Lab 4 key

# Lab 4 key - Lab day and time PHS 381 Biodynamics CENTER OF...

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Lab day and time: _____________________________ PHS 381 - Biodynamics CENTER OF GRAVITY/STABILITY/TORQUE Learning objective (COG stability): To increase understanding of center of mass (center of gravity), torque and stability. To be able to explain the variables that determine if you are stable or unstable. To understand how you can manipulate the position of your center of mass with respect to other parts of your body. Learning objective (Torque): To increase understanding of factors that influence torque Equipment: measuring tape dumbbells (or any weight) Activities: 1. CENTER OF MASS Perform vertical jumps using the following 2 techniques. (To do this you will need to find a wall that is higher than you can reach when you perform a vertical jump.) a. Jump as high as you can, when in the air assume a stretched out position with one arm extended as high as possible. This is the normal technique for a maximum jump and reach test. (mark the height on the wall reached by the hand of the extended arm). b. Jump as high as you can, when in the air assume a position in which your hip and knees are in a flexed position. As in the first technique extend one arm as high as possible. 2. TORQUE a. Choose a simple ‘1 joint’ free weight exercise (for example dumbbell curl, lateral raise etc). b. Perform this exercise using a weight. Using a tape measure to measure the distance of the weight from the joint around which the movement takes place. Calculate the torque at the joint of interest for 3 different joint positions (for this you will need to use some trig). You can choose three different positions (joint angles)(show work below) For instance, below are 3 positions of the elbow angle. If that were your exercise you just draw the elbow in 3 different positions and determine the torque being produced by the weight at the elbow joint in those 3 positions. (for this exercise the weight is the same in all 3 positions) (2 pts each)

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PHS 381 - Biodynamics Name ________________________________________ 3. STABILITY a. Stand facing the wall with toes touching the wall. Now, plantar flex your ankles so that you are standing on your toes. Try to maintain this position for two seconds without touching anything other than the wall and the floor. b. Stand with your right side and right foot against the wall.
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## This note was uploaded on 11/10/2011 for the course KNH 381LAB taught by Professor Staff during the Summer '11 term at Miami University.

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Lab 4 key - Lab day and time PHS 381 Biodynamics CENTER OF...

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