knock up1
British informal (In a racket game) practise before formal play begins.The idea came when they were knocking up one day last June on the grass courts at Roehampton....
- She knocks up with England's seventh seed Elena Baltacha and recently had the chance to play doubles with British number one Tim Henman when he visited the sports centre.
- The players are on court and are knocking up.
Synonyms
warm up, practise, have a practice game, hit a ball around
See parent entry: knock
knock-up2 
noun British
(In tennis or other racket sports) a period of practice play, especially before formal play begins.The final decision was deferred until after a final practice session today, but a light knock-up with Courteau confirmed her worst fears and Mauresmo sat courtside in the Rod Laver Arena with her head buried in a towel....
- I have been playing more squash recently and in the knock-up I again felt confident and was pulling off shots that surprised and impressed me for their accuracy and technique.
- Don't get me wrong, I enjoy a knock-up on the courts.