Strain (injury)

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Other namesMuscle strain, pulled muscle, torn muscle
2010-10-02 pulled hamstring.jpg
Two images of the same strain to the hamstring and associated bruising. One of the pictures was shot through a mirror.
SpecialtyEmergency medicine
3D Medical Animation Depicting Strain
3D Medical Animation Depicting Strain

A strain is an acute or chronic soft tissue injury that occurs to a muscle, tendon, or both (contractile components).[1][2] The equivalent injury to a ligament is a sprain.[3]

Signs and symptoms[edit]

Typical signs and symptoms of a strain include pain, functional loss of the involved structure, muscle weakness, contusion, and localized inflammation.[4] A strain can range from mild annoyance to very painful, depending on the extent of injury.


A strain can occur as a result of improper body mechanics with any activity (e.g., contact sports, lifting heavy objects, overstretching) that can induce mechanical trauma or injury.[2] Generally, the muscle or tendon overstretches and is placed under more physical stress than it can exert.[2] Strains commonly result in a partial or complete tear of a tendon or muscle, or they can be severe in the form of a complete tendon rupture.[5] The most common body location for strains to occur is in the foot, leg, or back.[5]

  • Acute strains are more closely associated with recent mechanical trauma or injury.
  • Chronic strains typically result from repetitive movement of the muscles and tendons over a long period of time.[2]

Degrees of Injury (as classified by the American College of Sports Medicine):[6]

  • First degree (mildest) – little tissue tearing; mild tenderness; pain with full range of motion.
  • Second degree – torn muscle or tendon tissues; painful, limited motion; possibly some swelling or depression at the spot of the injury.
  • Third degree (most severe) – limited or no movement; severe acute pain, though sometimes painless straight after the initial injury

To establish a uniform definition amongst healthcare providers, in 2012 a Consensus Statement on suggested new terminology and classification of muscle injuries was published.[7]

The classification suggestion were:

The major difference suggested was the use of "indirect" muscle injury verse "grade 1" to provide a subclassifications when advanced images were negative.

Indirect Muscle Injury FUNCTIONAL (Negative MSK US & MRI)[8]

  • Type 1: Overexertion-related Muscle Disorder
    • Type 1a: Fatigue induced
    • Type 1b: DOMS

• Type 2: Neuromuscular muscle disorder

    • Type 2a: Spine-Related
    • Type 2b: Muscle-Related

STRUCTURAL MUSCLE INJURY (Positive MSK US & MRI)[8] • Type 3: Partial Muscle Tear • Type 4: (Sub) total tear

DIRECT MUSCLE INJURY • Bump or Cut: Contact-related

Risk factors[edit]

Although strains are not restricted to athletes and can happen while doing everyday tasks, people who play sports are more at risk for developing a strain.[5] It is common for an injury to develop when there is a sudden increase in duration, intensity, or frequency of an activity.[5]


The first-line treatment for a muscular strain in the acute phase include five steps commonly known as P.R.I.C.E.[9][10]

  • Protection: Apply soft padding to minimize impact with objects.
  • Rest: Rest is necessary to accelerate healing and reduce the potential for re-injury.
  • Ice: Apply ice to induce vasoconstriction, which will reduce blood flow to the site of injury. Never ice for more than 20 minutes at a time.
  • Compression: Wrap the strained area with a soft-wrapped bandage to reduce further diapedesis and promote lymphatic drainage.
  • Elevation: Keep the strained area as close to the level of the heart as is possible in order to promote venous blood return to the systemic circulation.

