'I did 150 crunches every day for two weeks - this is what happened'

Our writer took on the crunch challenge and saw surprising results

Personal trainer Lucy Gornall did 150 crunches every day to see what would happen
(Image credit: Lucy Gornall)

If you’ve ever attempted to ‘tone up’ your midsection or researched the best workout for abs, you’ll likely have come across the classic crunch.

It could be described as the younger sister of the sit-up; a crunch involves raising just the head and shoulders off the ground whilst a sit-up involves raising your entire upper body off the ground. Both start in the same position; lying back on the floor, knees bent and feet flat on the ground, typically with hands by ears.

A crunch recruits the upper abdominals and, done properly, can help with upper core strength as well as encouraging those abs muscles to POP!

So, with a whole lot of time and energy to kill during lockdown, naturally I decided to do 150 crunches every day for two weeks, in a bid to find out exactly what would happen. After brushing up on the basics of how to do a crunch (as a personal trainer, I know that form is everything), I did a bit of research into the move itself.

It’s certainly somewhat of a debated move in the fitness world. As a flexion exercise - in that it decreases the angle of the body as upper and lower body ‘crunch’ together - the impact it could potentially have on the spine has been discussed. A study in the Strength and Conditioning Journal has found that a lot of continuous bending could ‘have a detrimental effect on spinal tissues’.

Plus, the same research has explained how, to increase core strength, a mixture of exercises is needed including non-targeted core moves (think squats, deadlifts, rows, etc). In fact, to work the abdominal muscles, a variety of abdominal exercises are needed.

So a toned core isn’t JUST about bashing out a load of crunches.

Either way, I devoted a good few minutes every morning to dropping down and doing 150 of these crunches. This is what happened...

My back didn’t like it. Neither did my neck.

Well, I guess I could have predicted this one following my ‘crunch research’ (see above). I think a big reason for the lower back soreness was because after about 50 crunches, my form did start to deteriorate. 

I was really crunching as quickly as I could, and as a result I was yanking at my neck to pull my shoulders off the ground, whilst pushing my lower back into the ground, when really I should have allowed for the curve in my spine to stay neutral.

You won’t lose fat doing crunches

Think you can go crazy on the crunches and watch belly fat melt away? Think again.

They say abs are made in the kitchen, and it’s true really. As a personal trainer, I would advise anyone wondering how to lose weight on their stomach to first and foremost sort their diet out. You can do all the ab exercises in the world but if there’s a layer of fat sitting on top of them, they won’t be showing.

Crunches certainly won’t burn off the tummy fat, as one study has proved.

Researchers observed 24 people, split into two groups, over six weeks. Both groups were given the same number of calories; one group was given abdominal exercises to perform, whilst the other wasn’t. After six weeks, there was no significant effect of the abdominal exercises on body weight, body fat percentage or abdominal circumference.

That’s not to say that a longer period of time wouldn't have made a difference, but it does pretty much suggest that crunching won’t burn fat.

I didn’t change my diet during these two weeks, and my body fat stayed the same throughout. Perhaps next time I will do the same crunch experiment, alongside a diet of cupcakes and crisps? Hmm, food for thought.

My upper abs toned - but my lower abs stayed exactly the same

I already knew that the crunch was specifically one of the best workouts for upper abs, but this confirmed it. My lower abs didn’t even feel a twinge. As in, zilch. However, looking at my stomach in the mirror after 150 excruciatingly painful crunches, I did see my upper abs looking more defined.

Personal trainer Lucy Gornall did 150 crunches every day to see what would happen

(Image credit: Lucy Gornall)

...So, there’s undoubtedly better ab exercises to choose from

There’s a wealth of other exercises that offer more bang for your buck when it comes to working and toning your core. 

Moves such as the plank work the entirety of your midsection. I am also a fan of a hollow hold. This is a tricky one, but essentially, you are balanced on your bum, legs straight out in front of you just off the ground. Your upper body is also off the ground, and arms are held out either side of your body in a straight line. Gaze remains forward. If you can hold this for a minute, I’ll give you a medal*.

*don’t hold me to this

150 crunches takes a long time

It’s such a small movement so I figured I could easily get them done in a minute. WHO was I kidding? 

Minutes ticked by and I feel like I could have been diagnosed with repetitive strain syndrome by the end. In fact, some days I popped my workout earbuds in or opened my iPad for some light relief whilst I crunched.

My abs felt stronger

Despite the niggles in my lower back and neck, which were both relieved by some light stretching (thanks for asking), I noticed my posture improve. It was as though my abs were a bit stronger so they were just holding me upright.

I had read that crunches could actually ruin your posture. In an article in the Strength and Conditioning Journal, there’s a theory that all these crunches could cause my back to round slightly - in turn causing a slump.

But, as I do devote time to stretching, perhaps this was negated for me.

So, would I do it again?

If this two weeks taught me anything, it's that being short on time means finding exercises that work several muscles at once, to really make the most of the minutes.

Whilst crunches do of course offer a good upper abdominal workout, that's pretty much all they offer in my eyes. I would certainly incorporate them into a bigger workout, but they wouldn't be my sole choice of exercise. Especially not 150 of the darn things.

Lucy Gornall
Lucy Gornall

Lucy is Health and Fitness Editor at various women's magazines, and also Editor of Woman&Home Feel Good You. She has previously written for titles including Now, Look and Cosmopolitan. She lives and breathes all things fitness; she works out every morning, and mixes it up with runs, weights, boxing and endless box jumps. She is also a Level 3 personal trainer and teaches classes at various London studios, primarily Digme Fitness. Lucy is pre- and post-natal trained and helps new mums get back into fitness after the birth of their baby. Lucy claims that good sleep, plenty of food, and a healthy gut (seriously, it's an obsession) are the key to maintaining energy and exercising efficiently. Saying this, she's partial to the odd Negroni on the dance floor with her friends.