Biomechanical Principles and Applications

Principles and
Mr. MacMillan
▪ 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
 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
Review of Movements from Anatomy
▪ Planes
– Sagital
– Frontal, Coronal
– Transverse
▪ Axis
– Horizontal
– Antereoposterior
– Longitudinal
▪ Kinematics
– describing movements with respect to time and space
▪ Kinetics
– examines the forces that produce the movement and result from the movement
Newton’s First Law: The Law of Inertia
An object will remain at
rest or in a state of
constant velocity unless
acted upon by an
external force
Newton’s Second Law: Law of Accelerations
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.
F = ma
Newton’s Third Law: Law of Reaction
For every action there is
an equal and opposite
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
 A checklist to use when identifying errors
 Techniques to use for error detection and
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
the body moving relative to one another
individual segment parts of
 Linear Motion When all parts of the body move the same distance, in
direction, at the same time
the same
 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
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)