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An Introduction to Biomechanics. PSE 4U Lecture Series. A field within Kinesiology…. The science of human movement Applying mechanical principles to the human body (eg. Force, velocity, acceleration, centre of gravity)
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An Introduction to Biomechanics PSE 4U Lecture Series
A field within Kinesiology… • The science of human movement • Applying mechanical principles to the human body (eg. Force, velocity, acceleration, centre of gravity) • Internal forces produced by muscles and tendons working against external forces of gravity, air resistance, water resistance and friction • Helps to evaluate performance of athletes and aid in recovery and prevent/examine sports injuries • In my degree…this was a 2nd year required course
Careers within Biomechanics? • As an ‘engineer of the body’…you might: Analyze a movement? http://youtu.be/pPLmCqGIotM Help a patient recover? http://en.wikipedia.org/wiki/Force_plate
Analysis of Movement • Practically all sports will have at least a preparatory phase, a movement phase and a follow through phase, whereas many will begin with a stance phase and end with a recovery phase.
Movement Phases • Stance • Allows the athlete to assume a comfortable and balanced body position from which to initiate the sport skill. • Preparatory • Often called the wind up phase, is used to lengthen the appropriate muscles so that they concentrically contract in the next phase
Movement Phases • Movement • Sometimes called the acceleration, motion or contact (is the action of the skill) • Follow Through • Begins immediately after the climax of the movement phase in order to bring about negative acceleration of the involved limb • Recovery • Used to regain balance and positioning to be ready for the next sport demand TASK 1: Choose a familiar sport movement and describe each phase with the information you have been given.
Physics review: Newton’s 3 Laws of Motion • 1. The Law of Inertia • Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. • 2. The Law of Acceleration • Force applied to an object causes acceleration of that object proportional to the force, in the direction of the applied force, and inversely proportional to the object’s mass. • 3. The Law of Reaction • For every action there is an equal and opposite reaction.
A quick quiz… • State which law(s) applies in the following cases: • Bobsled start • Hockey stop • Golf ball during a putt • Biking up a hill
Biomechanical Formula • ACCELERATION A = (v-u) / t • In this formula, the v is the object’s final velocity, u is its starting velocity, and t is the time it takes an object to travel a set distance.Expressed in m/s2.
Biomechanical Formula • FORCE F = ma • Where force is represented by F, acceleration is a, and mass of an object is m. Expressed in N (Newtons).
Biomechanical Formula • MOMENTUM M = mv • Where M is momentum, m is mass and v is velocity. Expressed in kg m/s.
Sample Problems • P. 162: F = ma • P. 164: Momentum • Worksheet
Types of Motion • Linear Motion – motion by an athlete in a straight line (e.g. sprinter) ** we will mostly be speaking in terms of linear motion. See table 15.1 (p. 229) • Rotational Motion – movement about an axis (e.g. cartwheel, somersault)
7 Biomechanical PrinciplesText p. 231 – 4 • With a partner, choose one biomechanical principle and write an abstract (summary) using appropriate vocabulary and terminology. • Use a sport specific example (not from the text!) to illustrate your principle. • There will be class time to discuss your principle and to take notes on others’ work.