Muscoskeletal injuries (wk6)

Question 1

Name and describe how musculoskeletal injuries arise

Answer 1

-Injury -> Damage to the cellular structure of human tissue resulting from the application of mechanical stress
-Mechanical stress -> ‘Amount of force acting within a structure’. Beneficial or injurious. 3 types of stress: compression, tension, shear
-Compression stress -> Particles pushed against each other.
-Tension stress -> Particles pulled away from each other
-Shear stress -> Particles slide relative to each other

Question 2

Describe the loading patterns which cause injuries

Answer 2

1. Compression load -> Equal and opposite forces applied. Creates compression stress within structure.
2. Tension load -> Equal and opposite forces pull away from each other. Creates tension stress within structure.
3. Shearing load -> Forces applied parallel to structure surface. Creates shear stress within structure. E.g. blister
4. Bending load -> Bending (the combination stress). INSERT DIAGRAM. Shear in the middle. E.g. Achilles tendon injury
5. Torsional load -> Twisting about an axis. Induces shear, compression and tension stresses. All 3 types of stress in the structure. E.g. ACL injury

Question 3

Draw the stress-strain curve

Answer 3

-Stress produces strain -> ‘Deformation of a body in response to stress’
-Stress strain curve -> Elastic limit – some injury happens in this section

Question 4

What are the 2 types of injury

Answer 4

1. Acute traumatic injury -> Results from a single episode of stress, exceeding a tissue’s tolerance. Creates microtrauma.
2. Chronic overuse injury -> Results from repetitive application of stress at levels less than a tissue’s tolerance. Creates microtrauma. Potential for tissue damage dependent on: magnitude of stress, total number of stress peaks, interval between stresses (recovery period) – inadequate recovery time can lead to greater injuries

Question 5

Describe and draw the overuse injury theory

Answer 5

-Overuse injury theory -> Remodelling rate > Rate of damage and stronger tissue -> Means that the body cannot keep up and leads to cumulative tissue damage

Question 6

Describe what categories injuries are based upon

Answer 6

1. Tissue type
2. Cause
3. Severity

Question 7

Describe ligament injuries

Answer 7

-Sprain -> Ligament sprain -> Caused by sudden over-stretch with joint in extreme position. Can be sorted into contact or non-contact.
-Grading ligament sprains -> Grade 1 – Microscopic tearing, Grade 2 – partial disruption, Grade 3 – Complete rupture

Question 8

Describe muscle injuries

Answer 8

-Strain -> Muscle strain -> Occur from: forceful ‘over-stretch’, forceful eccentric contraction, combination
-Grading muscle strain -> Grade 1 – Microscopic tearing, Grade 2 – Partial disruption, Grade 3 – Complete rupture (same as sprains)

Question 9

Describe bone injuries
-Including the overuse injury theory

Answer 9

-Acute – fracture
-Overuse – stress fracture.
-Acute skeletal injury (fracture) – A break in the structural continuity of bone and caused by sudden and excessive force.
-Stress fracture (chronic overuse) – Microfractures (stress injury) -> Small cortical fracture (stress fracture)
-Overuse injury theory -> Weakened tissue. Overuse injury makes an acute traumatic injury more likely.
-Who? – runners (tibia, femur, pelvis), golfers (ribs), dancers (toes)
-Chronic overuse – Weakened tissue. Overuse injuries make an acute traumatic injury more likely.
High-risk stress fractures – Stress fractures of femoral neck and middle anterior tibia can progress to acute fracture

Question 10

Describe tendon injuries

Answer 10

-Overuse – tendinopathy
-Acute – rupture
-Overuse tendon injury – tendinopathy -> Tennis elbow, golfer’s elbow and jumper’s knee. Collagen degeneration and disorientation (called pathophysiology)
-Weakened tissue in the tendon happens like bone (overuse injuries make an acute traumatic injury more likely)