Don't miss the HFES Annual Meeting in Denver, CO from October 13-17. 

The 6th Annual Applied Ergonomics Conference in Dallas, TX was a big success, the 7th Annual Applied Ergonomics Conference will be held in Orlando, FL from March 8-11, 2004.

To aid in the educational and research programs in Ergonomics and related fields, the Industrial Engineering Department maintains several extensive laboratories:

a. The General Ergonomics and Human Performance Laboratory is used for both undergraduate and graduate experimentation and demonstrations. It includes equipment for performance assessment (reaction time, performance time, learning, ... etc.).

b. The Biomechanics Laboratory includes anthropometric calipers, strength measurement devices, skin fold calipers, an anthropometric chair, hand tool investigation and evaluation apparatus, body segment parameter determination equipment, and a push-pull dynamometer. In addition to the maximum isometric strength measurement capability, the Biomechanics Laboratory also provides the capability of measuring dynamic strength (concentric and eccentric contractions using a Cybex II isokinetic dynamometer). The Biomechanics Laboratory also includes a lifting facility for the determination of lifting capacity of males and females, and interchangeable force plates. High speed 16mm motion picture cameras are available for research efforts. Biomechanical file analysis is facilitated through the use of Science Accessories Corp. digitizer with the sonic pen or cursor that is inputted into the IBM computer system. An instrumented treadmill is used to monitor ground reaction forces in consecutive steps. A 6-camera real time motion analysis system has been added to monitor human 3D motion more efficiently. In addition, a virtual reality (VR) racetrack is under construction. The VR system provides various realistic hallway scenes as a subject walks along an oval racetrack. The track is 4 feet wide and 70 feet in circumference sheltered by a fall arresting robot. 

c. The Work Physiology Laboratory includes bicycle ergometers, a programmable Collins treadmill to provide a wide range of loading profiles, Beckman Oxygen Analyzer, sampling gasometers, and readout equipment in the form of Beckman recorders, Sanborn recorders, and Physiographs. In addition, the laboratory includes a Beckman Metabolic Measurement Cart that can be used for the measurement of oxygen consumption/carbon dioxide production and basic pulmonary functions and an Ambulatory monitoring Ind. Oxylog for field oxygen consumption analysis. The work physiology laboratory also includes equipment for measuring blood pressure manually or automatically and several pieces of equipment for measuring, recording and quantifying EMG signals and recording and quantifying EMG signals and recording EKG and heart rate during rest and work. Heart rate, body temperature and other physiological parameters can be recorded from an ambulatory subject using an AMI Medilog. 

d. The Heat and Cold Stress Laboratory includes an environmental chamber with temperature range of 30 to 115 degrees F. The environmental chamber is 16 x 16 x 11 feet high and therefore can be used for single and group experiments. In this laboratory, additional equipment to measure heat stress is available including an air velocity meter, hygrometers, wet, dry, and black globe thermometers, and Reuter Stokes WIBGET heat stress monitors. 

e. The Human Factors Interface Simulation Laboratory is a new capability, which is currently being added to the department's extensive human factors facilities. The main feature of the laboratory is the Tele-robotics and Tele-operations system (TTS). The TTS is based on a Silicon Graphics high-speed computer image generator. Specifically, a Silicon Graphics 4D-85, which provides 16.7 Mhz, 13 MIPS, 400K vector generation and 90K Polygon generation, necessary for the real-time dynamic simulation of complex, color, high image quality, out-the-window visual scenes simultaneously with real-time updates of end-effector parameters on experimenter specified control/display suites. 

In addition to these special laboratories where Ergonomics investigations are performed, there are other laboratories used for other programs within Industrial Engineering. These include the Manufacturing Science Laboratory and the Metrology Laboratory. The department also maintains supporting facilities in the form of metal, wood, and electronic workshops where instrumentation for research and teaching can be manufactured and serviced. A photographic facility is also maintained by the department in support of the research and teaching activities. 


