1. Injury Response Process
Chapter 10

2. Why do we care about this process?
We must have a basic understanding of how the body responds to an injury.

3. Great Adaption Syndrome (GAS)
1. Alarm Stage
2. Resistance Stage
3. Exhaustion Stage

4. GAS: Alarm Stage Flight or fight response
Body tries to thwart effects of the stressor by readying defense systems
Increase blood supply to areas that need it
Cortisol is released to regulate inflammation, stimulate cellular activity, and prepare the body to deal with trauma.

5. GAS: Resistance Stage Longest phase
Plateau in body’s adaption to the stress
Body continues to adapt to the stressor
Body achieves physiological resistance

6. GAS: Exhaustion Stage
When body can no longer withstand the applied stress; failure occurs.
Result: traumatic or overuse injuries

7. GAS: Relationship to Trauma
Beneficial vs. Harmful stress
Harmful may be…
Too much force in a short period of time- macrotrauma
Repeated, low intensity forces- microtrauma

8. GAS: Relationship to Trauma
Amount of stress applied to body must be of proper intensity and duration for body to develop physiological resistance
To balance + and – stress, body adapts:
Wolff’s Law: applying enough stress but not too much
Hypertrophy: increase in muscle cell size
Remodeling of collagen fibers (scar tissue): apply stresses so will align properly

9. Definitions: Ischemia: decreased blood supply
Hypoxia: lack of oxygen supply
Inflammation: tissue reaction to injury
Edema: excessive accumulation of fluids
Hemorrhage: bleeding

10. Injury Process: 2 Parts Primary Reaction Secondary Damage
Tissue destruction associated with the traumatic force
Secondary Damage
Cell death caused by blockage of oxygen supply to the injured area
Enzymatic damage and mitrochondrial failure

11. Three Phases to Healing
1. Acute Inflammatory Response
2. Proliferation Phase
3. Maturation (Remodeling) Phase

12. Acute Inflammatory Response
Delivery of phagocytes and fibroblasts into the area
Formulation of granulation tissue: isolates the trauma)
Histamine released (increase capillary permeablity)- results in redness, heat, swelling

13. Inflammation Body’s defense mechanism
Body’s reaction to cell injury or death
Triggered by mechanical trauma (spraining a ligament, bacterial invasion, chemical irritation, or burns)

14. Do we want inflammation?
Essential part of the healing process
However, if the duration or intensity of the inflammation is excessive, the process becomes detrimental and chronic inflammation becomes a debilitating event
Body overreacts to trauma

15. Purpose of Inflammation
To control the effects of trauma and return the tissue to its normal state
Initially… contains, destroys, dilutes injurious agents and localizes damage
Pain that follows… alerts the athlete that damage has occurred
Muscle guarding: “Splints” the area

16. Cardinal Signs of Inflammation
Heat
Redness
Swelling
Pain
Loss of function

17. Proliferation Phase 72 hours-3 weeks
Number/size of fibroblasts increase
Ground substance and collagen to collect in injured area (scar tissue) in preparation to rebuild injured area.

18. Proliferation Phase
Revascularization: proteins produce new capillary beds and granulation tissue.
Fibroblasts lay down collagen to form seal over injured area and extracellular matrix is developed (mostly water content to reduce friction)
Collagen (Type III) is laid down haphazardly; controlled stress caused fibers to arrange themselves more orderly.

19. Maturation Phrase 3 weeks- 1 year
Collagen and fibroblasts align themselves and attempt to adapt to original tissue orientation.
Very important to apply controlled stress in this phase to properly align collagen.