Immediate treatment is usually an adjunctive therapy of NSAIDs and Cold compression therapy. Cold compression therapy acts to reduce swelling and pain by reducing leukocyte extravasation into the injured area.[11][12] NSAIDs such as Ibuprofen/paracetamol work to reduce the immediate inflammation by inhibiting Cox-1 & Cox-2 enzymes, which are the enzymes responsible for converting arachidonic acid into prostaglandin.[13][14] However, NSAIDs, including aspirin and ibuprofen, affect platelet function (this is why they are known as "blood thinners") and should not be taken during the period when tissue is bleeding because they will tend to increase blood flow, inhibit clotting, and thereby increase bleeding and swelling.[citation needed] After the bleeding has stopped, NSAIDs can be used with some effectiveness to reduce inflammation and pain.[citation needed]

A new treatment for acute strains is the use of platelet rich plasma (PRP) injections which have been shown to accelerate recovery from non surgical muscular injuries.[15]

It is recommended[16] that the person injured should consult a medical provider if the injury is accompanied by severe pain, if the limb cannot be used, or if there is noticeable tenderness over an isolated spot. These can be signs of a broken or fractured bone, a sprain, or a complete muscle tear.

See also[edit]


  1. ^ "Orthopaedic | Lecture Notes". Retrieved 2017-06-25.
  2. ^ a b c d Liaison, Ray Fleming, Office of Communications and Public (2017-04-10). "Questions and Answers about Sprains and Strains". Retrieved 2017-06-25.
  3. ^ Fitness For Dummies p 60, Suzanne Schlosberg, Liz Neporent, For Dummies, 2005, ISBN 0-7645-7851-0
  4. ^ Brumitt, Jason; Cuddeford, Tyler (November 2015). "Current Concepts of Muscle and Tendon Adaptation to Strength and Conditioning". International Journal of Sports Physical Therapy. 10 (6): 748–759. ISSN 2159-2896. PMC 4637912. PMID 26618057.
  5. ^ a b c d "Sprains, Strains and Other Soft-Tissue Injuries-OrthoInfo - AAOS". Retrieved 2017-06-25.
  6. ^ American College of Sports Medicine. Sprains, Strains and Tears. (2011, January 1). Retrieved June 25, 2017, from, American College of Sports Medicine
  7. ^ Mueller-Wohlfahrt, Hans-Wilhelm; Haensel, Lutz; Mithoefer, Kai; Ekstrand, Jan; English, Bryan; McNally, Steven; Orchard, John; Dijk, C. Niek van; Kerkhoffs, Gino M.; Schamasch, Patrick; Blottner, Dieter; Swaerd, Leif; Goedhart, Edwin; Ueblacker, Peter (1 October 2012). "Terminology and classification of muscle injuries in sport: The Munich consensus statement". Br J Sports Med. 47 (6): bjsports–2012–091448. doi:10.1136/bjsports-2012-091448. ISSN 0306-3674. PMC 3607100. PMID 23080315.
  8. ^ a b Stoller, David W. (2007). Magnetic Resonance Imaging in Orthopaedics and Sports Medicine. Lippincott Williams & Wilkins. ISBN 9780781773577.
  9. ^ 235
  10. ^ T. A. Järvinen, et al., "Muscle injuries: optimising recovery" , Best Pract Res Clin Rheumatol., 21 (2) April 2007, pp. 317-31.
  11. ^ k.dilshad. "Tissue Response to Injury" (PDF). Archived from the original (PDF) on 2017-10-31. Retrieved 2017-06-25.
  12. ^ "Cold and Compression Studies Cover Final 1r". Retrieved 2017-06-25.
  13. ^ "Clinical Pharmacology". Retrieved 2017-06-25.
  14. ^ TJ Noonan and WE Garrett, Jr, "Muscle strain injury: diagnosis and treatment," Journal of the American Academy of Orthopaedic Surgeons, 7 (4), July–August 1999, pp. 262-9, see web version (accessed August 25, 2008)
  15. ^ Halpern, Brian C.; Chaudhury, Salma; Rodeo, Scott A. (2012-07-01). "The role of platelet-rich plasma in inducing musculoskeletal tissue healing". HSS Journal. 8 (2): 137–145. doi:10.1007/s11420-011-9239-7. ISSN 1556-3316. PMC 3715623. PMID 23874254.
  16. ^ R. Neustaedter, "Natural Treatment for Injuries" (accessed August 25, 200

External links[edit]