If you have back pain, you probably don’t lift objects the same way as someone without back pain. There are strength differences between people with and without back pain. But how much load does the spine take when someone with back problems lifts compared to someone without back pain?
This was the question a group of researchers in a movement laboratory set out to answer. Using a new method of measuring muscle activity, the researchers evaluated how low back pain affects spine loading during lifting activities. “Load” refers to vertical (up and down) pressure through each bone of the spine. The researchers also measured the force of one bone moving against another in a sideways motion, called lateral shear.
People with low back pain showed much higher readings for both types of spine forces than people without pain. To be exact, they had 26 percent more spine compression and 75 percent more lateral shear. The greater loads were caused by the other muscles that contracted to help protect the low back.
This information is important because studies have shown that increased loads on the back can lead to degeneration of the discs. The disc is a jelly-like substance between each vertebra in the spine. It offers a cushion of protection for the spine during movement. For people with back pain, loading the spine can lead to further spine damage and long-term back problems. This is especially true when people lift heavy weights over a long period of time.
The study also compared the loads that come from lifting different weights at different heights. As expected, lifting heavier weights from down low increased the load on the spine the most. Excessive body weight also put extra strain on the back by adding to the compressive forces through the spine.
From these results, researchers can make recommendations for people with low back pain. First, anyone with back pain who is returning to work should arrange the workplace so that lifting is done from waist height. All objects should be lifted close to the body, with the arms close to the body. Second, lifting activities should be broken up and alternated with other tasks. This can help prevent a cumulative load over a long period of time. Finally, reducing body weight during the recovery process is very helpful in unloading the back.