1. Development of Ballistic Skills
chapter 7
Development of Ballistic Skills

2. Ballistic Skills
An individual applies force to an object in order to project it.
Common ballistic skills include throwing, kicking, and striking.

3. Overarm Throwing Throwing takes many forms:
Two-hand underhand
One-hand underhand
Sidearm
Two-hand overarm
One-hand overarm
The most common in sport games is the one-hand overarm throw.

4. Gauging Throwing Skill
Product measures (outcome)
Accuracy
Distance
Ball velocity
Process measures (movement pattern)
Developmental sequences
Each has advantages and disadvantages, but product measures often reflect skill as well as body growth and maturation during childhood and adolescence.

5. A Beginning Thrower (continued)
Drawn from film tracings available from
the Motor Development Film Collection,
Bowling Green State University

6. A Beginning Thrower (continued)
Drawn from film tracings available from
the Motor Development Film Collection,
Bowling Green State University

7. A Beginning Thrower (continued)
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8. Characteristics of Early Overarm Throwing
Early overarm throwing consists mostly of arm action.
The elbow points up.
The throw is executed by elbow extension alone.

9. A Proficient Thrower
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10. Proficient Overarm Throwing for Force
Preparatory windup used (weight shifts and trunk rotates back, arm swings).
Use of opposite leg, long step, and differentiated trunk rotation.
Upper arm and forearm lag back.
Movements are sequential to transfer momentum.

11. Developmental Changes in Overarm Throwing
Trunk action
None or forward–backward movement
Block rotation
Differentiated rotation
Backswing
None
Shoulder flexion
Upward backswing
Downward, circular backswing
(continued)

12. Developmental Changes in Overarm Throwing (continued)
Foot action
No step
Homolateral step
Short contralateral step
Long contralateral step
(continued)

13. Developmental Changes in Overarm Throwing (continued)
Upper arm action
Oblique
Aligned but independent
Lag
Forearm action
No lag
Delayed lag

14. Progression in Childhood
Throwers do not achieve the same step for each body component at the same time.
Some combinations of steps are observed more frequently than others are observed.
Not everyone reaches the highest step in each component; girls and women often remain in intermediate steps.

15. Throwing in Adulthood
Older adults demonstrate moderately advanced steps.
Gender differences are observed.
Ball velocities are moderate.
Musculoskeletal constraints might influence the movement patterns used.
(continued)

16. Throwing in Adulthood (continued)
Change is usually slight rather than rapid, is more often an increase in variability, and is usually a decline.
Change is typically in the control of movements (slowed speed or decreased range of motion) rather than coordination of movements.

17. Throwing for Accuracy
Throwers may use lower developmental steps for accuracy throws than for forceful throws.
If the distance for the accuracy throw still requires force, little change would be noted for that individual.

18. Kicking
The ball is struck; this can be difficult for children if the ball is moving.
Children must have perceptual abilities and eye–foot coordination to make contact.

19. Characteristics of Early Kicking
No step with nonkicking leg.
Kicking leg pushes forward.
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20. Intermediate Kicker
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21. Proficient Kicking
Preparatory windup used (trunk rotated back, kicking leg cocked, knee bent).
Trunk rotates forward.
Movement is sequential, with thigh rotating forward then lower leg extending.
Arms move in opposition to the legs.

22. Proficient Kicker
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23. Developmental Changes in Kicking
Movement pattern changes are not well documented.
Developmental steps have not been validated.

24. Punting The ball is dropped from the hands.
Punting is more difficult for children than kicking.

25. Characteristics of Early Punting
Ball is tossed up rather than dropped.
Punter often contacts ball with toes rather than with instep.
Drawn from film tracings available from
the Motor Development Film Collection,
Bowling Green State University

26. Proficient Punting
Arms are extended to drop ball before final stride is taken.
Arms then drop to sides and move into opposition with legs.
Punter leaps on to supporting leg, swings punting leg vigorously up to contact.
Punting leg is kept straight, with toes pointed.

