Why Strength at Long Muscle Lengths May Matter for Injury Prevention

Most Strain Injuries Happen at Long Muscle Lengths

A large proportion of muscle strain injuries — hamstring injuries during sprinting being the classic example — occur specifically when the muscle is under high tension while in a lengthened position, such as during the late swing phase of running.

Training Specifically Where the Injury Occurs

A landmark trial comparing two hamstring rehabilitation protocols found that a programme specifically emphasising strength training at long muscle lengths (the "L-protocol") produced a substantially lower rate of hamstring re-injury over the following year compared to a more traditional protocol emphasising shorter-length exercises (Askling, Tengvar & Thorstensson, 2013).

Why Training the Vulnerable Range Builds Resilience

The underlying logic is straightforward: if an injury occurs because the tissue lacks the capacity to tolerate load in a specific lengthened position, the most direct way to address that deficit is to progressively build strength precisely in that position — rather than relying solely on strength built at shorter, less vulnerable muscle lengths to transfer protection to the range where injuries actually occur.