Sport biomechanics – outline

1. 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

2. 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

3. 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/

4. 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 isfreeto move (e.g., baseball pitch) • Closed kinetic chain - simultaneous end segment movement, end segment meets with “considerable resistance “ (e.g., shot put)

5. Common movement patterns (Table J.1, p 336)

6. 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

7. Three-segment kinetic link model

8. Three-segment model: (Fig j.2, p 339)

9. Whip-like action of segmental system

11. Three-segment model when airborne:

12. Throwing motion (sequential)

13. Segmental sequence when throwing

14. Phases of pitching: • Windup (a-k) • Early Preparation (l-m) • Late preparation (n-p) • Release (r-u) • From: Feltner, M. & Dapena, • (1986) Dynamics of • shoulder and elbow joints of • the throwing arm during a • baseball pitch. Int J Biomech • 235-259.

16. Javelin – similar To baseball pitch

18. Shotput – some throw & some push

19. 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

20. Pushing Motions

21. Development of throwing motion