The word ergonomics comes from the Greek ergo (work) and nomos (rules, law). It can be simply described as the science that fits the job or activity to the person who is doing the job or activity. That may seem like a common sense statement, and in many ways it is.   People have been practicing ergonomics ever since the first person fashioned a tool or devised a better method to do something that was previously, slow, difficult or painful to accomplish. In a very real sense, all people (not just designers and engineers) practice ergonomics to some extent.

For instance, the famous engineer and philosopher Leonardo Davinci could easily be considered an early ergonomics practitioner. His detailed study of the human body aided him in the design of machines that were to be used by people. See the sketch below:


The development of ergonomics as a special effort has arisen from the expanding knowledge about the complexity of human capabilities and limitations and the increasing need to ensure the safe, efficient, interaction of people with products and environments. Stated simply, ergonomics or human factors is focused on designing products and systems for human use. Inherent in this design process is the goal to design systems which optimize system performance, safety, and user satisfaction.  Individuals who offer their services in the field of ergonomics are typically referred to as Professional Ergonomists or Human Factors Professionals. If you are interested in learning more about professional certification in ergonomics. Visit http://www.bcpe.org/  Texas Tech has a long tradition of educating students who go on to become leaders in the ergonomics field.  Contact the Industrial Engineering department for more information regarding the career paths of Texas Tech alumni. 

Texas Tech Industrial Engineering Home Page

Texas Tech College of Engineering

HF/Ergonomics Masters Theses completed at Texas Tech

HF/Ergonomics PhD Dissertations completed at Texas Tech

Links to Other Ergo/Human Factors Web Sites


Be sure to see details of  the Fitt's Law experiment performed by some of our undergraduate students on NASA's KC-135 aircraft in August!
Texas Tech NASA Project (click here)
Fitt's Law describes the manner in which the speed and accuracy of moving an object are determined by constraints of the movement task. 

The ergonomics laboratory has a number of exciting new projects underway. For example there are multiple projects dealing with applications of Virtual Environments or 'Virtual Reality' to improve safety, health, and productivity. 

Project 1

This project involves the use of a partial gravity suspension simulator to determine interactions between loading and variants of the optic flow field in order to aid astronauts as they transition from a microgravity environment (orbit) to the Earth's gravitational field near the Earth's surface (also called 1G). Visit this site often to see updates of the partial gravity simulation studies.

The picture above is a CAD model showing the main features of the partial gravity simulator. See how we constructed the simulator in the photos below. 


See Jeff testing out the partial gravity simulator. Our ability to achieve nearly constant tension levels throughout a wide vertical travel range is very unique. No other simulator uses our innovative design. 

Simulated lunar loping is quite interesting. 

 Actually, it's a lot of fun too! Our subjects are getting to do lot's of this locomotion so that we can better understand the adaptation of postural control mechanisms. 

Installation of the virtual environment projection system was the final major component for making the simulator operational. 

In order to make full use of the 6 by 8 foot opening in front of the partial gravity simulator, a special projector stand was created to allow for horizontal mounting of the projector. The projector can be configured in the rotated position shown or in a table mount position. Using the projector in this non-traditional orientation requires us to design our software with the rotation incorporated. The virtual environment created with such a large projection system provides an exciting immersive experience for the subject and a rich test bed for locomotion research. 

This side view of the partial gravity simulator reveals the 6 camera Motion Analysis system that is being used to collect kinematic data for our subjects. Kinematic data is the data that documents the limb positions and patterns of a subject over time. 

Be sure to check this site often for updates showing subjects in action within the simulation environment!

