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At the conclusion of this chapter, the student should be able
to:
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- 1. Classify activities involving sequential throwing,
kicking, or striking patterns according to the nature of the force
application.
- 2. Name and discuss anatomical and mechanical factors that
apply to representative throwing, kicking, or striking activities.
- 3. Perform a kinesiological analysis of someone engaging in
a sequential throwing, kicking, or striking skill under each of
these force application conditions: momentary contact, projection, continuous
application.
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A baseball pitcher throws a baseball across the plate and the
batter hits it to center field, an elderly man pitches horseshoes,
a young person spikes a volleyball, a student practices driving
a golf ball while a college athlete practices punting a football.
Once more, as is the case with pushing and pulling, a widely diverse
set of activities has a common denominator. Each of these activities involves
sequential movement of the body segments resulting in the production
of a summated velocity at the end of the chain of segments used.
During the summation of velocity, it is important to note that changes
are the result of an acceleration imparted through an unbalanced
force. The magnitude of the unbalanced force as well as the time
over which this force acts will determine the final velocity. This
concept of the force and the time over which it acts effecting final velocity
is called impulse (Chapter 12). Recall
that the change in momentum is equivalent to the product of the
force and time over which that force acts. The path produced by
the end point of this chain of segments is curvilinear in nature.
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Sequential segmental motions are most frequently used to produce
high velocities in external objects. Depending on the objective
of the skill, speed, accuracy, distance, or some combination, modifications
in the sequential pattern may be made. Greater or fewer numbers
of segments may be involved, larger or smaller ranges of motion
might be used, and longer or shorter lever lengths may be chosen.
Regardless of the modifications, the basic nature of the sequential
throwing, striking, or kicking pattern remains the same.
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Broer was the first to call attention to the similarity of movement
patterns used in seemingly dissimilar activities such as the baseball
pitch, the badminton clear, and the tennis serve (Broer and Zernicke
1979). Objective evidence of such similarities between throwing
and striking activities within each of the three major upper-extremity
patterns (overarm, sidearm, and underarm) was originally revealed
by the Broer and Houtz EMG investigations (1967) and confirmed by
Moynes and colleagues (1986).
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Atwater (1980) distinguished between the over-arm and sidearm
throwing patterns in terms of the direction in which the trunk laterally
flexed. When lateral flexion occurred away from the throwing arm,
an overarm pattern was used; lateral flexion toward the throwing
arm indicated a ...