Fitness expert reveals the most efficient floor exercise for sculpting abs...and it's not crunches

The race to get toned up for summer is on, but few people have spare hours to dedicate to the gym.

Thankfully, fitness pros have revealed the one exercise you should focus on if you're looking for toned tummy muscles.

According to the Minny Hustlers fitness duo - top personal trainers based in Minneapolis who boast 159,000 TikTok followers - that move is a Russian twist.

The exercise, which involves twisting your core while sitting on the floor and leaning back with your knees bent, targets the obliques on the side of the body and the deep core muscles, they say.

'It's a movement great for everyone because it can be modified by keeping your feet on the ground for beginners or lifted for an added challenge,' says Lo Lundstrom, a certified personal trainer and one half of the Minny Hustlers.

Other personal trainers have echoed this, including Peter Donohoe a National Academy of Sports Medicine certified personal trainer and core strength teacher at the Boston Ballet.

They advise practicing the movement two to three times per week in order to see results. 

'It’s a total core exercise that also works your balance, builds stability in your spine, and trims your mid-section all at once,' Donohoe told Yahoo.

 The experts say that unlike crunches and planks, Russian twists require you to use what's called a transverse range of motion, or rotation. This tones an increased quantity of muscle in the abdominal area.

As summer approaches many will be looking to replicate the snatched tummy of super-toned celebrities like Gigi Hadid. 

What's more, simply the act of holding yourself up at an angle requires a lot of core strength, which makes the movement useful for beginners too.

The experts say the move can also act as a leg workout, as variations include moving the legs back and forth to tone glute and thigh muscles. 

Personal trainer Amanda Hoffman warns gym-goers not to push themselves too far with speed.

'Keep it slow, keep it controlled,' she said. Other experts say it's important to be aware of risks to your lower back. If it feels painful or achey, stop, they say.