What is the difference between a sprain and a strain?

Jennifer J. Beck, MD
Pediatric Orthopedic Surgery
The difference between a sprain and a strain is that a sprain, as in an ankle sprain, is a ligament injury. That's when a ligament, which connects two bones, gets torn or weakened. A strain, like a hamstring strain, is an injury to a tendon or muscle. A tendon connects a bone to a muscle.
Athletes are vulnerable to acute injuries such as sprains and strains. A sprain refers to a soft tissue injury to ligament tissue that connects bone to bone. The most common sprain is the ankle sprain. A strain also involves soft tissue but refers to injury/damage to muscle tissue. More commonly, strains are referred to as “pulled muscles.”
Todd Brubaker, DO
Pediatrics
Both strains and sprains cause an acute onset of pain. A sprain is damage to the ligament in the joint, usually caused by trauma or a joint being taken beyond its functional range of motion. Sprains can cause a significant amount of swelling and bruising, and most commonly occur in ankles and wrists. In some cases, a severe sprain may take longer to heal than a fracture. A strain, (a.k.a. pulled muscle) is an injury to a muscle where the muscle fibers tear or are overstretched. Severe strains to the back or neck muscles could actually put someone out of commission for a significant amount of time.
Gautam P. Yagnik, MD
Orthopedic Surgery
A sprain is when you injure a ligament. A ligament is the tissue that connects bone to bone. You have ligaments in the knee and the shoulder. A strain happens to a tendon which connects muscle to bone. One of the most obvious tendons is the Achilles tendon which connects your big calf muscle to your heel. If you injure a ligament in the knee, that can also be a sprain. It is just terminology but it’s basically an injury to this tissue. 
RealAge
Administration

A sprain or strain occurs when a joint or a muscle is pulled or stretched beyond its normal range of motion. A strain, often referred to as a "pulled muscle," damages the muscle tissue and tendons, whereas a sprain damages the ligament that is attached to the bone and acts to hold the joint in place.

Many strains and sprains are minor enough to be treated at home. Some, however, can be serious enough to warrant medical attention.

 

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A sprain is any damage to the structural integrity of a ligament. A strain is any damage to the structural integrity of a muscle. (This answer provided for NATA by the Weber State University Athletic Training Education Program.)
Over-stretching of muscles and tendons, which can occur when external and/or internal forces go beyond the capacity of the muscle to maintain appropriate contraction and/or length, is called a “strain.”

An acute twisting or overextension of a joint can lead to tears in the ligaments (which hold joints together). The tearing or over-stretching of ligament tissue is called a "sprain."

Strain and sprain injuries range from mild to severe. In mild cases, just a few fibers are torn or over-stretched. In general, strain and sprain injuries are commonly treated by doctors of chiropractic with outstanding outcomes. Severe injuries, where there is a tear through the full thickness of the structure, may require surgical intervention.
Gerald M. Silverman
Chiropractic Medicine
Strains occur when the muscle fibers or connective tissue bonds become slightly separated or pulled apart by heavy lifting or forceful exertion of the muscle. Sprains occur when muscle or connective tissues actually become torn by the significant shearing forces of direct physical trauma. In either case, if the external forces are great enough, muscle or connective tissue bonds can be separated.
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A STRAIN is an injury to a muscle-tendon unit (the tissue at the end of a muscle that attaches the muscle to a bone). A SPRAIN is an injury to a ligament (a strong band of tissue that connects two bones across a joint). In both cases, injury may include:

  • Overstretching
  • Partial tearing
  • Complete tearing

It is often hard to find the cause of a strain or sprain when there is a lot of swelling.

Jill A. Grimes, MD
Family Medicine
A sprain happens to ligaments, the tissue that attaches bone to bone. A strain occurs in muscles or tendons (tissue connecting muscles to bones).

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.