearing activity. The bones become more susceptible to fractures.
In many traditional Okinawan karate-do and Chinese martial arts, body conditioning is crucial as part of the training routine to strengthen muscles and bones, as well as to elevate the pain threshold. Uechi-ryu karate-do emphasizes conditioning on knuckles, forearms, abdomen, tips of toes, dorsal feet, shins, thighs and calves by repetitively blocking and striking the areas to produce slight trauma to them. Other practices like rubbing, knuckle push-ups, rolling a stick on the shin are formulated for conditioning purpose as well. The principle founded by the ancient Chinese masters is the same as the Wolff’s law theory: the bones become denser and stronger after bearing a long period of dynamic mechanical loadings provided by the body conditioning, thus minimize the possible injuries caused by training and sparring.
However, if the applied mechanical loadings are beyond the power of (re)modeling, it leads to fatigue or stress fractures. This problem is very common to athletes who run and jump on the hard surfaces such as distance runners, basketball players, and ballet dancers. The most common affected bones are femur, tibia, navicular and metatarsals. Similarly, martial artists who overtrain themselves may encounter the same problem, when the stresses applied to the bone exceed the bone’s ability to adapt. Therefore it is important for martial artists to ensure the training is done within safe bounds.
