Scientific Method of Problem Solving
• Develop (define and delimit) the problem
• Formulate the general hypothesis:
– Overload training improves strength
– (e.g., 3 sets of bp 3 d/w will improve bp strength)
• Formulate the specific hypothesis:
– If A (general) is true, then B (specific) will be true
– (e.g., if the general hyp is true, then posttest > pretest)
• Gather , analyze, and interpret the data
– If B is true (significant difference), what about A?
– If B is not true (no sig diff), what about A?
• Discuss the results
– Is B without A very unlikely, or are there alternative
explanations?
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, Ch 18, esp
365-369
Biomechanical correlates of participation in
sports: areas of interest and effort
• Evaluate process – technique – optimize efficiency, or
outcome
• Injury potential/prevention
• How to enhance acquisition of sport skills– motor learning
• Design appropriate conditioning programs to enhance
performance
• Equipment Design and Selection
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–
ground-foot interfaces
protective equipment (pads, gloves, head gear)
striking implements
balls
Sports playing surfaces
Exercise and Sport Biom Prof Org
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American College of Sports Medicine
International Society of Biomechanics in Sports
Biomechanics academy of AAHPERD
North American Society of Biomechanics
International Association for Sports Surface Sciences
International Society of Biomechanics
American society of Biomechanics
Canadian Society of Biomechanics
European Society of Biomechanics
Formosan Society of Biomechanics
International Sports Engineering Association
International Shoulder Group
ISB Technical Group on the 3-D Analysis of Human Movement.
European Society for Movement Analysis in Adults and Children
Sport biomechanics journals
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Research quarterly for exercise and sport
Medicine and science in sport and exercise
Journal of applied biomechanics
Sports biomechanics
International journal of sport and health science
Journal of sports sciences
Sports engineering
Pediatric exercise science
Journal of orthpaedic and sport physical therapy
Journal of biomechanics
Journal of athletic training
Journal of strength and conditioning research
Journal of electromyographic kinesiology
Sports medicine
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
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
Throwlike and Pushlike Movement Patterns
• 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
American
Sports
Medicine
Institute
analyzes
pitching
(www.asmi.org)
The kinetic chain illustrated in
baseball pitch
Poor technique can cause both
injury and poor performance
Throwlike and Pushlike Movements
• 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. 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
Developmental stages of throwing
• Stage 1- ball thrown primarily with elbow
extension – no rotation of thorax or arm
• Stage 2 - Thoracic rotation accompanies backward
motion of the arm. The throw is initiated by the
arm swing forward. Some arm rotation as well as
forearm extension at various times
• Stage 3 - step is taken with same side foot to
initiate throw
• Stage 4 – step is taken with contralateral foot,
thoracic rotation, arm rotation, elbow extension
Side arm striking pattern: The
baseball swing
Stance
Stride
Lift front foot
Bat begins moving forward
Follow-through
Ball-bat impact
Swing
Description of
the baseball
swing