Hamstring tendinopathy

Proximal hamstring tendinopathy is a chronic painful condition of the common tendon of the hamstring muscles, where it inserts on the lower part of the ischium. It mainly presents as deep pain in the lower buttock, sometimes difficult to pinpoint, which appears or worsens during activities that place heavy demands on the hamstrings: fast running, accelerations, sprinting, uphill running, changes of direction, jumps or prolonged sitting.

It is particularly common in distance runners, sprinters, footballers, rugby players, dancers and athletes whose activities require rapid hip flexion movements combined with knee extension.

The term “tendinitis” is commonly used, but “proximal hamstring tendinopathy” is generally more appropriate: the condition corresponds more to a disruption of the tendon’s structure and mechanical capacity than to simple acute inflammation. It can appear gradually, without any clearly identified trauma, or follow an initial episode of overload or a musculotendinous injury that was not adequately rehabilitated.

The hamstrings mainly comprise the biceps femoris, the semitendinosus and the semimembranosus. The biceps femoris has two heads: a long head and a short head. Proximally, the semitendinosus and the long head of the biceps femoris share a common origin at the ischial tuberosity, while the semimembranosus has a separate but adjacent proximal insertion.

This anatomical arrangement explains why the pain is generally felt at the proximal origin of the hamstrings, just below the gluteal fold. The proximal tendon lies in an anatomical region simultaneously subjected to tensile stresses, compressive stresses, hip and knee movements, and the forces generated during running and sprinting.

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Function of the hamstrings

The hamstrings contribute to hip extension (running, accelerations, climbing stairs, pushing movements, jumps) and to knee flexion. They also play an important role in the dynamic stabilisation of the knee and pelvis, and help brake the lower limb during fast running by controlling the movement of the leg before ground contact. They must therefore be able to produce and absorb large forces at high speed.

Biomechanics: why the tendon becomes painful

Tendinopathy generally appears when there is an imbalance between the load applied to the tendon and its capacity to withstand it. Certain situations are particularly demanding for the proximal tendon: marked hip flexion combined with knee extension places the tendon under high tension, which is notably the case during fast running and accelerations. A strongly flexed hip position also increases compression of the tendon against the ischial tuberosity — an important concept in rehabilitation, because some positions are painful not only because they stretch the tendon, but also because they increase its compression.

A common mistake is to regard hamstring pain as the result of a lack of flexibility. Yet in proximal tendinopathy, systematically trying to “stretch the tendon” can sometimes perpetuate the symptoms: stretches combining hip flexion and knee extension place the proximal tendon precisely in a position of high tension and compression. Management therefore aims to gradually restore the tendon’s capacity to withstand these stresses rather than to avoid these positions permanently.

Proximal hamstring tendinopathy frequently affects distance runners and sprinters, but also footballers, rugby players and dancers — more generally, all athletes whose activities require rapid hip flexion movements combined with knee extension (sprinting, accelerations, changes of direction).

It can also affect people who do little sport, notably through pain triggered by prolonged sitting. A change in training load (introducing sprints, fast intervals, hills or speed work) is often more decisive in the onset of symptoms than the presence of any particular anatomical abnormality.

Proximal hamstring tendinopathy generally appears when there is an imbalance between the load applied to the tendon and its capacity to withstand it. Several factors can promote its onset.

Training load factors

A sudden increase in training volume or intensity, too rapid a return after a break, a large increase in mileage, the recent introduction of interval sessions, a return to sprinting, more hill sessions or strength exercises that place heavy demands on the hamstrings are the main load factors. A runner may tolerate a given weekly volume perfectly well and then develop pain after abruptly introducing sprint sessions, fast intervals, hills or speed work.

Biomechanical factors

High exposure to hip flexion, hamstring weakness, a strength deficit in the posterior chain, a lumbopelvic control deficit or poor tolerance of loads at long muscle lengths also promote the onset of symptoms.

