WILLPOWER LIFTING

Complete 8 rounds, for 5 mins total each round. If you finish before the 5 mins are up, rest. Some people may be able to finish in 3 mins; others will be looking at 40 minutes of steady effort. ‘The real test comes in rounds 5 to 8, where you may no longer be resting at all,’ says Britton. ‘The goal is not just to survive but thrive as you try to beat your previous score.’

01/AIR SQUAT 40 REPS

With feet at shoulder-width (A), bend at the hips and sink until your thighs are just past parallel to the floor (B). Keep your chest up, back straight, knees in line with your feet. Stand up. You can make up time here, though try not to rush at the expense of quality reps.

02/KETTLEBELL/ DUMBBELL SWING 30 REPS

Now it will start to sting. With feet a little past shoulder-width apart, bend down to grab the weight from between your legs

(A). Drive your hips forward to swing the bell up to shoulder height (B). Maintain momentum. Split this into two sets of 15 if you’re struggling.

03/SIT-UP 20 REPS

A bit of respite – sort of. Sit with the soles of your feet touching and your knees bent and pushed apart, as if stretching your hips

(A). An ab mat might help to support your back. Lie down, reaching back to tap the floor behind your head, then touch your toes (B).

04/BURPEE 10 REPS

We love to hate ’em. Squat down, place your hands on the floor and jump your legs back into a press-up position in one fluid movement

(A). Drop your chest to the floor then jump your legs in and leap up, clapping overhead as you jump (B). Feeling the burn now?

05/PRESS-UP 5 REPS

Finish up with 5 good-quality press-up reps. Place your hands slightly wider than your shoulders, keep your body straight with your core and glutes tight, and lower (A).

Push up until your arms are extended

(B). Far too easy? Add a clap at the top of each rep.