An Introduction to Biomechanics

1. An Introduction to Biomechanics PSK 4U Lecture Series

2. 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

3. Careers within Biomechanics? • As an ‘engineer of the body’…you might: Analyze a movement? https://youtu.be/aJjv8tWbj4c Or https://youtu.be/qtXz6qocciM Help a patient recover? http://en.wikipedia.org/wiki/Force_plate

4. 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.

5. 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

6. 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.

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… • Let’s apply these laws in the following cases: • Bobsled start • Hockey stop • Golf ball during a putt

9. Biomechanical Formula • ACCELERATION A = (v2-v1) / t • In this formula, the v2is the object’s final velocity, v1 is its starting velocity, and t is the time it takes an object to travel a set distance.Expressed in m/s2.

10. 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).

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

12. 7 Biomechanical PrinciplesText Chapter 12 • 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.