Sport biomechanics – outline Reading assignments: –Kreighbaum & Barthels – Module J (pp 335-...
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Transcript of Sport biomechanics – outline Reading assignments: –Kreighbaum & Barthels – Module J (pp 335-...
Sport biomechanics – outline
• Reading assignments:– Kreighbaum & Barthels – Module J (pp 335-
353, 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• Evaluate process - technique• Injury potential/prevention• How to enhance acquisition – motor learning• Design appropriate conditioning programs to
enhance performance• Equipment Design and Selection
– 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
– 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
Three-segment 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. Windup (a-k)2. Early Preparation (l-m)3. Late preparation (n-p)4. Release (r-u)
From: Feltner, M. & Dapena,J. (1986) Dynamics of shoulder and elbow joints ofthe throwing arm during a baseball pitch. Int J Biomech235-259.
Javelin – similarTo 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