Muscle and Tendon Injury (Strain) • classification • cause • Pathology • Treatment

Subarna Debbarma (BPT, DNHE)


Muscle and Tendon Injury (Strain)

A muscle strain, or pulled muscle, is an injury to your muscle fibres (a torn muscle). You may strain a muscle if you stretch it beyond its normal comfortable range or make it work too hard or fast. Muscle strains are common and can happen to any muscle in your body.

Strains most commonly occur in the:

•lower back



•hamstring muscle, which is located in the back of the thigh

Causes of muscle strain

There are lots of things that might cause you to strain a muscle. You may strain a muscle if you:

•are exercising – for example, playing sport

•have strained a muscle in the past fall

•move or twist suddenly – for example, sprinting or catching a falling child

•have a heavy blow to your muscle – for example when playing contact sports such as rugby

•are overweight because this puts more stress on your muscles

•do a repetitive movement that puts stress on your muscle – for example, painting a ceiling all day

•don’t have enough strength in your muscles for the activity you’re doing

•you don’t warm up properly before you exercise

•your muscles are tired or weak and not used to the activity you are doing; tired muscles are less able to support your joints.

Injury to the muscle is classified into four categories on the basis of damage to the muscle tissue:

1. Grade I strain: Superficial contusion 

2. Grade II strain: Deep and widely spread contusion

3. Grade III strain: Partial rupture of the muscle or tendon

4. Grade IV strain: Complex rupture of the muscle or tendon

Grade I Strain or Contusion

This injury results mostly from a blunt injury.


1. Intact fascia

2. Minimal intramuscular bleeding causing patchy localized haematoma

Clinical features

1. Localized pain and tenderness

2. Reflex muscular spasm

3. Limitation of movements close to the injury

4. Typical signs of inflammation may be present


Being abundantly vascularized, the process of healing is speedy and complete. However, original muscular tissue is replaced by fibrous tissue resulting in a decrease in the efficiency of contraction.


Treatment by applying the principles of RICE Cryotherapy in the form of ice application for the first 24 h is very effective (three to four sittings of cryotherapy each for 20 min)

Beneficial effects of cryotherapy

•Reduces tissue oedema (Mc Master and Liddle, 1980; Masten,Questad & Masten, 1975)

•Slows down localized blood flow (Abramson, Tuck, Lee, Richardson & Chu Luke, 1966; Knight and Londerce, 1980)

•Lowers intraarticular and intramuscular temperature and reduces pain (Cobbold and Lewis, 1956; Wakim, Porter & Krusen, 1951; Johnson, Moore, Moore & Oliver, 1979; Chambers, 1969; Lane, 1971; Rocks, 1979)

•Reduces metabolic function and brings about vasocon- striction (Clarke, Mellon & Lind, 1958; Janssen and Waaler, 1967)

•Reduces sensory and motor nerve conduction velocities (Fox, 1961; Lee, Warren, & Mason, 1978)

•Produces analgesia by increasing the threshold of stimula- tion of pain nerve fibres (Stangel, 1975)

•Increases neuromuscular function 

•There may be an increase in the muscle strength after the Treatment

Grade II Strain (Deep and Wide Contusion) - Possibly Due to More Violent Blunt Trauma


•wide and deep haematoma

•Intact fascia

•Greater number of muscle fibres are traumatized 

•More internal bleeding

•More than one muscle group may be involved 


•More severe localized pain and tenderness 

•Severe reflex muscle spasm

•Fascia may remain intact or may be torn

•Loss of voluntary active movement 

•Attempted isometrics elicit sharp pain

•Both intra- and intermuscular bleeding may occur

Grade III Strain (Partial Rupture)

There is tearing of greater number of muscle fibres.

It may involve more than one muscle groups.

Fascia may be partially torn.

Widespread intra- and intermuscular bleeding may occur.


Grade III strain is caused by incoordinated sudden violent muscle pull when the muscle is not prepared for it (e.g., sudden violent stretching of the muscle in a contracted state, as in sports). Although the torn muscle fibres are replaced by fibrous tissue (scar), adequate function of the injured muscle can be regained if it is kept supple by relaxed early mobilization and controlled stretching manoeuvre.