The partial gravity simulator is being used to help discover the ways in which the goals of the person (to maintain balance, move efficiently, etc.) and environmental constraints combine to enable successful standing or locomotion both at 1 G (gravitational acceleration close to the Earth's surface) and in altered gravitational environments. Modeling efforts are underway to generate improved simulations of human movement under a variety of environmental conditions. The equation above, borrowed from Newtonian mechanics, highlights the stiffness, viscosity, and acceleration aspects of human locomotion models. Our approach to modeling human motion involves several steps: 

Goals of this Research

This research is a natural extension of the many human movement investigations and simulation efforts that have been conducted at Texas Tech's Ergonomics Laboratory. This project represents the first time that a partial gravity suspension simulator is being coupled with sophisticated computer generated imagery to create such a compelling and environmentally challenging virtual environment. If you have an interest in learning more about these innovative research techniques for studying postural control, you may contact Dr. Simon Hsiang, or Jeff Brewer through the Texas Tech IE department. 

We are able to create a wide array of virtual environments for our subjects to 'walk through'. Give it a try!


If you live near Lubbock and have an interest in participating in the upcoming partial gravity experiments, please contact the IE department at 742-3543 or Jeff Brewer directly at 785-4108. Pilot studies are underway, but more subjects are needed so be sure to contact us!

Project 2                                                               

This project examines the visual perception component that may contribute to whether a person slips or falls when they encounter a slippery surface. Texas Tech has been one of the premier institutions for examining slips and falls for a number of years. The emphasis of our research is moving beyond the detailed description of the slip/fall event and looking closely at the factors which comprise the person's preparation process before a slip or fall occurs.

 Many factors contribute to the probability of occurrence of a slip or fall. The conjecture of this study is that the degree of human perception of the surface slipperiness is among those factors. In addition, it is hypothesized that the surrounding environment (ceiling height, room width and orientation, lighting intensity and arrangement, etc.), and not only the floor surface, contributes to the human perception of the surface slipperiness. Due to the impracticality of conducting such a study with many environments, the researchers studied the applicability of performing the tests in a virtual environment. In a dark and completely enclosed space (2m´ 2.5m ´2.5m), the subjects were presented with graphical images of different environments on a computer monitor and asked to evaluate the slipperiness of the surfaces in the images. The subjects were made to believe that the actual floor surface on which they were standing was changed with the changing of the images, and were also asked to evaluate the slipperiness of the actual floor. There was a noticeable difference in the subjects’ perception of the floor slipperiness throughout the trials regardless of the fact that the floor was never changed. The use of virtual environments is therefore verified as an accepted method of slips and falls testing in a limited laboratory environment.  

Do you live close to Lubbock and have an interest participating in slip/fall research? If so, please contact the IE department (742-3543). We are currently conducting a slip/fall study and need more subjects ages 18 - 80. If you happen to be over 80 years of age and in reasonably good health (can walk well)  you are welcomed to participate.

This figure shows the key components of our slip/fall track and arresting system that is used during many of our slip fall experiments. Two of the experiments planned for the Spring 2001 semester will use this apparatus.

When we encounter a slippery surface, what should we do?



¨      The objective: maintain balance and minimize slip distance

¨      To accomplish this: (1) reduce step frequency, (2) shorten step length, and (3) lower the center of mass of the body.

¨      Questions

-         Why is the gait strategy mentioned above useful for adapting to the slippery surface?

-         How do we prepare to step onto a slippery surface?

-         Are there any differences in adaptation gait strategy between younger and old people?

¨      In order to investigate this topic, we must know what human gait is, how the human controls body segments, and how the human interacts with the environment.

¨      We are interested in (1) the dynamics of human movements and (2) how to apply knowledge of human dynamics to help people.

