“Our aim today is to have a 15-shot rally over the net in the short service box.” I’m learning tennis from Ben, an longstanding member of the Magdalen Park tennis club in south London, and also my very good friend. The place is insanely busy; who are all these people who can play a 90-minute game on a Wednesday morning?

They’re fitness freaks, is what they are: this used to be the game of gents, all white trousers and elegance, “about touch, fine motor skills, languid elegance, volleying”, Ben says. Now, it’s all strength and stamina. The play has changed, the rackets have changed, the stars have changed, even the speed of the ball has changed – which you’d think would make no difference to the novice, who doesn’t know a chopper grip (old-fashioned, straight-through, flat shot) from a western grip (topspin, up and over). But it does make a difference: first, the way you learn is the way you play for ever (Ben still occasionally plays with his forearm perpendicular to his upper arm, because the chap who taught him in the 70s had a pin in his arm following a Spitfire accident). Second, tennis is now a fitness thing; a place where you’ll see the body-conscious.

According to Scott Smith, a personal trainer who is on the Australian Tennis Board, tennis is enough on its own to keep a person fit into their 80s. “There’s a lot of lateral movement, your heart rate is increasing, you’re doing short, sharp bursts of high intensity, so it’s like mini interval training. You’re forced into dynamic movement.”

It’s none of those things, of course, until you can play it. Ben thinks it takes four to five years to reach a base level of proficiency. Someone else says eight weeks. Those timescales are equally unachieveable if you don’t take to it, which I assumed I wouldn’t, since the first requirement is hand-eye coordination, which I lack. But I last checked when I was 10, and things change: I’ve spent my life thinking I couldn’t hit a moving thing. It turns out the intervening decades playing beer pong have actually wrought an improvement.

We started off just bouncing a ball on the centre of the racket; fine. We had a rally over the net, and got to 34 with a fair wind. We spent ages, and I mean ages, with me just throwing a ball at a particular spot on the fence. It went everywhere; it even hit someone on an adjoining court. We transmuted these nursery throwing-skills to a fledgling serve. I couldn’t have told you where it would land, but I definitely hit the ball. I learned how to hold a racket, thumb and forefinger in a V-shape, and how to position it: “I’d hold it vertically,” Ben said, “Today’s topspinners would position it at a much greater angle. Come to think of it, tennis has completely changed. My weapon was my serve, now the weapon is top-spin.” How ironic. It’s ended with me feeling 10ft tall and him feeling terrible.

What I learned

With a technical sport, like tennis, you have to be fit to make the right mental decision. When you’re puffing, you make bad choices.