Should you strengthen your low back muscles with back extensions?

If you’ve been told to strengthen your low back muscles, it’s completely understandable you might think turning to back extension exercises is the way to go. After all, the more you work the muscles the stronger they’ll get, right? Well, not necessarily.

Just because your back muscles are strong does not mean you will be able to avoid back pain; I know plenty of really strong people who struggle with a bad back. Back extensions are not the answer, but there are other options. 

What do I mean by back extension exercises?

 When I talk about back extensions there are two types of exercise, in particular, that I am referring to:

1. Using a rack, leaning your hips onto the cushioned part and bending forwards. 
2. Laying on the floor, lifting your chest up and bending backwards.

How do back extensions impact on your spine? 

It’s important to understand the impact that exercises such as back extensions can have on your spine and the muscles surrounding it.

But first let’s look at a little anatomy, focusing on a couple of muscles in the lower back, the longissimus and the iliocostalis. These adjoin your lower back and go all the way up your spine to your ribs and even up as far as your neck – on the video above you’ll see diagrams to illustrate this. 

When you extend the spine, whether by bending it extensively forwards or backwards, these muscles act like hands twisting and squeezing a sponge, exerting a huge force of compression on the spine. In fact, it’s been calculated that the first of the exercises mentioned above puts 4,000 newtons of compression around your spine, while the second, 6,000 newtons. The equivalent of 400-600 kilos of compression around your spine essentially squashing it. That’s a lot of pressure that may not directly cause back pain, but would certainly, over time, contribute to spinal issues. 

So what can you do instead? 

Obviously, any amount of movement in the longissimus and the iliocostalis will exert a certain amount of pressure on the spine, that’s how they’re designed to work. The goal is to minimise this stress, keep it to a manageable amount and avoid spinal fatigue and risk of pain. 

In order to exercise the same muscles in a more therapeutic way, I always recommend using the Bird Dog exercise. That is kneeling on the floor placing your hands in front of you, shoulder width apart and then lifting your opposite arm and leg alternately.

Watch the video for a demonstration of this technique.

The Bird Dog still exercises the relevant muscles but puts much less stress on your spine, 3,000 newtons, up to half the amount of the back extension exercises. 

And it’s not just about strengthening, it’s about protection too

Alongside the Bird Dog, it’s worth doing some work to strengthen your abdominal muscles or core, the plank or side plank for instance. When these muscles are activated at the right time and in the right way they will act as protection for your spine, helping it to tolerate a greater load safely.

You’ll find an overview of how to carry out the plank correctly as well as the Bird Dog in the tutorial 4 exercises that strengthen your stomach muscles without wrecking your spine. 

Back training for rehabilitation or pain prevention should be about building resilience and robustness of your core so it is able to stabilise and support your spine. Setting out to strengthen the longissimus and iliocostalis directly using back extensions is more of a body building technique not a therapeutic one. It may give you stronger back muscles, but not necessarily a healthier spine or pain free back.