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.
Dave Seminara wrote a great story about an astonishing historic rally between two womenâs tennis players, and I will share some facts from his article here on Womenâs Tennis Blog. Vicki Nelson and Jean Hepner played the longest rally in the history of professional tennis, which included 643 shots and was played when Hepner had a set point in the second set tiebreak, which lasted 1 hour and 47 minutes on its own. Can you believe it? After the 29-minute long rally Nelson went for a winner and won the point. She was also the winner of the match, after 6 hours and 31 minutes of play. Final score was 6-4 7-6(11). Not surprisingly, the marathon was the longest match in tennis history for nearly twenty years, and is still the longest match completed on a single day. When the rally was over, Nelson collapsed with cramps in her legs.