There are two main reasons for lumbar pain after more work: First, because of the greater force during work, resulting in excessive tension and fatigue of muscle tissue to form strain, will produce more local metabolites, usually in the activity of the blood circulation is faster, so the accumulation of metabolites is not obvious, so the symptoms are not obvious, but after the work of rest state blood circulation will appear But after work, the blood circulation will drop, which will lead to an increase in the accumulation of metabolites, so the pain symptoms of the waist will appear after more work. Second, because the waist itself has a chronic aseptic inflammatory lesions, such as previous lumbar injury, not completely healed state on the waist activities, resulting in the formation of local elasticity and toughness of the decline. After more work will lead to the location of the elasticity decline, again by excessive stretching stimulation and new injury, will also appear back obvious pain symptoms.