Lecture 9 - Muscle Injuries

Question 1

What is the structure of muscle?

Answer 1

made up of muscle fibres (or cells)

Question 2

What is the function of a muscle?

Answer 2

to generate power

Question 3

What are the 4 muscle actions? Briefly explain.

Answer 3

1. isometric: generates force without changing length (static position)
2. isotonic: generates force while changing length
3. concentric: muscle shorten when generating force
4. eccentric: muscle lengthens when generating force

Question 4

How do muscle adapt to training?

Answer 4

They increase their cross-sectional area and they have a rapid response

Question 5

What are the 2 direct muscle injuries?

Answer 5

• contusion
• laceration

Question 6

What are the indirect muscle injury/disorder?

Answer 6

• muscle strain
• fatigue induced muscle disorder
• delayed onset muscle soreness (DOMS)
• neuromuscular muscle disorders

Question 7

What is a muscle contusion? How do we treat it?

Answer 7

muscle contusion is a muscle bruise caused by an external force

treatment:
acute stage: immobilization and compression for first 24-48hrs
progressive physio:
- gentle active and passive pain free stretching
- isometric strength, then move to isotonic strength when pain-free (with resistance)
- functional and sport specific movements once full and pain free ROM achieved
- RTS when field testing done w/o pain and limitations (mild - 5-7 days, moderate and severe - 4-6 weeks)

Question 8

What are some complications of muscle contusions?

Answer 8

• acute compartment syndrome
• myositis ossificans (bone forms inside muscle)
• muscle fibrosis (scar tissue does not function properly)
• chronic pain and weakness
• recurrent injury

Question 9

What is the mechanism that causes muscle strain?

Answer 9

tensile forces usually close to myotendinous junction

Question 10

What are the signs and symptoms of a muscle strain?

Answer 10

• pop, bump, swelling
• pain on active contraction and passive stretch
• decreased ROM
• loss of function

Question 11

What are the most common muscle that get strained?

Answer 11

• hamstrings
• quadriceps
• gastrocnemius

Question 12

What is the standard rehab for muscle strains?

Answer 12

• mobilization (active movement, passive stretching)
• progressive strengthening
• functional exercises

Question 13

What are the 2 types of neuromuscular disorders? Briefly explain.

Answer 13

1. spinal or spinal nerve related (nerve damage in spine, nerve root or plexus, leads to increased muscle tone, pain, tingling, numbness, weakness)
2. Neuromuscular end-plate related (muscle cramps and fatigue) - muscle fatigue leads to dysfunction of neuromuscular control leading to increased alpha MN activity which increase muscle tone causing over contraction

Question 14

What are the 2 hamstring rupture types? What are the mechanism of each?

Answer 14

1. sprinting related (late kicking phases when sprinting - B-skip kick out)
2. stretching related (slow movements, stretching)

Question 15

What is important is hamstring strain assesments?

Answer 15

• spinal examination
• neural testing
• biomechanical evaluation

Question 16

How can we prevent hamstring injuries?

Answer 16

• proper training and enough recovery
• eccentric strength (injury happens during late kicking phase)
• exercises like nordic hamstrings and stiff leg deadlifts

Question 17

What is the healing process of muscle?

Answer 17

Destructive phase: hemostasis and inflammation
Repair phase: proliferation
Maturation phase: remodelling

Question 18

What type of exercises have bee shown to prevent running related overuse injuries in adult novice recreational runner?

Answer 18

Hip and core exercises