The hamstring group of muscles is part of the posterior chain of the hip/ leg.  They are not as large as the quadriceps on the anterior side of the body; they have more length to them and are more tubular than broad.  However they are equally important, as they are responsible for hip extension and knee flexion.  Hence they are used a lot for every day walking and running.  The hamstrings are antagonists to the quadriceps muscles.  The muscles that work in synergy with the hamstrings are gluteus maximus, sartorius, gracilis and the gastrocnemius.

Three muscles make up the hamstrings group.

All three hamstrings originate at the ischial tuberosity; they broaden out and then become slimmer as they get closer to the knee, ultimately ending in long thin tendons posterior to the knee.  All three insert at different points.  The biceps femoris long head inserts at the head of the fibula, and the biceps femoris short head at the lateral lip of the linea aspera.  The semitendinosus inserts on the proximal medial shaft of the tibia.  The semimembranosus inserts on the posterior aspect of medial condyle of the tibia.  The latter two insertions along with the sartorius and gracilis form a duck foot like insertion called the pes anserinus.

Because the hamstrings are biarticular, they will affect the health of the knee, hip and even back.  Most athletes who are tight in their hamstrings can suffer a host of problems.  For example, when squatting with a heavy weight, they will not be able to lower their hips past 90 degrees.  This keeps them working in a ‘safe’ mid range zone, but exasperates the issue as the hamstring will not be fully lengthened. Then when it comes time to explode out of the squat, the full length of the hamstring muscles are not utilized.  This can get into a vicious circle, ending in weak and tight hamstrings.

Tight hamstrings also shed light on knee pain.  Again, let’s take the bottom of a heavy squat example.  If the hamstrings are too tight and do not allow full hip extension, the quadriceps will take over from the inefficient hamstrings, putting a tremendous load and strain on the knee.  Remember, all four quadriceps converge to form a single tendon above the knee that attaches to the top and sides of the patella, before attaching via the patellar ligament to the tibial tuberosity.  So if the quadriceps group works needlessly overtime, it’s going to affect the knee.

And there’s more!  Back pain also can be attributed to tight hamstrings.  Since the hamstrings are attached to the ischial tuberosity, tightness can tilt the pelvis back.  When this happens the lumbar vertebrae flex forward, adding compression to the vertebral discs.  It gets worse if we bend forward as the flexion is then coming from the lumbar spine.

Strengthening your hamstrings or keeping them strong is just as important.  Most dominance in sports comes from hip extension/explosion.  Take a runner as an example.  If a runner continually loads his anterior chain while running, he will weaken his hamstrings.  This pertains to proper running technique, whereby the hamstrings are asked to fire every time the leg is picked up off the ground. The inability to fire the hamstrings, can cause the hamstrings to tear, as they will not be able to take the constant load developed by the contracting quadriceps and the momentum that the hip extension generates.  There will be a drop in running speed as the hip flexors jam up, and the hamstrings contract earlier in the stride.

If you’re looking for a great hamstring stretch (among other things), check back for  a clip on Friday!

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Dear Hamstrings, Why Must You Be So Tight?

Yasmen Mehta

Yasmen, a native of India came to the United States to train as a ballet and modern dancer. Yasmen was the Artistic Director and choreographer for the California Contemporary Dancers for 16 years, touring nationally and internationally. She became a competitive short track speedskater after that and is the current gold medalist in the State of California. Speedskating brought her to CrossFit in 2009, and she is Endurance, Mobility, and Level 1 certified for CrossFit as well as YTU Certified. She wants to make a difference through her work with people from different walks of life.

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Tim Godwin

Thanks Yasmen,
I have really tight hamstrings and it often makes it difficult to get my pelvis into the correct tilt for yoga poses. This could also be a contributing factor as to why I also have knee pain. I’m looking forward to watching the video clip on how to get a great hamstring stretch.


This has been one of the biggies for me. I am a runner who does not take the time to stretch out my hamstrings. YTU has provided some great activities to stretch and strengthen this area and along with using the YTU balls, this has helped alleviate some of the knee pain I have had.


As a runner, this is definitely thought provoking as I do experience periodic knee pain. I will definitely incorporate more hamstring strengthening into my regime. Thank you!


Excellent reminder of how often it is something above or below that is the root of the pain.


Hi Chelsea,

Thanks for your comments on the article. I think you answered your own question. If you can feel your hammies are tight, then they are tight. My rule of thumb is to work the entire region as they are all connected and muscles that do not slide and glide over each other informs other muscles as well. Look at the adductors, external and internal hip rotators, quads and even the calves.

Chelsea Fuller

Hi Yasmen,

Thank you for this post, and all the anatomical information you provided. I have been having trouble with my right low back, glutes, and knee. I’ve also noticed that on this side my hamstrings are way tighter. In addition, to the weight lifting example you gave, what can be some other causes of strained or injured hamstrings? I am unsure if my discomfort is originating from my piriformis or hamstrings. Also, is it unusual to only experience this tightness on one side?


