Biomechanics Flashcards
What are the three types of deformations?
- Tension: Stretching a material along its length
- Movement: Deformation caused by mechanical motion
- Pressure: Deformation due to compressive forces acting uniformly on a surface
Define relative deformation.
Measures the degree of deformation, proportional to the applied force and inversely proportional to the cross-sectional area of the material
What is Young’s Modulus?
A mechanical property measuring a material’s stiffness under tension, defining how much strain a material undergoes under stress
What is the unit of Young’s Modulus?
Pascals (Pa) or Nm^-2
What characterizes Hookean materials?
- Obey Hooke’s Law: deformation is proportional to applied force
- Linearly elastic
What is the potential energy formula for Hookean materials?
U = 0.5kL^2, where k is the stiffness constant and L is deformation length
Provide an example of a Hookean material.
Steel
What characterizes non-Hookean materials?
Do not obey Hooke’s Law
Provide an example of a non-Hookean material.
Rubber
How does mechanical strain relate to deformation for small deformations?
Mechanical strain is proportional to relative deformation
What happens to the graph of mechanical strain beyond the elastic limit?
The graph deviates, showing non-linear behavior
What is viscous resistance?
Measures the non-ideal behavior of materials during deformation-relaxation cycles
What are the components of muscle deformation?
- Plasticity: Ability to maintain deformation after removing external force
- Elasticity: Ability to stretch and return to the original size
- Viscosity: Resistance to changes in shape under dynamic conditions
- Solidity Margin (Tension Bound): Flexibility of the muscle system under tension
What happens to free energy during reversible or irreversible deformation?
Free Energy decreases
How is chemical energy transformed during muscle contraction?
Directly transformed into mechanical energy without intermediate energy forms like heat or electricity
What happens to bound energy during irreversible deformation?
Increases due to heat dissipation caused by friction and viscosity
What is the state of entropy in non-living systems?
Entropy is maximum, indicating equilibrium
What is the state of free energy in living systems?
Free energy is maintained low by consuming energy to stay organized
What are the two types of muscle contractions?
- Isometric Contractions: Static contraction where the muscle length remains unchanged
- Isotonic Contractions: Dynamic contraction where the muscle length changes
What are the two types of isotonic contractions?
- Eccentric: Muscle lengthens under tension
- Concentric: Muscle shortens under tension
What does Hill’s Equation describe?
The inverse relationship between muscle contraction speed and the force generated
What is the equation for Hill’s Equation?
(F + a)(v + b) = constant
According to the First Law of Thermodynamics, what does muscle internal energy equal?
The sum of released heat (Q) and consumed energy (W)
What is the formula representing muscle internal energy?
ΔU = Q + W
How does muscle contraction efficiency relate to load range?
Increases with an optimal load range
