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OBJECTIVES:
Biomechanics is an "interdisciplinary field" combining
several different sciences.
A sport biomechanist is a scientist or researcher that studies
human motion or sports performance.
Knowledge of biomechanics is important in the sports industry for
those who design equipment.
In this activity, you will examine
the range of motion of your knee, wrist
and shoulder and observe that these body parts act like
different types of mechanical joints.
STEPS TO FOLLOW:
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Compare the motion of your knee to
the range of motion of your wrist or
your shoulder. The knee, wrist and shoulder
act as different types of joints.
Your knee acts like a hinge. Think of a door or
cabinet hinge. The door can open and close,
but does not operate in any other direction.
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Your body has different types of muscles.
Bend your leg at the knee and then straighten
your leg to its original position.
Bending a joint is
referred to as flexion; straightening that bent
limb is called extension. Muscles operate with a
pulling motion. Muscles do not push.
In general there is a muscle (or set of muscles)
that are used to bend joints and limbs - these
are called flexors. Different muscles, called
extensors, are used to straighten the limb.
Work with a partner.
Sit down on a chair. Extend your leg straight out. Without straining, bend
your knee under your thigh.
Using the protractor, have your
partner record the angle your lower leg makes with your upper leg.
Record this information on your data sheet.
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MATERIALS:
Data Sheet
Pencil
Protractor
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Look at your own arm. Without
moving other parts of your arm or
straining, bend
your wrist forward, backward, and side to side.
Observe the direction and
range of motion of your wrist.
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Work with a partner. Position your wrist vertically (straight
up and down). One at a time, repeat the
motions in Step 4. Using the protractor, have your
partner record the angle your wrist makes from this vertical position
on your data sheet. Your wrist acts like a
mechanical joint
called a universal joint.
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Without moving other parts of your arm or straining observe the
direction and range of motion of your elbow. Move your
elbow forward, backward, and side to side.
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Work with a partner. Extend your arm into a horizontal position (straight
out). One at a time repeat the motions in Step
6. Using the protractor, have your partner record the
angle your elbow makes from this horizontal position on your
data sheet.
What type of mechanical joint does your elbow act like?
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Without moving other parts of your arm or straining observe the
direction and range of motion of your shoulder. Describe the
motion your shoulder makes and record it on your
data sheet. Your shoulder acts like a
mechanical joint
called a ball and socket joint.
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Compare your results from Step 3, Step 5, Step 7 and Step 8.
What conclusions can you make?
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