Better exercises to stretch the hamstrings

Posted on July 29, 2013

(Last Updated On: April 6, 2016)

Before we can understand the how to stretch the hamstrings, we need to understand how they work.


Common hamstring talk:

The hamstrings are three muscles. The semimembranosus, semitendinosus, and biceps femoris, which has a long and short head. The semis are inside (medial), the biceps outside (lateral). They all start at the top of the hip behind your ass (ischial tuberosity), and connect below the knee.

Hamstrings with cadaver

Because they cross two joints, the hip and the knee, they have two actions, one at the hip; one at the knee.

They pull the hip back, hip extension:

Hip extension

And pull the knee back, knee flexion:

Knee flexion hamstring action

Uncommon hamstring talk:

Because the hamstrings start at the pelvis, then can exert a force there as well. The hamstrings can pull the pelvis down, posteriorly tilting it and concurrently flexing the lower back:

Anterior tilt posterior tilt pelvis

Left = Lumber extension.
Right = Lumbar flexion.

Never mentioned hamstring talk:

As said, the hamstrings connect below the knee, at the tibia and fibula. Not said, the hamstrings connect on the sides of these bones.

Semimembranosus connecting inside (medial) to the tibia:

Semimembranosus hamstring muscle

Semitendinosus connecting inside (medial) to the tibia:

semitendinosus hamstring muscle

Biceps femoris, long and short head, connecting to the outside (lateral side) of the fibula:

biceps femoris long head hamstring muscle

Biceps femoris short head hamstring muscle

Because of these attachments the hamstrings can exert a rotational force at the knee. The medial hamstrings, semimembranosus and semitendinosus, can rotate the bottom portion of the leg inward; the lateral hamstring, biceps femoris, can rotate the bottom portion of the leg outward.

Rotation at the tibia

Left side = Medial hamstrings.
Right side = Lateral hamstrings.

Finally, the hamstrings form a connection with the gastrocnemius, the calf, which forms a connection down to the foot. Courtesy of the Anatomy Trains philosophy:


Superficial backline anatomy trains

You can see the connection with the back as well.

Main takeaways

From top to bottom: The hamstrings are involved in

  • Lumbar flexion
  • Posteriorly tilting the pelvis
  • Extending the hip
  • Flexing the knee
  • Rotating the tibia
  • And are related to ankle plantarflexion

Reversing these actions, we can potentially increase the effectiveness of stretching our hamstrings when we:

  • Extend the lower back
  • Anteriorly tilt the pelvis
  • Flex the hip
  • Extend the knee
  • Rotate the tibia in either direction
  • Dorsiflex the foot

Let’s start stretching those bastards.

But are they even tight?

Assessing the hamstrings posture

The most common assessment out there people seem concerned with is an anterior pelvic tilt.

anterior pelvic tilt alignment

Because the hips are rotated anteriorly and the hamstrings pull the pelvis posteriorly, it’s common to assume the hamstrings are “weak / lengthened” in an anterior pelvic tilt. As we’ve gone over though, the hamstrings play a role in what happens at the hips and the knees. If we only look at the hips we’re missing half the picture.

Neal Left Side (Less Quality)

Neal Left Side Plumb Line

A person who appears to have some anterior pelvic tilt:

Neal Side Pelvis Close Up

May also appear have some knee flexion going on:

Neal Side Knee Lines Close Up

The hamstrings may appear lengthened at the hip attachment, but they are, if anything, shortened at the knee connection. Think of a rubber band, if you pull the rubber band out from one end but bring it in from the other, what happens to it? Nothing. It doesn’t get stretched.

Because muscles aren’t exactly like rubber bands, from the above photos we could deduce: The hamstrings are perhaps underactive in hip extension but overactive in knee flexion. Helping to understand why, “Strengthen the hamstrings” isn’t a solution for an anterior pelvic tilt. Or, contrary to the internet world, why “Just deadlift” does not solve everything. This is the type of person who should probably stop deadlifting for a while. (It promotes lumbar extension / anterior pelvic tilting and knee flexion.)

