Loading of the MSk system

Question 1

Define Injury (Bartlett 1999)

Answer 1

Injury occurs when the load applied to a tissue exceeds it’s failure tolerance

Question 2

What are the two crucial factors of an injury?

Answer 2

• Load (Sum of forces and moments of forces)

- Characteristics of loaded structures

Question 3

Define Strain

Answer 3

A measure of how much a material is deformed. Strain is calculated as a percentage of change

Question 4

Define Stress

Answer 4

• A measure of how much the material resists deformation

- Load per unit cross-sectional area in MPa (100 N/cm2)

Question 5

What is Young’s modulus of elasticity? (E) And what does it do

Answer 5

• Ratio between stress and strain. E = stress/strain

- Measures the stiffness of a material

Question 6

What are the stages in the SSC?

Answer 6

• Preload
• Elastic energy storage
• Reflex potentiation

Question 7

Define Resilience

Answer 7

Amount of energy returned/Amount of energy stored

Question 8

What leads to a hysteresis loop?

Answer 8

• When properties display viscoelasticity

- Stress-Strain curve is not the same in loading and unloading

Question 9

What can increase tendon strength and resilience?

Answer 9

Strength training

Question 10

What are the characteristics of ‘better performing tendons’?

Answer 10

Stiffer passive tendons

• Smaller pre- and braking phase muscle activation
• Less tendon strain
• Stiffer tendon and more efficient recoil…
• Less muscle activity (contraction) and thus more efficiency.

Question 11

How would you go about training for a ‘better performing tendon’?

Answer 11

• Increase muscle-tendon stiffness
• Develop muscle strength
• Increase the cross-sectional area of important tendons