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.
Tennis is one of the most popular racquet sport in all ages and gender around the world. There are two game format in tennis including single and double games. Firstly, a single game is a game where a player playing one on one game against their opponent. Secondly, a double game is a game play by a team of two players against their opponent. Every player equipped with a racquet that strung with cord to hit the tennis ball into the opposition court and around or over the net.