One of the biggest shifts in hamstring research over the last 20 years is the importance of strength at longer muscle lengths. Because hamstring strains typically occur during the late swing phase of sprinting. At that moment, the hip is flexed, the knee is extending, and the hamstrings are near their longest length while producing extremely high levels of force. Research has shown that training at longer muscle lengths can shift where the hamstring produces peak force. In simple terms, the muscle becomes stronger in the stretched positions where injuries commonly occur. Researchers have also found increases in hamstring fascicle length following long-length eccentric training. Longer fascicles appear to reduce the amount of strain placed on individual muscle fibers during high-speed running. That’s one reason exercises like RDLs, Nordic curls, razor curls, and other long-length hamstring variations continue to show up in high-level athletic programs. The goal isn’t to make you...