1. Chapter 8
The Injury Process

2. Sports Injury Affects different types of tissues.
Musculoskeletal system involved in significant portion of injuries.
Follows a healing process characterized by:
Acute phase (Inflammatory)
Resolution (Fibroblastic)
Regeneration/Repair phases (Maturation and Remodeling)

3. The Physics of Sports Injury
Types of tissue
Connective Tissue
Connective tissues are the most common type of tissue in the body.
Connective tissues include bone, cartilage, fascia, tendons, ligaments, retinaculum, and joint capsule.
Epithelial or Skin (for protection, secretion, and absorption)
Muscular (for contraction)
Nervous (for touch and conductivity).

4. The Physics of Sports Injury
Muscle/tendon/fascia are thought to be injured by excessive tension during contractions.
Eccentric contractions
In some sports, nearly 50% of acute injuries involve either tendon or muscle.
Tendons are extremely strong structures; strains occur most often at the distal musculotendinous junction (MTJ).

5. Mechanical Forces of Injury
Types of Force
Compressive
Tensile
Shear

6. Mechanical Forces of Injury
Each type of tissue has a limit for how much force it can withstand (critical force).
Age, temperature, skeletal maturity, gender, and body weight can affect the mechanical properties.
Tendons and ligaments are designed to resist tensile forces.
More vulnerable to shear and compressive mechanisms.
Bones are designed to resist compressive forces.

7. The Physiology of Sports Injury
Whenever tissues are damaged as a result of an injury, the body reacts quickly with a predictable sequence of physiologic actions designed to lead to ultimately to the repair the involved tissues.
Within minutes the inflammatory process begins.
Resolution, regeneration, and repair of the injured tissues.

8. The Inflammatory Process
Normal signs and symptoms of inflammation include:
Swelling or Edema.
Pain.
Reddening of skin (erythema).
Increased temperature in the affected area.
Loss of function.

9. Inflammatory Phase Millions of cells are destroyed due to trauma.
Damage to blood vessels results in blood flow into interstitial spaces causing swelling and a hematoma.
A hematoma is the localized collection of blood in the damaged area.
Vasoconstriction immediately slows blood flow to prevent further damage and is followed by vasodilation, which brings essential chemicals to repair the injury site.

10. Inflammatory Phase Purposes:
The acute inflammatory process results in a walling off of the damaged area from the rest of the body.
The process acts to clean up the debris and provide chemical and enzymatic components for healing.
The acute phase lasts up to 3 or 4 days, unless aggravated by additional trauma.

11. Inflammatory Phase
In response to injury, chemicals are released that affect vascular system and nearby cells. The effects of these chemicals are:
Degradative (cellular breakdown).
Vasoactive (vasodilators).
Chemotactic (attract scavenger cells).
Fluid accumulation, blow flow obstruction, and decreased oxygen sources may lead to secondary injury.
Secondary metabolic injury
Secondary enzymatic injury

12. Inflammatory Phase Vasoactive and Chemotactic Responses
Release of histamine
Vasodilation/Permeability
Release of bradykinins
Pain/Vasodilation/Permeability
Hageman Factor is responsible for the manufacture
Release of prostaglandins
Blood clotting.

13. Inflammatory Phase Because of vasodilation and vessel permeability:
Plasma proteins, platelets, macrophages, neutrophils, and leukocytes move out of capillaries and into damaged tissue.
Neutrophils and leukocytes engage in the beginning stages of phagocytosis (damaged cell eating).
Macrophages migrate into the damaged area to continue phagocytosis.

14. Inflammatory Phase Phagocytosis: Removes dead or dying cells.
Helps begin healing via arachidonic acid.
Arachidonic acid is formed by a combination of leukocyte enzymes and phospholipids derived from cell membranes.
Catalyzes the production of leukotrienes which attract polymorphs & monocytes (specialized leukocytes) and histocytes (specialized macrophage).

15. Resolution Phase
Polymorphs, monocytes, and histocytes migrate into the area of injury.
These cells break down cellular debris and set the stage for regeneration and repair.
Balance between tissue breakdown (lysis) and tissue build up (synthesis) allows for growth of new tissue.

16. Resolution Phase Angiogenesis is the formation of new capillaries.
Essential for the provision of nutrients and removal of waste products.
Connective tissues heal by forming scar tissue that begins to develop 3–4 days after the injury.
Fibroblasts (proteoglycan- and collagen-producing cells) migrate into the damaged area and can mature into several different types of cells.
Bone tissue heals by way of specialized cells (osteoclasts and osteoblasts).

