Tight Hamstrings: What Causes Tight Hamstrings?

If you often find yourself wondering ‘why do my hamstring feel tight?’, then you’re not alone. Tight hamstrings are a common problem that affect both athletes and sedentary office workers.

Most people try to cure feelings of tightness through stretching. But, depending on the root cause of the tightness, stretching won’t relieve tension, or improve your flexibility.

Many people complain of tight hamstrings when they have the sensation of tightness down the back of the leg between the buttock crease and the knee. Others believe they have tight hamstrings when they can’t touch their toes.

While it might seem like common sense to blame the hamstrings for these problems, the truth is, neither are necessarily caused by limitations in the hamstrings. Instead, weak muscles, your posture, or nerves could be to blame.

One way is to test if your hamstrings are the problem is to perform certain tests (check below for a simple test you can try). This will crudely help you differentiate between nerves and muscles.

However, if you are getting any back pain, numbness, tingling or weakness then you should contact a medical professional. Remember, it is easier to change something when you have only had it for a few weeks rather than letting it get to the chronic phase!

Hamstring Anatomy

• 3 muscles make up the group of hamstring muscles: biceps femoris, semimembranosis and semitendinosis
• These muscles start at the base of the pelvis, which in Pilates we know as the sit bones.
• The muscles run over both the hip and the knee joint down the back of the thigh and connect the pelvis to the knee.
• The main action of the hamstring muscles are hip extension and knee flexion.

Nerve Anatomy

• The sciatic nerve is the biggest nerve in the body and the one that most people associate with back pain.
• It starts in your lower back and runs down the back of your thigh, between the hamstrings and down the calf to the bottom of the foot.

Why Might I Have Tight Hamstrings?

Biomechanical Problems

Many of our clients at our Physio clinic and Pilates studio complain of having tight hamstrings. In many of these cases, the hamstrings are tight because they are protecting an injury, meaning they are trying to do a job they are not designed to do. Often this is due to weakness or poor activation in the muscle groups that are better designed to do the job.

This may be the case if you have a large curve in your lower back (known as lordosis). With this postural issue, your hamstrings have to work constantly to try and stop you getting pain when you lean backwards. Your hamstrings are likely to feel tight as a result – but stretching them to try and get some relief will do more harm than good as it will take away this protective mechanism.

So, instead of stretching, focus on strengthening and stabilising the pelvis, lower back and hips. By doing exercises like bridging or Nordic hamstrings, you can get better recruitment around the glutes and abdominals. This allows the hamstrings to ‘let go’ as the right muscles are doing their job.

Increased Nerve Tension

The second reason for tight hamstrings can be neural tension.

Nerves don’t like being stretched and doing so can often cause increased irritation and increased pain. If you do try to stretch then it is important to remember that you can feel great immediately afterwards but that it can increase your pain a few hours later.

Plus, if tension in your hamstrings are caused by neutral tension resulting from a structural problem, like in your lower spine, then stretching can make the symptoms worse. Structural problems in this sense refers to people diagnosed with disc problems or widespread degeneration.

Remember, if you are getting any numbness or pins and needles into the buttocks or legs it is important to see a Doctor or Physio who can assess you properly.

Previous Injures

If you have played a lot of sport which involves lots of changing direction, speed or repetitive impact, you may have a history of injury to the hamstrings, inner thigh or around the pelvis. This will change what you feel, and also how the hamstrings move under load.

Regular exercise to strengthen the surrounding structures to support the hamstrings can help this problem. Foam rolling and massage work can also help. If you have had a history of this it is best to see a Physio for advice as simple strengthening may not be enough.

Posture

If you’re someone who sits all day every day slouched over your desk at work you may find poor posture is giving you that feeling of tight hamstrings.

As a Physio, I can tell if this is the cause of someone’s tight hamstrings by getting them to squat. Those with poor posture from desk work immediately tuck their bum underneath and let their knees go really far over their toes. They also often have to lift their heels and cannot get down very far into a squat position.

For this issue to be resolved, the person’s movement mechanics need to be improved. This can be done through 1-2-1 Pilates sessions with an experienced clinical teacher. During these an instructor will teach healthy movement patterns that involve parts of the body moving as and when they need to, rather than all in one go.

Why Are Tight Hamstrings A Problem?

If the hamstrings, rather than nerves, are the problem, then it can have negatively impact the body in a number of ways.

Firstly, your posture will change. This is likely to change the position of your pelvis and lower back, and can flatten the curves in your lower spine as well as change the tension in your pelvic floor, which causes other problems as well. Changes to your posture, which will alter how you sit and stand, can impact the entire body and cause problems elsewhere.

