So you’ve been told you need to strengthen your core and someone has shown you or suggested to you, or you’ve read on the net or in a magazine that crunches are a good exercise to achieve this. They will strengthen your core and help your bad back, preventing further back pain and giving your a great set of stomach muscles.
It sounds great in theory , a simple exercise that will give you great looking abs and strengthen your back. Unfortunately it is completely wrong. I know what you are thinking, “every magazine, fitness article, fitness instructor and many Personal Trainers recommend crunches as a means of strengthening your core, how can they all be wrong?”
Unfortunately many of these experts use information that is severely outdated. Our knowledge of the human body is evolving at a rapid rate and those who don’t make the effort to keep up with the latest knowledge will be using outdated and often wrong information.
Remember when the experts said that marathon was too demanding an event for women to compete in (1984 was the first Womens marathon in the Olympics). Research has know shown that women can compete against the men in endurance events and in some ultramarathons the winner has been female.
Static stretching was a must do before exercise. Research has shown that you are more likely to become injured if you static stretch before exercise than if you did nothing at all. Despite this you still see people stretching before going for a run!
A while ago people did sit ups with their feet held by either a machine or person. We then discovered that this would use the hip flexor muscles more which create more shearing force in the lower back and increase back pain , not reduce it. They also worked the abdominal muscles less.
There’s just three examples of how knowledge has changed the way we approach exercise.
Those people recommending crunches to help strengthen your core and/or help your lower back don’t understand how the body really works and they are quite possibly weakening your core and making you more susceptible to injury.
Bear with me whilst I explain
What is the core?
When we talk about strengthening the core we need to understand that the core is not simply a group of abdominal muscles that work together to support your back. It is made up of all the muscles that attach to the pelvis; the abdominals, spinal muscles, pelvic floor muscles, deep hip muscles, scapula and shoulder girdle muscles. These muscles are not one big group of muscles that all activate as “the core”. They act interdependently depending on the load placed on them.
Core strength – for what?
If we want to strengthen the core the first question we need to ask is, for what? The strength gained from an exercise is specific to the movement, load and speed of the exercise.
If we struggle to sit ourselves up when we get out of bed in the morning then crunches may be a very useful exercise. But when was the last time you went to get up in the morning and found you couldn’t lift your upper body up, you tried to but could barely lift your upper body off the bed?
Typical daily activities that we could benefit from a stronger core would be walking, bending down to pick up a child or shopping bags, gardening, sweeping, walking up and down stairs, playing with children or pets and playing sport.
How many of those activities involve lying on your back and raising yourself half way up using your stomach muscles? I know what you are thinking – “ Ok you may have a point but when I do crunches I feel my abs work and I want to have good looking abs so they cant hurt can they?”
The short answer is yes doing crunches can make your core worse and if you want good looking abs there are far better ways than doing crunches.
How can crunches possibly weaken your core?
Crunches teach the rectus abdominus ( the 6-pack muscle) to work together with the external oblique’s (and to a lesser degree the internal oblique’s) to perform a partial sit up. During this exercise relatively few other muscles such as your hip muscles are involved since you are lying on your back. The more you do of them the more the brain becomes adept at contracting these muscles without any other muscles working.
Now when we actually go to perform a useful activity such as playing with our kids or playing sport where we need our abdominal muscles to co-ordinate with our hips, lower back, middle back and shoulder blade muscles the brain doesn’t know how to perform this as it is used to activating the abdominals with no other muscles working.
It would be like a musician in an orchestra who has never practised with anybody else suddenly asked to play at the Royal Albert Hall with an entire orchestra. The musician would lack the skills to co-ordinate their playing along with the other members of the orchestra. No amount of practising by themselves will ever prepare them to play in an orchestra. In fact the more they practice by themselves the more bad habits they will fall into making it harder to become adept at playing with an orchestra.
Now think of the orchestra as the human body with all its muscles, tendons and ligaments all working together to produce effective movement. If we train just a few of these muscles in a way that doesn’t teach them to integrate with the rest of the body then we are making our core WORSE.
Can crunches improve my posture?
The more you perform an exercise the more the muscles adapt. Have you ever noticed some of the big guys in the gym who walk around with their arms half bent because they have dome so much bicep work their biceps wont allow them to extend their arms fully? The same can happen with your stomach muscles. If you perform lots of crunches without balancing it up with lots of middle back extension work your posture will become more rounded , I’m guessing the hunchback look is probably not the one you are after!
What about just getting great looking abs?
Lets ignore everything I’ve just said and pretend you don’t care that doing crunches will make you more susceptible to injury , will increase the chances of back injury, worsen your posture and make you less able to integrate your core with the rest of your body. Lets say the only thing you care about is getting a six pack. Surely crunches must help that?
As you can probably guess, no. I have never met a client or person who wouldn’t have a six pack if it wasn’t covered with a layer of fat. Almost everybody could have a six pack if they managed to lower their body fat to under 10% for males and 20% for females ( approx). So if lowering body fat is the key to getting a six pack how much effect do you think lying on the ground ( or ball) performing crunches will have compared to another set of squats or push ups?
Big compound exercises that get your heart rate up and high intensity interval training is the key to a six pack.
Just an interesting aside – did you know you core works more during a squat than it does crunching?
Crunches – are they any good at all?
For most people they will weaken your core leading to more chance of back pain. If you play a sport or do an activity that involves sitting up from the ground (I cant think of any but there may be some) then crunches may be a good exercise.
SO if you want to weaken your core , waste your time, increase the chance of injury , worsen your posture then crunch away. If however you want to improve your core strength, improve your posture, become better able to handle your daily activities and have great looking abs then have a look at this Yes its targeted to runners but it will give you a much better understanding of what you should do to work your core now that you know what you shouldn’t do.
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