Download Activity Overview

Puppet on a String:
Marvin Hangs Around for an
Engaging Look at Movement
Using a simple marionette, the student will be able to:
u Observe how muscles and bones work together to move joints
u Observe that joints are operated by opposable muscles
u Distinguish between joint flexion and extension
u Observe that muscles can work only by pulling (contracting)
Activity Description:
Students will construct a tag board moveable figure named Mobile
Marvin. Mobile Marvin’s body segments will be attached using
brads, so that moveable joints are formed. By attaching strings, as in
a marionette, students will be able to simulate the jobs of the brain,
nerves, muscles and bones to orchestrate specific movements in their
Mobile Marvin puppet. From their observations, students will infer that
muscles work only by pulling, that at least two opposable muscles
must operate a joint and that muscles and bones must work together
to allow movement.
Activity Background:
Bones are required for movement, but cannot move on their
own. They must be moved by the contraction and relaxation
of skeletal muscles. Skeletal muscles are attached to bones
and create lever systems throughout the body. Levers
in the human body are designed to produce speed and
versatility. The human body converts the linear force of
muscle pull into rotational movement around the joint.
Muscles work in opposable (antagonistic) pairs to
operate joints. This means each muscle or muscle group
that performs a specific movement has another muscle
or muscle group to perform the opposite movement. This
arrangement is necessary because muscles move joints only by pulling
and not by pushing. An example of an opposable (antagonistic) pair of
muscles would be the biceps and the triceps, which operate the elbow
joint. A muscle which causes a joint to bend is called a flexor. A muscle
causing a joint to straighten is called an extensor. The biceps is an
example of a flexor, while the triceps is an example of an extensor.
Aging®/M.O.R.E.
Positively
2007©The University of Texas Health Science Center at San Antonio
Discrepant Design
Activity Objectives:
Activity Overview
Activity 1A
LESSON 1
ACTIVITY 1A
1
Activity Materials: (per 2 students)
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2 Craft sticks
Glue
Fishing line or string
Scissors
Mobile Marvin Cutout from Mobile Marvin Lesson
(pattern included)
Brads
Tag board
Single-hole punch
Hole reinforcers
Activity Management:
The background information is left off of the student pages so that
students can observe as much as possible about the movement of Mobile
Marvin’s joints. While students will make many correct inferences, it is
very important to thoroughly “process out” the activity so any misconceptions or misunderstandings can be corrected.
Consider giving the construction of the Mobile Marvin “puppet” as a
homework assignment – perhaps just ahead of a long weekend.
Students may want to make an enhanced version of Marvin from
colored paper or wood, or even dress Marvin for his “exercise debut.”
References Used:
Hamill, J. & Knutzen, KM. (2003). Biomechanical basis of human movement (Second Edition). New York: Lippincott Williams & Wilkins.
Aging®/M.O.R.E.
Positively
2007©The University of Texas Health Science Center at San Antonio
Discrepant Design
When a muscle contracts, it becomes shorter and thicker, and pulls on
the bones to which it is attached causing movement around the joint.
When the muscle relaxes, it becomes longer and thinner and cannot
move a joint by pushing. When muscles are at rest, they remain in a
state of tension or tone to help maintain body position or posture.
Muscle contraction and relaxation are controlled by the brain through
nerve stimulation. There are numerous nerve endings associated
with the fibers that make up each muscle. These muscle fibers can be
stimulated by nerves in varying numbers to control the strength of
muscular movement.
Activity Overview Continued
Muscles are attached to the periosteum (protective covering) of bones by
tendons. The biceps muscle is attached to the scapula (shoulder blade)
by two tendons. The point of attachment is called the muscle origin.
The triceps origin consists of three tendons; one attached to the scapula
and two attached to the top of the humerus (upper arm bone). The
muscle insertion is the point at which the muscle is attached to the bone
that will ultimately move as the muscle contracts. For example, the end
of the biceps opposite the origin is attached to the radius (bone in the
lower arm) and forms the muscle insertion at that point of attachment.
LESSON 1
ACTIVITY 1A
2