Juoksija-lehti: The Importance of Hamstrings

Read original article with images: Tärkeät takareidet Juoksija-lehti 7-2018 (pdf, FI)

Hamstrings are an extremely valuable tool for runners. If the hamstrings are healthy and functioning correctly, a runner’s legs can take steps forward effectively. However, if the hamstrings are injured or in poor condition, they make running difficult. World-class expertise on treating hamstring injuries can be found in Finland.

Text by Ari Paunonen
Many people who have been running for a long time are likely to have experienced the following symptoms: after running for long distances, their hamstrings feel tight and weak, and their steps do not strike properly. They also feel discomfort when each foot swings up in the air. Due to the heavy strain their buttocks are subjected to, they feel like they are on fire; sitting is often painful after a short while.

"Many runners experience adverse symptoms in their hamstring muscles at some point in their careers", says orthopedic surgeon and specialist in sports medicine Dr. Lasse Lempainen, who treats patients at Mehiläinen Neo Sports Hospital, in Turku.

Lempainen knows what he's talking about; as an orthopedic surgeon, he specializes in treating knee and ankle injuries, as well as muscle and tendon ruptures. In 2009, he published his doctoral thesis on hamstring injuries and their surgical treatment.

Lempainen's mentor is Professor Sakari Orava. Both Turku-based surgeons work together as a team, and their patients include, among others, the star players of the FC Barcelona football team.

Henrik Ingebrigtsen, star of the Norwegian national olympic team, also received treatment for a long-term injury in Turku last year. He won a medal this summer.

Several different causes for injuries

The symptoms familiar to endurance runners are back pain, poor performance, and tightness. Sprains and tears are more common in more intense sports activities such as sprints, jumps, and ball games. In these sports, performance requires strong and quick power generation, a high range of motion, and sudden changes of direction.

Tears also occur as a result of severe cramps.

Everyday accidents can surprise anyone. When a person slips, for example, the knee may bend and stretch beyond its normal range of motion if the leg and tendons become abruptly stretched to their limits. Such slipping accidents can easily occur in sports such as orienteering and skiing.
"As a rule, people between the ages of 35 and 60 are more prone to slipping accidents. They happen only occasionally to people in their twenties because the flexibility of their younger bodies still provides adequate protection", Lasse Lempainen says.

Professor Pekka Peltokallio, a renowned sports surgeon, says in his book Typical Sports Injuries (2003) that 50% of sprinters and 20% of long-distance runners have experienced tears in their hamstrings.

In Lempainen’s opinion, excessively intense training of the thigh muscles is one of the reasons for the prevalence of hamstring injuries seen in athletes. The power increases, but at the same time, the muscles also get tight and their elasticity decreases.
In most cases, hamstring injuries are difficult to deal with. They recover slowly and recur easily.

"Often, the hamstring injuries that are most difficult to deal with are those that affect tendon tissue even though they are believed to be muscular injuries", Lempainen tells about his experiences.

Muscle scarring often heals by itself and muscle function returns. However, sometimes after injury muscle / tendon can be longer and scarred, thus making the muscle weak. Therefore, it cannot produce as much strength as it did before. Sometimes, a partially torn and scarred tendon may become too tight, which can be a problem.

Adolescents are particularly prone to injuries near the sit bones to which the hamstrings are attached. This is due to the fact that, during their growth spurt, their bones grow faster than their muscles and their tendons and this causes an excessive strain at the point where the tendons attach to the bone, which makes it particularly prone to injury when subjected to the stress of vigorous physical activity. In the worst-case scenario, as a result of the injury, the growth plate can be fractured from the bone.

Important muscles for running

The three hamstring muscles (see the attached anatomical image) extend between two joints. Their upper ends attach to the sit bone, under the buttocks, and their lower ends attach below the knee joint. Their main task is to stretch out the hip joint and curl the knee, but also to control the movements of these joints as a sort of "brake”.
Hamstrings are important running muscles. Together with the buttocks, they produce the movements that make it possible for a human to take steps forward. The importance of hamstrings becomes more apparent when we try to run hard. If they are not in the best condition, it will not be possible to achieve the best possible performance; even at the individual level.

Each of the three hamstring muscles attaches to the bone with its own tendon.

According to Lempainen, new and noteworthy information is the so-called central tendon structure.
"The central tendon extends deep into each muscle. It can tear and scar due to injury, which significantly affects the healing process of said injury. Some smaller injuries can even cause a complete rupture of the central tendon", Lasse Lempainen says.