This is why your Physio or Pilates Instructor often spends time looking at areas of the body away from your current complaint: the problem is often coming from higher up!

An important thing to remember: a feeling of tightness does not necessarily mean these muscles are shortened in length. In fact, it could be the fact the hamstrings are always switched-on, or are switched-on more than they should be, that are creating theses sensations.

Are My Nerves Or Hamstrings The Problem?

This simple test can help you identify whether your nerves or muscles are to blame for feelings of tightness.

• Place a straight leg out in front of you and bring your ankle towards your head. Swap from this flexed ankle position to a pointed ankle position.
• If you find you have a big difference in hamstring flexibility with your ankle flexed vs ankle pointed then it is likely not to be hamstring tension but rather nerve tension.

How Can I Stretch My Hamstrings?

• You stretch your hamstrings by moving your pelvis away from your lower leg to take the origin and insertion further away from each other.
• This should be a flat back position NOT rounded forward and your pelvis should be going into anterior tilt. This is where the hip bones at the front point down towards the floor rather then up towards the ceiling.
• The ankle position does not matter in a true hamstring stretch. But if the foot is pointing in or out it will change where you feel it in the hamstring.

How Can I Stretch My Nerves?

• You can ‘stretch’ your sciatic nerve with your leg straight and your ankle pulled towards your head. Remember that nerves are really long, so you don’t truly stretch them. Instead, you encourage them to slide and glide in and out of the joints and other tissue more fluidly.

Are My Hamstrings Tight Or Short?

When it comes to hamstrings, the final thing to consider is whether they really are ‘tight’, or if they might actually be ‘short’. These two muscular states are very different, and require different treatment approaches.

A short muscle refers to a muscle at rest (when a muscle is not in use) which is structurally shorter. The muscle fibres are closer together and overlap more.

2. A tight muscle does not refer to its resting state, but when it is in contractile state. This is when a muscles tenses and fibres shorten, usually during movement. In a tight muscle the nervous system wires the muscle to be constantly contracted at a very low level, even when the muscle isn’t in use. We quite often use the term ‘tone’ to refer to the resting contractile state of the muscle.

• The nervous system is a big part of what affects tone. When we are stressed, over-trained or in pain, muscles tend to have a higher resting tone. When we train well, are coping with general daily stresses and doing active recovery, our resting muscle tone is more normal.
• You can’t easily tell if a muscle is short or tight unless you have expensive equipment/gadgets. Most of the time this is not worthwhile unless you are training for a big sporting event. Generally, a short muscle will not change flexibility drastically over a short period of time, but a tight muscle will.

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What Our Experts Say

One of the biggest misconceptions is that every tight hamstring simply needs more stretching. More often, the body is responding to weakness, poor movement patterns or nerve sensitivity. Identifying the underlying cause allows treatment to target the real problem, helping people move more comfortably and reducing the risk of recurring injuries.

Amy Moffat, Clinical Pilates Instructor

Key Takeaways

• Tight hamstrings are not always caused by shortened muscles. Weakness, posture, nerve tension and previous injuries can all create the sensation of tightness.
• Stretching is not always the answer. If the hamstrings are acting as a protective mechanism or symptoms are caused by nerve irritation, stretching may provide little benefit or even aggravate symptoms.
• Improving hip, pelvic and trunk strength can often reduce hamstring tightness by allowing the hamstrings to work more efficiently rather than compensating for other muscles.
• Poor posture and prolonged sitting can alter movement patterns, increasing the feeling of tightness and affecting overall movement quality.
• Persistent hamstring tightness, especially when accompanied by back pain, numbness, tingling or weakness, should be assessed by a healthcare professional.

Conclusion

Feeling like your hamstrings are tight does not necessarily mean they need stretching. Understanding whether the problem stems from the muscles themselves, nerve tension, posture or movement mechanics is the key to choosing the right treatment. A tailored programme of strengthening, movement retraining and, where appropriate, mobility work is often far more effective than stretching alone and can help improve flexibility, reduce discomfort and prevent future problems.

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Education is key 

These blogs are designed to give information to everyone, however, it is important to remember that everyone is different! If you have not seen one of our therapists and have any questions about injuries, what you have read or whether this may be useful to you, please just ask. We are more than happy to help anyone and point you in the right direction. Our biggest belief is that education is key. The more you understand about your injury, illness and movement, the more you are likely to improve. 

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