© 2015 J. Tritschler • Department of Biomedical, Industrial, and Human Factors Engineering Wright State University • 3640 Colonel Glenn Hwy.

© 2015 J. Tritschler • Department of Biomedical, Industrial, and Human Factors Engineering
Wright State University • 3640 Colonel Glenn Hwy. • Dayton, OH 45435
BME/ISE 3211 Human Biomechanics I Course Project, Fall 2015
Due Date: 30 October 2015
Overview
This document outlines the BME/ISE 3211 Human Biomechanics I Course Project in which biostatics analysis
is used to design rehabilitation parameters for a patient with a torn distal biceps tendon. Each student will
construct a free-body diagram of the human elbow/tendon system, perform static analysis of the system with an
external load placed in the hand, calculate theoretical tendon tensions for a set of specified angles and loads,
display data graphically, and design rehabilitation parameters within constraints set by an injury specialist. A
formal report is to be submitted with all relevant info and conclusions.
Background
You are a consulting biomedical/industrial engineer assisting an employer in a prominent regional
manufacturing company. An employee has torn a distal biceps tendon and must undergo rehabilitation. An
injury specialist has performed tests and advises that the injured tendon should not be subjected to forces
exceeding 500 N during rehabilitation.
The employee’s job requires routine handling of parts ranging from 2-6 kg. During manipulation of these parts,
the employee must extend the arm with supinated palm and hold the forearm in a horizontal position such that
the angle between the long axis of the upper arm and the forearm ranges from 30°-70°. Your task is to perform
biostatics analysis to determine if any of these loads causes tendon tension to exceed the value advised by the
injury specialist. From this analysis, you will prepare a report for submission to the employer.
Theoretical System Parameters for Biostatics Analysis
Fig. 1 shows a pictorial diagram of the extended forearm holding a load in the supinated hand. Assume that the
axis of rotation of the elbow is fixed at point O and that the distance between O and the attachment point of the
distal biceps tendon is a = 5.7 cm. The mass of the entire forearm including hand is mb = 1.66 kg and its center
of gravity is located b = 21.0 cm from O. Define the load in the hand as mc; its center of gravity is located c =
40.6 cm from O. Define Fm as the biceps tendon tension. Assume that the line of action of Fm is parallel to the
long axis of the upper arm throughout the specified range of motion. Therefore, define ? as the angle Fm makes
with the forearm; i.e., with respect to horizontal.
Fig. 1: Pictorial diagram of the extended forearm handling a variable mass.
© 2015 J. Tritschler • Department of Biomedical, Industrial, and Human Factors Engineering
Wright State University • 3640 Colonel Glenn Hwy. • Dayton, OH 45435
Report Guidelines and Grading Rubric
1) Prepare an electronically-generated free-body diagram of the system utilizing the parameters outlined
above. You may use shapes in MS Word or the drawing program of your choice. Include all
dimensional information and a coordinate system. (20%)
2) Derive an expression for the magnitude Fm in terms of ? and mc. Hint: you only need one rotational
equilibrium equation to do this. (20%)
3) Compute Fm for each of five masses placed in the hand [mc = 2.0, 3.0, 4.0, 5.0, and 6.0 kg] at each of
five angles of distal biceps tendon tension [? = 30, 40, 50, 60, and 70°]. Prepare a table with these 25
values of distal biceps tendon tension, with ? placed along the x-axis (columns) and mc placed along the
y-axis (rows). Label and caption this table. Highlight values that exceed the limit advised by the injury
specialist in a suitable color. (20%)
4) Generate a graph with five smoothed-line scatter plots (including data points) showing Fm (y) vs. ? (x)
for each of the five masses using Excel or MatLab. Draw a heavy line on the graph in a suitable color
indicating the tension limit advised by the specialist. Likewise, generate a similar graph showing Fm (y)
vs. mc (x) for each of the five angles and a line indicating the advised tension limit. Label and caption
both graphs. (20%)
5) Prepare a formal report with the following sections: (20%)
• Cover Page
o name of the university and department
o title of the report
o submitted by: (your name)
o submitted to:
o date of submission
• Introduction and Purpose
o You may paraphrase the description of the problem in this assignment, but don’t simply
copy and paste it.
• Data and Results
o Include all diagrams, derivations, equations, tables, and charts.
• Discussion
o Discuss the figures in the table and charts and address the following questions:
 What happens to the theoretical magnitude of distal biceps tendon tension as the
arm becomes fully extended; i.e., ? approaches zero degrees?
 What does this suggest about the limitations of our analysis?
• Conclusions and Recommendations
o Should the injured employee undergo on-the-job rehabilitation?
o Specify design parameters for a rehabilitation algorithm based on your computations.
You may consult with a classmate regarding help with graphs or double-checking derivations, but all reports
and corresponding work are individual for this assignment.