If you would like more information regarding the current slip/fall research, please contact Woo-Hyung Park  

Project 3                                                                   

Over the last 60 years, investigations involving slips and falls have been conducted in order to better improve the understanding of the causes, mechanics, and prevention of falls. Nevertheless, information learned regarding slips and falls remains very limited. Researchers have, for the most part, studied slips and falls from a mechanical standpoint. Their research thus far has focused on studying slip resistance using a measure of friction known as the coefficient of friction (COF) as well as other topics closely related to COF such as COF measuring devices and shoe and floor material. This includes numerous studies focused on investigating the relationship between slipping and the shoe/floor material interface.
 This research involves identifying the relationship between the visually perceived information of the surrounding environment and the biomechanical adjustments made by a human in motion  in order to adapt to the visually perceived environment. The hypothesis used is that humans change their gait pattern in order to accommodate for the environment that is perceived  by processing visual information while the perceived environment and the actual environment may not necessarily be identical.  Below are several hallway scenes which may have different effects on a person's perception of floor slipperiness.

 wpe1C.jpg (14180 bytes)  wpe1E.jpg (17057 bytes)    wpe20.jpg (17375 bytes)    wpe22.jpg (17056 bytes)

wpeB.jpg (19490 bytes)    wpeD.jpg (17006 bytes)    wpeF.jpg (19740 bytes)    wpe11.jpg (19299 bytes)

wpe13.jpg (21507 bytes)    wpe15.jpg (21584 bytes)    wpe17.jpg (20441 bytes)

To learn more about this series of experiments, visit Hisham Besheer's web site: VR/Slips and Falls (click here)

Project 4                                                                                     

Biomechanical modeling has always been a strong focus of the Texas Tech Ergonomics Program. An description of biomechanical modeling and a recent biomechanical study are listed below.

Biomechanical Modeling

1. Why, where and when is biomechanical modeling important?

Biomechanics is the study of the effects and control of forces that act on or are produced by living tissue. Its major classifications are (1) sports biomechanics; (2) clinical biomechanics (including cell, tissue, dental, cardiovascular, respiratory, orthopedic, rehabilitative, spinal, gait biomechanics); and (3) occupational biomechanics. The most common variables investigated in biomechanical analysis are

  • Axial Force - force components acting normal to the tissue surface of interest.
  • Shear Force - force components acting tangent to the tissue surface of interest.
  • Moment - the tendency of a force to cause rotation about some axis, and is equal to the magnitude of the force multiplied by the perpendicular distance from the center of rotation.
  • Stress - force per unit area upon a cross section.
  • Strain - the ratio between the change in the dimensions of living tissue under longitudinal loading (tension or compression) and its original size.
  • Creep - increasing strain due to constant loading over a long period.
  • Fatigue - mechanical failure due to repetitive (cyclic) loading. The lower the loading force, the more cycles that can be applied before failure.
  • Elasticity - property of a tissue to return immediately to its original dimensions following loading.
  • Plasticity - property of a tissue to retain its change in size and shape when the load causing the change is removed.
  • Viscosity- property of a tissue not to deform instantaneously from an applied load.
  • Brittleness – a property of a tissue that has no or limited plastic deformation.
  • Ductility – a property of a tissues that exhibits significant plastic deformation.
  • Biomechanical models are frequently used to (1) summarize a body of information; (2) divide a complex process into unitary functions; (3) divide a complex physiological process into identifiable steps; (4) provide insight into structure-function relationships; (5) summarize one system in order to understand the implications for another system with which it interacts.

     2. What are the main issues/problems surrounding biomechanical modeling?

    Generally, there are three components in a model: the inputs, the embedded mechanism and the outputs. Given the inputs and outputs, a system identification model is designed to find the embedded mechanism. Given the outputs and the embedded mechanism, a control model is designed to find all the plausible input signals. Given the inputs and the embedded mechanism, a simulation model is designed to find all the possible outputs. No model can represent reality with full accuracy. Models are abstractions; as such, they are necessarily flawed. By nature, models are either overly simplified or overly complicated. The complexity of a model depends on the objectives of the model. A justifiable biomechanical model should have (1) minimal number of variables (e.g., principle of parsimony), (2) sufficient explanatory variability, (3) repeatability, (4) robustness, and (5) validated outcomes.

