Class 2 Flashcards
(14 cards)
How is mechanical stress defined and what are its common units?
is defined as the force applied per unit of cross-sectional area, typically measured in pascals (N/m^2). Common units include megapascals (MPa) and gigapascals (GPa)
What is mechanical strain?
change in length/ original length. it measures the deformation experienced by the tissue when stress is applied
what does wolff’s law state?
Wolff’s law states that bone adapts to its mechanical environments - it becomes stronger when expose to high stresses and weaker when the stress is reduced
What is Davis’s law and how does it relate to soft tissues ?
Davis’s law (1867) explains that soft tissues (ligaments, tendons, and fascia) adopt to the mechanical demands placed on them, similar to bone, by remodeling in response to the stresses they experience.
How do ligaments and tendons differ in their function?
Ligaments connect bone to bone, stabilizing joints, while tendons connect muscle to bone, transmitting the force generated by muscles to produce movements.
Why is it important to be aware of these tissues and their mechanical properties?
They allow us to evaluate if “D<C” at tissue level.
Why is it challenging to measure the mechanical properties (D and C) of tissues in a living person?
the complexity of the human body and the variability of tissue responses make it difficult to accurately measure D and C in vivo, which limits precise injury risk prediction
What is elasticity?
materials ability to return to its original shape immediately after the removal of an applied stress or strain
define viscoelasticity
is a property of materials where their response to stress or strain is both time and rate dependent. This includes phenomena like creep and stress relaxation
Which tissues in the human body exhibit viscoelastic properties?
ligaments, tendons, cartilage, and fascia are all viscoelastic, and bone shows viscoelastic behavior to a lesser extent.
Why is understanding viscoelasticity important in ergonomics?
Because viscoelastic tissues can accumulate damage from repeated or sustained loads over time, understanding their behavior helps in designing tasks and interventions to prevent injuries.
What is the force-length relationship of muscle?
States that the maximum force a muscle can produce depends on its length. Since muscle length varies with posture, the force output is optimized at a specific muscle length
what does the force-velocity relationship means ?
Means that the max force a muscle can produce depends upon how quickly you do a task
How does force-length relationship affect muscle strength in everyday tasks?
Because muscle lengths changes with different postures, the strength available for a task is dependent on how optimally the muscle is positioned; deviating from the optimal length reduces force production.
