Muscle Contraction and Human Movement Flashcards
how does human movement occur?
as a result of a force
what 2 things can forces that create human movement be?
internal
external
what is internal movement?
force individual can control
muscles work to move bones/joints
what is external movement?
force from outside an individuals control
give an example of an external force?
gravity
what is the name given to the most important ‘mover’?
prime mover
what is the term given to a muscle creating internal force?
mover
what do our muscles to when experiencing external force?
work to counteract (i.e control movement against it)
what 3 types of muscle contractions are there?
concentric
isometric
eccentric
what is concentric muscle contraction?
muscle shortens during activity (the attachments get closer)
what is isometric muscle contraction?
muscle stays the same length
what is eccentric muscle contraction?
muscle lengthens during activity (attachments get further away) to a maximum of its full length
when do muscles typically experience eccentric contraction (2 ways)?
when resisting a force
because its relaxed (passive)
what is an example of isometric contraction?
when a muscle strains against resistance but doesnt change length
e.g. pushing against a wall; it is preventing a movement taking place/stabilising
what is an agonist?
mover
what is an antagonist?
muscle/other force that can perform the opposite movement to what is occurring
what type of movement does an antagonist muscle typically do?
lengthens (usually relaxing but sometimes contracts eccentrically)
what is the primary role of most antagonist movement?
slow a muscle down e.g. after throwing a ball- the mover stops creating force and the antagonist works eccentrically to slow the movement
when is gravity the mover, and what is the muscle(s) acting against it?
gravity=mover
muscle=antagonist (working eccentrically)
what is the stabiliser?
muscle/force stabilising against the prime mover to create more efficient movement at fixed muscle attachment
give an example of a stabiliser?
finger flexion= wrist extensor is stabiliser
what is a support muscle?
muscles working statically against the pull of gravity
what is a neutraliser?
muscle/force preventing unwanted movement when mover can perform more than 1 function at the mobile muscle attachment
what is a synergist?
muscle/force working with contracting muscle
what is the base of support (BOS)?
area of body in contact with supporting surface and contact between supporting surface and floor
what is the BOS when standing?
2 feet + space between them
what is the centre of gravity?
point in body where weight and forces acting as a result of limbs/segments of the body are approximately equal
where in the human body is the COG regarded as being?
S2 vertebrae
what is the line of gravity (LOG)?
a theoretical line from the COG to the ground
what happens to the LOG when the body moves?
it moves accordingly
why is it important that the LOG is within the BOS?
if not the person will fall