Loosen up if you have cramps

Cramps are the mildest of muscular injuries and often heal quite quickly.
Not all the causes of cramps are known with certainty, but they at least involve a disturbed electrolyte balance, fatigue, muscle tension, and previous tears.
Cramps cause minor damage to muscle fibers, which usually begins to heal within a few days.

When a person starts to feel a jerky feeling or a small sharp pain in the muscles caused by a cramp, he or she should stop the physical activity they are performing so that no worse damage occurs.

An intense cramp can take an athlete by surprise, for example, when performing quick bursts of strenuous physical activity where the pace and muscular strength are tough and the athlete will try to forcefully carry on. In such a situation, a cramp can cause an even worse rupture.

"A cramped muscle is tight, sore, and hard. After a few days, the injured muscles can be rubbed gently and light training in water can begin. Hard stretching should be avoided in the early stages of rehabilitation", Lasse Lempainen advises.

The same guidelines that apply to the treatment of the hamstrings can also be applied to the prevention of cramps. In addition, athletes need to get used to their own performance. If endurance runners, for example, go through sufficient specialized training, this will prevent cramps.

Hamstring syndrome is a common problem for athletes

Endurance runners usually start experiencing just a few mild symptoms, with no obvious sudden injury. Hamstring syndrome is familiar to experienced endurance runners, and may be particularly troublesome for those who undergo high-intensity training. With age, steps begin to shorten and pelvic posture deteriorates, which only increases strain on the buttocks.

Hamstring syndrome can also affect a less mobile person, such as, for example, someone who just carries loads and/or works in a factory.

"There is a tendon overload condition in the background of stress disorder that leads to the development of painful tendinous tissue. This kind of tissue slowly increases the tension of the tendons and thus weakens the elasticity of the hamstrings", says Lempainen.

The syndrome is also associated with the hamstrings and is unfavorable to the biomechanics of running. Since it causes a weak muscle condition in the mid-body, the hips easily tilt forward. In other words, it makes the runner adopt a "seated” running position where the lower back is not aligned correctly and the buttocks lean backwards. When running in such a position, the hamstrings are always over-stretched, which increases the strain put on them. This deteriorates the function of the buttocks as well. (See the article "Check Your Position”, Runner, 9/2017)

In the end, this leads to chronic and painful hamstring syndrome, which may require surgical treatment.

"I meet patients with this problem regularly. Some of them come from abroad. It is quite common for them to be endurance runners or triathletes. Many have been trying to get effective treatment for the pain in their hamstrings or buttocks for years. When they arrive for treatment, they cannot even sit without feeling pain. It is hard to imagine that physiotherapeutic treatment would help them in such a situation if it has already been tried for years”, Lasse Lempainen says.

Hamstring syndrome surgery is quite demanding. It is used to make the tendon tighter and thicker by cutting some of its length. This syndrome can also irritate the sciatic nerve, so it must be released during the surgery sometimes. In any case, the surgery creates the conditions necessary for the tendon to recover.

The recovery and rehabilitation process usually takes between 3 and 6 months, as it also involves the correction of posture defects, buttock-activation exercises, and learning about better running techniques.

"Ideally, hamstring syndrome should be caught in the early stages, when the first symptoms appear, so that the patient does not need to go through surgery. Maintaining muscle elasticity, proper strength training, varying the types of training, and ensuring a proper amount of rest are good ways to prevent the worst injuries”, Lempainen explains.

Hamstring compartment syndrome

The hamstrings may also create compartment pressure, similar to what happens with the lower-leg in shin splints. Muscles swell during exertion due to increased blood circulation, which can tighten the muscle’s fascias. Adhesions can also develop between the muscle fascia and the muscles, which hinders the muscles’ elasticity and increases tension.
Muscles begin to weaken due to exertion and their performance is impaired. The sciatic nerve is particularly sensitive in this situation.

"Compartment syndrome may require surgery to open the muscle’s fascias. The surgery is simple, the recovery and rehabilitation process is often quick, and the symptoms that have long affected the patient disappear.”, Lempainen says.

Often, the compartment syndrome of the hamstrings improves when the patient stops engaging in intense sports activities. However, if medical procedures allow the patient to participate in sports for several more years relatively easily, why not use this option?

Growing pains

In adolescents, the ischial tuberosity, or sit bone, develops slowly. This can cause problems even for boys who are old enough to be conscripted into the army.
Growth spurts can sometimes lead to pain and they make adolescents particularly prone to certain injuries. This is because the bone grows faster than the muscle and the tendon, and this increases tension at the points where the tendon attaches to the bone (which, in turn, causes irritation). Simply playing a regular sport can cause pain in this situation.

