Hamstring tightness is a common issue especially for those who participate in prolonged sitting. For those with a need or desire for increasing hamstring flexibility and hamstring strength, the individual’s foot position may be an important factor to take into consideration during exercises.
There is a common misconception that “grabbing the toes” is a key technique in facilitating a hamstring stretch.
A short anatomy lesson
There are several muscles that act to flex the knee joint. The “hamstrings” are a combination of Biceps Femoris, Semitendinosus and Semimembranosus which all act to flex (bend) the knee joint as well as extend (straighten) the hip joint. The Gastrocnemius (calf muscle) also works to flex the knee and connects to form the Achilles tendon and also serves to plantarflex the ankle.
To stretch the calf, it is best to dorsiflex (toes towards the body) the foot while keeping the knee extended (leg straight) to create the longest possible path for the muscle. Similarly, to stretch the hamstring, we must create the longest possible path for the muscle by flexing at the hip and extending at the knee.
The problem that arises is that the calf has a relatively short belly with a long tight tendon. The calf muscle can be stretched with only a few degrees of ankle dorsiflexion. The calf is usually stretched to its max well before the hamstring. This is why we often suggest you stretch the “true Hamstring” first and then stretch out the whole leg incorporating the calf muscle.
To address hamstring flexibility, we must remove the stretch of the calf by pointing the toes away from us. Practically, hip flexion can be increased and the stretch feeling moves up from the back of the knee into the belly of the hamstring.
Effect on Other Hamstring Exercises
As has been mentioned to gain a better Hamstring stretch the calf muscle must be limited by pointing toes away from the body rather than back towards the body, this should in turn help promote correct muscle recruitment.
An example of applying this concept occurs when using the lying leg curl machine. The exercise usually involves lying face down with resistance just above the heel. Flexing the knee while the foot is in dorsiflexion can result in a predominately calf strengthening exercise rather than the hamstring strengthening that is desired. Often the calf is weaker and although it feels like there is more tension, the calf is dominating the movement and the hamstring is underutilised and improves at a slower rate. To effectively target the hamstring in this exercise, the toes must be pointed away to negate the calf’s activity. This is why for most clients we suggest a Swiss ball leg curl rather than using the lying leg curl machine.