Keywords: hamstring, strain, muscle tear (PubMed Search)
Prevalence varies by sport ranging from 8 to 25 percent with a high recurrence rate frequently during the ensuing sport season, usually in next 2 months but may extend up to one year!
Highest in sports that involve rapid acceleration and deceleration
3 highest risk sports - football and men’s and women’s soccer
Average time lost 17-21 days
Injury much less common in younger athletes
The hamstring is composed of three muscles: the biceps femoris, semitendinosus, and semimembranosus.
Primarily involved in knee flexion and hip extension
Biceps femoris is most commonly injured
Simple grading system using 3 grades
Grade 1 – mild strain
Grade 2 – Partial tear
Grade 3 – Complete tear
Proximal injuries are more common than distal injuries, occurring at the musculotendinous junction
Avulsion fractures of the ischium occur rarely occur in adults but may occur in skeletally immature athletes
When watching a sporting event you will see the athlete grab the buttock or upper thigh. They usually cannot return to play. Most grade 2 or 3 injuries will require crutches. If seeing them the following day significant bruising may be seen.
Numerous modifiable and non-modifiable risk factors have been identified including:
*Weakness of ipsilateral quadriceps or contralateral hamstring, hamstring, hip & quadriceps tightness/poor flexibility, poor warm-up, sudden increased training volume and muscle fatigue.
*Older age (risk increase may begin as early as age 23)
Prior hamstring injury (up to 6x increased risk)
**Premature return to sport increases the risk of reinjury
Differential Diagnosis: Lumbar radiculopathy, sciatic nerve irritation or compression, stress fracture of femur.
Refer to sports medicine/orthopedics for avulsion injuries, complete proximal complete tears and partial or complete distal tears