    The general objective of sports biomechanics is maximization of athletic performance. Biomechanical techniques can be applied clinically for the goal of reducing abnormality. The objective of occupational biomechanics is the examination of the physical interaction of workers with their tools, machines, and materials so as to maximize worker’s performance while minimizing the risk of musculoskeletal disorders. The most reported work-related injuries of musculoskeletal disorders are (1) lower back pain (LBP), (2) injuries related slips, trips and falls, and (3) repetitive motion disorders of the upper extremities. These disorders have a multifactorial pathology and onset can be acute (e.g., due to overexertion) or chronic (e.g., due to overuse).

     3. What are main options for addressing the issues raised?

    Among the three common areas of musculoskeletal disorders, LBP has the most complex nature, and has the highest cost associated with disability. For years, two basic questions have remained elusive -- (1) is the pain real? (2) where is the pain coming from? Clinical studies suggest that the origin of LBP can range from the discs (herniation/disruption) to the facets, from the ligaments to the muscles. The anatomic levels involved range from the L3/L4, the L5/S1 to the sacroiliac joint. Thus, the pain could be from any location of the lower back area. This area is compact and redundant with various muscles and ligaments, and serves as the bridge between the upright torso and the lower extremities. During physical activities, such as lifting, some muscles act as prime movers or coactivate with other muscles (e.g., psoas and abdominis) to provide stiffness. With very limited mechanical advantage both mobility and stability are achieved. Since the structure performs an important role in transferring the forces and the bending moments from the upper torso to the lower extremities, it is under tremendous stress. Three types of questions are frequently asked by biomechanical practitioners:

  • Can the stress due to load, speed or their combination be consistently reduced?

  • Can force mechanical advantage be reliably maximized by using mechanical assistance, and/or can the task sequences be alternated to reduce the frequencies of motion?

  • Can equilibrium or balance be recovered from errors (e.g., misjudgment on weight, size, or balance) due to unexpected situations?

  • While some psychologists suggest using the psychophysical approach to determine the maximum acceptable weight for lifting and other manual materials handling, the conventional biomechanical approach is the reduction of spinal loading. This can be achieved by decreasing the load or the moment imposed by the combination of the body and the load. Based on the moment-reduction strategy, several guidelines on lifting techniques have been developed, such as:

  • Decrease the load size and weight;

  • Decrease the pace of work;

  • Avoid coupling the movements of twisting and bending;

  • Keep the load within two straddled feet and close to the body;

  • Make the load trajectory smooth, and,

  • Avoid jerky motions.

  • Remember to Think before you Lift!   

    Below is a brief description of a recent biomechanical modeling study performed in the ergonomics lab:

    Three Different Lifting Strategies for Controlling the Motion Patterns of an External Load

    Coordination of various components of the human body during the course of lifting are very complex and difficult to control.  This study hypothesized that strategies used to control the motion patterns of the external load may be applied to control coordination and also to control the level of compressive force on the lumbosacral joint.  A simulation of lifting based on the optimization approach was introduced to generate three classes of unique dynamic motion patterns of the external load directed by three different objective functions.  The first objective function was to maximize the smoothness of the motion pattern of the external load.  The second objective function was to minimize the sudden change of the center of gravity of the body-load system.  The third objective was to minimize the integration over time of the sum of the square of the ratio of the predicted joint moments to the corresponding joint strength during the course of lifting.  Eight subjects were recruited to perform 40 lifts using each of the three optimal motion pattern of the load.  Compressive forces on the lumbosacral joint were computed and compared.  The data showed with statistical significance that subjects using the motion patterns of the external load suggested  by the first objective function had the lowest compressive force peaks.  Thus, this study has satisfied two goals: (1) it indexed and synthesized three motion patterns of the external load by three biomechanically unique objective functions, and (2) it established the association between the spinal loading and the  control of the  motion patterns of the external load during lifting.


    The figures above illustrate the type of lifting task performed. Contact Dr. Simon M. Hsiang for further information regarding this study.


