We report six cases of a novel syndrome of acute, exertional low back pain in football players, five in college and one in the National Football League. All six are African Americans with sickle cell trait (SCT). The acute low back pain is severe and can be disabling, and the condition can be confused with muscle strain, discogenic pain, stress fracture, or other problems in athletes. Our evidence shows that this syndrome is caused by lumbar paraspinal myonecrosis (LPSMN), which likely often contributes to the lumbar paraspinal compartment syndrome. We explain why we believe SCT is a risk factor for LPSMN in football conditioning/training, although SCT is not requisite for this syndrome, which has been reported rarely in other sports (e.g., snow or water skiing) and especially in weight lifting that targets lumbar muscles. The clinical course of LPSMN in football can be mild and allow return to play in a week or two, or it can be severe and lead to long-term sequelae. Knowledge of this syndrome will enable athletic trainers and team physicians to diagnose it early, treat it properly, and lessen its effect. Further research will help us learn how better to prevent it.