Introduction to Sports Biomechanics: Analysing Human Movement ...

QUALITATIVE ANALYSIS OF SPORTS MOVEMENTS
GLOSSARY OF IMPORTANT TERMS (compiled by Dr Melanie Bussey)
Degrees of freedom Used in movement analysis for the set of independent displacements
that specify completely the displaced or deformed position of the body or
system. Used more broadly in motor learning and control.
Deterministic model A model linking mechanical variables with the goal of the movement;
most often used in qualitative analysis.
Ecological motor learning Holds that all movements and actions are influenced or
constrained by the environment. Environmental information is necessary to shape
or modify the characteristics of movement to achieve specific actions or tasks.
Efficacy The ability to produce a desired amount of a desired effect.
Inertia The reluctance of a body to move.
Kinaesthesis The ability to sense proprioceptively (from sensory receptors within the
body) the movements of the limbs and body.
Projectile An object (or person) – that has been flung into the air. See also projection
angle, projection height and projection velocity.
Projection angle (release angle, take-off angle) The angle at which a projectile is
released. See also projection height and projection velocity.
Projection height (release height, take-off height) The difference between the height at
which a projectile is released and the height at which it lands. See also projection
angle and projection velocity.
Projection velocity (release velocity, take-off velocity) The velocity at which a projectile
is released, may be broken into horizontal and vertical components. The magnitude
of the projection velocity, with no indication of its direction, is the projection
(release, take-off) speed. See also projection angle and projection height.
Range The horizontal distance a projectile travels.
Redundant In the context of motor control, this is the duplication of critical movements
in a system to increase the versatility of the system – there is more than one way to
locate a system or segment in a given position.
Sequential movement A movement that involves the sequential action of a chain of
body segments, often leading to a high-speed motion of external objects through
the production of a summed velocity at the end of the chain of segments.
Stretch–shortening cycle A common sequence of joint actions in which an eccentric
(lengthening) muscle contraction, or pre-stretch, precedes a concentric (shortening)
muscle contraction.
Torque The turning effect, or moment, of a force; the product of a force and the
perpendicular distance from the line of action of the force to the axis of rotation.
Trajectory The flight path of a projectile determined by the horizontal and vertical
acceleration of the projectile and its projection speed, angle and height.
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