Many people complain about lower back pain during and after abb workouts in the gym. There are two main reasons as to why is not widely understood in the sporting community.
Probably the least understood culprit of low back pain during crunches and other abdominal exercises is the role that the hip flexors have in bringing the trunk upwards during these movements. As seen in the picture below the major hip flexors originate in the lower back and cross over the hip joint to attach onto your femur. In ordinary movements such as walking their role is to bring your leg upwards. However, they also contract in the opposite direction when your lower legs are stationary in order to bring your trunk upwards during the crunch movement.
This can become a problem when excessive load is placed through the hip flexors instead of the abdominal muscles, or if they are unusually tight (office workers have this problem frequently due to sitting for extended periods!).
The other major issue that can cause lower back pain with abb exercises is to do with advanced abdominal exercises being performed before the abdominals can sufficiently control the movement. The end result of this is excessive lower back extension (bending backwards) which is felt as pain. A great example of this is dragon flags. If the abdominals cannot control the downward phase of this movement the lower back bends too much and people can and do experience pain in their lower back.
The simplest solution to both of these problems is to perform abdominal exercises that are appropriate for your strength level in order to prevent too much lower back extension. In order to minimise the influence of the hip flexors during crunches and other exercises is to ensure that your lower legs are not being fixed by an external source – such as someone holding onto your legs. This allows your hip flexors to work harder than your abdominals. Additional stretches can be done to help loosen the hip flexors which in turn reduce the compressive load being placed through the lower back.
The last aspect to touch on is form! It is critical that when performing abdominal workouts to roll through the movement bringing your ribs towards your hips as opposed to keeping a straight back and bringing your shoulders upwards. This places more bias on the hip flexors and by now I’m sure you can guess what occurs when that happens.
If you ever need further advice on lower back pain, correct form or gym programming feel free to come by your local north perth physio clinic PhysioLogix for a consultation.