It would be interesting to know just how many of the people who now take active part in sport hated games at school. Randolph Hutton, head of English at Aldersley High School in Wolverhampton, and a fourth dan black belt in karate, is one of them. "I had hay fever then, and I hated running about getting out of breath."
He decided to take up martial arts when he started teacher training at Wolverhampton University in 1980. At that time, the Bruce Lee phenomenon was at its height, and there were about 150 students in the karate club.
After six months or so, Randolph knew that he wanted to do more than just recreational karate. "I saw the black belts and the instructors who were all champions, and I wanted to be like them. I saw how they dealt with obstacles, both in their technique and within themselves."
So he stuck to it and gradually climbed through the ranks, combining a teaching career with becoming a top Central Region competitor - one of the 30 or so of this country's karate elite, and one of the tiny minority to hold the fourth dan black belt.
Karate is a highly disciplined activity. It was this aspect that attracted Randolph to the sport: the precision, the respect shown to opponents and colleagues. Everyone bows when they enter the "dojo" or training area; training partners bow to each other before and after they work together.
"A flick of the head isn't good enough," says Randolph. "It has to be formal. The bow symbolises that if you win, there is no bad feeling. It also means that you don't spend the session apologising for mistakes or for hurting someone."
Now, at Wolverhampton University's karate club, Randolph is the senior instructor or "sensei" (teacher). This is not by choice or appointment, but by virtue of his rank as a fourth dan black belt. By tradition, the privilege of wearing the black belt brings with it the duty of teaching others.
The training is fascinating to watch. On an average session, there are half a dozen students in the group, at all levels, including another black belt who has travelled some distance to work with Randolph. They stand in line facing him, as he gives instructions, pitched according to individual levels of ability.
He watches intensely as his students practise the stylised body movements, punches and kicks that make up the sport. The essence is muscular control, and Randolph makes minute corrections to his students' feet and arm positions.
His own agility and control is astonishing; he demonstrates a sudden high kick that looks as if it will take a student's head off but which suddenly stops with his bare foot just touching the cheek. All the time blood-curdling screams accompany aggressive punches and kicks. These have a purpose beyond being merely terrifying.
"It's important that everything at the moment of impact is absolutely rigid - it's not just your fist, it's your whole body - which is why you can kick your way through a door. The screams focus all the muscles simultaneously, like when you sneeze."
By contrast, Randolph's instructing style is quiet. He allocates tasks in a normal voice, with a minimum of chat, and then goes around making individual comments and adjustments. Each time, to signify understanding, students cry "Oss!" meaning, "I understand!" There is no joking, no small talk, no let-up in the formal intensity of the session.
This structure, Randolph explains, ensures progress and purpose through the session. "It leaves little time for students to ask questions. You do it, and then you can ask questions afterwards. It avoids having the student say, 'I'm afraid of this'. And the seriousness means that a student can't say, 'While I'm laughing and joking I don't have to tackle this'."
Back in the classroom his teaching is not so very different. "I can't be quite so rigid," he says. "But I do reach a point where I decide that the questions have to end and I'm going to go on."
Does this mean that he regards himself as a living exponent of karate or "karateka"?
"It does tend to be part of the thinking. A simple example might be just body posture and walking. You do tend to carry yourself with more confidence."
It is the same disciplined approach, combined with a high level of fitness (Randolph runs and trains with weights), that enables him to combine his sport with his teaching career.
Nevertheless, although in 1997, at the age of 35, he won the Central Region championships, he has now retired from active competition and devotes himself to instructing.
"It's because of the meetings and the paperwork," he says with some regret.
* English Karate Governing Body, 58 Bloomfield Drive, Bath BA2 2BG. Tel: 01225 834008.l Karate Union of Great Britain, 20 Waterford Road, Oxton, Wirral L43 6UU. Tel: 0151 652 1208