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An Introduction to Biomechanics

An Introduction to Biomechanics. PSE 4U Lecture Series. BIOMECHANICS. Science of human movement Internal forces produced by muscles and tendons working against external forces of gravity, air resistance, water resistance and friction

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An Introduction to Biomechanics

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  1. An Introduction to Biomechanics PSE 4U Lecture Series

  2. BIOMECHANICS • Science of human movement • 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 • 7 Principles of Human Movement

  3. 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.

  4. 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

  5. Movement Phases • Movement • Sometimes called the acceleration, motion or contact (is the action of the skill) • Follow Thru • 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.

  6. Tennis Serve • Stance: • Behind Baseline; Ball hand facing net • Preparatory • Racket Arm and Shoulder are moved back • Movement • Bringing arm forward for racket to make contact; racket arm moves in same direction and accelerates until … • Recovery • Arm changes direction; weight forward; move forward

  7. 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.

  8. 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

  9. More physics review: Levers • Every moveable bone in the human body, acting alone or in concert with others, is part of a lever system that facilitates movement. • Terms to know here: fulcrum, resistance, force, load, axis

  10. Three types of Levers Figure 15.3 (p. 230) • In a Class I Lever (e.g., teeter-tooter, neck joint), the fulcrum is located between the effort and the resistance (load). • In a Class II Lever (e.g., a wheelbarrow), the resistance is between the force and the fulcrum. • In a Class III Lever, (e.g., snow shoveling) the force is between the fulcrum and the resistance.

  11. Some helpful hints… • In levers; * muscles are usually force * weight or load always acts on the body as gravity would * fulcrum is usually a joint or where two bones meet

  12. 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.

  13. 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).

  14. Biomechanical Formula • MOMENTUM M = mv • Where M is momentum, m is mass and v is velocity. Expressed in kg m/s.

  15. Sample Problems Workbook • P. 162: F = ma • P. 164: Momentum • Worksheet

  16. 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)

  17. 7 Biomechanical PrinciplesText p. 231 – 4 • With a partner, choose one biomechanical principal 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.

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