The classic picture is that of an athlete describing deep pain in the buttock, just below the gluteal fold, appearing during fast running or after sessions. At first, the pain may be mild and present only after training, the next day or after a fast session; it may then gradually appear during activity. At a more advanced stage, it can become troublesome when sitting, driving, running slowly, going uphill or doing strengthening exercises. Its distinctive feature is often its insidious and chronic nature.

The main symptom is low buttock pain, generally located in the lower part of the buttock, near the ischial tuberosity, sometimes slightly more medial or lateral. It may be described as deep, dull, localised and sometimes burning. It typically appears when accelerating, sprinting, taking long strides, running uphill or changing pace, and may be worse a few hours after training or the next day — a phenomenon that is particularly important to monitor as the load is progressed.

Prolonged sitting can become particularly uncomfortable: the patient tends to change position regularly, sit on one buttock, use a cushion or avoid hard seats. This feature is highly suggestive when the pain is clearly located at the origin of the hamstrings.

Clinical examination

The examination should look at the precise location of the pain, reproduction of symptoms, hamstring strength, tolerance to lengthening, lumbopelvic function and any neurological signs. However, no single test can establish the diagnosis with certainty: it relies on the consistency between the clinical history, the location of the pain and several provocation tests.

Palpation looks for tenderness at the ischial tuberosity and the common hamstring origin — pain reproduced precisely at this spot is an important finding, although simple local tenderness is not enough to establish the diagnosis. Provocation tests generally put the hamstrings under tension by combining hip flexion and knee extension, sometimes with an added resisted contraction; reproduction of the usual pain is more informative than a simple stretching sensation.

Strength assessment looks for reduced strength in knee flexion or hip extension, a right/left asymmetry, or poor tolerance of slow and fast contractions — but maximal strength alone is not enough: an athlete may have normal strength on manual testing yet be unable to cope with repeated sprints, changes of pace or high-speed running; functional capacity must therefore be assessed progressively.

Posterior buttock pain is not always tendinopathy: the neurological examination looks for radiation below the buttock, pain running down the thigh, paraesthesia, numbness, motor weakness or changes in reflexes, which would point towards irritation of the sciatic nerve or a lumbar origin.

Surgery is rarely necessary for simple proximal tendinopathy; it is not a first-line indication. It may be discussed in specific situations: very disabling chronic pain despite well-conducted rehabilitation, a significant tendon injury or partial tear, proximal avulsion, tendon detachment or major functional deficit.

Proximal hamstring avulsion must be distinguished from chronic tendinopathy: it generally occurs suddenly, with a snap, sudden pain, a tearing sensation, extensive bruising, marked weakness and difficulty walking or running. An MRI is generally needed to determine the number of tendons involved, the degree of retraction and whether the avulsion is complete or partial; management depends on this.

After proximal repair, rehabilitation is much more gradual: protection of the repair, recovery of mobility, muscle reactivation, progressive strengthening, closed-chain work, then running, accelerations, sprinting and sport-specific movements. Follow-up studies show return-to-sport rates often above 90%, but with average timescales of several months.

Healing time varies greatly. A recent, mildly irritable form may improve within a few weeks, whereas chronic tendinopathy may require several months of rehabilitation. The decisive factor is not only the time elapsed since the onset of symptoms, but above all the initial severity, the duration of the condition, the sporting load, the quality and consistency of the rehabilitation programme, the ability to control load and the possible presence of a structural injury. Long-standing pain does not therefore mean a permanently damaged tendon.

Prevention relies mainly on maintaining sufficient hamstring capacity: regular hamstring strengthening, glute and trunk work, single-leg exercises, exercises at long muscle lengths and gradual exposure to speed.

In athletes who sprint, it is particularly important to maintain regular exposure to fast running rather than sprinting only after long periods without speed work. Prevention also involves good management of training loads, avoiding increasing volume and intensity at the same time.