Sport biomechanics – outline Reading assignments: –Kreighbaum & Barthels – Module J (pp , Ch 11 (pp ), esp pp on baseball pitch –Adrian – Ch 17, esp pp , –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 –

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 of the throwing arm during a baseball pitch. Int J Biomech

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