Muscle Injury Treatment & Symptoms

Functional muscle injury cause pain and impact movement but do not have identifiable structural changes. Structural injuries involve actual damage to the muscle fibers. While the term “Muscle Strain” is frequently used to describe these injuries, the term “muscle tear” better reflects the structural damage.

Functional muscle injury is caused by overexertion or neurological input. Overexertion can result in fatigue induced muscle disorder with the primary symptoms of “aching” and “tightness.” Delayed onset muscle soreness (DOMS) is the latent development of pain following unaccustomed activity, usually including decelerating movements and eccentric muscle contraction. DOMS is characterized by pain during activity and at rest, muscle stiffness, and altered movement patterns.

Muscle pain of neurological origin can stem from the spine (e.g., nerve root compression) or from dysfunctional local neuromuscular control mechanisms:

• Spine-related muscle disorders are characterized by increased tone and “aching,” and the underlying source must be identified and managed.
• Muscle-related neuromuscular disorders are characterized by cramp-like pain, aching, and localized increased tone. These symptoms may be relieved by stretching.

Structural muscle injuries involve an acute episode and often result from a sudden forced lengthening. Often occurring at the weaker musculotendinous junction, muscle tears are further classified as minor partial, moderate partial, and total, depending on the amount of involved tissue.

See Also: Hamstring Muscles

Muscle Injury Classification

Muscle Injury sources can be from Exertional, Neuromuscular, Muscle Tension Related or Direct Blow injury.

Exertional

Type	Classification	Symptoms	Clinical Signs
1A	Fatigue-induced disorder	Increase in the longitudinal muscle tone as the result of overexertion, change of playing surface, or activity patterns	Diffuse, dull pain; “tight muscles” reported
1B	Delayed-onset muscle soreness (DOMS)	Generalized muscle pain following exercise, especially those involving eccentric contractions	Acute inflammation related pain; pain at rest that persists hours to days following activity

Neuromuscular

Type	Classification	Symptoms	Clinical Signs
2A	Spine-related neuromuscular muscle disorder	Increase in longitudinal muscle tone as the result of structural spinal or lumbopelvic disorders	Increased muscle tension that increases with activity and decreases at rest. Pain may increase with muscle stretching or the application of pressure.
2B	Muscle-related neuromuscular muscle disorder	Spindle-shaped area of increased muscle tone as the result of dysfunctional neuromuscular control (e.g., reciprocal inhibition)	Aching with progressive muscle tension (spasm)

Muscle Tension Related

Type	Classification	Symptoms	Clinical Signs
3A	Minor partial muscle tear	Tearing of less than one muscle fascicle/bundle	The patient may report a “snap” followed by a sharp, stabbing pain.
3B	Moderate partial muscle tear	Tear diameter is greater than one muscle fascicle/bundle.	The patient reports a “snap” at the time of injury, with a noticeable sensation of tearing. Muscle function will be limited.
4	(Sub)total muscle tear/ tendinous avulsion	Tear involving the complete, or near complete diameter of the muscle or tendon, frequently located at the musculotendinous junction	Noticeable tearing. The patient experiences a definite snap followed by immediate disability of the muscle.

Direct Blow

Type	Classification	Symptoms	Clinical Signs
Contusion	Direct injury	Trauma caused by blunt trauma leading to hematoma	Dull pain that may increase with time (proportional to the increased size of the hematoma)

See Also: Hamstring Strain

Muscle Injury Symptoms

Patients with muscle injury will often describe a “snap” following by a sharp localized pain at the time of injury. Moderate and total tears result in palpable defects, ecchymosis, and edema that may extravasate distally.

Functionally, patients will compensate to avoid activating or elongating the involved muscle. Total tears may not result in a complete loss of joint function due to compensation by secondary movers.

The same mechanism that produces a tear in a skeletally mature individual may result in an avulsion of the muscle’s origin or insertion in skeletally immature individuals.

Radiographs and magnetic resonance imaging (MRI) are used to rule out apophyseal avulsions.

Tears occur more frequently in muscles that span two joints than they do in one-joint muscles.

Examination Findings

History of Current Condition:

• Onset: Acute
• Pain characteristics: Pain is initially located at the site of the injury, which tends to be at or near the junction between the muscle belly and tendon. After a few days, pain becomes more diffuse and difficult to localize.
  The distal musculotendinous junction is most often involved.
• Mechanism: Tears usually result from a single episode of overload of the muscle as the result of an eccentric contraction.
• Risk factors: Imbalance in the strength of the agonist/antagonist muscle groups; History of injury to the involved muscle; Muscle tightness and improper warm-up before activity.

Functional Assessment:

Compensatory movement patterns will be observed in motions requiring control or strength from the involved muscles.

Inspection:

• Ecchymosis may be evident in cases of moderate or total muscle tears.
• Gravity causes the blood to pool distal to the site of trauma.
• Swelling may be present over or distal to the involved area. In severe acute cases or in a chronic condition, a defect may be visible in the muscle or tendon

Palpation:

• Point tenderness and increased tissue density associated with spasm exist over the site of the injury, with the degree of pain increasing with the severity of the injury.
• A defect may be palpable at the injury site.

Joint and Muscle Function Assessment:

• Active range of motion: Pain is elicited at the injury site. In the case of moderate or total tears, the patient may be unable to complete the movement.
• Manual muscle test: Muscle strength is reduced. Pain increases as the amount of resistance is increased. Total tears result in total a loss of function of the involved muscle.
• Passive range of motion: Pain is elicited at the injury site during passive motion in the direction opposite that of the muscle, placing it on stretch.

Joint Stability Tests:

• Stress tests: Stress tests of the ligaments crossing the joint(s) serviced by the muscle should be performed. Tears may occur as the body attempts to protect against ligament injury.
• Joint play: Rule out hypermobility.

Neurovascular Screening:

• Use to rule out nerve entrapment that clinically appears as a strain.
• Tearing of muscle may also damage peripheral nerves.
• Vascular Screening is within normal limits.

Differential Diagnosis

Differential Diagnosis for muscle injury include:

1. Tendinopathy,
2. underlying joint instability,
3. stress fracture,
4. nerve entrapment,
5. avulsion fracture.

Muscle Injury Treatment

Muscle injury that occurs as the result of exertion is often managed symptomatically using thermal modalities. Light to moderate exercise and stretching assist in reducing symptoms and restoring muscle function.

The interventions for neuromuscular related conditions focus on resolving the underlying neurological condition (e.g., nerve impingement, disc herniation).

Type 3A and 3B muscle tears are initially managed using cryotherapy and stretching as tolerated.

Rehabilitation focuses on strengthening both the involved muscle(s) and the antagonist muscle group with the goal of restoring appropriate muscle balance. Type 4 muscle tears (ruptures) often require surgical correction.

Q&A For Patient

References

1. Mueller-Wohlfahrt HW, Haensel L, Mithoefer K, Ekstrand J, English B, McNally S, Orchard J, van Dijk CN, Kerkhoffs GM, Schamasch P, Blottner D, Swaerd L, Goedhart E, Ueblacker P. Terminology and classification of muscle injuries in sport: the Munich consensus statement. Br J Sports Med. 2013 Apr;47(6):342-50. doi: 10.1136/bjsports-2012-091448. Epub 2012 Oct 18. PMID: 23080315; PMCID: PMC3607100.