Exercise ScienceExercise ScienceSection 15: Biomechanical Principal and Section 15: Biomechanical Principal and

ApplicationsApplications

An Introduction to Health and An Introduction to Health and Physical EducationPhysical EducationTed TemertzoglouTed Temertzoglou Paul Challen Paul Challen

ISBN 1-55077-132-9ISBN 1-55077-132-9

Equilibrium and the Conservation Equilibrium and the Conservation of Energyof Energy• Newton’s theory (and biomechanics) rests on two

assumptions:– Equilibrium

– More than one force acts on a body, but no change in velocity results

– Conservation of energy– Energy can never be created or destroyed, but

can only be converted from one form to another

Isaac Newton’s “Model Universe”Isaac Newton’s “Model Universe”• Three Laws of Motion

– 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

– The Law of Acceleration• A force applied to a body causes an acceleration of

that body of a magnitude proportional to the force, in the direction of the force, and inversely proportional to the body’s mass

– The Law of Reaction• For every action there is an equal and opposite

reaction

Types of MotionTypes of Motion• Linear (or translational) motion

– Movement in a particular direction

– Force generated by the athlete’s muscles and the resulting motion is in a straight line

• Rotational motion– Movement about an axis– Force does not act through the

centre of mass, but rather is “off-centre,” and this results in rotation

Lever SystemsLever Systems

• Every moveable bone in the human body is part of a lever system that facilitates movement

• Three classes of levers– Class I lever (e.g. teeter-totter)– Class II lever (e.g. wheelbarrow)– Class III lever (e.g. snow shovelling)

Lever SystemsLever Systems

• Class I lever (e.g. teeter-totter)– The fulcrum (axis) is

located between the force (effort) and the resistance load

Lever SystemsLever Systems

• Class II lever (e.g. wheelbarrow)– The resistance is between

the force and the fulcrum

Lever SystemsLever Systems

• Class III lever

(e.g. shovelling)– The force is between the

fulcrum and the resistance

Seven Principles of Seven Principles of BiomechanicsBiomechanics

• The seven principles of biomechanics – Allows you to gain insight into movement

dynamics

• The Coaching Association of Canada’s National Coaching Certification Program (NCCP) Level 2 Theory course sets forward these seven principles grouped into four broad categories:– Stability– Maximum effort– Linear motion– Angular motion

StabilityStability

• Principle 1:– The lower the centre of mass, the larger the

base of support, the closer the centre of mass to the base of support, and the greater the mass, the more stability increases

• Principle 1 has four subcomponents:– The height of the centre of mass– The line of gravity– The base of support– Mass

Maximum EffortMaximum Effort

• Principle 2:– The production of

maximum force requires the use of all possible joint movements that contribute to the task’s objective

Maximum VelocityMaximum Velocity

• Principle 3:– The production of

maximum velocity requires the use of joints in order – from largest to smallest

Linear MotionLinear Motion• Principle 4:

– The greater the applied impulse, the greater the increase in velocity

• Principle 5:– Movement usually

occurs in the direction opposite that of the applied force

Linear MotionLinear Motion

Angular MotionAngular Motion • Principle 6: – Angular motion is

produced by the application of a force acting at some distance from an axis (torque)

Angular MotionAngular Motion

• Principle 7:– Angular momentum is

constant when an athlete or object is free in the air

Applications in BiomechanicsApplications in Biomechanics• Performance improvement

– Coaches and athletes focused on “performance improvement” within the aspects of technique and sport training

• Injury prevention and rehabilitation– High level of interest in biomechanics from sports

medicine specialists, trainers, and injured athletes in relation to “injury prevention and rehabilitation”

• Fitness and personal training– Biomechanical analysis can be applied both to

exercise and to equipment

Injury Prevention and Injury Prevention and RehabilitationRehabilitation

• Progressive resistance training to improve muscular endurance, size, and tensile strength of both muscle and connective tissue can be integrated into the off- and pre-season schedule

• Specific design of aerobic and muscular warm-up tailored to the activities planned for the workout will bring more injury prevention value to the session

• All key muscles to be used must be stretched • Muscle imbalance needs to be addressed

Fitness and Personal TrainingFitness and Personal Training

• Biomechanical analysis begins by examining the method of execution of an exercise; such analyses enable one to give advice concerning:– The position of joints to isolate specific muscles– How to align the movement to the muscle– How to combine muscles for optimal results– The optimal speed for the objective– The best starting position and range of motion

for an exercise– How to modify the leverage to gain a greater

strength output