Sport biomechanics – outline
• Reading assignments:
– Kreighbaum & Barthels – Module J (pp 335353, Ch 11 (pp 370-384), esp pp 372-375 on
baseball pitch
– Adrian – Ch 17, esp pp 333-339, 352-356
– Review article on throwing and injuries
– Review article on overweight and underweight
baseballs
Biomechanical correlates of participation in
sports: Areas of interest, effort, & potential
contributions
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Evaluate process - technique
Injury potential/prevention
How to enhance acquisition – motor learning
Design appropriate conditioning programs to
enhance performance
• Equipment Design and Selection
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–
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ground-foot interfaces
protective equipment (pads, gloves, head gear)
striking implements
balls
Exercise and Sport Biom Prof Org
• American College of Sports Medicine
• International Society of Biomechanics
• International Society of Biomechanics in Sports
North American Society of Biomechanics
• Website: biomechanics worldwide
– http://www.per.ualberta.ca/biomechanics/
Throwlike and Pushlike Movement Patterns
• Usual objectives of throw and push patterns
• projection of objects for greatest horiz or vert dist
– ex : javelin, discus, shotput
• projection of objects for accuracy with speed a factor
– ex: volleyball, tennis, racquetball, baseball pitch
• Movement pattern terminology review
• Throwing patterns are further defined as underarm, sidearm, or overarm
(see Table J.1, p 336)
• Skills listed under each pattern differ because of constraints
– ex: rules governing implement or ball, rules governing target.
• Open and Closed chain movements
• Open kinetic chain - sequential segmental action, end segment is free to
move (e.g., baseball pitch)
• Closed kinetic chain - simultaneous end segment movement, end segment
meets with “considerable resistance “ (e.g., shot put)
Common movement patterns
(Table J.1, p 336)
Throwlike and Pushlike Movement Patterns (2)
• Characteristics of throw-like patterns
– can be a strike or a kick
– high end-point velocity is critical
– sequential segmental action, object lags behind elbow and/or shoulder
• Open kinetic link model - Figure J.1, p 338; J.2, p 339
• Linear motion of a point on a rotating segment: V = r
• Sequencing segmental rotations - kinetic link principle
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system has a base and a free open end
segmental masses progressively decrease
an external torque is applied at the base to initiate the movement
segmental rotational acceleration is timed sequentially
• A model of an open kinetic link system - Fig J.4, p 343
• Throwlike movements performed while in the air - Fig J.5, p 345
Three-segment kinetic link model
Threesegment
model:
(Fig j.2,
p 339)
Whip-like action of segmental system
Three-segment model when
airborne:
Throwing motion (sequential)
Segmental sequence when throwing
Phases of pitching:
1.
2.
3.
4.
Windup (a-k)
Early Preparation (l-m)
Late preparation (n-p)
Release (r-u)
From: Feltner, M. & Dapena,
J. (1986) Dynamics of
shoulder and elbow joints of
the throwing arm during a
baseball pitch. Int J Biomech
235-259.
Javelin – similar
To baseball pitch
Shotput – some throw
& some push
Throwlike and Pushlike Movements (3)
• Pushlike patterns - Simultaneous segmental actions
– Objective is accuracy, or large motive force
– Distal segments move simultaneously, resulting in rectilinear
movement of distal segment
– Four differences in throw and push (p 350). In throws:
• distal segment “lags back”, segments move sequentially, object moves
curvilinearly, wheel-axle movements (shoulder and hip rotation) involved
• Movements lie on a throw-push continuum, the location
depending on constraints of performer and object:
– performer strength and skill
– object mass, size, and shape
Pushing Motions
Development of throwing motion