Give It A Curl!

Many athletes are quite familiar with hamstring injuries sidelining their play. Risk factors commonly cited for this occurrence are strength deficiencies and shorter fascicle lengths (Bourne et al., 2018). Sports that involve sprinting, jumping, rapid accelerations, decelerations and change of direction place high mechanical loads on the lower body. The hamstrings, in particular, must handle significant eccentric forces.

Whether prehabilitative or rehabilitative, the Nordic curl is often incorporated to improve the eccentric capacity of this biarticular musculature. Ample electromyographic studies have demonstrated the varying contributions of the biceps femoris (long and short heads), semimembranosus, and semitendinosus depending on the muscle-tendon unit lengths. In comparison to the Roman chair or single leg dead lift, the Nordic curl generally has the highest peak hamstring muscle forces and results in more fascicle lengthening (Van Hooren et al., 2022).

The utility of this exercise is frequently undermined due to its poor execution. As an example, the latter half of the motion poses increasingly higher knee flexor activation due to the effects of gravity as the trunk tilts forward. This is specifically where athletes’ vulnerabilities are exposed with many not having the strength to handle the loads at greater knee angles. These small degrees of knee flexion are also the positions where injuries frequently appear. By altogether abandoning this position the athlete misses the opportunity to strengthen themselves where they need it the most. Likewise, if the athlete isn’t properly anchored, they won’t be able to achieve the desired range. Another person may not have the ability to maintain their partner’s lower legs in place at these ranges either.

In addition, in order for the patella to slide properly along the patellofemoral groove the knees should be free and not pressed into the ground. If the lower legs are parallel to the floor, it will also allow an athlete to reach greater knee extension in comfort.

 …now give it a curl!