27. An Advanced Punter Drawn from film tracings available from
the Motor Development Film Collection,
Bowling Green State University

28. Developmental Changes in Punting: Arms
Ball-release phase
Upward toss
Late drop from chest height
Late drop from waist height
Early drop from chest height
Ball-contact phase
Arms drop
Arms abduct
Arm opposition

29. Developmental Changes in Punting: Legs
Ball-contact phase
No short step, ankle flexed
Long step, ankle extended
Leap and hop

30. Sidearm Striking Various body parts can be used.
Implements can be used.
Mechanical principles are similar for all striking tasks.
Focus here is on one-hand sidearm and one-hand overarm with an implement.
Principles can be applied to other striking tasks.

31. Characteristics of Early Sidearm Striking
Chopping motion (elbow extension)
Little leg and trunk movement
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32. Intermediate Striker Drawn from film tracings available from
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Drawn from film tracings available from
the Motor Development Film Collection,
Bowling Green State University
Click image to view video

33. Proficient Sidearm Striking
Sideways preparatory stance and a long step
Differentiated trunk rotation
Horizontal swing through large range of motion, with arm extended before contact
Sequential movements
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34. Developmental Changes in Sidearm Striking
Sequences for foot and trunk in the overarm throw can be used.
Trend to use trunk rotation (none, then blocked, then differentiated).
Plane of the swing progresses from vertical to horizontal.
(continued)

35. Developmental Changes in Sidearm Striking (continued)
Grip changes from power grip to “shake-hands” grip.
Elbows are away from the body and extended before contact.

36. Overarm Striking Without an implement (volleyball serve)
With an implement (tennis serve)

37. Characteristics of Early Overarm Striking
Limited trunk rotation
Swing with a collapsed elbow
Little or no lagging with the swing forward
Looks much like early throwing

38. Proficient Overarm Striking
Lower and upper trunk are rotated more than 90 degrees.
Elbow is held between 90 and 119 degrees at start of forward movement.
Racket lags behind arm in forward swing.
Movement is sequential.

39. Developmental Changes in Overarm Striking
Trunk, upper and lower arm, and leg sequences similar to overarm throwing
Preparatory trunk action
No trunk
Minimal trunk rotation
Total trunk rotation
(continued)

40. Developmental Changes in Overarm Striking (continued)
Elbow action in ball-contact phase
Very small or very large angle
Intermediate angle (2–89 degrees)
Ideal angle (90–119 degrees)
Spinal and pelvic range of motion
Less than 45 degrees
Rotation of 45 to 89 degrees
Rotation of 90 degrees or more
(continued)

41. Developmental Changes in Overarm Striking (continued)
Racket action
No racket lag
Racket lag
Delayed racket lag

42. Older Adult Striking Jagacinski, Greenberg, & Liao (1997)
Studied iron shot (did not require maximal force).
Older golfers reach peak force earlier in swing.
Older golfers may need to exert more force for the same shot compared with younger golfers.
A few older golfers were less accurate than younger golfers but most were just as accurate.
(continued)
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43. Older Adult Striking (continued)
Haywood & Williams (1995)
Studied tennis “first” serve.
Studied older servers at moderate levels.
Two former teaching professionals were categorized at the highest levels (they maintained the coordination of movements).
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44. Ballistic Skills: Summary
Proficient performance demonstrates the mechanical principles.
Developmental trends are toward proficient mechanical performance.
A forward step and more trunk rotation are used.
Trunk rotation is differentiated.
(continued)

45. Ballistic Skills: Summary (continued)
Projecting limb shows more and more lag.
Probably not all individuals reach highest steps.
Older adults appear to maintain the coordination of ballistic movements fairly well.

46. Assessment of Ballistic Skills
Developmental sequences can be used as checklists.
Individuals are considered to be in a developmental step if the majority of a set number of executions (typically five) are in that category.
Observation should be conducted from the appropriate direction.
Side views show forward step, trunk action, and lagging.
Rear views show arm angles.