We need to look at the knees in a posteriorly tilted hip as well. Even though the hamstrings are tightened at the hip attachment, they may be lengthened at the knee attachment. The knees may be in hyperextension:

Posterior Pelvic Tilt hips extended

Posterior Pelvic Tilt hips extended with lines

So again, our rubber band is being pulled from one direction but getting slacked from the other.

What the hell is going on here?

It’s all relative

When faced with these types of situations we’re forced to asked things such as the following:

  • Is the amount of anterior pelvic tilt greater than the amount of knee flexion?

For instance (numbers are for example purposes), if the pelvis rotates anteriorly 5 inches (lengthening the hamstrings 5 inches), but, the knees flex 8 inches (tightening the hamstrings 8 inches), then overall, the hamstrings have been tightened 3 inches (8 – 5 = 3).

  • Is the amount of posterior pelvic tilt greater than the amount of knee extension?

For instance, if there’s a posterior pelvic tilt of 5 inches, then the hamstrings are tightened 5 inches. If there’s a simultaneous 2 inches of knee extension, lengthening the hamstrings 2 inches, then the hamstrings have been (overall) tightened 3 inches (5 – 2 = 3).

Another example. Apparent anterior pelvic tilt with significant hip extension going on:

Neeraj Side (Less Quality)

Neeraj Side (Less Quality) Plumb Line

Neeraj Close up Pelvis

Even though the presence of an anterior pelvic tilt causes one to assume the hips are automatically in flexion, you can see quite a bit of hip extension going on:

Neeraj Side (Less Quality) Hip extension lines

And what extends the hips? The hamstrings. If the hip are in extension the hamstrings may actually be shortened, even with an anterior pelvic tilt going on. An APT is not a clear indication the hips are flexed.

Rotation at the knee

Remember, the hamstrings don’t just work in a forward and back motion. They play a role in twisting too.

This is much simpler. Look at the front of the knee and foot. Do they face the same direction? Or different directions?

Right knee (left in picture) almost straight; left clearly turned in:

Jeremy front knee lines

You can also assess this by looking at the back of the knee. Do both hamstrings (medial and lateral) appear the same? Or is one more prominent than the other?

Medially rotated femur

RIght leg: Notice the medial hamstring is more prominent than the lateral.

Jennifer back hamstring crease

Often the knee will point inward and the foot outward. Meaning the femur is rotated inward and the lower leg outward.

Feet turned out knees turned in with lines

Some people out there, whom I really respect, seem to believe this is indicative the medial hamstrings are overactive. I’m not so sure. Because the medial hamstrings connect below the knee, I’m not convinced they can exert a medial rotation above the knee at the femur. I think the adductor magnus may have a more important role as it connects to the lower femur.

adductor magnus

As well as indicative the lateral hamstrings (biceps femoris) are working overtime, as the rotate they bottom leg outward.

At the end of the day though, this doesn’t really change our approach to loosening the hamstrings.

For now, understand:

  1. The hips only tell part of what the hamstrings are doing.
  2. The hamstrings play a role in rotation at the knee.
  3. Assessing the hamstrings in movement is crucial. Posture only tells us so much.

After all that, rather than trying to eye ball various alignments and rack your brain with anatomy,

Just make the person move

Before I go over how I like to assess hamstring length, let’s go over issues with other methods.

Toe touching

Seated Toe Touch Hamstring Stretch

The most obvious issue with toe touching is it promotes lumbar flexion.

Standing Toe Touch

If the lower back rounds there’s a very good chance -even if the knees are kept straight- the hamstrings are being lengthened from one end but tightened from another. Meaning we’re not really assessing their length.

During a toe touch a certain amount of lumbar flexion is expected, and what we’re really concerned with is the amount of lumbar flexion relative to hip flexion, but I find this is too hard to eye ball and just not necessary to deal with. And flexing people’s backs is rarely advised.

Moving on.

Active straight leg raise 

I’m by no means an expert on the Functional Movement Screen. Forgive me if I misrepresent things. 

The active straight leg raise in the functional movement screen (FMS) seems to be a popular method of assessing hamstring length. I’ve heard some repeatedly state it’s actually not a hamstring length test. Rather, it’s an assessment for the pattern of a straight leg raise test. However, in Gray Cook’s (inventor of the FMS) Movement book he states the test is “much more than a hamstring length test.” Leading me to conclude it’s, amongst other things, a hamstring length test. Plus, everyone seems to use it for hamstring length.

