Musculoskeletal System

Question 1

What are body biomechanics factors?

Answer 1

Theres are intrinsic factors in injury; they are caused by body size, shape etc

Question 2

Uncontrollable factors affecting injury?

Answer 2

• Age
• Gender
• Musculoskeletal deformities such as flat feet and leg length discrepancies

Question 3

Define Injury

Answer 3

Injury occurs when the load applied to a tissue exceeds its failure tolerance

Question 4

Two crucial factors why injury occurs

Answer 4

1. The load
   (the sum of the forces and moments of force acting)
2. The characteristics
   (of the loaded structures)

Question 5

Define a chronic (overuse) injury

Answer 5

Results from repeated overloads with insufficient time for recovery.

Question 6

Define acute (traumatic) injury

Answer 6

Results from a single or a few repeated episodes

Question 7

What are the five different types of load?

Answer 7

1. Tensile (Tension)
2. Compressive
3. Shear (Opposite/broken leg in rugby)
4. Torsion (Twisiting)
5. Bending

Question 8

Five different load characteristics that are import in injury?

Answer 8

1. Type of load
2. Magnitude of load
3. Rate of load
4. Frequency of load
5. Stain

Question 9

Define stain?

Answer 9

Strainis a measure of how much a material is deformed, and stressis a measure of how much the material resists this deformation.

Strain is calculated as a percentage of change.

Question 10

Define Stress?

Answer 10

Load per unit cross-sectional area

Question 11

Define young’s modulus of elasticity

Answer 11

Also known as the elastic modulus, it is the ratio between stress and strain and measures the stiffness of the material.

Question 12

The three stages involved in the stretch-shortening cycle are?

Answer 12

1. Preload
2. Elastic energy storage
3. Reflex potentiation

(Example skipping)

Question 13

Define Resilience?

Answer 13

The amount of energy returned as a percentage of the amount of energy stored during deformation.

Energy losses occur in materials because some of the strain is not recoverable, and the combination of viscous and elastic components of biological materials therefore leads to a hysteresisloop.

Question 14

High passive stiffness of tendons means what four things?

Answer 14

1. Smaller pre-and braking phase muscle activation
2. Less tendon strain
3. Stiffer tendon and more efficient recoil
4. Less muscle activity (contraction) and thus more efficiency.

Question 15

Three training aims for better performing tendons?

Answer 15

1. Increase muscle-tendon stiffness
   (e. g., through plyometric training).
2. Develop muscle strength
   (not necessarily size).
3. Increase the cross-sectional area of important tendons
   (e. g., through strength training, endurance training)

Question 16

Stretch Shortening Cycle

Answer 16

eccentric contraction enhances force

production in the succeeding concentric contraction

Question 17

Stages of SSC?

Answer 17

• preload
• elastic energy storage
• reflex potentiation (Komi, 1992)