What is it? A weighted ball, around the size of a watermelon.

How much does it cost? If you’re a member of a gym, you’re bound to find a sad row of neglected medicine balls by the stretching area. If you’re not, they cost about £40 each, which does seem a little steep.

What does it promise? Improved core strength, flexibility, range of motion, coordination, and upper- and lower-body strength. They’ve been around in one form or another for thousands of years. That has to be a good thing, right?

What’s it actually like? I rarely see anyone using medicine balls now that kettlebells have come along with their easy handles and celebrity endorsements. But while there’s nothing wrong with kettlebells per se, they do lack the primal, tactile thrill of the medicine ball.

What the medicine ball has over the kettlebell is the fact that you can lob it around. If you’re working in pairs, you can rest your back on a large inflatable swiss ball and toss them to each other, which is a terrific core workout. Then there’s the slam, where you hurl the ball to the ground as hard as you can over and over again, which is possibly my favourite exercise of all time.

But the beauty of the medicine ball is that it’s so versatile. Use them for sit-ups and press-ups and lunges and shoulder-presses. Before your next gym visit, search the internet for medicine ball exercises, and thank me later.

Best and worst bits I love medicine balls. However, it pays to get the technique right if you want to get the most out of them, so find some tutorial videos before you wade in blindly.

Is it worth it? Yes.

• This article was amended on 9 April 2016 to fix a mistake in the headline