Muscle Tear: Pathophysiology and Rehabilitation

Most Common Causes of Muscle Tear

Muscle tear is a type of sports injury or muscle injury that occurs when a muscle is overstretched or over-contracted beyond its limit. There are many movements and conditions that can cause a muscle tear as:

  1. Sudden Exertion: This can happen when you suddenly apply a large amount of force to a muscle such as an uncontrolled Landing after a jump or rapid change of direction of the limbs during different sports or exercises.
  2. Direct Trauma: This can happen when you hit or fall on a muscle such as tackles in soccer or rugby.
  3. Overuse: This can happen when you repeatedly use a muscle beyond its limits such as overloading the muscles during weight lifting.

Muscle tears can range from mild to severe, depending on the quantity of the broken muscle:

  1. Partial Muscle Tear ( only a part of the muscle is damaged ).
  2. Complete Muscle Tear ( the entire muscle is damaged ).
Mild muscle tears may only cause minor pain and discomfort, while severe muscle tears may cause severe pain, swelling, and bruising.

Muscle tears can occur in any muscle, but they are most common in these muscles:

  • Hamstrings
  • Quadriceps
  • Calf and Soleus Muscle
  • Groin Muscles
  • Shoulder Muscles

Muscle Tears can take several weeks or even months to heal completely.

Pathophysiology of Muscle Tear

The pathophysiology of the muscle tear can be divided into three phases:

  • Phase 1: Inflammation Process

The inflammation process starts in the immediate aftermath of the muscle tear, during which our immune system responds to promote healing and defend from infections. During this phase, the body releases chemicals (Histamine, Nitric Oxide ) that cause the blood vessels to dilate and become more permeable. This allows white blood cells and other immune cells to rush to the injured area to fight off infection and begin the process of repair.

  • Phase 2: Proliferation Process

The proliferation phase begins about 3-5 days after the injury. During this phase, the body begins to produce new tissue to repair the damaged muscle fibers. 

These new fibers are formed by a process called myogenesis which is a complex process that involves the activation of satellite cells, which are dormant cells that are located within the muscle tissue. Satellite cells are responsible for the growth and repair of muscle tissue.

The proliferation phase can last for 2-3 weeks.

  • Phase 3: Remodelling Process

The remodeling phase begins about 2-3 weeks after the injury. During this process, the body begins to remodel the new muscle fibers making them stronger and more organized.

The new muscle fibers must be aligned and connected to each other. This process is called sarcomere alignment which is important for the strength and function of the muscle.

During the remodeling phase, the tissues are more organized as there is an alignment of the new muscle fibers in the same direction as the original muscle fibers.

The final step in the remodeling phase is the deposition of collagen. Collagen is a protein that is found in connective tissue. Collagen helps to strengthen the muscle and provide support banding the muscle fibers together.

Biomechanic of Muscle Fibers after a Muscle Tear

The biomechanics of muscle fibers after a muscle tear is a complex process that involves the interaction of many different factors such as:

  1. The severity of the muscle tear.
  2. The location of the tear respects its tendons and joint.
  3. The age and health of the individual.

The severity of the muscle tear depends on the number of muscle fibers that have been damaged ( partial or total muscle tear ). 

The location of the muscle tear is a fundamental aspect both for the symptoms and functionality of the torn muscle. A muscle tear in the middle of a muscle is more dangerous than a tear near the end of a muscle. This is because the two ends of a tear in the middle of a muscle are more likely to be pulled apart, which can lead to further injury. Additionally, tears in the middle of a muscle are more difficult to heal than tears near the end of a muscle.

The age and health of the individual reflect on the biomechanic quality of the muscle such as flexibility and strength. 

In general, the biomechanics of muscle fibers after a muscle tear is characterized by the following:

  • Reduced strength and power. Muscle tears can cause a significant loss of strength and power in the affected muscle. This is because the tear decreases the number of muscle fibers that contribute to the muscle contraction.
  • Reduced range of motion. Muscle tears can also cause a reduction in the range of motion in the affected joint. This is because the tear can cause scar tissue to form, which can reduce muscle flexibility and length, restricting the movement of the joint. Furthermore, scar tissue can increase the friction between connective tissue and muscle fibers, reducing their mobility.
  • Increased risk of re-injury. Muscle tears are more likely to re-occur, especially if the individual does not properly rehabilitate the injured muscle. A re-injury is most likely to occur where there is the formation of scar tissue as this is a rigid trigger point ( anelastic connective tissue ) that is more susceptible to mechanical stress.