Sarah R

Great detail of the different potential causes of knee pain and back pain and an important reminder that the source of pain is often not the origin of the pain.


I am working with a friend right now who is dealing with knee and back pain, and the Quickfix Rx: KneeHab DVD sounds perfect for him. We have been working on hamstring and quad stretches (he is 55 and hasn’t actively stretched in almost 25 years), and this article / that DVD will be perfect material for him to review and progress with at home. So often people talk like their hamstrings or quads are all one muscle, and you highlight really well how separate they are, and the need to use them through their full range of motion. Thanks!

Matt Halawnicki

Great article on the potential of knee pain in relation to hamstring tightness.


Yasmen – Thank you for this insight! I have notoriously tight hamstrings and have struggled on and off with knee pain over the years. I do step aerobics a lot and have always attributed my knee pain to that practice, but it never occurred to me that there could be a connection between my knee pain and my tight hamstrings. I’m going to do some conscientious squats to test my range of motion to see if my hamstrings are the likely culprit.

Jen Wende

A valuable article and great information to take into consideration when I receive clients with knee pain. You have also inspired me to take a closer look at the mechanics of my personal squat, and dive into how I am truly using those muscles

Cathy Mook

This was great information, I knew tight hamstrings were associated with low back issues, but I never put the connection with the knee. I have tight hamstrings and had an issues with my inner left knee. So I was working the sartorious not the hamstrings.c

Emma McAtasney

I feel certain that tight and weak hamstrings can contribute to knee pain. My quadriceps were so much stronger! Once I began giving my hammies more attention, the knee pain drastically reduced!


I’ve been experiencing some knee pain every since I broke my femur in a skiing accident many years ago. It’s interesting to me to think about how the quads, which were totally emaciated after the cast and had to be rehabiliated might now be a contributor to the knee pain. I also think there is ligament damage, but I’m going to keep exploring this in my YTU classes and see what I can find. The pain only really flares up when I go hiking, and specifically when I hike down the mountain…hello quads!

Ann Knighton

Great Article! Yes, confirming hamstrings definitely effect knee health. I drive several hours a day and my right leg is in contraction. My knee health is always a challenge. Just started with Jill’s “Knee Hab DVD”.

Elise Fabricant

Clients often come to me with knee pain but I rarely think of the hamstrings as the culprit. This article will help me keep the whole leg in mind when looking at the knees, especially for all the flexy yogis I work with who tend to strengthen their quadriceps so much and only stretch their hamstrings. I’m wondering if this might also be the case of my friend who has recently running and is experiencing knee pain? Ultimately, I’m still confused as to how to asses the cause of knee pain, especially now that I understand how the hamstrings could… Read more »


I first heard about the connection between knee pain and hamstrings last spring when I took part in a workshop with Kathryn Bruni-Young. She said that people with knees that make cracking or popping sounds (that’s me!) have weak hamstrings. I’m still trying to figure out why… Any idea? Anyway, I then realised that my hamstrings were actually weak and that was why my running technique was not optimal. Since then, I’ve been trying to make them stronger and hope that will hep me run a little faster.
Thank you for this interesting article!


This is a great blog. It can really help the average person understand the hamstrings and the value to maintain strength and flexibility in them. As an LMP I hear a lot of people complain about knee pain, and or low back pain for that matter and its very rare for someone to assume that their hamstrings are the cause of either of these symptoms. Its very important for us to educate our students on compensation patterns, tightness and weakness in their hamstings. Even though the hamstrings are not as large as the quads, they are equally powerful, if not… Read more »

Kaiitrin Doll

I am currently recovering from a hamstring injury nothing major but (consistent tightness and pinching pain while trying to lengthen the hamstrings) it seems to be taking forever. Any recommendations on exercises I can do to help speed up the recovery process. Should I focus more on ball rolling on the IT band and quads? I’m feeling frustrated.

lulu yen

Knee pain can be caused by a sudden injury, an overuse injury, or by an underlying condition, such as arthritis. Treatment will vary depending on the cause. Symptoms of knee injury can include pain, swelling, and stiffness. i do love how you dig into other cause that might trigger the knee pain. i do ask my clint to consult with the specialist before i help them.


I will definitely be reading some of the other articles and links suggested here, as I’m starting to see that hamstring issues are probably the root of times I end up in pain – this helped a lot! But I am just learning all of these muscles and insertions and congruencies so forgive me if this question is silly! If hamstrings are not working at their best and the quads have to overwork, this seems to say that there with be anterior knee pain. What if the knee pain is in the back, behind the knee (in my book, what… Read more »

Garrett Plumley

Thanks Yasmen! I was wondering if you have a good que, or way to scale this skill, to help trained people to fire the hamstrings more at the bottom of a squat? I’m not sure that I fully understand how to turn on the hams at that point of the moment. I believe that I’m very guilt of only using quads, which lead to my own knee pain.


