What are the key components of a physical exam for a hamstring injury?

Physical Examination of Hamstring Injury

The physical examination for hamstring injury should focus on identifying sharp, well-localized posterior thigh pain with palpable tenderness, assessing pain reproduction with functional loading maneuvers, and documenting visual signs of injury including swelling, ecchymosis, and asymmetry. 1

Essential Components of the Physical Examination

History and Pain Characteristics

• Sharp or stabbing pain in the posterior thigh that increases with activity and may subside after warm-up, with pain typically well-localized to the posterior thigh 1
• Pain progression patterns help stage the injury: early stage shows pain primarily during activity that subsides after warm-up, progressive stage demonstrates increasing intensity and duration, and advanced stage presents with pain even at rest 1
• Document the specific mechanism of injury, as eccentric loading during muscle lengthening is the typical injury pattern 2

Inspection

• Visual assessment for swelling, ecchymosis, and asymmetry in the affected posterior thigh compared to the contralateral side 1
• Evaluate posture and gait patterns, as these are considered among the most important initial assessment factors by expert consensus 3
• Observe for visible deformity or palpable defects that may indicate complete rupture requiring surgical intervention 2

Palpation

• Palpate for well-localized tenderness that corresponds to the location of pain experienced during activity 1
• Identify the specific location of maximal tenderness along the hamstring muscle bellies, as injury location helps estimate the duration of the convalescent period 4
• Palpation of muscle bellies is considered one of the most valuable components at initial assessment according to both literature and expert opinion 3

Functional Testing and Special Maneuvers

• Perform pain reproduction tests with maneuvers that simulate hamstring loading, which are key diagnostic findings 1
• Range of motion testing (active, passive, and resisted) should be included, with studies showing high specificity (1.00) for passive and resisted range-of-motion tests 5
• Manual muscle testing is identified as a relevant diagnostic factor and should be performed within 2 days post-trauma 3

Strength Assessment

• Assess for loss of function and strength deficits, as these indicate injury severity 2
• Document any asymmetry in hamstring and hip extension strength compared to the contralateral side 6

Critical Differential Diagnoses to Exclude

The examination must differentiate hamstring strain from:

• Sciatic nerve irritation or compression through referred pain testing 1, 3
• Hip arthritis, which may present with posterior thigh pain 1
• Chronic compartment syndrome 1
• Proximal hamstring avulsion from the ischial tuberosity, which requires longer immobilization and may need surgical intervention 2

Red Flags Requiring Immediate Advanced Evaluation

• Severe pain that does not improve with rest 1
• Inability to bear weight on the affected leg 1
• Palpable defect suggesting complete rupture with loss of function, which should be operated on 2
• Persistent symptoms despite appropriate rest and conservative measures 1

Timing and Documentation Considerations

• The most relevant diagnostic factors should be assessed within 2 days post-trauma for optimal prognostic value 3
• Document specific findings systematically, including pain location, palpable tenderness, functional test results, and visual signs 3
• Consider that seemingly isolated clinical findings may represent more extensive injury requiring imaging confirmation 4

When to Proceed to Imaging

MRI without contrast is the definitive imaging modality when clinical examination warrants further evaluation, with near-perfect detection rates for hamstring injuries and 100% detection rate for proximal hamstring avulsions (compared to ultrasound's limited 58.3% detection rate) 1. Imaging is particularly indicated when there is suspicion of complete rupture, proximal avulsion, or when symptoms persist despite conservative management 1.