How long can you plank for? This is one of the ultimate core strength tests, so it’s perfect for our next gym challenge.

Whoever performs the longest plank without moving or resting will win a £30 Sainsbury’s gift card – just in time for Christmas!

To take part when you’re in the gym, you must be on your forearms and toes with your body in a straight line – other adaptations will not count. Then, when you’re done, simply write the time down on our gym board.

So, go on – get practicing, and good luck!