When John came to see me with a recurrence of his back problem he was really fed up. He had been going to the gym and doing the core stability exercises that he had been shown by the instructor. He had been exercising two or three times a week since his bad back had recovered 3 years before and he felt fit and strong. His back felt great too. He didn’t do anything to upset his old problem – it just came on. Unfortunately he had been doing the wrong back exercises. The exercises he had been doing actually contributed to his back pain.
The last time John’s back was bad all he needed was a short course of chiropractic care and he was fine again. He wanted to prevent his back getting bad again so decided to get fit. Usually this is a good idea. People who exercise regularly tend to get a lot less back ache.
John asked the instructors at the gym to put together a program with his back in mind. The program they came up with included a mix of upper and lower body exercises and abdominal exercises to help with core stability. The program relied heavily on machines to provide the weights and resistance – even for the abs. Here is the first problem.
Abs machines, the sort where you sit in them with straps or a bar across your chest, can aggravate back problems. Worst of all they aren’t that good at working your core stability muscles which are important for back strength. There are safer and more effective abdominal exercises that are easy to do – when you know how.
John was doing two other exercises that could also be irritating his low back. The first one was a deadlift. Deadlifts are one of the commonest reasons gym users end up at a chiropractors. Even when done well there is a risk of damaging the low back discs. When done badly they can destroy a healthy back.
The other exercise that concerned us was a leg press. In this exercise you sit in the machine, load up the weight and push a plate away from you with your feet. Because your leg muscles are so strong you can move large weights. Lifting your own body weight is not that unusual. Again this is a disaster for the back, not because of the weight itself but rather that your low back is flexed forward when you load it up.


If there is one thing the low back discs hate it is bending forward and then having a load applied as happens when you lift something. The reason has to do with the architecture of the disc itself. The disc consists of a tough outer wall with a jelly inside. Some have likened it to a doughnut but I prefer thinking of it like a toffee eclair. As you bend forward the toffee like core is forced backwards against the back wall of the disc. If you compress the disc in this position, as you do when you lift a weight or do a leg press, then the core or nucleus, exerts huge forces against the wall. This can cause the wall to crack.
Once that tough outer coat splits or cracks then pain can come on. The pain can last for a very long time and be intense. If the crack is big enough then the toffee can ooze out and press on the nerves causing sciatica. Because the disc is slow to heal the pain can become chronic.
The good news is that other exercises can easily strengthen the low back, allowing the discs to heal and help prevent further pain. In the second part of this article we will show you how to exercise safely at the gym and protect your back from harm.
Update:
Following criticism on Twitter by several physio’s of the piece above I thought it would be useful to provide the reference for the views expressed. Most of the work comes from an excellent book by Prof Stuart McGill Low Back Disorders – Evidenced Based Prevention and Rehabilitation published in 2007. In a 27 kg deadlift McGill found the compression and shear forces amounted to 7000N – enough to damage some weak spines.
On an anecdotal basis we regularly see people who claim to get back pain associated with certain gym exercises. Deadlifts are the commonest cause amongst these by a long way. In the case above, John was in a 1:1 training session with a gym instructor so can be assumed to be doing the exercise correctly. He still got injured and he felt the moment his back went on the deadlift.
There are other safer ways of exercising the muscles worked in a deadlift and we prefer to recommend these. There are some people who will benefit from deadlift training , especially if their work or play requires conditioning in these movements.
Matthew Bennett
Picture credit: Adrian Valenzuela