When you bend at the low back, you increase the muscular demands, the tension on the ligaments, and the pressure in the discs of the low back.
In this picture, a flexed spine contributes to abnormal stresses.
The pressure and stress increase when you lift heavier objects and if this is done repetitively, the cumulative effect can also cause injury and back pain.
Here are some rules to remember:
- Warm-up before you lift.
- Have a Plan Before you Lift – make sure you have a clear path to where you would like to set down the object you are lifting.
- Test the Load – if the load seems too heavy for you, make sure you have someone help you out.
- Keep your back relatively straight and bend your knees. Tighten your abdominals to stabilize the low back before you lift.
- Keep your feet slightly greater than shoulder-width apart so you have a good base of support.
- Use the power of your thighs to lift the load. Your gluteal and thigh muscles are much more capable of lifting heavy objects.
- Keep the load close to your body at the level of your waist if possible. This decreases the torque on your low back.