Hamstring Training: Anatomy and Function

The majority of individuals, and I include athletes in this, have pretty shocking hamstring development. The importance of the hamstrings cannot be underplayed in sport and exercise, they are crucial for so many reasons. Why then, does it seem as if their training is little more than an afterthought in conventional programming? The hamstrings need specific attention in order to get the most of out of them; a few sets of leg curls at the end of a workout simply won’t cut it.

In order to work out how to train them, we need to know what they do. Here’s a little hamstring refresher for you.



The hamstrings are bi-articular – this means they function over two joints. As a group, they act concentrically (to shorten) to provide flexion at the knee, extension at the hip and rotation of the tibia. They comprised of these three separate muscles:

  • Biceps femoris:

Originates from the ischial tuberosity of the pelvis (long head) and lower third of the posterior aspect of the femur (short head) and inserts on the head of the fibula. Concentrically provides knee flexion, hip extension and external rotation of the tibia.

  • Semimembranosus:

Originates from the ischial tuberosity of the pelvis and inserts on the posterior aspect of the medial condoyle of the tibia. Concentrically provides knee flexion, hip extension and internal rotation of the tibia.

  • Semitendinosus:

Originates from the ischial tuberosity of the pelvis and inserts on the posterior aspect of the medial condoyle of the tibia. Concentrically provides knee flexion, hip extension and internal rotation of the tibia.

Now, there are other muscles that work synergistically with the hamstrings over the hip and knee joints, but we won’t go into the details until we break down the exercises.

Fibre Type

The hamstrings are predominantly composed of fast twitch muscle fibres; about 70% or so. When you consider that muscle groups such as the glutes and quadriceps are about 50:50, we can see that the hamstrings are designed for high forces and high velocities. A little look at how we need them to function helps tell us why.

Hip Extension

Triple extension (ankle, knee, hip) is the basis for running, jumping and squatting, the foundations of movement. Hip extension is the most powerful and important component of this triple threat. Although the glutes are the main workhorse of hip extension, the hamstrings are thought to account for about a third of the torque generated. They have a key role in providing propulsion and need to be trained accordingly.



Nothing screams hamstrings as much as sprinting, just as nothing makes your hamstrings scream as much as sprinting. The hamstrings play a dynamic and complex role during locomotion, their function changing from phase to phase. We need to be aware of these functions in order to train for them effectively. Here’s a little phase-by-phase breakdown:

  • Support phase: co-contract with the quadriceps to stabilise the knee.
  • Propulsive phase: assist in hip extension to provide the propulsive force.
  • Early recovery phase: flexion of the knee to cycle the leg ready for the next stride.
  • Late recovery phase: provide eccentric control as the knee extends in front of the body.


The hamstrings play a crucial role in providing stability at the knee joint, probably the most fundamental function they serve. They function eccentrically and/or isometrically to control and decelerate knee flexion, think exercises such as heavy split squats or lunges. Well-conditioned hamstrings provide an effective co-contraction with the quadriceps, working to reduce anterior shear force, knee valgus and rotation of the tibia. Remember the rule of specificity, we need to train in deep flexion in order be strong in this range. You’ll be missing a trick if you’re not.


In the next instalment, later on this week, I’ll show you how to break up hamstring exercises into categories and ensure that you’re covering all the angles.

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  1. Pingback: Hamstring Training: Knee Flexion | Maloney Performance

  2. Sean,
    Doing some research and came across you site, I like your articles on hamstring development. I also read one of your recent posts on Proprioceptive neuromuscular facilitation, what are your thoughts on using this technique and the prevention of hamstring tears for field sport athletes?

    • Maloney Performance

      Hi Chris,

      Thanks for the comment. I don’t think it really has much of a place in the prevention of hamstring injuries, limited ROM doesn’t really predispose injury from my own experience – research is mixed though. Hamstring tightness can be a good thing in some athletes – a concept called protective tension – as it helps create stability. In some athletes stretching may therefore increase risk. The most important thing would be to strengthen the hamstrings eccentrically with exercises such as RDLs and Nordics, these will both strengthen and increase ROM. Backwards running may be a good idea too, I know Dan Pfaff has talked about lower incidence of injury in groups/positions with more backward movements.

      Hope this helps,

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