Slides in this set
How we move
Primarily, movement is brought about by the contraction and relaxation of muscles on the
bones which form joints.
Muscles Bones Joints
Produce movement by exerting The moving bones in a joint are Consist of two or more bones that
force on tendons which in turn pull called articulating bones. make contact and can move against
on bones. The two bones that form a joint do each other.
They mostly cross at least one joint not move equally in response to a Moving joints are also called
and are attached to the bones that muscle contraction; one bone is articulations.
form that joint. generally held in its original Most muscles that move joints lie
When a muscle contracts it pulls position by the action of other alongside bones and do not lie on top
one articulating bone towards the muscles. of the joint, it is usually the tendon at
other. The attachment of a muscle the insertion end of a muscle that lies
Most movements are produced tendon to the stationary bone is over the joint.
from antagonistic pairs or groups - called the origin, the attachment to
several muscles working together. the moving bone is called the
A muscle that produces the desired insertion.
action is called the agonist or prime
A muscle that acts to produce the
opposite action of the
agonist/prime mover is called an
antagonist (e.g. it relaxes while the
Synergists are muscles that stabilise
a joint to prevent unwanted
Fixators are muscles that stabilise
the origin of the prime mover.…read more
Planes and Axis of Motion
Sagittal: splits the body into left Transverse: passes through the body
and right halves (through the (through the hips) from side to side,
midline), forward and backward forward and backward movements.
movements. Generally where flexion and Generally where flexion and extension
extension movements occur (bicep curls, movements occur (bicep curls, sit-ups,
sit-ups, knee extensions). knee extensions).
Frontal: splits the body into front and Frontal: passes through the body
back halves (through the head and arms), from front to back (through the
side to side movements. Generally where stomach). Generally where abduction
abduction and adduction movements and adduction movements occur
occur (raising and lowering limbs to the (raising and lowering limbs to the side
side). and cartwheels).
Transverse: divides the body into top Longitudinal: passes through the
and bottom halves (through the hips), body from top to bottom (from
turning movements. Generally where head to feet), turning movements.
rotational movements such as Generally where rotational movements
pronation and supination occur. such as pronation and supination occur.…read more
Types of Muscle Contraction and Joints
Muscle Contractions: Joints:
Isotonic muscle changes length Hinge two articulating bones wedged
whilst contracting together so that it only allows direction
in two ways (back and forth)
Isometric muscle contracts and
Ball & socket most moveable joints,
doesn't change length, no movement
ball shaped end of one bone fits into
occurs the cup shaped end of another bone
Eccentric muscle lengthens as it allowing a wide range of movement
contracts Pivot rotational movement occurs,
Concentric muscle shortens as it sideways movement without
displacement or bending occurring
Saddle two bones fit together like a
rider in a saddle, allowing bending
articulation without sliding
Gliding joint allows only gliding
movement where the opposed
surfaces of bones are flat or almost
What is a lever system?
Simple mechanisms that involve a rigid bar moving around a fixed point when a force or effort is applied
to overcome a resistance.
For the body to perform movements, the bones of the skeleton act as a series of levers against which
muscles can pull.
What are the levers function in the body?
Give greater speed to an object by throwing or kicking it.
Overcome a heavy resistance with little effort.
Give a wider range of movement.
What are the components of a lever system?
Fulcrum the joint itself in the human body.
Resistance also known as the load. In the human body Remember:
this may be the weight of an object/body part/object trying to be moved. "1 2 3, F R E"
Effort Point where the force is supplied by the contracting muscle
(insertion point of the muscle)…read more
Types of Levers in the body
1st Class Lever:
"see saw" lever
Function: used to increase speed of an object
Only two examples in the body neck and elbow
2nd Class Lever:
Function: increase in force can be used to overcome
Only one example in the body: foot
3rd Class Lever:
Function: increases speed or distance rather than force
Accounts for all other joints in the human body
"1 2 3, F R E"…read more