Transcript BIOMECHANICS APPLICATIONS

THROW Pattern PUSH Pattern
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proximal segments in front
of projectile with distal
segments behind projectile
sequential for 
v
curvilinear path
mostly wheel-axle
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all segments behind
projectile pushing the
projectile or load
simultaneous for 
F
rectilinear path
mostly lever motions
Movement Patterns - Related Skills
Underarm
Sidearm
Overarm
Kick
Badminton
Bowling
Hockey
Horseshoes
Volleyball
Baseball
Discus
Hammer
Handball
Squash
Tennis
Volleyball
Badminton
Baseball
Cricket
Javelin
Tennis
Volleyball
Football
Rugby
Soccer
Swimming
Constraints: Throw/Push Continuum
Mass of projectile
 Volume/Size of projectile
 Shape/Profile of projectile
 Target Area for projectile
 Strength/Power of person
 Skill of person
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OPEN Kinetic Chain
CLOSED Kinetic Chain
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Throw or Kick
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Jump or Push or Pull
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End Segment Free
[e.g. hand, foot]
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End Segment Restrained
[e.g. foot, hand]
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sequential movement
of body segments
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simultaneous movement
of body segments
Throwlike Patterns
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1. Proximal Parts Move First
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2. Distal Parts Lag Behind
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3. Achieve either :
maximum distance [ HORZ or VERT ]
OR
maximum velocity
Fig J.1
page 338
1. segment A is accelerated which gives L to entire
system: segments A, B, and C
2. A rotates cw while B and C lag behind
3. A is THEN decelerated by muscle T
4. To conserve L, B accelerates cw THEN
decelerates, C then accelerates cw
Transfer L to arm
by
reducing/stopping
L in shoulders
 End Point v due to decreasing r
L= mk² x 
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See FIG. J.1 on page 338
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initial k is from axis “a” to top of segment C
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when segment A decelerates, the k changes to
the distance from axis “b” to top of segment C
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when segment B decelerates, the k changes to
the distance from axis “c” to top of segment C
v=r
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final velocity of hand or foot or implement @
release/impact determines projectile v
r =
 d from the axis of rotation [e.g. joint] and
the contact point of release/impact
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see FIG J.12 on page 352 with regard to r
Kinetic Link Characteristics
system of linked segments with a fixed base and
a free open end
 more massive segments @ proximal end
 least massive segments @ distal end
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initial motion caused by T applied to base
 T gives entire system L
L= mk² x  OR L = I
Sequential Motions
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1. proximal/massive segments move first giving
L to entire system
2. external T decelerates proximal segments
3. to conserve L, next segment, which is less massive,
accelerates with rotation now occurring about a new
axis and a smaller k
4. Each successive segment/link accelerates achieving
  than previous segment due to both m and k
getting progressively smaller
Airborne Reaction Rotation
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See FIG 15.16 on page 514
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VB spiker abducts hip and/or flexes knees to
 I (I = mk²) in lower extremities
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turntable demo
Lever Motions
Wheel-Axle
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Flexion/Extension
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Medial/Lateral Rotate
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Protraction/Retraction
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Pronate/Supinate
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Abduction/Adduction
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Inversion/Eversion
Wheel-Axle Motions
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muscle T rotates a bone which becomes an axle
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the wheel is the adjacent segment positioned at an
angle to the axle
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the wheel r (radius) is modified via flexion/extension
or adduction/abduction
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see FIG J.6 on page 346 and FIG J.12 on page 352
THROW / PUSH for Speed and Accuracy
FIG J.8
page 349
FIG J.10
page 350