|Photo by Larkery|
One cause of low back muscle strain is having an unhealthy spine through habitual poor posture. If you sit all day in a slumped position, your low back is loaded into a forward or flexed position, and the muscles of your back are continually stretched. As a result, you may be more likely to strain a back muscle from light tasks such as loading/unloading the dishwasher.
Not only does slouching affect your back muscles, but it causes your disks to bulge backwards. The more pressure from bad posture, the more likely your disks cannot realign properly. This leads to pinched nerves, which shoot pain or other symptoms down your leg(s), such as sciatica.
On the other hand, those with a healthy spine (through repetitively good posture and exercise) may tolerate light tasks but strain their backs when doing more strenuous work such as moving furniture. It is important that both individuals practice good posture and body mechanics in order to avoid straining the low back during routine daily tasks, and especially during difficult physical activities.