A prefix is a series of letters, or a word, that is added to the  beginning of a word and changes the meaning. For example, in the  word midnight, mid is the prefix.
The more vigorous an activity, however, the more calories youâll burn. Changes in body weight are related to both the duration and intensity of play. Playing singles tennis at average intensity expends 300-600 kcal/h, while high intensity tennis training expends 450-900 kcal/h. Diabetes. The incidence of diabetes worldwide of persons aged 20 or above in 1995 was 4% (approx. 135 million), a figure that will increase to approx. 5.4% (300 million people) by 2025.
Fans live for long points. But exactly how much action is there in a tennis match? We took a stopwatch and timed two matches at the U.S. Open last week to find out.The answer: Not as much as you'd probably think. In the two matches we studied, only 17.5% of the time was spent actually playing tennis.ans live for long points. But exactly how much action is there in a tennis match? We took a stopwatch and timed two matches at the U.S. Open last week to find out.