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Basic Biomechanical Factors and Concepts

Anatomy and Physiology

Zgabay

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Outline

Introduction Levers Anatomical Levers Laws of Motion

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Biomechanics

________________- study of the mechanics as it relates to the functional and anatomical analysis of biological systems and especially humans Necessary to study the body’s mechanical

characteristics & principles to understand its movements

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Biomechanics

____________- study of physical actions of forces

Mechanics is divided into: ____________ ____________

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Biomechanics

_____________- study of systems that are in a constant state of motion, whether at rest with no motion or moving at a constant velocity without acceleration Statics involves all forces acting on the body being in

balance resulting in the body being in equilibrium

_____________- study of systems in motion with acceleration A system in acceleration is unbalanced due to unequal

forces acting on the body

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Biomechanics

Kinematics & kinetics ___________- description of motion and includes

consideration of time, displacement, velocity, acceleration, and space factors of a system‘s motion

___________- study of forces associated with the motion of a body

Mechanical advantage Load/effort or load divided by effort Ideally using a relatively small force, or effort to move a

much greater resistance

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Outline

Introduction Levers Anatomical Levers Laws of Motion

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Introduction to Levers

__________: Simple machine that operates according to principle of torques

__________: The turning effect of a force

T = _____

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F

d How can you change torque?

1. __________

2. __________3. ________________

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d Optimal direction = 90 degrees

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Function of Levers

Two functions:

1. __________

2. __________

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Function of Levers

Force Examples?

Common traits? ____________ ____________ ____________ vs. ________________

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F R

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Function of Levers

Speed/ROM Examples?

Common traits? Rigid bar Fixed point Lever movement vs. resistance movement

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F R

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Components of a Lever System

Lever: _____________ Fulcrum: _______________________ Force:

______________________ ______________________

Moment arm: d _________________ _________________

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More Concepts

____________ advantage Levers designed for force

____________ disadvantage Levers designed for speed/ROM

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F R

Mechanical advantage or disadvantage?

How does mechanical advantage affect movement of the lever?

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Advantage: Small effort moves big resistance

Disadvantage: Big movement required to move resistance a small distance

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Human Application?

Lever?

________________________ Fulcrum?

________________________ Applied force?

________________________ Resistance force?

________________________

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Classification of Levers

Lever classification based on the relative location of:

1. Axis of rotation/fulcrum (A)

2. Resistance force (R)

3. Applied force (F)

A R F

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First Class Lever

____________: (A) – Axis of rotation/fulcrum Mechanical advantage Mechanical disadvantage Examples

___________

___________

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Advantage or disadvantage?

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Second Class Lever

___________: (R) – Resistance force Mechanical advantage

Always

Mechanical disadvantage Never

Examples

_______________

_______________

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Third Class Lever

___________: (F) – Applied force Mechanical advantage

Never Mechanical disadvantage

Always Examples

__________________________________________

27Baseball, tennis?

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Human Application

First class lever _____________________________________

29(A) – Axis of rotation/fulcrum

(F) – Applied force

(R) – Resistance force

Mechanical advantage or disadvantage

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Human Application

Second class lever _____________________

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Mechanical advantage or disadvantage?

Not many in the body

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Human Application

Third class lever ______________________

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Mechanical advantage or disadvantage?

Many of these in body

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In general, is the human body built for force

application or speed/ROM?