Lecture notes, lecture 1 - Basic biomechanics chapter 1 PDF

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Basic Biomechanics Chapter 1...

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Chapter 1

What is Biomechanics? Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

McGraw-Hill/Irwin

© 2014 The McGraw-Hill Companies, Inc. All rights reserved.

What is biomechanics?

bio

mechanics

The term biomechanics combines the prefix , meaning “life,” with the field of (both internal muscle forces and external forces.) In biomechanics we analyze the . Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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Sub-branches of Biomechanics •

: study of systems in constant motion, (including zero motion)

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: study of systems subject to acceleration

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: study of the appearance or : (Force can be thought of as a push or pull acting on a body.) Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What is kinematics?

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. Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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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, 7th edition By Susan J. Hall, Ph.D.

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What is kinesiology?

Kinesiology is the study of human movement. Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What is sports medicine?

Sports medicine is an umbrella term that encompasses both clinical and scientific aspects of exercise and sport. Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions or problems are studied by biomechanists?

Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists? 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.)

Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists?

Some biomechanists investigate what causes different species of animals to transition from walking to running. (And how do you get animals to walk/run on a treadmill in order to study this?) Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists? 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. What kinds of exercise should astronauts do while in space in order to preserve as much bone as possible? (photo courtesy of NASA)

Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists? Loss of bone density is also a problem on earth. Osteoporosis is a condition common in elderly individuals in which bone mass and strength are so damaged that normal daily activities can cause bone fracturing and pain. What can people do to prevent the development of osteoporosis?

Scanning electron micrograph of human osteoporotic bone. Note the cracks compromising bone structure.

Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists? Diminished bone density leads to increased incidence of fractures among elderly individuals, especially when sustaining a fall. To help prevent falling among elderly individuals, biomechanists study balance and fall prevention. What can older individuals do to maintain a steady gait? Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What problems are studied by biomechanists? The gait of individuals with cerebral palsy is characterized by knee flexion during stance. Biomechanists study ways that surgeons can change muscle attachment sites to help normalize movement patterns in children with various disorders.

Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What problems are studied by biomechanists?

Design of prosthetic limbs, including legs and feet that store and return mechanical energy during gait, is another problem addressed by biomechanists. Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What problems are studied by biomechanists? To address the problem of serious lower extremity stress fractures that have required hip replacements in young, competitive skaters biomechanists have invented a revolutionary new figure skate with a hinged ankle that dramatically reduces landing impact forces.

Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists?

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? Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists?

What technique modifications can contribute to performance improvements in the throwing events in track and field? (Biomechanists have studied these.) Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists?

What technique modifications can contribute to performance improvements in the jumping events in track and field? (Biomechanists have studied these.) Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists? Computerized biomechanical analyses of golf swings are commonly available at golf courses and equipment shops. Biomechanics can play a role in optimizing the distance and accuracy of all golf shots, including putting. A common technique recommendation is to maintain a fixed center of rotation during the swing.

Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists?

Pitching can lead to stress injuries of the elbow and shoulder joints. What pitching technique characteristics minimize the mechanical stresses to these joints? Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists? 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?

Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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What questions are studied by biomechanists?

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…) Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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Qualitative vs. Quantitative pertaining to quality (without the use of numbers) For example: strong, skillful, agile, flexible, fast • : involving numbers For example: running speed = 5 m/s height = 1.75 m mass = 68.2 kg

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Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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Qualitative vs. Quantitative

Quantitatively, the robot missed the coffee cup by 15 cm. Qualitatively, he malfunctioned. Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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Qualitative vs. Quantitative

Coaches rely heavily on qualitative observations of athletes’ performances in formulating advice about technique. Basic Biomechanics, 7th edition By Susan J. Hall, Ph.D.

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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, 7th edition By Susan J. Hall, Ph.D.

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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, 7th edition By Susan J. Hall, Ph.D.

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