Fundamentals of Biomechanics

absolute angle: an angle measured to a
non-moving (inertial) frame of reference
acceleration: the rate of change of velocity
(vector)
accelerometer: a device that measures acceleration
actin: the thin filaments in a myofibril that
interact with myosin to create muscle
tension
accommodation: a decrease in biological
response to an unchanging stimulus
action potential: the electrical potential
change during depolarization of nerves
and activated muscle fibers
active tension: the tension created by the
contractile component (actin–myosin
interaction) of activated muscle
affine scaling: image scaling technique
used to measure in a plane not perpendicular
to the optical axis of the camera
in 2D cinematography/videography
agonist: an anatomical term referring to the
concentric action of a muscle or muscle
group for presumed to create a specific
movement
aliasing: distortion of a signal by an inadequate
sampling rate
analog-to-digital (A/D) conversion: the
process of taking a continuous signal
and sampling it over time (see “sampling
rate”) to create a digital (discrete
numbers) representation
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APPENDIX A
Glossary
anatomy: the study of the structure of the
body
angle–angle diagram: a kinematic graph of
one variable plotted against another
(not time) that is useful in the study of
coordination of movements
angular acceleration: the rate of change of
angular velocity (vector)
angular displacement: the change in angular
position (vector)
angular momentum: the quantity of angular
motion, calculated as the product of
the moment of inertia times the angular
velocity (vector)
angular velocity: the rate of change of angular
displacement (vector)
angular impulse: the angular effect of a
torque acting over time: the product
of the torque and the time it acts (vector)
anisotropic: having different mechanical
properties for loading in different directions
antagonist: an anatomical term referring to
a muscle or muscle group that is presumed
to oppose (eccentric action) a
specific movement
anthropometry: the study of the physical
properties of the human body
aponeurosis: connective tissue within muscle
and tendon in the form of a flat
sheet