Tim Bowen gets the ball rolling with these sport-related idioms.

Let’s get the ball rolling (make something start happening). Sport plays such a prominent role in the lives of so many people that it is unsurprising that there are a large number of idioms with a sporting connection. Many involve a central term in the world of sport, the word ball. If you are on the ball, for example, you are well-informed and quick to understand what is happening and what must be done. If, on the other hand, you have several balls in the air, you are trying to do a number of different things at the same time. If someone plays ball they take part in something and play fairly. This expression is often used in the negative, as in, 'Peter didn't really play ball in the last project.  The rest of the team worked overtime but he put in very little effort.'

If the ball is in your court, it is now your responsibility or turn to take action or make a decision rather than somebody else's and you will no doubt have to do things off your own bat (do them on your own initiative). In that situation, it is rather unlikely that you will be having a ball (really enjoying yourself) or punching the air (celebrating), although it is by no means impossible. It is more likely that you will find yourself on a sticky wicket (in a difficult or embarrassing situation). Whatever happens, don’t pull any punches (express your opinions or criticism clearly) and don’t score any own goals (do something that accidentally harms you when you intended to harm someone else). The most important thing is to know the score (know the truth about something, especially when it is unpleasant) and remember that when things go wrong it is all part of the game (a normal part of a particular activity). It may be easier to pass the baton to someone else (let them take over).

Taken from running races, the expression quick of the mark indicates a necessity to be quick at something, as in 'The sale starts at 9 am tomorrow.  It's bound to be popular so you better be quick of the mark and get their early.'

From archery and shooting, if something hits the target or is on target it means it is successful or is going to be successful, for instance, 'Our sales hit the target last quarter and we are on target to meet our goals this quarter too.'. When this success happens, you may hear the expression back of the net used to indicate someone's happiness with this result, usually over a competitor,  for example, 'We gained a 12% rise in profits this quarter compared to our closest rivals. Back of the net!'

Something that starts can be described as kicks off, as in, 'The meeting kicks off at 3pm.' Kick off time also means starting time. This idiom comes from football.

A person's average score in golf is known as par. Any score over or above this in an individual game can be described as  over or under par. The expression under par can also be used to describe someone who is functioning below their usual rate, for example, 'Mike is usually very efficient but today he appears to be a little under par.'