The treatment consists of adjusting the amount and intensity of physical activity (which puts a strain on the muscles and tendons) according to the level of pain being felt. Completely ceasing all physical activity is only rarely necessary. Vigorous stretching does not help in this case; on the contrary, it often makes the problem worse.

In strenuous sports activities, the growth plate may, at worst, break off from the ischial tuberosity, which may require surgical treatment.

Cautious stretching

Stretching is an important part of preparing for an intense sports activity. Muscles act like springs into which energy is loaded with suitable stretching before engaging in physical activity.
Stretching is also necessary in order to develop the required range of motion for the particular sport to be played.

When it comes to the legs, light stretching is often essential. However, do so cautiously and use your judgment.

"Prolonged stretching is harmful to injured hamstrings. It usually only makes things worse. Stretching for a long period increases the load; especially on the sit bone,” Lempainen recalls.
The amount of mobility-enhancing exercises can be increased during the final stage of the recovery period for hamstring injuries. Before the patient can return to performing vigorous exercises at maximum intensity, the leg must have recovered its full range of motion.

Strength training protects the body

Having adequate muscle strength is important in preventing injuries.

"Several types of squats and pelvic lifting movements are effective individual exercises for the hamstrings and the buttocks. Being able to reach a "sitting” position with the thighs aligned horizontally is sufficient,” Lempainen says.

However, he does not recommend flexing the knees so much that the buttocks touch the calves. Squats are a good exercise when performed moderately, but heavy squatting overstrains the knee joints, which can be too hard, for example, for the meniscus.

There is a traditional thigh exercise favored by sprinters, known today as the Nordic hamstring curl. To perform it, a person must first kneel (Protect your knees by placing a soft pad under them!) and then have his or her ankles secured in place with the help of an assistant or some other support. This is the starting position. The movement itself consists of leaning the hips straight forward and then returning to the starting position.

This exercise is very demanding, so it should be performed very moderately at first.

"An easier exercise is to lie on your back, lift your knees up, and then push down on the floor with your feet while a partner assists you by securing your feet so that they stay in place,” Lempainen advises.

Urgent tendon surgery

Lasse Lempainen specializes in muscle and tendon surgery. When a complete rupture of the tendon occurs, the tendon comes loose from the bone and the muscle-tendon unit can retract up to 10 centimeters from its attachment point. If this injury is left untreated, the muscle’s strength will always be inferior. Over time, scar tissue can form in the area where the rupture occurred, but if the rupture was clean and the muscle-tendon unit remains retracted, this will result in a loose and weak muscle.

"The patient will be able to use that muscle in everyday life and in light exercise. However, he or she will not be able to participate successfully in vigorous physical activities or sports competitions because the muscle will be weak and prone to cramps. Therefore, in such cases, surgery is usually necessary. During the surgery, the tendon is restored to its optimal length,” Lempainen says.

These two work in professional sports

Turku-based orthopedists Lasse Lempainen and Sakari Orava have a direct link to the star-studded world of professional sports. They belong to FC Barcelona’s medical network. Lempainen is one of the club’s consultants regarding the treatment of muscle-tendon injuries.

"Hamstring injuries are common in football, and surgery is sometimes necessary. With the club's chief physician Ricard Pruna, I will change my hearings regularly,” says Lempainen.

"FC Barcelona has a worldwide support network to treat various types of injuries. The club has a magnetic resonance imaging scanner within its premises. All necessary estimates of disability and treatment plans will be prepared soon after the injury occurs. They seek the best expertise wherever it can be found.”

Lasse Lempainen was one of the contributors who participated in the writing of the book Muscle Injury Guide: Prevention of and return to play from muscle injuries, by FC Barcelona and FIFA (Barça Innovation Hub, 2018).

"Finnish sports teams could learn important lessons from the models developed by FC Barcelona. Many years of experience in treating muscle injuries have been compiled within the covers of this book,” Lasse Lempainen says.


Lasse Lempainen
39 years old, born in Turku, Finland
My sports career
Participated in orienteering races at national level as a youth and as an adult.
Professional credentials
Specialist in orthopedics and traumatology. Knee, foot and ankle surgeon. Tendon surgeon.
Surgical treatment of hamstring injuries and disorders - the clinical spectrum from chronic tendinopathy to complete rupture, University of Turku 2009.

After the dissertation, he continued his research on treatments for muscle and tendon injuries.


Hamstring surgery indications:

When does surgery become necessary?

