Muscle Strain and Muscle Fatigue

Symptoms | Tests for Diagnosis | Treatment | Prognosis

Most back pain is believed to be caused by soft tissue injury. Nonspecific back pain, which commonly occurs between the ages of 20-55 years, may be due to a single type of soft tissue injury, such as a muscle strain, or to a combination of soft tissue injuries (muscle, ligament, and other connective tissues).

Muscle strain, also called "tight muscles" or "pulled muscles", is usually a result of muscle overuse from prolonged exercise or extremes of physical activity.  Two major muscle groups of the back (extensor and flexor muscles) are actually composed of many smaller individual muscles - if any of these smaller muscle bundles become over-fatigued, over-stretched, or torn, discomfort or mild to significant pain and, possibly, some immobility can occur. 

Muscle strains have degrees of severity that require different types of treatment and levels of care.  In mild muscle strains, fibers are usually intact.  More serious muscle strains have torn muscle fibers and or complete disruption of muscle fibers.  These injuries require a thorough evaluation, treatment, and follow-up.

Muscle strain should not be confused with muscle contusions, which are caused by direct blows or trauma to the muscle and often occur during contact sports.


Strained muscle fibers may attain a state of sustained contraction and feel like a hard knot within a muscle. Moving becomes painful and limited, and may also feel sore or have a feeling of 'twitching'.  Most people have experienced mild back strains that spontaneously heal with rest or had a leg cramp (a "charley horse") that walking quickly improves.  With more serious muscle strains, symptoms are more acute.  The symptoms of a muscle strain can also mimic the painful condition of sciatica or claudication.

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Tests for Diagnosis

For symptoms of lower back or leg pain, the history taken by your doctor will include questions about lifestyle, at home and work, and what types of regular or unusual physical activity you engage in.  Questions about dehydration are related to issues of muscle strain, whether your muscles are hydrated (have enough water); muscle cramps can be brought on by dehydration from excessive sweating, diarrhea, or vomiting.

Diagnostic tests include physical examination and a neurological examination as well as evaluation by X-ray or other imaging modalities. Routine laboratory tests may be done to rule out metabolic causes.  Your doctor may ask you to complete a survey related to attitudes and beliefs about back pain, work, and other social issues as part of a comprehensive treatment approach.

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Treatment for muscle strains includes rest, ice during the first 48 hours, heat and ice alternated thereafter, elevation of the affected extremity, and medication for pain and inflammation, if necessary.

Strain injuries must be evaluated before beginning any exercise program to prevent worsening of the injury or prolong healing.  If the strain is mild, light stretching exercises may be prescribed to help relax the muscle fibers.  For more serious muscle strains with muscle damage, exercises usually include strengthening or stretching for the upper and/or lower back and legs.  Biofeedback is a treatment method using relaxation, where patients learn to voluntarily relax their back muscles during moments of stress or pain.

As part of protecting you from future muscle injuries, instruction you in improving and maintaining correct posture while standing, sitting, and walking is useful.

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Recovery from nonspecific muscle strain of the lower back is uncomplicated and the prognosis for full recovery excellent. Pain relief and a return to normal activity or sports is related to the severity of the initial injury as well as to how the patient adheres to treatment, physical therapy, and follow-up visits. 

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