Strain = injury to the muscle or musculotendinous junction

• Muscle strains typically concern the superficial muscles working across 2 joints, such as the rectus femoris, semitendinosus, and gastrocnemius muscles.
• Muscle strain usually occurs in eccentric exercise (lengthening the muscle when slowing or stopping the movement)

Sprain = injury to the ligament.

Muscle contusion = occurs when a muscle is subjected to a sudden, heavy compressive force, such as a direct blow to the muscle.

Risk factors:

• Types of sports (e.g. ankle sprain higher in court games)
• Anatomical variation - e.g. flat foot may increase risk of injury
• Eccentric exercise
• Muscle tendons that span 2 joints e.g. rectus femoris, semitendinous

PC

• Acute Sx onset - suggests sprain/strain
• Severe pain
• Swelling (can take 24hrs for full swelling to become apparent)
• Bruising
• Limited ROM
• weakness

History and physical examination are key in diagnosis and grading of the injury as grade 1 (mild), 2 (moderate), or 3 (severe with complete rupture).

Investigations