Basic Anatomy of Stretching the Hamstrings

*Updated 4/27/18
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There are four muscles that make up what we call the 'hamstrings', which are located on the backside of your thigh. The muscles are:

Additionally, part of the adductor magnus acts as a hamstring muscle by function.

By standard definition, we will consider the 4 muscles listed above in the bullet points to be the hamstrings as a group.

When talking about a muscle or a muscle group, it's important to know where the muscles attach because you will then know how it affects the joint(s) the muscles cross.

Some muscles cross multiple joints and some cross only one. When a muscle crosses two joints it's called a biarticular muscleBi meaning two and articular meaning joint (a joint in medical language is often referred to as a bony 'articulation').

Three out of the four hamstring muscles are biarticular. They cross the hip joint and the knee joint. Only the short head of the biceps femoris is a uniarticular joint (crossing one joint). It crosses only the knee.

The three muscles other than the short head begin on the ischial tuberosity, a part of your pelvis. They then travel down the back of your leg and attach below your knee joint.

The biceps femoris muscles are on the outside or lateral part of your thigh and attach on the lateral part of your lower leg.

The semimembranosus and semitendinosus attach on the medial or inside part of the lower leg.

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Indications for Stretching

Whenever a muscle crosses more than one joint, as do three of the hamstring muscles, we have to consider the position of both joints and how that affects stretching. It's usually much easier to stretch a biarticular muscle than a uniarticular muscle because you can move multiple joints to stretch it.

Arguably you are unable to stretch the short head of the biceps femoris. Since the vast majority of people can fully lock the knee joint, the limitation is never the biceps femoris.

Since the other three mucsles cross the hip joint, you can stretch them across the knee and hip joint.

When the hip joint goes into flexion and the knee stays in extension (knee straight) you are able to stretch those three hamstring muscles.

If the low back (lumbar spine) is flexed (rounded), it makes it harder to stretch the hamstrings because it brings the ischial tuberosity closer to the other attachment point.

To stretch a muscle you have to separate the connection points of the muscle from each other.

How to Stretch the Hamstrings

Now that you understand the basic anatomy of the hamstrings and how that relates to stretching (make sure to watch the video if you can't visualize it from just reading the text description), what are methods for actually stretching the hamstrings?

That deserves it's own post and video, which you can access here.


In this post you learned the following:

- The names of the 4 hamstring muscles
- Part of the adductor magnus performs a hamstring action
- What a biarticular and uniarticular muscle are
- How positioning the bones and joints that muscles cross affects the stretch
- A link to a specific post and video to stretch this area of your body

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Lower back and hip mobility program product photo

Need help with your lower back and hip mobility?

Follow our program, which will show you exactly what to do and how

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