Are crunches bad for your back?
By Coach Hunter Bennett
Well, it depends.
I firmly believe there is no such thing as a ‘bad’ exercise.
While some exercises may not be suitable for a particular person, and at a particular moment in time, that doesn’t make them bad.
For example, if someone has recently had a stress fracture, I am probably not going to give them box jumps.
That would be stupid.
But that doesn’t mean box jumps are bad – just that they are not suitable in this specific instance.
And crunches are no different.
Are crunches bad for your back?
Crunches were once a staple in every fitness program on the planet.
But things changed.
Some research came out suggesting that your spine can only handle finite number of ‘crunches’ before it causes a disc injury.
And this research drove thousands of fitness professionals off crunches for life.
But there is a kicker here.
This research was not performed on humans.
It was performed on the spines of dead pigs.
Now, I should note the issue here isn’t that this research was conducted on pigs (their spines are much like humans).
The issue is that pigs were, well, dead.
Living human tissue has the capacity to adapt to load. As such, when stress is applied to it, it becomes stronger and more resilient.
And this includes the connective tissue found within your spine.
But dead tissue does not have this capacity.
Moreover, in the research mentioned above, disc injury often occurred after thousands of crunches – which is not how people exercise.
Most people head to the gym, do a few sets of 6-12 (maybe sets of 15-20 if they are feeling particularly masochistic), then take a couple of days to recover before doing it all again.
In short, they place a moderate amount of stress on their body and give it time to adapt, rather than doing thousands of crunches in a row.
All of which indicates that this research may not be an accurate representation of what occurs in practice.
So, crunches: good or bad?
Well, like anything, it depends.
I personally don’t know of any research showing that crunches cause back pain in healthy, living, humans.
In my mind, damage might occur when the load placed on the spine exceeds its ability to adapt. This is something that is going to change on an individual basis, and is likely dictated by several different factors, including:
- How fast load is increased during training
- Health status
However, as spinal discs can adapt to load, we could argue that crunches might have a positive effect on spine health (assuming they are performed in a safe and progressive manner), much like deep squats have on knee health.
Although, this is speculation on my part.
I mean, as far as I know, there is no research demonstrating that crunches improve spine health either.
Should I do crunches?
While I believe that crunches have been unfairly demonized by the fitness industry, I do not think they are a good fit for everyone.
It comes down to training status, and context.
Should the normal gym-goer do crunches?
Every single day you flex your spine.
It could be to tie your shoes, pick up your kids, or get into the car.
It is something you need to do.
As such, I would argue that you need to train the ability to flex your spine under load. This will increase your strength in these positions, making you more resilient.
Crunches may offer a way to help you better control and stabilize your spine, which I suspect may also reduce your risk of lower back injury.
Should athletes do crunches?
If you play a sport, should you do crunches?
Spinal ﬂexion strength and power is important for many sports.
If you think about wrestling, track and field, tennis, martial arts, baseball, cricket, golf, and literally any team sport, it becomes apparent that you need to move your spine explosively to perform well.
To optimize performance, exercises that work the abdominals in a way that replicates these movements is important – and some variations of the crunch may fit here.
Should people with lower back pain do crunches?
People with lower back pain are one that may benefit from avoiding crunches for the time being.
When someone presents with low back pain, there is some evidence to suggest that it can be the result of muscular weakness, where the abdominals and hip musculature are not strong enough to stabilize the spine.
This results in all the muscles of the lower back tightening up to splint the spine, which causes a heightened pain response.
Although this will not be true for everyone, it is something that should be considered.
And this is when crunches may become a bad idea.
Because they take the spine through a large range of motion, they can ‘turn up’ this splinting response, which may increase pain and tightness.
This does not mean that those with lower back pain should avoid crunch-type exercises for ever. But they should avoid them until they have developed enough abdominal strength using stability-type exercises first.
After which, they should be able to tolerate them safely.
Spinal Stability Exercises
Before prescribing any dynamic trunk ‘movement’ type exercises (like crunches), I like to make sure that a person has a good amount of trunk stability.
I like to think of this as ‘protective strength,’ which ensures that you can tolerate more demanding exercises safely.
These include things like:
- Planks and side planks
- Pallof presses
- Bird dogs
These types of exercises should be embedded within a larger program frequently to maximise spinal stability.
Dynamic Abdominal Exercises
Once you have built a strong and resilient set of abdominals that stabilise effectively, it might be time to throw in some dynamic abdominal exercises.
Some of my favourites include:
- Crunches, reverse crunches, and oblique crunches
- Cable rotations
- Hanging leg raises
Good Crunch Technique
Now, before we finish, I want to make some quick notes on good crunch technique (in fact, this applies to all of the exercises listed above).
- Take it slow: Make sure the movement is slow and controlled.
- Maintain good neck position: Avoid ripping your head forward, and instead try and keep your chin tucked so your neck is in line with your spine.
- Focus on using your abdominal muscles: Actively contract them as hard as possible. If you feel like you are using your arms or head to start the movement, then you are doing it wrong.
Easy as that.
Are crunches bad for your back: the final message
There are no such thing as bad exercises — even crunches.
In fact, they may even make your lower back more resilient.
Just make sure you use them wisely.