    Project 1                                                          

    This project was completed in the spring semester of 2001 and involves comparing backpack load carrying with flexible pole carrying. This research is an extension of research performed in the early 1990's. Have you ever seen a person carrying two loads - one at each end of bamboo pole? Have you ever wondered whether this method is better than the typical 'backpack' method of carrying loads in the US and other Western countries?


    Carrying loads with flexible poles is common in many parts of the world. Is this type of load carrying superior to using a backpack that is more rigidly attached to the body? If so, it is important to specify the situations in which flexible pole carrying can be advantageous and to determine what lengths of flexible poles are most desirable. To investigate these questions an analysis of gait parameters, shock transmission, oxygen consumption, load trajectory control, don and removal techniques, and subjective opinions was conducted. Four subjects (two male, two female) ran at a constant 3.0 m/s carrying a load equal to 15% of their body weight either in a backpack or using a flexible pole apparatus. Three lengths of flexible poles were used: 3.6 m, 3.0 m and 2.5 m. Subjects preferred to use the short and medium poles instead of the long poles. Impact forces on the shoulders were significantly greater for the backpack condition. Oxygen consumption increased by 12% to 20% above the unloaded running condition with each carrying method. This data (given the short familiarization sequence and individual differences) supports the findings in previous research showing oxygen consumption increases in direct proportion to the mass supported by the muscles in trained subjects. Although, it appears that the length of the compliant poles is critical for ensuring that load-carrying safety and comfort is superior to the backpack method. 


    Photo with subject

    Another subject showing difference between backpack and long poles

    The table above describes various characteristics of the 4 subjects, subjects 1 and 2 were in relatively good physical shape and subjects 5 and 6 were in very good physical condition. 

    Dependent Variables

    1. Load forces on shoulders -measured with Chatillon force transducer
      It was assumed the load on the shoulders was evenly distributed across both shoulders.

    2. Ground reaction forces - measured with Kistler force plate mounted under Gaitway treadmill – allowed for the following data to be collected: stride length, contact time, weight acceptance rate, push-off rate, maximum vertical forces, impulse

    3. O2 consumption measured with SensorMedics 2900 Metabolic Measurement Cart (MMC)

    4. Psychophysical measures of ‘ease of load carrying’. These consisted of questionnaires administered after every running trial and a final questionnaire completed by the subject once all trials were completed (see appendix for detail).

    5. Video tape of running trials (collected using VHS recorder)

    Experimental Factors

    1. Loading level
      1. Unloaded
      2. Carrying load equal to 15% of body weight
    2. Carrying method
      1. Backpack
      2. Dual springy poles 3.6 meters in length
      3. Dual springy poles 3.0 meters in length
      4. Dual springy poles 2.5 meters in length



    This study has closely examined the differences between carrying a load in a backpack (typical in Western countries) and carrying loads suspended upon poles of varying lengths (typical in Far Eastern countries). The results do not conflict with and generally support previous research which discovered that carrying loads on compliant poles does not reduce the energy cost of load carrying though they do appear to reduce impact forces on the body. Although, the length and compliance of the poles along with the amount of load carried are very important for realizing these reduced impact forces. Also, this study has examined in more detail the aspects of load control (via qualitative and subjective data) to understand the occasions when compliant pole carrying should be considered superior to backpack carrying and vice versa. Overall, shorter poles were preferred by the subjects here to enable greater load control and reduced shoulder forces. It is recommended that compliant poles be considered helpful when load levels are high (less stooping to don load), terrain elevation does not change rapidly, wide open areas are available, loads are not very fragile, rapid changes in direction, orientation, and speed will not be required and subjects are familiar with this technique.


    With regard to further research, the frequency characteristics of compliant pole motion should be investigated further, along with the ways in which anthropometric differences (subject mass - magnitude and composition) influence stride length and other characteristics of gait in running subjects. Investigating these items at the same time may provide further insights and improve the ability to model running gait using the mass, spring, and damper approach. Improved models of both walking and running gaits may reveal clues as to how people such as select African women can carry loads with little or no energy cost.

