The humble plank is something of a wonder exercise for your core.

Not only does it promote core stability and balance, but it works around 20 muscles across your shoulders, back, arms, legs and glutes – meaning it's not just an abs exercise.

But if you've been using the same old plank in every abs workout for the last few months, it's probably time to change it up for something more interesting and challenging.

Keeping your workout routine varied is key to achieving more lean and toned muscle – so incorporate these plank variations into your next abs session for better results.

1. Shoulder touch plank
Start in the standard plank position – palms on the floor with hands slightly wider than shoulder width, feet together and toes on the floor, with your body in a straight line. Reach your right hand to touch your left shoulder. Place it back on the floor and use your left hand to touch your right shoulder. This is one rep – aim for 30.


2. Side plank (with added extras)
Place your left forearm and left foot on the floor, stacking your right leg on top. Hold for 30 seconds and switch sides. For more of a workout, raise your right hand up towards the ceiling and/or lift your right leg as high as you can without dropping your hips.


3. Reverse plank
A toughie, but so good for the core and the upper body. Sit on the ground with your legs straight out in front of you. Place your hands on the floor next to your hips with your fingers pointing forward. Lift your hips and aims to keep your body straight from chin to toes. Hold for 30 seconds.


4. Plant jacks
Nothing like a hint of cardio to get the heart rate up. Start in a standard plank position, then jump your feet outwards, as if you were doing a jumping jack. Return to the start position. This is one rep – aim for 30, moving as quickly as you can while maintaining a good form.


5. Plank row
You'll need a set of medium weights (with flat, not rounded edges) for this one. Hold one weight in each hand and get into the standard plank position. Bend your left elbow and slowly raise it up, so it's pointing toward the ceiling and you're holding the dumbbell at your side. Keep your elbow in tight to your side. Place your hand back down and repeat with the other arm. This is one rep. Aim for 15.


6. Knee-to-outside-elbow plank
The name's a bit of a mouthful, but it's easier than it sounds. Get into standard plank position. Pull your left knee forward as far as you can, aiming to touch your left elbow. Return to start position and repeat with right knee. This is one rep. Aim for 30. Keep looking forward the whole time, as looking back to check where your knee is will cause you to round your shoulders.