BME3101 Biomechanics Track Lab Experiment October 22-26

Dr. K. Gielo-Perczak, 10/14/2012 Page 1 of 2

Balance control testing: can we expect reproducibility in human movement data?

Overview

Generally, the lab will aid in your understanding of the Biomechanics Track concept.

In this laboratory you will measure and analyze balance control of human body during

standing and determine the effects of arm and leg position on the movement of center of

gravity and body stability.

The laboratory will be designed and performed in groups of four students. Each individual

students understanding of the lab material will be assessed by an individually written laboratory report with analysis of the data collected as a team (to be clear, you will work

together to do the lab, run the statistical analysis, and write the lab report, but it is considered

academically dishonest if each student does not perform the test to gather his/her nine

measurements).

Each student is required to learn the AccuSway users manual, NetForce acquisition and BioAnalysis AMTI software packages.

Background and objectives

Consider yourself as a starting biomedical engineer working for a video game company.

Your task it to make the game more realistic by adding accurate COG information for college

students arms and legs. The company would like to know which COG values are more reproducible between the arm and leg movements. They also would like to know why there is

a difference.

The objective of the lab is to help you learn how to detect the influence of Center of Gravity

on body balance during different body positions.

The lab experiment will aid in your understanding of the concepts involved in analysis of

human body balance data. The laboratory provides a more hands-on and comprehensive

experience in Biomechanics Track.

Challenge

Your challenge is formulate and test hypothesis about arm vs. leg measurement

variability.

Body balance control is complex phenomena and you may observe how many factors can

have influence on Center of Pressure movement. Please note, that your body position, height,

weight, head orientation, angular positions of body segments, your mental focus during

taking balance recordings, environmental (lab) noise, history of potential injuries at ankle,

knee or hip joint, ALL have potential influence on your balance.

BME3101 Biomechanics Track Lab Experiment October 22-26

Dr. K. Gielo-Perczak, 10/14/2012 Page 2 of 2

Experimental approach

Each student of a team will participate in the experiment and recordings of three body

positions on a platform will be taken: 1) quiet standing with parallel feet, 2) standing with

parallel feet and raising a right arm in frontal plane, 3) standing and raising a right leg in

frontal plane. Each student will perform three trials at each body position. Then the students

in each team should pool their data.

Before you start your data recording, choose your preferred sports activity. Create a

Subject#.xls file with info on a gender, height and weight (recorded by using AMTI

AccuSway force platform and N!)

Hint, look at the 95% ellipse area for center of pressure and Avg. COP (Center of Pressure)

velocity to see which moves more. How you can interpret the changes if any in Avg. COP

velocity recordings?

Required analysis

For the experiment, you must perform balance control tests, download the data,

1. print statistical information from BioAnalysis software, 2. print 95% ellipse area and

analyze the results for each position. Which do you think will be more variable and why,

holding arm or leg? Test type by comparing variability of COP (95% Ellipse Area).

For your lab report (< 4 pages), you must describe your methods (e.g., number of trials, test

conditions, etc.) and provide the definitions and data information of COP-X Avg. (cm), COP-

Y Avg. (cm), Standard Deviation X COP, Standard Deviation Y COP, 95% Ellipse Area, COP Avg. Velocity (cm/sec).

You should also discuss your conclusions based on your findings (i.e., were your hypotheses

correct?). The written portion (description and conclusions) should be one typed page, the

COP areas should be included on a single plot, and the summary data, dimensions, etc.,

should be presented in tabular format.

The report must be done individually, but each team member should do calculations then

compare the results with the other team members. Each student experiment recordings must

be included in the Appendix with the students name who completed that test clearly indicated.