    *For a more complete discussion of the project results click here. To get a complete copy of the study, please contact Jeff Brewer or Dr. Simon Hsiang.

    Project 2                                                       

    Virtual reality (VR) systems promise to deliver dramatic improvements to areas such as training, rehabilitation, and entertainment. Success in each of these areas is being realized by VR systems, although the reports of motion type sickness (simulator sickness) and disorientation are still prevalent among users. What is it that makes a VR system effective and pleasing for the user? This project examines the relationship between various optic flow presentations and the effect they have on a 'system user' who is attempting to synchronize their treadmill walking speed with the visual stimulus. 

    What exactly is Optic Flow? 

    Optic Flow can be defined as the relative movement of points across the visual field as a person moves through an environment. In other words, it is what you see as you move. Interestingly, as we move through the world our visual system is very effective at using elements of the optic flow field to determine which objects are stationary and which objects are in relative motion with the environment. 

    This experiment involves a subject on a treadmill viewing a simple computer generated optic flow pattern represented by small circular points of light. The density (number of light points) and the rate at which dots appear to move towards the observer are manipulated. The subject's goal is to synchronize their treadmill speed with their interpretation of the optic flow speed. A number of interesting findings have resulted from this study. 


        View of treadmill and monitor inside of test apparatus.

    Above is a computer model of the apparatus set-up (right rear section removed). Below is a representation of the visual displays and the experimental factors. 


    Conducting this experiment gave some of our students experience with the way optic flow information can be used by the body to provide relatively consistent mapping of a treadmill walking speed to a particular optic flow presentation. The main finding in this study was that optic flow density and expansion rate did have a positive and linear influence on the treadmill speeds chosen by subjects at the 'right' speed matching the optic flow field with their haptic and proprioceptive  sensations. 

    Sixty randomized presentations of optic flow during 3-4 hour testing sessions for six subjects confirmed the positive and linear relationship. One interesting finding included the fact that a strong feeling of self-motion was induced for 5 of the 6 subjects. That is somewhat surprising given the small visual angle subtended by the imagery (15 degrees). It is thought that the radial optic flow pattern and the extremely dark surroundings enabled such a strong illusion of self motion when using a relatively small (21 inch along diagonal) monitor. 

    Project 3                                                       

    This project involved Medication Error Research:

    Medication errors make up a large part of the number of errors that occur in the healthcare system.  Studies have revealed that on the average there are 1-2 medication errors for every ten prescriptions that are filled.  Deficiencies in information underlay many of these errors.  These deficiencies in information relate to similar labeling and packaging, look-alike brand names, and sound-alike brand names. This research has focused on the information that is contained in the actual words of the drug names, and how the format of the text of the drug name is portrayed on the drug container and the prescription label.  Different formats have been created that break up the drug name into parts that help identify the dissimilarities between drug names.  For instance, the formats such as  LEVOXINE”, “LEVOXINE”, and “LEVOXINE” use large fonts and color to break the drug names up.  These different formats have been used in sorting tasks in which pharmacists must sort stacks of prescription labels into slots labeled with the drug name.  The speed at which prescription labels can be sorted and the number of errors associated with the placement of incorrect prescription cards into the wrong slot have been quantified.  It is the goal of this research to identify the format that produces the quickest sort time and the fewest number of errors with the least amount of variation between subjects.  It is hoped that this research will help identify ways to reduce medication errors.

    Here you can see Aaron discussing the apparatus he built for conducting the prescription label sorting task.


    Here are close ups of the sorting bins.

    Results of the Medication Error Research Study

    The data from this research show that using medication labels with the format LEVOXINE” produce the fewest number of medication errors. With this format yellow highlight is used to breakup the drug name. The data also show that using medication labels with the format “LEVOXINE” produce the fastest sort times. With this format red text is used to breakup the drug name. The use of yellow highlight had the smallest standard deviation for medication errors, while the use of red text had the smallest standard deviation for sort time. The use of yellow highlight and red text in medication labels both show promise in reducing the number of medication errors and increasing the efficiency of pharmacy operations.

