Introduction to Sports Biomechanics: Analysing Human Movement ...

Movements in the horizontal plane about the vertical axis
External and internal rotation, shown in Figure 1.5, are the outwards and inwards
movements of the leg or arm about their longitudinal axes – these movements
are also known, respectively, as lateral and medial rotation. External and internal
rotation of the forearm are referred to, respectively, as supination and pronation.
Rotation to the left and rotation to the right are the rather obvious terms for
horizontal plane movements of the head, neck and trunk.
Horizontal flexion and extension (or horizontal abduction and adduction), shown
in Figure 1.6, define the rotation of the arm about the shoulder joint or the leg
about the hip joint from a position of 90° abduction. In sports biomechanics,
movements from any position in the horizontal plane towards the anterior are
usually called horizontal flexion and those towards the posterior horizontal
extension. (In strict anatomical terms, these movements are named from the 90°
abducted position; the return movements towards that position are called reduction
of horizontal flexion and extension respectively).
Movements of the thumb
THE ANATOMY OF HUMAN MOVEMENT
Figure 6.1 Movements in the frontal plane about the sagittal axis: (a) lateral flexion; (b) pronation; (c) supination.
The movements of the thumb, shown in Figures 6.2(a) to (c), may appear to be
confusingly named.
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