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Transcript Intro+to+Qualitative+Biomechanics

How Do I Move?
Chapter 7
The Science of Biomechanics
• The study of the structure and functions of
biological systems by means of the methods
of mechanics
Hatze, 1974
We might think of biomechanics as the “physics
of human movement”
 Examines the internal and
external forces acting on the
human body and the effects
produced by these forces
 Aids in technique analysis
and the development of
innovative equipment
 Draws on knowledge from
sports medicine, physical
therapy, kinesiology, and
biomechanical engineering
The 7 Basic Principals of Biomechanics
They all fall under the following 4 categories
• Stability
• Maximum Effort
• Linear Motion
• Angular Motion
Principle 1 – Stability
• 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 2 – Maximum Force
• The production of maximum force requires
the use of all possible joint movements that
contribute to the task’s objective.
Principle 3 – Maximum Force
• The production of maximum velocity requires
the use of joints in order – from largest to
Principle 4 – Linear Motion
• The greater the applied impulse the greater
the increase in velocity.
Principle 5 – Linear Motion
• Movement usually occurs in the direction
opposite that of the applied force.
Principle 6 – Angular Motion
• angular motion is produced by the application
of a force acting at some distance from an
axis, that is, by torque. The application of
torque produces changes in angular motion.
Principle 7 – Angular Motion
• angular momentum is consistent when an
athlete or object is free in the air. Once an
athlete is airborne, he or she will travel with a
constant angular motion.
Review of Movements from Anatomy
• Planes
– Sagital
– Frontal, Coronal
– Transverse
• Axis
– Horizontal
– Antereoposterior
– Longitudinal
• Kinematics
– describing movements with respect to time and
• Kinetics
– examines the forces that produce the movement
and result from the movement
Qualitative Analyses
Involves obtaining information, visually or auditorily,
to asses performance
It requires:
A framework within which skilled
performance can be observed
A set of principles with which
movement can be analyzed
A checklist to use when identifying
Techniques to use for error
detection and correction
Quantitative Biomechanics
Types of Motion
Linear motion
General motion
Angular motion
Types of Motion
 Translation refers to movement of the body as a unit without
individual segment parts of the body moving relative to one
 Linear Motion When all parts of the body move the same distance, in
the same direction, at the same time
 Rectilinear motion occurs when movement follows a straight line
 Curvilinear motion occurs when the movement path is curved but
also linear
 Identify the external forces acting on the human body
 Describe the resulting motion
 Describe the expected path and motion of any projectile
 Differentiate between similar skills
 Determine the degree of stability possessed by an athlete
 Understand the causes and effects of actions
 Qualitatively analyze simple sport skills that involve
throwing, striking, or hitting an object
Preliminary Steps for Analyzing Human Motion
Step 1
 Identify the system to be studied, which is to separate the
object of interest from its surroundings
Step 2
 Identify the frame of reference in which the movement
takes place
Step 3
 Identify the type of motion that is occurring, the body
planes in which movement takes place (sagittal, frontal, or
transverse), and
 Identify the axes of rotation about which rotational
motion occurs (sagittal, frontal, or vertical)