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How Does A Muscle Repair? (Strains – Part 2)

Greyhound stretchingWhen the muscle has been torn :

Stage 1 is the inflammatory response. This typically lasts for 3 to 5 days. The area will be sore and very tender to the touch

Stage 2 – Regeneration of muscle fibres

Stage 3 – Formation of scar tissue – where the fibres have torn there is a gap. The body lays down scar tissue made of collagen to anchor the two ends together. The matrix of collagen fibres forms the scar within the muscle so inhibiting the muscle movement

Stage 4 – Maturation of Scar Tissue – the dense network of collagen becomes stiffer, harder and restrictive causing shortening of the muscle and its surrounding fascial network. Quite often it will cause the misalignment of bones and in the case of spinal muscles the subluxation of the vertebrae in the area affected by the scar tissue.

The 3 Phases of Muscular Repair – Acute, Sub-Acute and Chronic Stages

bruise on a dog following injuryStage 1: The Acute or Inflammatory Stage. (Day 1-3)

When the muscle tears inflammation occurs immediately due to bleeding into the site of the injury and is characterised by pain, heat, swelling, bruising and tenderness to the touch. Initially the dog should be rested. Ice should be applied to the area to help reduce inflammation and provide relief. The dog should not be exercised at this stage or allowed to do things such as:

  • Dashing out into the garden
  • Jumping on/off sofas


  • Struggling with activities of daily living
  • Inflammation
  • A sudden onset of pain, dog may yelp/scream/shake
  • Unable to weight bear for anything from a few minutes to 3 days. Owner may then seethe dog, lame, stiff, sore, off their food.

Stage 2: The Sub Acute Stage. (Day 4, then up to 6 Weeks)

This is the stage where the body starts to repair the damaged tissue and is crucially the time where it is most prone to re-injure as the muscular tissue is still weak and inflamed. An owner may see stiffness, intermittent (or on/off lameness) and other changes such as unwilling to jump in/out of the car, go up and down stairs. The dog may slow down significantly on their walk. The sub acute phase is the most likely time that the tissue will tear again; this is called the Strain Re-Strain Cycle.

When the muscle is torn the process of muscular repair begins. Numerous satellite cells are stimulated to divide. After division they fuse with existing muscle fibres to help regenerate and repair them. Granulation tissue, fibrin and type 1 collagen are then produced by the body to essentially bind or ‘glue’ the torn site together. This new formation is called scar tissue and is how the body repairs itself after a strain.

A fully trained Canine Massage Therapist will be able to feel your dog’s scar tissue and help to remodel the fibres.

NB: Once scar tissue is in the muscle it will always be there and can never be broken down 100%. It can however be made more supple and flexible by taking into account the other tissue to which it is adhered, helping to release the associated fascial net, make the tissue more supple, pliable and therefore less prone to re-injury.

Why Is The Body Likely To Re-injure Itself in Stage 2?

Scar tissue is fragile and not yet strong enough to hold the site of the injury together.
Range of motion increases yet the tissue is not strong to enough to respond as it would in a normal environment.
Small twists and movements as the muscles are under contraction can cause a restrain; there does not have to be a significant event as is commonly thought.

Stage 3: The Chronic Stage (3 Weeks – Weeks, Months or Years)

The scar tissue has now matured and is stable enough to strongly bind the tissue together. Scar tissue in a chronic phase can reduce a muscle’s flexibility by up to 50%. Massage therapy can help to significantly improve this with regular care.

An area of scar tissue feels:

  • Tight
  • Restricted
  • Like a dull persistent ache
  • Stiff
  • Can cause a loss of appetite

It will:

  • Restrict range of motion of the joint
  • Inhibit normal activities

An owner may see:

  • An area which the dog is reluctant to have touched/groomed
  • Conversely some dogs are very good at presenting the area where they

The area that sustained injury is now well into healing and scar tissue has now been modified by the body. By this point, pain is decreased or gone, except when the muscle is overused or the joint reaches its full range of motion. Exercise, physical therapy, and lots of joint movement are recommended.

Chronic Injuries May include Some Or All Of The Following:

  • Pain with movement is dull or achy, not sharp
  • Pain at the very end of a range of movement
  • Dull ache at rest
  • Bruising is gone
  • Signs of inflammation are gone
  • Scar tissue is maturing

If you missed part 1 of this blog click here.

Author:  Natalie Lenton

For more information visit Natalie Lenton‘s Biography

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