Treatments and Rehabilitation after Muscle Tear

First of all, it is important an early diagnosis of muscle tear, as very often mild muscle tears are missed as they cause minor pain or muscle dysfunction.

The diagnostic gold standard for a muscle tear is an Eco-Scan.

Experienced Physiotherapists or Sports Therapists can detect muscle tears with palpation of the muscles too. Under palpation, the muscle tear feels like a little depressed area that indicates the rupture of the muscle fibers.

If we assess a muscle tear with a clinical assessment instead of the diagnostic one ( Eco Sacn ), we have to be careful with the location of the bruised area of a torn muscle. Most of the time the bruised area is located a few centimeters down the location of the muscle tear because the blood went down the muscle because of gravity.

The photo below shows a Semitendinosus Muscle Tear with a bruised area located a few centimeters down the muscle.

Semitendinosus Muscle Tear

The rehabilitation of a muscle tear is an important part of the healing process.

The goal of rehabilitation is to restore the strength, power, and range of motion of the affected muscle.

Rehabilitation typically involves a combination of different actions  that include:

  • RICE Approach: rest, ice, compression, and elevation of the muscle affected. Resting the injured muscle is the first thing to do after the injury. This means avoiding any activities that put stress on the damaged muscle. Applying ice to the injured muscle for 15-20 minutes at a time can help to reduce inflammation, swelling, and pain. Compressing the injured area with an elastic bandage can also help to reduce swelling. Elevating the injured area/limb above the level of your heart can also help to reduce swelling.
  • Physical Therapy: This includes both Hands-On treatment and Physio Exercise to recover the range of motion, strength, and flexibility of the muscles and related joints.
  • Taking over-the-counter pain relievers: Over-the-counter pain relievers, such as ibuprofen or paracetamol, can help to relieve pain and inflammation. Before taking any medication it is important to talk to your doctor first. The doctors can help you to choose the right drug for your needs and make sure that it is safe for you to use.
  • Gradual return to activity: you must increase the intensity of exercises with graduality in order to give time for the damaged muscle fibers to adapt again to the load.
  • Massage Therapy: Massage therapy such as Sports Massage can help to ease muscle tension around the tear and improve blood flow to the injured area. Massage can speed up the recovery time and waste cell removal during the healing process of the damaged muscle.

With proper rehabilitation, most people will be able to fully recover from a muscle tear and return to their previous level of activity. However, it is important to note that it may take several months for the muscle to fully heal.

How to Reduce The Scar Tissue after a Muscle Tear

It is important to note that it is not possible to completely eliminate the production of collagen tissue because it is part of the natural healing process.

However, we can reduce the amount of collagen tissue that is produced and improve the healing process.

There are a few things you can do to reduce the formation of scar tissue after a muscle tear, and these include:

  • Early diagnosis and treatment as described above.
  • Compression with a bandage: This is very important mainly when there is a tear in the middle of the muscle because the two ends of the tear are more likely to be pulled apart. The more the two ends of the tear pull apart, the less chance that the muscle fibers are reconnected with new ones. This is a condition that increases the amount of connective tissue to reconnect a torn muscle.
  • Deep Tissue Massage: Deep Tissue Massage is a type of massage that can help to break up scar tissue and reduce muscle stiffness created at the two ends of the tear. In addition, deep tissue massage can improve blood flow, the removal of waste cells, and speed up the recovery time.
  • Instrument-Assisted Soft Tissue Mobilization: This is a special hands-on therapy that can be performed by a highly experienced Physiotherapist or Sports Therapist with the utilization of tools with different shapes that can fit the different muscles and body parts. It is advisable to perform this therapy for at least after 2 weeks the muscle injury, during the Remodelling Phase. If performed properly, this therapy can be a key factor in both a better alignment of the new muscle fiber ( sarcomere alignment ) and less and more organized scar tissue ( connective tissue ).
  • Collagenase: Collagenase is an enzyme that can help to break down collagen, which is the main component of scar tissue. Be aware that this drug should be always used under your doctor’s prescription!
  • Gradually increase your activity level as the muscle heals: This will help to build new muscle fibers and less scar tissue. Light muscle activity helps for better muscle fibers alignment and more organized connective tissue distribution. Additionally, this will help to prevent re-injury.


The ultimate tip for a Muscle Tear

Muscle tear is quite an important muscle injury.

If you may think or have a muscle tear, it is important to see a doctor or your trusted physiotherapist to get a diagnosis and discuss treatment options.

With proper care, most muscle tears will heal completely.

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