Crunches vs plank: what is most effective for a stronger core?

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Which core exercise is the most effective: planks or crunches? 

Whether you prefer to dedicate an entire workout to your abdominals or throw a couple of moves into your full-body training sessions, targeting your core is crucial for stability, mobility and avoiding aches and pains. Crucial stuff, you’ll agree. Yet some exercises are more beneficial than others when it comes to strengthening your midsection, so it’s important to choose your workouts wisely. 

Who takes home the crown when it comes to core work’s two main players: planks (the ultimate game of mental challenge) or crunches (an old school favourite)?

“Both of these exercise target your rectus abdominus - those are the muscles that run down the front of your stomach - so there’s merit in doing both crunches and doing planks,” says fitness trainer Emma Obayuvana.

The benefits of a plank

Targets multiple muscles 

“When you really are mindful of your form, the plank targets muscles way beyond your abdominals. It will activate your hip flexorsquadsglutes and delts as you’re squeezing in the hold and keeping yourself away from the floor,” says Emma. 

Great time under tension

“When holding a plank, the work is constant,” says Emma. “In a crunch, you give the abdominal muscles a slight respite as you reach the floor, but in the plank you are just holding continuously.” That means that the muscles are under tension for as long as you hold the exercise, leading to “strength, balance, and endurance gains,” according to Emma. 

Extra challenging variations

In a 2013 study by Les Mills Lab, researchers found that “abdominal and lumbar (back) muscle activity was greatest when balance was challenged, by adding complex movements to these traditional core exercises.” Essentially, adapting the plank leads to even more core engagement, while still working on multiple muscles. For example, a plank with a knee lift toward the opposite side of the chest increases ab activation by 30%  and oblique activation by 20%. Plus, a plank with hand reach gives 20% more abdominal activation than a crunch.

Less risk of injury 

Many people find that they struggle with low back or neck pain when attempting the crunch. “It can be easy to get the form wrong by lifting through the shoulders and straining the neck. Bad form can also result in feeling uncomfortable throughout the spine,” says Emma. While it’s important to keep your form perfect in plank too, there’s less risk of doing damage as there’s less compression of the spine, according to a 2018 study. 

Plank vs crunches

The benefits of crunches

Isolation exercise 

“As the crunch targets just the abs and the hip flexors, without much other activation, it is great for isolation work,” says Emma. That means it’s perfect to pop on the end of a session when your other muscles are fatigued but you want to finish with some ab work, or if you need to give your upper body a rest day after a big session the day before. 

Easy to adapt

“You can get even more targeted muscle activation with simple tweaks of the crunch,” says Emma. “For example, you can work into the oblique with a bicycle crunch, or hit the lower abs with a reverse crunch.” 

No wrist work 

Crunches are better than planks for those who can’t take a lot of weight through their wrists or shoulders due to injury or weakness, but still want to target their core. 

Less may be more

Doing crunches just one day a week can improve muscle endurance, according to a paper published in the Journal of Sports Medicine and Physial Fitness. Researchers compared those who performed crunches one, twice and three times a week and found a similar improvement in all three groups. 

The winner? 

Both exercises have benefits, but for a full core workout that hits the deep abdominals, obliques and back, it has to be the plank. “I don’t want to discount crunches totally, because they can be great,” reminds Emma. “But generally, I’d always opt for a full-body burner that you can adapt to your level with less risk of injury.” 

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Images: Getty

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