Active Straight Leg Raise Hamstring flexibility

Here’s why I’m not big on this assessment.

1) You need to be cognizant of the hip capsule

A common movement issue at the hip is lack of posterior glide of the femoral head. Because of this the femur tends to glide too far forward (anteriorly). This will often happen during hip flexion, especially maximal hip flexion. What does the active straight leg raise attempt to do? Significantly flex the hip.

What may appear as limited hamstring flexibility may actually be the femoral head gliding forward into the pelvis. The bones may clunk together -why people with hip pain often feel pinching and catching- preventing further hip flexion.

Hip picture normal

Hip pain ABnormal

By providing some posterior glide for the person you may suddenly find they have a greater amount of hip flexion and hamstring flexibility than originally thought.

Passive straight leg raise w:Glide

Right hand is providing posterior glide.

2) The pelvis isn’t starting from a true neutral and can move quite a bit

When a person is completely supine (on their back) the lumbar is flat, which means -compared to a normal amount of lordosis- it is flexed, meaning the pelvis is posteriorly tilted, which shortens the hamstrings from the hip attachment.

When you then attempt to fully flex the hip and extend the knee, even if the person gets to 90 degrees, the hamstrings aren’t completely on stretch. Granted, if the person can’t straighten their leg with the lower back flexed they aren’t going to be able to do it with the lower back extended. (So I’m likely being a bit too picky here.)

Going right with this, you need to make sure the person doesn’t allow any greater amount of posterior tilting as the leg raises.


Supine Hips Flat Good

Often turn into this,

Supine Hips Raising

I’m not sure if this is something the assessment is designed to look at. It very well could be. But from how I’ve seen people use this assessment, it seems ignored.

A better way

We can take principles from the active straight leg test and then make it better. We keep the person supine, but instead of actively raising the leg, we passively pull the knee in.

Supine Knee Extension starting position

This helps generate posterior glide on the femoral head, giving us a greater chance of not irritating the hip in any way. From there, we can then actively straighten the leg.

Supine Leg Kick Pretty Good

Someone who is a bit stiff.

I don’t focus much on the bottom leg. The only point is I don’t keep the bottom leg completely straight, like in the active straight leg raise. Doing so encourages the knee and hip to fully extend / hyperextend. Neither of which are desirable. In the ASLR test this is part of the assessment i.e. the extension ability of the bottom leg. For this post, we’re concerned with hamstring length; not hip extension length.

I’ll comment on supporting the lower back in a minute.

What we’re looking for

During this movement we’re looking for compensations indicative of stiff hamstrings.

1) The knee

The most obvious compensation is the person can’t generate full knee extension.

Supine Leg Kick Limited Knee Extension

2) The hips lift off the ground / the lower back rounds

The back should stay flat:

Supine Hips Flat Good

Not lift:

Supine Hips Raising


Make sure to look at both legs even though only one is moving. The hamstrings can rotate the pelvis; one side may stay flat but the other lifts.

3) The person generates knee extension from hip extension

Said another way, the person’s knee travels to the ground. Rather than stay straight:

Supine Leg Kick Pretty Good

The knee extension is accompanied by hip extension.

Supine Hamstring Knee extension with hip extension

This is what I was talking about earlier: Hip extension and knee extension tend to go hand in hand. You can see how the hamstrings may play a role in knee extension.

4) Rotation at the knee

We want to look out for the knee turning inward.

Medial rotation of femur during knee extension

Because the adductor magnus is also on stretch during this movement, I believe this is a sign the adductor magnus is trying to fight the stretch. (Lateral rotation of the femur would put it fully on stretch; it doesn’t like that.) Others seem to think this is the medial hamstring. Regardless, we don’t want the compensation.

Slight lateral rotation of femur during knee extension


If all the above is satisfactory, we can take things further getting an ever better idea what’s going on / improve the stretch.

1) Pull the toe to the stomach.

Remember that connection to the calf muscle? By dorsiflexing the ankle we can generate a greater stretch and get a better idea of the stiffness in the entire posterior leg.