Thanks for such an informative article! I have perpetually tight hamstrings, and its quite fascinating to hear what an all around role they can play in overall body health!

Bridget Hughes

Thank you for your post, I am an avid tennis player and have recently pulled a hamstring and have been recuperating it.
In the meantime while it heals, I think diving into the knee work with the balls will help. Great post!


As I have been fighting some knee pain, I have been regularly hitting up the it band, supra-patellar pouch, TFL, and sartorius. I have been neglecting the idea of the hamstrings playing a role in this. I will see if this clears up additional slack to the area!

Yasmen Mehta

Thanks Amanda,
Most functional movement where you use your posterior chain like running, squatting, lunging will strengthen your hamstrings. However if you have a knee issue, this can be challenging. You can box squat that would help, keeping the box high and the shins vertical. The other way to go is to try and isolate the muscles like on a GHD raise machine.

Amanda Kou

This is a really interesting article. I have always believed I had a bad knee but never really thought about what causes the bad knee or what could be contributing to make it worse. When I do certain yoga poses (trigonasana on my bad knee side) I can feel it in my hamstrings. Do you have any recommendations on how to strengthen your hamstrings knowing you have a bad knee?

Gina Decker

Excellent information about the hamstrings. I knew tight hamstrings could cause back pain but knee pain was new to me. I remember a friend who was performing a clean and jerk movement and blew out both his knees. Ouch! Maybe those hammies were a little too tight.

Geoff Brown

I am currently doing my YTU Teacher 1 Training and would love to apply these movements to Crossfit. I think that it is completely applicable and your article on knee pain and the hamstring is so relevant to the repetitive Olympic lifting that is apart of so many high intensity workouts these day.I love the concept that our bodies can only move as far as our restrictions. I think that so often we concentrate on the area that is in pain and not on the muscles that are strained, support and surround the compromised area.

Yasmen Mehta

Thanks Lisa, I love to squat. Front squats with the barbell in a front rack position will use the quads a bit more. But in a more used back squat, where you put the weight on your back, the hammies have to do most of the work. If a person is using their quads too much in a back or air squat, they may be initiating the movement by driving the knees forward first, instead of creating torque (ext’ rotating hips as feet stay parallel) and letting the butt go back a bit while maintaining the integrity of the spine.… Read more »

Lisa Swanson

This was a great read. I knew that overworked Quads could cause knee problems, but I didn’t link tight hamstrings to that same problem.
I’ve always looked at the anterior aspect of the thigh, noting to clients that they do too many squats, strengthen the Vastis on the lateral side more than the Vastis on the medial side hence pulling on the knee cap causing such pain. I didn’t realize that a tight hamstring could cause the Quad to overwork, as you say, from coming out of a deep squat.
Interesting. And thanks for the information.

Yasmen Mehta

Hi Clara and Paula, Thanks for posting on my article. I wrote the article, because we don’t always think of hamstrings as the culprit for knee pain. However in both your cases, I would look at the obvious culprit – the quads. Pain in the back of your knee could be your miniscus too. I would use the balls to role out the quads muscles in a cross fiber manner and use a roller on the IT band. On the roller to lie on your side perpendicular to the roller and rock toward your back ribs and then forward instead… Read more »

Clare Chura

Yasmen, I viewed your most recent post on asymmetrical uttanasana and loved it! I’m a big fan of that pose (In fact, I’m certain that I left a comment on that post.). My hamstrings are quite flexible, and forward fold isn’t a highly challenging pose for me. Unfortunately, I still experience knee pain in some poses that require knee joint flexion (IE: warrior I/II, extended side angle). After a few breaths, I have to pull out of the pose for a break. Could this be a result of my hamstrings not being entirely flexible? Are you aware of any potential… Read more »

Paula B

Great post! I am sill trying to understand the relationship between the muscles on my left side of the body:-) Every day I get a referral pattern in a different area. I started spinning a few months ago and noticed that my hamstrings are taking a load of tightness that is clearly affecting my knees. if I sit on the floor in Vajrasana for a few minutes I am not able to get up right away. The back of my knee locks and the hamstrings freeze at the origin. I need a few times of bending and straightening the knee… Read more »


Interesting article! I have a torn menicus and now my hamstrings and hips are tight. It begs the question which came first?! I do have a tendency to work my quads more than other muscle groups, squat after squat after squat! It just shows how everything really is connected in the body!

catherine yiu

As soon as i saw the title of this article… i had to read further. Ive been having knee pain on my right knee for a few months now and couldnt find the cause of the problem. Now reading your article– i think i may have the answer. I squat very heavy on the smith machine and the leg press. With the want to constantly improve my weight to see results i may be 1. tightening up my hamstrings too much, so my quads are taking all the work and straining my knee. It completely makes sense now– from over… Read more »

Yasmen Mehta

Thank you Nan and Elissa for your comments. It’s amazing how Jill has shown us that we can take care of ourselves and others with a little bit of knowledge and the right tools!


