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Biomechanics of Sports Injury > Loading of the Musculoskeletal System > Flashcards

Flashcards in Loading of the Musculoskeletal System Deck (21):
1

What is Injury

When the load applied to a tissue exceeds its failure tolerance

2

What are the two crucial factors in Injury?

Load
Characteristics of Load Structures

3

What are the 4 things we cannot change?

What are the 3 things we can attempt to change?

Age, Gender, Surfaces, Load

Fatigue, Skill, Fitness Levels

4

What are the 3 types of injury?

1) Chronic - repeated overloads without recovery
2) Acute - single/few repeated episodes
3) Overtraining - result in injury - psychological

5

What are the 4 different load characteristics?

Type of Load, Load Magnitude, Load Rate, Frequency

6

What are the 5 types of load?

Tension, Compression, Torsion, Bending, Shear

7

What is load magnitude?

how much of the load occurs

8

What is load rate?

rate of change of force over time (f/t)

9

What is load frequency?

How it affects overuse injury - load reps and reps

10

What is the difference between stress and strain?

Stress - how much resists the change

Strain - amount of deformation that arises from an applied load

11

What are the variables measured in the stress-strain relationship?

How much is 100N/cm2 in Megapascals?

Strain = % of change

Stress = load per unit of CSA - N/cm2

1 MPa

12

What is Young's Modulus of Elasticity?

The ratio between stress and strain - measures stiffness of the joint

13

What is the difference in young's modulus between a spanner and a Theraband?

Spanner has high young's modulus = high strain

Theraband has low young's modulus = low strain

14

On the graph what define A, B and C and ER, PR and HR?

A = proportional limit
B = elastic limit
C = failure point
ER = elastic range (where it can go back to normal)
PR = plastic range (cannot return to normal)
HR = Hookean Region (where elastic body is deformed)

15

What is the relationship between muscle stiffness and the stretch shortening cycle?

What are the stages of the SSC?

eccentric activity enhances force production in the proceeding activity = increases stiffness

Preload --> Elastic energy stored --> reflex potential

16

What happens to muscle stiffness when you grow older?

Muscle stiffness increases and is therefore more resistant to change

17

What is resilience?

If a tennis ball has 50% resilience, how high will it bounce back up if dropped from a metre?

amount of energy returned as a % of the amount of energy stored during deformation

0.5m

18

What is a hysteresis loop?

Area within the loop is the amount of energy absorbed during one load/unload cycle

19

By what percentage does Achilles tendon lose energy and how can it be improved?

10% - can be improved through resistance/strength training

20

What does high passive stiffness in tendons infer?

Reduced braking phase muscle activation - get tired later on in races
Reduced tendon strain
Reduced muscle activity = improved running efficiency

21

What does training aim to achieve to stiffness?

- Improve muscle tendon stiffness through Plyometrics
- Increase muscle strength not size
- Improve CSA of important tendons to reduce the risk of injury