Lumbar paraspinal compartment syndrome is an uncommon cause of acute lower back pain. It can result from intense physical activity or as a complication of surgery or medication. Lumbar paraspinal compartment syndrome without external trauma is rarely reported in literature. We report a case of compartment syndrome that followed back muscle exercise and caused rhabdomyolysis. MRI findings include bilateral bulging of the paraspinal muscle, hyperintensity on T2-weighted image, and heterogeneous enhancement. Moreover, loss of intramuscular vasculature on a contrast-enhanced CT scan attributed to diagnose compartment syndrome in this case.