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.
Find out here... Whether you're playing singles or doubles, the rules of table tennis are essentially the same. However, for doubles play there are a few subtle variations to the rules of table tennis.ule 2.10.01.11 states that a team loses a point... If a doubles opponent strikes the ball out of the sequence established by the first server and first receiver. This means what it says ... if you hit the ball out of sequence, the table tennis doubles rules say you lose the point.