Mechanical Work, Energy and Power Flashcards
Mechanical energy
measure of ability to do work at an instant in time
Work
measure of energy flow from one body to another
Energy stored in a segment is…
stored as potential and kinetic (linear + rotational)
Law of conservation of energy
applies at every point on a body
Internal work
work done ON segments
External work
work done ON (external) load
Muscles are generators of ________ _______ & ___________ of energy
mechanical energy
absorbers
What happens during concentric contraction?
Work of muscles = POSITIVE
muscle moment is in the same direction as angular velocity
What happens during eccentric contraction?
Work of muscles = NEGATIVE
muscle moment acts in opposite direction to angular velocity e.g. flexor muscle during extension
Energy transfer is taking place b/w 2 segments due to
translational movement of joints
2 reasons for inefficiency
- inefficiency in conversion of metabolic energy to mechanical energy
- neurological control of that energy
Metabolic efficiency
- conversion at tendon
- efficiency depends on conditioning of muscles, fatigue, diet etc
Metabolic cost of _________ _____ exceeds that of ___________ ______
Metabolic cost of POSITIVE WORK exceeds that o NEGATIVE WORK
Efficiency is a measure of
- how well biochemical energy is converted into mechanical
- how well the neural system performs in controlling that conversion
What does the contractile element do?
Turn nerve signals into an ACTIVE FORCEEEE