When surgery is required:

  • When 2-3 tendons rupture completely at the upper part of the hamstrings especially if the patient is an athlete who actively participates in competitions.
  • When a tendon ruptures completely and there is a clear tendon and muscle retraction, especially if the patient is an athlete. If there is no significant retraction, the recovery process can proceed without surgery.
  • When growth plate fractures if the gap is greater than 1 cm.
  • When a total rupture of the lower part of the hamstring tendon occurs.
  • When severe ruptures occur, an early surgical intervention shortens the recovery period.
    Surgery can be performed later if the injury does not improve via therapy. Based on the correct diagnosis made in the early stages.

How long does recovery and rehabilitation take?

  • If it is only a muscular injury, the patient can gradually start running after 2-3 weeks.
  • If the central tendon is damaged and there is a clear hematoma, 8-12 weeks.
  • The worst injuries are those involving the rupture of 2–3 tendons on the upper part of the hamstrings, which requires surgery. The recovery often takes 3-4 months and requires proper physiotherapy.
  • The recovery period for hamstring syndrome surgery often lasts 3 to 6 months, and it includes posture correction, buttock-activation exercises, and learning better running techniques.


Orthopaedist Lasse Lempainen believes that hamstring muscles will remain in good condition with a varied exercise regimen that maintains muscle elasticity and range of motion, and an adequate level of strength. If only one type of exercise is performed, the strain is more intense and often affects the same part of the body.

Varying the exercises also gives the muscles enough time to rest and recover, because that way they are not subjected to the same strain all the time.

When it comes to strength training, Lempainen recommends doing so lightly.

"Exercise-type training for the athletes and young people should be performed without additional weights. When jumping, they should pay particular attention to hip/pelvis control. Having good core strength also makes hamstring movements easier,” Lempainen advises.

Running must be done at different speeds and intensity levels. This should include sprinting, running downhill, and hurdles training.

Cycling is a good exercise to keep the hamstrings in good condition. However, it should be done with lock pedals, which better distribute the strain between both ends of the hamstrings. In order to better develop the hamstrings themselves, it is necessary to engage both the hamstrings and the buttocks when cycling.

The same goes for water running. Performing different types of exercises is also important here. Aqua running and swimming are two completely different exercises in terms of the stress the hamstring is subjected to.

In muscle care, it is advisable to opt for relaxed shakes and transverse friction massages.

"Each athlete has different hamstrings. Training should be tailored to meet each individual’s needs. This may be a problem when it comes to teenagers who participate in team sports, because they are often taught to perform the same exercises without considering their different stages of growth.”

Developing hamstring flexibility at home

Traditional long-term stretching is not usually the best way to stimulate the recovery of the hamstring muscles. It is also advisable to perform full-body exercises (which has better results) rather than to exercise each individual muscle separately.

This easy exercise improves the mobility of the hamstrings. Adopt the half-knee position and gently move your upper body back and forth. You should feel a light stretch on the hamstrings.

  • The posterior chain mobility exercise has a beneficial effect in many posterior muscles, from the soles of the feet all the way up to the back:
    In the initial position, the soles of the feet and the palms of the hands are kept on the floor, with the knees extended as much as possible within the limits of their mobility. The distance between the hands and the feet will be is based on your own mobility.
    Start by moving the head inwards between your hands and your core, towards your knees. Perform 10 to 15 gentle pumping movements, breathing in before starting the exercise and during the recovery phase of each repetition, and breathing out during the stretching motion itself.
  • Perform this easy exercise at home to strengthen the hamstrings and the buttocks. Lie on your back, lift your hips up and lift one leg up in the air. Make sure the leg you lifted up is straight (the knee must be fully extended). Slightly move your hips back and forth while engaging your hamstrings and your buttocks.
  • The anterior chain mobility exercise has a beneficial effect on many frontal muscles, from the frontal thigh muscles all the way up to the chest muscles:
    In the initial position, the knee and the hip of the forward leg are both bent at a 90-degree angle, with the foot planted firmly on the floor. The back leg is extended backwards and almost completely straight, with ball of the foot resting on the floor. You should feel a slight stretch in the hamstrings of the leg that is extended backwards.
    Start the exercise by pressing the hips slightly forward and down. At the same time, stretch your arms up and pull them back behind your head as far back as possible, which will also cause a stretching sensation in the abdominal and chest muscles.

Perform 10 to 15 gentle pumping movements, breathing in before starting the exercise and during the recovery phase of each repetition, and breathing out during the stretching motion itself.


Lasse Lempainen
ortopedian erikoislääkäri
urheiluortopedian dosentti


Lasse Lempainen (Pihlajalinna)