Management of grade II and III strains

During the first 24 h

Immediate application of RICE principles

Immobilization of the limb in a splint or a pressure isometric bandage

Begin with pain-free isometrics both in speedy and sustained mode against pressure bandage with the limb elevated 

Vigorous active exercises to the uninvolved joints

From 48 to 72 h:

Pressure bandage is removed and pain-free relaxed rhythmic movements are begun in a small pain-free range. 

Carefully controlled gentle stretching is introduced.

Soothing thermotherapy modality followed by progressive mode of exercise is initiated.

Light ADLs, may be assisted with the normal limb (self- assisted), are introduced and non-weight-bearing (NWB) crutch walking is started. 

During 48-72 h:

Vigorousity and the duration of exercises are progressed. 

Ultrasonic exposures are ideal to reduce pain as well as hae- matoma, if present.

Light functional activities are continued with NWB crutch walking.

After 72 h:

Usually the pressure bandage is off by now, unless swelling persists.

Gradual introduction of self-resistive exercises incorporating exercise patterns of proprioceptive neuromuscular facilita- tion (PNF) is included if feasible and pain free.

Systematic introduction of the DeLorme technique of repeated maximum strength (RMS) is tried.

Allow carrying or lifting heavier weights and all FWB in ambulation in a graduated manner. Preinjury functional status should be restored within 3-6 weeks.

Advise against overuse or recurrence.

Grade IV Strain (A complete rupture)


Causes can be severe lacerative trauma or a violent stretching of a muscle during active contraction. It may occur through the tendon or close to the point of its attachment to the bone. It results in a piece of bone getting avulsed along with the tendon . Avulsion may occur due to attrition of the tendon or roughening of the bony groove in which it lies or as a result of sharp and violent laceration. It is associated with the rupture of a blood vessel with haema- toma developing in the gap between the ruptured frag- ments. It is replaced by vascular fibrous tissue. This vascular fibrous tissue eventually organizes as scar tissue prone to developing shortening or contracture.


There will be loss of the primary function of the involved muscle, e.g., in the rupture of the tendoachilles, active toe raising test will be POSITIVE, even though the patient may be able to perform weaker plantar flexion by using peronei and the long toe flexors. 


A palpable gap may be felt at the point of a complete rupture

Tearing of the fascia

Considerable intra and intermuscular bleeding

Gross swelling over the site of rupture and its periphery 

Clinical features

Severe localized pain and tenderness

A snapping sound may be heard by the patient

A total loss of muscular contraction 

Severe reflex muscular spasm

A visible gap in the continuity of a muscle at the site of rupture


There is no alternative to surgical repair.

Opening the ruptured site, haematoma is evacuated and suturing of the fascial sheath is performed. Direct muscle repair is avoided.

Compression bandage is applied.

Limb is immobilized (in elevation) for 2-3 weeks.

Light, pain-free, speedy or slow-speed isometrics are per- formed at the earliest.

Faradic stimulation over the repaired muscle will be useful in maintaining and influencing fast as well as slow twitch muscle fibres, in the distribution of motor units and the fusiomotor systems (Pette 1980).

Superficial thermotherapy could be altered to deep heating thermotherapy to improve circulation, to reduce pain, to increase metabolism; selective action on different tissues and generalized and localized relaxation (Griffin and Karselis, 1978).

Management of a Ruptured Tendon

A ruptured tendon is usually sutured and immobilized for 2-9 weeks. The period of immobilization actually depends upon various factors like the method and type of suture, and the expected degree of stress on the tendon. For example, a large tendon bearing excessive stresses, like tendoachilles, needs 9-10 weeks of postop immobilization. The treatment follows the same routine as described for grade IV muscle rupture, except the following:

Extra emphasis should be put on low-load stress on the sutured tendon.

Careful progressive application of tensile loading is required.

Strength training exercises with deep friction massage and ultrasonics play an important role in the maintenance of the tendon length.

Thorough guidance should be provided on the correct appli- cation of sustained self-stretching.

Slow-stress activities can be started by 10-12 weeks.

Competitive sports can be allowed after 16-18 weeks with several practice sessions.

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