Jefferson Curl (J-Curl) Think of this as a controlled, slowly rounded, stiff-legged deadlift. From Sommer: “Progress slowly and patiently. Do not rush. For this type of loaded mobility work, never allow yourself to strain, grind out reps, or force range of motion. Smooth, controlled movement is the order of the day.” The ultimate goal is body weight on a bar, but start with 15 pounds. I currently use only 50 to 60 pounds. This can perform miracles for thoracic, or mid-back, mobility, all while helping the hamstrings in the pike position.