History
See the list below:
-
The onset of pain and/or weakness is usually sudden and may occur during an explosive movement, such as sprinting.
-
Patients may report hearing an audible pop at the time of injury.
-
Onset of posterior thigh pain is often near the beginning or near the end of the sport activity. This is consistent with the belief that fatigue and lack of warm-up are factors that may lead to muscle injury.
-
Patients may only have a sense of apprehension due to a feeling of inadequate leg control as a result of the injury.
-
Patients may report pain with sitting or while walking uphill or ascending stairs.
-
Swelling and ecchymosis may accompany more severe injuries.
Physical
See the list below:
-
Physical findings are absent in many hamstring injuries.
-
The patient often has pain with active knee flexion against resistance. The procedure is performed with the hip in a neutral position and the knee in an extended starting position.
With the patient in a prone position and the affected extremity's knee flexed at 90 º, palpate from the ischial muscle origins to their insertions. This minimizes patient pain, which can limit detecting muscle defects.
Next, with the patient in the supine position and the hips flexed to 90 º, the maximum tolerable active and passive knee extension angle should be noted and compared to the contralateral leg. This allows the physician to assess the severity of the injury and to monitor future rehabilitation progress.
-
In severe cases, swelling and ecchymosis may be present.
-
With a complete hamstring rupture, the muscle may contract into a ball, with an accompanying strength deficit.
Causes
See the list below:
-
The major predisposing factors are lack of warm-up, poor flexibility, fatigue, and a hamstring-to-quadriceps ratio less than 50%.
-
A previous hamstring injury is the most recognized risk factor for injury. A study of elite track and field athletes with acute, first-time, unilateral hamstring muscle strains found that low-grade hamstring muscle injuries may lead to a higher risk of reinjury than high-grade injuries. [15, 16, 17]
-
Poor running style, especially overstriding, predisposes some runners to hamstring injuries. Overstriding stretches the hamstring and places it in a position of active insufficiency.
-
Dyssynergia secondary to dual innervation of the hamstring muscles may also be a factor that contributes to hamstring injuries.
-
Rapid growth seen during adolescence sometimes leads to tight hip flexors with a resultant anterior hip tilt. This can cause a natural predisposition to hamstring injuries for this age group.
