Hamstring Strain

Hamstring strains and ruptures comprise a very large percentage of musculoskeletal injuries during activities and sporting events amongst all age groups of the athlete. Different types of hamstring injuries include lacerations, contusions, delayed-onset muscle soreness, and strains. Muscle strains are the most common type of hamstring injuries. Hamstring strains occur most commonly at the musculotendinous junction of the hamstring musculature due to vigorous contractions.

The muscle group is prone to injuries due to the explosive nature of movement in sports and thus causing overload and overstretching of the hamstring musculature. The other causes may be:

·         Previous injury

·         Poor muscle strength

·         Poor flexibility

·         inadequate warm-up

·         Fatigue

·         Imbalance

·         Overuse

This condition is most commonly seen in:

·         Athletes involved in soccer, football, rugby.

·         Dancers and water skiers.

·         Sports involving cross-country skiing, downhill skiing, judo, cricket, and bull riding.

The hamstring muscle group consists of three muscles: the semimembranosus, the semitendinosus, and the biceps femoris (long and short heads). The symptoms can be seen in any one or all the muscles.

·         Pain

·         Muscle spasm.

·         Swelling

·         Tenderness

·         Bruising

·         Decreased muscle strength

·         Loss of function

The severity of hamstring strain can be classified into three degrees:

Severity                                            Symptoms                                            Signs

·         Grade I represent strain or pulled muscle.

·         Grade II represents a partial tear with some significant injury.

·         Grade III represents a complete rupture of the muscle.

Hamstring muscle injury involves an intramuscular tendon or aponeurosis and adjacent muscle fibers (biceps femoris during high-speed running. There is a quick contraction that causes a strain, tear to the tendon or large muscles at the back of the thigh. The muscles are stretched beyond their limit.

Magnetic resonance imaging (MRI)

On Magnetic resonance imaging (MRI) acute injuries typically show up as high signal intensity.

Plain radiographs

Plain radiographs should be obtained as the initial imaging modality to rule out a fracture, and evaluate any avulsion injuries.

Ultrasound

Ultrasound may be used as a secondary tool to evaluate partial or complete tears.

Strength

The patient in a prone position and the hip stabilized at 0⁰ of extension, knee flexion strength is examined with resistance applied at the heel in both 15⁰ and 90⁰ of knee flexion.

Range of motion

Range of motion is assessed for both the hip and the knee joints. Passive straight leg raise (hip) and active knee extension test (knee) are used to estimate hamstring flexibility and maximum length and presence /absence of a palpable defect in the musculotendon unit. With the patient positioned prone, repeated knee flexion-extension movements without resistance through a small range of motion may assist in identifying the location of the hamstring muscles and tend

Palpation

Palpation of the posterior thigh is useful for identifying the specific region injured through the pain provocation as well as determining the exact tendon. With the knee maintained in full extension, the point of maximum pain with palpation can be determined

·         Oral nonsteroidal   anti-inflammatory drugs (NSAIDs) like naproxen, ibuprofen.

·         Corticosteroid injection

·         (medication not to be taken without doctor’s prescription)

Techniques used by the physiotherapist

Physiotherapy treatment of hamstring injuries is directed towards the restoration of strength and flexibility of the muscle group. The goal is to maximize muscle regeneration and minimize dense, restrictive scar formation.

1: Rest

Short immobilization is advantageous in limiting the extent of the dense connective tissue scar at the site of the injury. Use of crutches and bed rest for severe grade II and grade III hamstring injuries.

2: Ice

The physiological effects of ice are beneficial in the healing process ice should be applied to the hamstring in a plastic bag and wrapped directly over the posterior thigh with an ace bandage.

3: Modalities

Electrical stimulations

4: Compression

Gentle compression is used with a firm compressive bandage placed around the high.

5: Elevation

To reduce edema and allow the return of fluid to the heart, elevate the extremity above the heart level.

6: Isometric exercises

Sit on a firm surface with the involved leg in slight flexion and the heel on the mat. Push the heel into the firm surface and then pull towards the buttock. The program uses concentric contraction with no pain.

7: Isotonic exercises with light weights

With the improvement in motion, the weights can be increased

8: Pain-free passive range of motion exercises

 Sit on a firm surface with a stock on the foot. Place a towel around the foot as if the foot is in a sling. Gently pull the towel to bring the heel towards the buttocks.

9: Heel slides

Sit on a firm surface with a sock on the foot or a towel under the heel. Gently flex the knee with the foot approaching the buttocks, then return to the starting position.

10: Wall slides

Lie on a firm surface with the feet resting on the wall. Slowly begin to walk the feet down the wall.

11: Standing concentric isotonic exercises

Stand near a table or wall for support. Place a cuff weight on the involved leg to bring the heel toward the buttocks in a slow controlled manner.

12: Isokinetic exercises

Lie prone on the table with a stabilizing strap placed across the hips. The involved leg will also have a stabilizing strap placed across the thigh. The ankle is strapped into the movable arm. The therapist then programs the computer to perform the movement at a certain speed and angle.

13: Rolling stool

Sit on a rolling stool and propel forward. Begin by using both the legs simultaneously, progressing to alternating the lower extremities.

14: Prone eccentric exercises

Perform same as concentric, except quickly flex the lower extremity and return to the starting position a slow controlled manner.

15: Standing eccentric isotonic exercises

Same as standing concentric exercise, except flex the lower extremity quickly and return to the starting position in a slow and controlled manner.

16: Pelvic tilt hamstring stretching

Sit on the edge of the chair with the spine in a neutral position. The involved leg is straight, with the heel resting on the floor and the toes in dorsiflexion. The uninvolved leg is in a comfortable position with the hip and the knee flexed at 900 degrees. Lean forward bending on the hips. A stretch will be felt at the posterior thigh.

17: Other activities include Walking, jogging, sprinting, static cycling