17. Regeneration and Repair
Scar formation may take up to four months.
Scar tissue can be 95% as strong as the original tissue.
Stress on the tissue is helpful for rehabilitation.
Stress encourages the new collagen fibers to form in parallel lines, a much stronger configuration.
Exercises are critical to this process.

18. Regeneration and Repair
Healing depends on the structures involved:
Tendons/ligaments may take the longest in order to return to their strong/elastic state.
Muscle tissue heals quickly due to the amount of capillaries.
New collagen and fibers will form along the lines of stress to make a strong configuration.

19. Pain and Injury
Pain results from sensory input received through the nervous system and indicates location of tissue damage.
Everyone copes with pain differently.
Pain is not a useful indicator of injury severity.
Pain is as much psychological as physiological.
Blocking of pain
Messages concerning sensory information travel quicker through the nervous system and are able to block pain messages.

20. Intervention Procedures
Sports medicine community has no clear set of criteria for first aid treatment of acute soft- tissue injury.
Cryotherapy includes bags of crushed ice, aerosol coolants, ice cups, ice water immersion, and commercial cold packs.
After the acute phase, thermotherapy is appropriate (i.e., hydrocollator packs, moist warm towels, and ultrasound diathermy).

21. Intervention Procedures
Modalities such as ice, heat, ultrasound, electrical stimulation can be used to assist healing.
Most electrical modalities should ONLY be used under the supervision of trained allied health personnel.
Pharmacologic agents can be used, such as anti-inflammatories and analgesics.
If they must be prescribed by a physician, these agents represent treatments that are beyond the scope of the coach.
OTC drugs should also be used with caution. (Consult parents when athlete is under 18 years of age.)

22. Cryotherapy
Direct application of cold may reduce vasodilation in the first few minutes after injury.
Cold application has analgesic effect and reduces muscle spasm.
Application of cold can decrease recovery time by reducing secondary hypoxic injury.
Courtesy of Ron Pfeiffer

23. Cryotherapy Crushed ice in a plastic bag is an inexpensive modality.
In extremities, elevation and compression are also helpful in treatment.
Elastic wrap secures the ice bag to the body.
Risk of frostbite is minimal with crushed ice.

24. Cryotherapy
Traditional recommendations for crushed ice application is minutes.
Recent research showed a greater reduction in pain when ice was applied 10 minutes on, 10 minutes off, 10 minutes on compared to 20 minutes of continuous ice application.

25. Thermotherapy Thermotherapeutic agents
Should NEVER be applied to an acute injury while redness and heat are present.
Increase vasodilation, available oxygen and permeability.
Are useful in the final phases of injury repair.

26. Pharmacologic Agents
Steroidal drugs and Non-sterodial anti-inflammatory drugs (NSAIDs)
Both affect aspects of the inflammatory process (swelling and pain).
Steroidal drugs resemble gluococorticoids, but the exact mechanism of their action is unknown.

27. Pharmacologic Agents NSAIDs are very popular drugs.
Common NSAIDs include aspirin, ibuprofen, naproxen, indomethacin, and naproxen sodium.
NSAIDs block the conversion of arachidonic acid to prostaglandin.
Anti-inflammatory, analgesic, and antipyretic effects.
Research is inconclusive regarding NSAIDs’ effect on tissue healing and strength.

28. Pharmacologic Agents Steroids: Steroids must be used with care.
Decrease amount of chemicals released by lysosomes thereby decrease permeability of capillaries and reducing phagocytosis.
Reduce local fever.
Steroids must be used with care.
They can interfere with collagen formation, decreasing connective tissue strength in injured area.
Steroids may be injected or taken orally and include drugs such as:
Cortisone, hydrocortisone, prednisone, and dexamethasone.

29. RICE
Best approach to the care of soft tissue injury is RICE along with prescribed pharmacologic agents and supervised rehabilitative exercise.
R = Rest
I = Ice
C = Compression
E = Elevation

30. The Role of Exercise Rehabilitation
Properly supervised physical activity is very effective for many injuries.
Such exercise can have a positive effect on collagen formation and return of muscle strength.
Early mobilization of the joint or muscle will assist in the healing process.

31. Exercise Rehabilitation
Collagen formation and tissue regeneration require 2 to 3 weeks.
Rehabilitation must be supervised by professionals with appropriate training, such as a BOC-certified Athletic Trainer or a Physical Therapist with sports medicine training.

32. Exercise Rehabilitation
Rehabilitative exercise is a four-phase process.
Passive exercise
Active assisted
Active exercise
Resistive

33. Exercise Rehabilitation
Injury rehabilitation should be considered an ongoing process.
Injury-specific exercise should be a permanent component in training and conditioning.
Without this approach, the likelihood of re-injury is high.