Lecture 10 - Architectural & Structural Factors Affecting Strength & Power

Question 1

What is maximal force proportional to?

Answer 1

• The number of fibres placed parallel to one another.

Question 2

Why doesn’t CSA explain all the differences in strength?

Answer 2

• Inability to activate entire muscle
• Co-activation of antagonist muscles
• Limitations with measurement of strength and muscle size
• Measure size of one muscle instead of muscle group
• Use of ACSA instead of PCSA
• Different specific tension

Question 3

What is specific tension ?

Answer 3

• The force that a single fibre can exert per unit of cross-sectional areas.

Question 4

How can training history influence fibre quality?

Answer 4

• Power training can increase fibre quality, whereas body-building may be detrimental.

Question 5

What is the difference between pennate and non pennate muscles?

Answer 5

• Pennate muscles have their fibres arranged at an angle to the muscles line of pull and are thicker, have more sarcomeres packed into a set volume of muscle and have higher strength capabilities.
• Have their fibres arranged parallel to the muscles line of pull, have increased range of motion and velocity producing capabilities

Question 6

What are the influence of pennation angle (high or low) on functional muscle properties?

Answer 6

• High pennation = Increased strength - pennation allows the packing of more muscle fibres per cross-sectional area thus generating greater force.
• Low pennation = Increased range and velocity

Question 7

What is an effect of greater fascicle length on pennation angle?

Answer 7

• Greater fascicle length appears to limit the degree of change in pennation angle.

Question 8

What is the effect of eccentric exercise on muscle fascicles?

Answer 8

• Longer fascicles
• Smaller pennation angles
• Greater eccentric strength and subsequent decreased injury risk.

Question 9

What are the differences between fusiform (Non-pennate) and pennate muscles?

Answer 9

• Fusiform muscles are great for fast contractions.

- Their absolute force of contraction is small compared to pennate muscle groups

Question 10

What is RFD? and what is it derived by?

Answer 10

• Rate of Force Development (RFD

- Derived from force or torque-time curves recorded during explosive/ballistic voluntary contractions

Question 11

What factors can influence muscle RFD?

Answer 11

• Fibre type
• Pennation angle
• PCSA (physiological cross sectional area ) equals higher RFD.