Hamstring stretch toe up

Hamstring stretch toe down calf stretch

2) Provide some lumbar support

By putting an arch in the lower back, which is normal and healthy,

Supine Lumbar Support Proper

We anteriorly tilt the hips a bit, further putting the hamstrings on stretch.

Make sure the support is under the lower back; not the hips. The hips should be touching the ground.



This is a great idea for someone with an often posteriorly tilted pelvis. We help get some of that lordosis back, while more effectively stretching the hamstrings. In someone with an anterior pelvic tilt, but hyperextended knees and hips, we could leave the pelvis alone. That way we flatten the lower back a bit (reversing the APT), but get some work into full hip flexion (reversing the hyperextension). Our assessment has turned into a nice corrective exercise.

Which is the point. The best assessments are also corrective exercises.

Let’s bring it all together in a video:

Issues with other methods

The above certainly isn’t the only way to loosen the hamstrings. But, hopefully you can see how much there is to consider when stretching them, and I think the above method helps make matters easier. Let’s go over how other methods often miss the above factors.

Toe touching

I covered this earlier. It’s common to substitute hip flexion with lumbar flexion, lessening the effectiveness.

Frankenstein walking

Substituting lumbar flexion for hip flexion happens in this exercise too:

Frankenstein walk hamstring stretch

It’s very hard to keep the knee straight and get any dorsiflexion.

Frankenstein walk hamstring flexibility with lines

Because of the speed of the movement it’s very hard to 1) Detect these flaws and 2) Correct them.

Walking RDL

This seems to be coached rather well regarding eliminating lumbar flexion.

Walking RDL

However, too much knee bend is common.

(I realize the guy is holding weights here. It's just to illustrate a common form flaw.)

To those saying you can coach a straight knee: It’s not a great idea to load a locked knee. And if our goal is 90 degrees of hip flexion with full knee extension, that’s what you’d be suggesting. You’re also assuming the person is coordinated enough to not allow that knee to go into hyperextension.

Exercise looks cool; knee does not.

Exercise looks cool; knee does not.

Although, I will say the first picture is pretty damn good.

Walking RDL

Next, while the lower back may not be flexing as much, it’s often rotating.

Walking RDLs bad lumbar rotation

It’s common for one leg to have stiffer hamstrings than the other, causing an asymmetrical pull on the lower back, causing a lower back prone to rotating. You can coach people to prevent this, but it’s hard. Especially if the person is stiff (the people most likely to be attempting these things). It’s very hard to know if you’re rotating without another pair of eyes (trainer / coach) as well. You could try a mirror, but looking off to the side during this is likely to cause balance issues.

With this exercise you’re also saying working on lumbar extension is ok for everyone with stiff hamstrings. Go back to the pelvic alignment section if needed, but I’ve gone over extensively how lumbar extension is not always desirable when loosening the hamstrings. Especially loaded lumbar extension. (Gravity is resistance.) Not to mention excessive lumbar extension is the most common cause of lower back pain. And this is one aspect of the exercise you can’t eliminate. You’re going to extend the spine, and you’re going to load it through extension, AND challenge the person’s balance.

The irony of this exercise is the people who can do it properly probably don’t need to do it for the purpose of improving their hamstring flexibility. Maintaining? Alright, maybe. I suppose my overarching point with this exercise is if you have stiff hamstrings you probably can’t do this exercise well enough. You have to improve your hamstring stiffness through other means first.

Downward dog / Yoga push-up

Downward dog hamstring flexibility

I actually like this exercise and use it quite a bit. However, I often advocate doing it with the assistance of a mirror. Because the motion is slow, and the feedback of the mirror (or someone watching), it can be done well. For some though, they’re simply too stiff and it doesn’t work. Similar to the RDL notes above.

You can see someone rotating here:

Downward Dog improper with lower back twisting front view

Here’s me talking to someone as they go through this. You can see the same issues we’ve been talking about with the lower back, knees and feet.

Foam rolling

Same shit, different day.

Foam Roll Hamstrings with lines

Along with a bunch of other issues beyond the scope of this post.

If this was helpful, consider buying me a few beers-

Or maybe you’d like an extra pair of eyes to help catch something like above.

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