Sports Research at the University of Tokyo

It is not just athletes who are seriously into sports at the University of Tokyo. In this section we introduce some of the "powerful Socrates" at the University, faculty members who are daily engaged in research and education relating to sports. Several sports researchers from among the many at the University of Tokyo describe the most interesting themes in sports research today.

Muscle

Muscle will save aging Japan

― You are known as the “guru of muscle.” Have you always had an interest in muscle? (Fig. 1)

During the summer vacation of my first year in high school I would study every morning, and then go training and swimming every afternoon. By the time the new term arrived my body had almost doubled in size from all the training. That was when I first got a taste of the sense of enjoyment from training and building up my body. At university I joined the bodybuilding and weight-lifting club (B&W club) and as I continued to train some questions started to creep into my mind, like how can such small muscles exert such tremendous power. It was then that I started to get interested in how muscle works and I have been immersed in that research for 36 years since then.

For the last 20 years my main research theme has been on how muscles get larger and stronger when you train them (Fig. 2). I thought that this would be something that would be easy to understand, but once I started my research I realized that answers would not come so quickly. When you think about it, it is not necessarily obvious that muscle training should result in muscles growing larger. We still don’t know everything there is to know about muscle development, perhaps only about 60 percent. I think it will be another century or so before we know everything.

― Muscles appear to be simple organs, but in actual fact they are very complex aren’t they?

To engage in an empirical study of which of the various training methods being used is the most effective is incredibly difficult and requires a great deal of time and effort. Although taking the time to engage in such a study is one way of going about this research, I have chosen to first clarify the mechanism by which muscles enlarge and then consider methods of training that would be able to maximize the effect of such a mechanism.

If we could clarify the mechanism by which muscles enlarge we would probably be able to devise training methods for all people, even those who are bedridden. What I hope to do is to find a training method that would help to improve the lives of the bedridden, the frail and the elderly, by assisting them in developing their muscles. If this proves to be possible it would be of great use to society in general.

It was in the process of seeking to clarify the mechanism whereby muscles enlarge that the theory behind kaatsu (pressure) training was discovered, namely that if you train when your blood vessels are constricted, this has the effect of helping muscles to enlarge. However, restricting the blood vessels involves a certain amount of risk. So, we started looking for methods that would produce the same effect, but without constricting blood vessels.

The answer to the conundrum about how to gain the effect of kaatsu training without constricting blood vessels was “slow training,” or “Low-intensity resistance exercise with slow movement and tonic force generation (LST).” Slow training is a method whereby you maintain the force exerted by the muscles without release while moving slowly and gently (Fig. 3). For example, in practical terms, if you are doing squats it means not straightening your knees fully, and if you are doing abdominal crunches, it means ensuring that your back never touches the floor fully.

The initial purpose of slow training was as a method to prevent the need for nursing care. Since the introduction of nursing care insurance in 2000, which was the year in which concerns about the declining birthrate and aging population were first spotlighted as a matter of concern for the future, the large number of people who became bedridden as a result of falling over has become an issue and demand for muscle training for the elderly has increased. Given the need for a method of training that does not require special equipment and is effective without placing an unduly heavy burden on the body, slow training was well-received as a response to this need.

― I see. So slow training is a specific method that will be a great help in Japan in the future, particularly in view of the aging population?

Naturally I am not thinking in such grandiose terms, but I believe that in 10 or 20 years from now, slow training will certainly be of some use in improving the lives of Japanese people.

The muscles of our bodies fulfill four roles. The first is that they produce the power by which we move our bodies. Whatever movement it may be, whether it is standing up, breathing or talking, the power to perform these activities comes from our muscles. Our muscles are the engines for all movement. The second role our muscles perform is to generate body heat. Although it may be difficult to imagine that muscles are capable of creating heat, as we age and our muscle mass decreases we become more susceptible to the cold, to gaining weight and also to diseases such as diabetes. Muscle training is important as it helps to prevent lifestyle-related diseases. The third role of muscles is to act as a pump. Through repeated contractions the muscles enable blood to flow around our bodies. Of particular importance are the muscles in our lower bodies. In the same way as “economy class syndrome,” or deep-vein thrombosis, if we remain inactive for long periods our legs swell up and we become more susceptible to blood clots. Contractions of the muscles in our lower body prevent this. The fourth role that muscles play is to absorb external impacts. Muscles act as a layer of protection for our internal organs, helping to prevent damage from external impacts. Our inner muscles also perform an important role by ensuring that our joints remain stable and in the correct position.

So, to summarize, muscles act as an engine, a heater, a blood pump and as a protector. As we get older our muscles atrophy resulting in our body’s capacity to implement these four functions becoming weaker. This can lead to people not being able to lead a fulfilling life.

― Why does muscle mass decrease as we get older?

That is a really difficult question. The mechanism behind aging is not understood at all. Although even children are aware that as we age our hair goes white, we get more wrinkles and our backs start to bend, there is still no scientific answer from the life sciences as to why these things happen. Basically no reason has yet been discovered as to why hair should turn white and wrinkles increase in number. Everyone experiences aging as time passes. However, despite the fact that our bodies are capable of rebuilding themselves, once a hair turns white it stays white and wrinkles cannot be ironed out once they have appeared. These are things that are unchangeable and the body cannot undo them once they have occurred. The question of why we age is one that has still to be answered.

Aging is a phenomenon that does not create problems in the wild. In ancient times, when humans lived in a wild environment, almost all people would die prior to reaching old age, either due to climate, predators or disease. As civilization and technology have progressed people have now reached a stage where they can generally live up to around the age of 80 years, and this is what has brought about the aging phenomenon. However, as humankind will never regress to that ancient wild environment in which we once lived, what we must do now is to find ways to overcome aging. Unless we ensure that people who once may have retired at the age of 55 can continuing working in good health and vitality until even the age of 70, we will not be able to overcome the challenges presented by aging. Our muscles are one of the foundations for a healthy life into old age.

― So can we assume that slow training is something for the elderly?

Slow training is not just a method for the elderly or frail, it can also be effective, for example, in the rehabilitation of injured athletes. This is because immediately after suffering injury athletes are unable to immediately return to their normal heavy muscle training routine. In addition, by exercising slowly without releasing the tension in the muscles it is possible to boost their capacity to stabilize joints. If people are able to move in a way that helps to maintain a stable posture, then their overall stability will improve. This leads to a virtuous cycle whereby movement and exercise becomes more stable, making it more difficult to sustain injuries. If various types of exercise and training are further combined, this helps people to acquire technical skill and also have the stability to utilize the skills they acquire.

In addition, the movements of Tai Chi are similar to slow training and studies of the muscle activity patterns for both methods show many commonalities. The reason why doing Tai Chi in the morning helps to bring the body into balance and promote well-being is probably due to the fact that the movements of Tai Chi promote the secretion of hormones. This discovery in ancient times through experience is probably why it is still practiced today, more than 300 years later.

If I am being honest I would have to say that slow training is a method that is not for me personally. I prefer training methods where you push yourself to your limits, just up to the point where you are near collapse, and training slowly with light weights seems boring in comparison. However, as I am getting older I am finding my standard training regimen tougher and tougher so I am starting to include some slow training methods in my routine. Although it may be better for young and healthy people to carry on with their hard training methods, slow training is ideal for the less young and those who are not so sure of their physical capabilities.