introduction to biomechanics

1. Chapter No. 01
What is
Biomechanics?
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
McGraw-Hill/Irwin

2. 1-2
What is biomechanics?
The term biomechanics combines the prefix bio, meaning “life,” with
the field of mechanics, which is the study of the actions of forces,
(both internal muscle forces and external forces.) In biomechanics we
analyze the mechanical aspects of living organisms.
mechanics
bio
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.

3. 1-3
Sub-branches of biomechanics:
• statics: study of systems in constant motion,
(including zero motion)
• dynamics: study of systems subject to
acceleration
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
• kinematics: study of the appearance or
description of motion
• kinetics: study of the actions of forces (Force can
be thought of as a push or pull acting on a
body.)

4. 1-4
What we visually observe of a body in motion is called the
kinematics of the movement. Kinematics is the study of the size,
sequencing, and timing of movement, without regard for the forces
that cause or result from the motion. The kinematics of an exercise
or a sport skill is known, more commonly, as form or technique.
What is kinematics?
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.

5. 1-5
What is kinetics?
Kinetics is the study of forces, including internal forces
(muscle forces) and external forces (the forces of
gravity and the forces exchanged by bat and ball).
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.

6. 1-6
What is kinesiology?
Kinesiology
Athletic training
Exercise
physiology
Adapted physical
education
Biomechanics
Sport psychology
Sport philosophy
Motor behavior
Sport art
Pedagogy
Sport history
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
Kinesiology is the study of human movement.

7. 1-7
What is sports medicine?
Sports Medicine
Cardiac
rehabilitation
Exercise
physiology
Athletic training
Biomechanics
Other medical
specialties
Sport psychology
Sport nutrition
Motor control
Physical therapy
Athletic training
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
Sports medicine is an umbrella term that encompasses both
clinical and scientific aspects of exercise and sport.

8. 1-8
What questions or problems
are studied by
biomechanists?
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.

9. 1-9
What questions are studied by biomechanists?
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
When not subject to
gravitational force,
astronauts lose significant
amounts of bone mass.
(Bone atrophies when not
subjected to forces.)
Exercise, however, is
known to increase bone
mass. So what kinds of
exercise should astronauts
do while in space in order
to preserve as much bone
as possible?

10. 1-10
What questions are studied by biomechanists?
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
Whether lifting
weights or lifting
boxes in industry,
the act of lifting
places major
mechanical stress
on the low back.
What lifting
kinematics
(techniques) can
minimize this
stress?

11. 1-11
What questions are studied by biomechanists?
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
How do toddlers
learn to balance
their torsos on little
legs unaccustomed
to walking? (This
question spans the
fields of
biomechanics,
motor learning, and
motor
development.)

12. 1-12
What questions are studied by biomechanists?
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
Pitching can lead to stress injuries of the
elbow and shoulder joints. What pitching
technique characteristics minimize the
mechanical stresses to these joints?

13. 1-13
What questions are studied by biomechanists?
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
Recreational runners, as well as athletes in
many sports, often stretch before a work out.
Does this actually help or hinder performance?
(Increasing evidence suggests the latter…)

14. 1-14
What questions are studied by biomechanists?
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
What biomechanical elements of running
technique enable some sprinters to dominate
over others who are just as well trained and
have just as strong physiological attributes?

15. 1-15
Qualitative vs. Quantitative:
• qualitative: pertaining to quality (without the
use of numbers)
For example: strong, skillful, agile, flexible, fast
• quantitative: involving numbers
For example: running speed = 5 m/s
height = 1.75 m
mass = 68.2 kg
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.

16. 1-16
Qualitative vs. Quantitative:
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
Quantitatively, the robot missed the coffee cup by 15 cm.
Qualitatively, he malfunctioned.

17. 1-17
Qualitative vs. Quantitative:
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
Coaches rely heavily on qualitative observations of athletes’
performances in formulating advice about technique.

18. 1-18
Steps in Solving Formal Quantitative Problems:
• Read the problem carefully.
• List the given information.
• Write down what quantity is to be solved for.
• Draw a diagram of the problem situation.
• Select the appropriate formula to use.
• Review the problem statement to determine if
more information can be inferred.
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.

19. 1-19
Steps in Solving Formal Quantitative Problems:
• Substitute the given information into the
formula.
• Solve the equation for the unknown variable.
• Do a “common sense” check of the answer.
• Box in your answer, including the correct units
of measurement.
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.