Muscle Fibre Tear: Grades, Treatment and Recovery

A muscle fibre tear, also known as a muscle strain or pull, is the tearing of muscle fibres caused by a sudden contraction or excessive stretching of the muscle. It is one of the most common injuries in sports, especially in sports that require sprints, changes of direction or explosive movements.

The most commonly affected muscles are the hamstrings (back of the thigh), the calves, the rectus femoris of the quadriceps and the adductors. The injury typically occurs during running, jumping or kicking, at the moment when the muscle contracts while in a stretched position.

The difference from a muscle contracture is the mechanism: a tear appears suddenly, whereas a contracture sets in gradually.

The most typical symptom is a sharp, sudden pain at a specific point in the muscle, in the middle of an effort. Many people describe it as being hit by a stone or a whiplash, and it often forces them to stop on the spot.

In the following hours the pain stays localised and appears when contracting or stretching the muscle. If the tear is moderate, a bruise may appear within a day or two and gradually track downwards with gravity, for example from the thigh towards the knee or from the calf towards the ankle.

Muscle fibre tears are classified into grades according to the extent of muscle damage:

Diagnosis starts with an examination: how it happened, where it hurts, which movements provoke it and how much strength the muscle has kept. To confirm the tear and measure its size, the reference test is a musculoskeletal ultrasound scan, which tends to be most informative after the first 24-48 hours, once the haematoma is clearly visible. In doubtful cases or large injuries an MRI may be requested.

At Fontanet Medicina i Fisioterapia we perform the ultrasound in the clinic, so we know which grade you have and can plan the timeframes on real data rather than by eye. There are situations, however, in which you should see a doctor as soon as possible:

Immediate treatment following a muscle fibre tear is crucial for the prognosis. In the first 48-72 hours, we apply the PEACE & LOVE protocol, which has updated the older RICE and POLICE protocols.

PEACE (immediate phase): Protection of the area, Elevation of the limb, Anti-inflammatories avoid (do not interfere with natural inflammation), Compression with bandaging, Education about the injury. LOVE (subsequent phase): Optimal Loading that is progressive, Optimism (positive attitude), Vascularisation (gentle cardiovascular activity), Exercise (early mobilisation).

In practice, during the first few days it is best to avoid deep massage over the area, forced stretching and heat, and to keep moving within what the pain allows.

Muscle fibre tear rehabilitation follows a progressive protocol that respects the biological healing times of muscle tissue. At our physiotherapy centre in Tarragona, we personalise each protocol according to the grade of injury, the affected muscle and the patient's sporting demands.

In the first phase, we work on controlling oedema and pain with gentle manual therapy, electrotherapy and pain-free active mobilisation. We progressively incorporate isometric, concentric and finally eccentric exercises, which are fundamental for proper healing and orientation of the muscle fibres.

The final phases include plyometric work, speed exercises and sport-specific movement before giving the all-clear for return to sport. Skipping any of these phases is the main cause of recurrences.

Most of the muscle fibre tears we see in the clinic are in the thigh, and which muscle is involved changes both the prognosis and the way we treat it.

The hamstrings are injured during high-speed running, in the final part of the stride. They are the slowest to recover and the most likely to recur, because athletes go back to sprinting before they have regained eccentric strength. The quadriceps tears mainly when kicking and during changes of pace, and the rectus femoris is the most exposed because it crosses two joints. Adductor tears appear in leg-opening movements and changes of direction, and are typical of football.

Even so, the grade of the injury matters more than the muscle: a mild hamstring tear recovers faster than a moderate quadriceps one. That is why the first step is to measure the real extent of the damage with an ultrasound scan, rather than relying on how much it hurts in the first few days, which is misleading.

A calf tear, especially of the inner (medial) head of the gastrocnemius, is one of the most common tears outside football. It is known as "tennis leg" because it happens when accelerating, braking and jumping in tennis and padel, and also when running uphill.

It feels like being hit by a stone in the upper, inner part of the calf, and it is often hard to go up on tiptoe or put the heel down when walking. If a haematoma forms between the gastrocnemius and the soleus, the muscle underneath, recovery usually takes longer, which is why ultrasound is useful here too.

Two things are worth ruling out: if the pain is lower down, near the heel, and you can barely push off with the foot, the Achilles tendon needs to be checked; and if the calf swells and becomes warm without a clear strain, a blood clot. As a rough guide, a mild calf tear usually allows pain-free walking within one or two weeks, while a moderate one generally needs four to eight weeks before returning to sport.

Muscle fibre tears have a high recurrence rate (up to 30% in the first months after returning to sport). Prevention is based on proper warm-up, eccentric strength training of vulnerable muscles, adequate hydration and nutrition, and respecting rest periods between training sessions.

Prevention programmes with eccentric exercises such as the Nordic Hamstring exercise for hamstrings have been shown to significantly reduce the incidence of injuries in athletes. If you have suffered a muscle fibre tear, do not return to sport until the entire rehabilitation protocol is completed.