Great article. So interesting to see how all muscles are connected and affect each other. I’m a dancer and a few years ago had knee surgery after tearing my MCL. While healing I had to restrengthen all the hamstring, quad, and hip muscles. Especially all of those little stabilization muscles! Now if I ever neglect stretching after dancing, I tend to get knee, hip, or back pain from the tight muscles all being neglected. Strengthening and stretching is key!

Nan Huson

This was a good article, since it gave me a different point of view on what to look at when I have a client with knee pain. I have definitely tended to look first at the quadriceps. I know about the connection between low back issues and tight hamstrings, but now the article makes intuitive sense and provides a useful perspective for me, a personal trainer.

Yasmen Mehta

Thank you all for your posts. As you may have guessed I work with a lot of very athletic folks, who get very tight after their work outs. However, if you do have very loose hamstrings, and you only do yoga, you may want to mix it up a bit. I personally do CrossFit, which basically throws everything in the basket. Flexibility and strength are on two ends of a stick and you have to find a balance.


So appreciate this in-depth post on hammies!! While still digesting all the anatomy present in this reaction, your illumination of the “biarticular” hamstring makes so much sense. I used to run in my teens, but by 19 or so, a faint but pervasive knee pain that showed up after every run alerted me that something was up. Sure the knee pain could have resulted from a host of reasons; nonetheless your post gives me a more WHOLE sense of the biomechanic picture. Will definitely try YTU balls on the ischal tuberosities..!


My head is exploding on the complexity of the hamstrings! Thank you for this article. It shows that everything is connected!! I believe I had a back injury (running in high heels while catching a flight) maybe, because my weight was thrown forward it made me not be able to fire those hammies! Thoughts?

Barbara Treves

I have a couple of clients with knee problems and this article has shed some light on where I need to focus my attention as I train them. I’m hoping they will be able to see results within 6 weeks.


I loved this article about the hamstrings! I feel I have the total opposite problem as most people – as a yoga instructor, I have extremely open hamstrings and sometimes I get nervous that I will eventually tear my bicep femoris from being TOO open. Do you have any suggestions that would strengthen the area, without putting too much pressure on my knees?

Great article!

Kimberly Lou

Great blog on hamstrings. I conquer!. SO important to keep your body in balance. Using Jill’s balls has improved my routine. I roll out my IT Bands and activate my glutes before each leg workout, which have saved my knees.

Laurie Streff Kostman

Terrific article on the complexity of the hamstring group in relationship to the knee, back, and the opposing quadriceps muscles. As an avid cyclist / spinner I find it is easy to defer to quadriceps strength as those are the muscle being coaxed to ‘bully’ the work during those kinds of activities. Hence, I have suffered from tight and weaker hamstring and low back muscles, as well as occasional knee pain. Until reading this article it didn’t occur to me that my knee pain might very well be due to weaker hamstring muscles. Though I have used the YTU balls… Read more »


Loved reading this blog, great information and context offered here! I just want to emphasize the point made in this article about the importance of strengething the hamstrings in addition to just flexing them. I have long hamstrings and can easily enter most poses, but I have realized that they are not as strong as the other surrounding muscles, which causes problems in the pelvis and lower back. There are many YTU exercises I do for strengthening, but ball rolling them after a good day’s workout is just priceless!


After much self discovery, I too came to the conclusion ( based on my pain accountability), that my hamstrings are to blame for my tight hips and knees.
I started thinking that by dong some light jogging, i could warm my muscles up and then, I could do some deep stretches. Also, I feel the abdomen plays a key role, in hamstring tightness.

Yasmen Mehta

Thanks for your comment Pooja. As an athlete, I never try and stretch my hamstrings cold. You can role on the ball at the attachment on the ischial tuberosity, that wont hurt anything and does loosen them up, but if I am going to sprint for example, I warm up my whole posterior chain in a dynamic way and leave the passive and active static kind of stretching for after. I also feel if you are going to take a joint or muscle to end range, it’s not going to budge much if there is no heat/blood flowing in the… Read more »


It’s really interesting to see where all three hamstrings originate and insert. I’ve noticed that my hamstrings are flexible in certain positions and not in others. Likely a difference in flexibility in one hamstring vs the others. I have a consistent (everyday) yoga practice. I’ve noticed that when I do yoga after a run I have much greater flexibility in my hamstrings than when I begin a yoga practice cold. This is likely due to the heat generated by my body post run. Is it better to stretch the hamstrings when in this heated state? Will this help me to… Read more »