    The results of this study can be applied to the current operations of pharmacies. In hospital pharmacies medications are pulled from bins that are marked by labels containing only the medication name. When these bins are stocked, the medication name is the only piece of information that is used to identify the correct bin. Also, when medications are obtained from the bins, the label is again the only piece of information that is used to identify the correct bin. The results of this study could be used to redesign the labels of bins, which contain medications that have names similar to other medications. Pharmaceutical companies may also use the information from this study to redesign the package labels of medications that have names similar to other medications. Any pharmacy operation that uses the medication name to identify a medication could benefit from the redesign of medication labels based on the information from this study.

    This research was meant to help identify ways to reduce the number of medication errors. It was identified by this study that the use of different sized text and color in the design of medication labels does help to reduce the number of errors. Further studies may look closer at the sort times between yellow highlight and red text label designs. Also, further studies may identify the amount of contrast that is needed when using yellow highlight or red text in medication labels. Research on the location of the medication word on the medication labels may provide relevant information on the reduction of medication errors. New information is the key in understanding and preventing medication errors.

    The medication error research study was performed by Aaron Ross - a  recent graduate of our Industrial Engineering Master of Science program. Aaron's specialization was in the area of Human Factors and Ergonomics. If you have questions concerning his research project, you may contact him by email,  Aaron Ross.


    Simon M. Hsiang, Ph.D.; Associate Professor

    Fred Schneider; machinist/laboratory technician
    Graduate of German Trade School
    Over 20 years of experience as a machinist
    (aircraft components, precision tooling, molds, ... you name it,
    he has probably built it)

    Woo-Hyung Park (Ph.D student)

    Texas Tech University, 1999 –
    Seoul National University (Korea), M.A. (Psychology), 1997
    Seoul National University, B.A. (Psychology), 1988
    Korea Air Force Academy, B.S. (Industrial Engineering), 1983
    Korea Air Force, 1983 – 1997

    Current Research Area: Investigating the dynamics of human movements in slip and fall situations in order to (1) investigate the effects of anticipation and the adaptation mechanisms people use when interacting with their environment, (2) build a mathematical model to simulate these mechanisms, and (3) find the difference in the above mechanisms between younger and older people.


    Jeffrey D. Brewer, CPE (Ph.D student)

    Ergonomist for Raytheon, McKinney, TX, 1998-2000
    M.S. from Texas Tech, 1997
    B.S. from St. Mary's University, San Antonio, 1996
    Engineering Co-op for Bausch & Lomb, 1993-1996
    United States Marine Corps Reserve, 1989-1997

    Specialties: Occupational Biomechanics, Ergonomic Program Development and Implementation (for office and manufacturing environments), Industrial Ergonomics Training, Design and Implementation of man-machine systems to enable safe and efficient manufacturing processes (complex material handling systems, hand tools, process control devices, computer aided assembly methods, etc).

    Current Research Area: Investigating postural control mechanisms used to enable stable standing and locomotion following perturbations induced by simulated partial gravity environments.

    Goal: Discover critical environmental cues that are used by the body (either in open-loop or closed-loop fashion) to maintain stable dynamic postural control and allow for rapid adaptation to acceleration changes in a simulated partial gravity environment. These cues will be used to generate a dynamic postural control model that can be used to explain adaptation responses (for additional information see Current Projects section above).

    Hobbies: Sailing, rock climbing, running, swimming, mountain biking, playing classical guitar, photography

    These links are a mixture of university web sites and industry web sites that describe current research efforts, products, and services available to the ergonomist or human factors professional. The first link will introduce you to the human factors program in the psychology department at Texas Tech. At the bottom of the list are links to the Human Factors and Ergonomics Society and the Occupational Safety and Health Administration - where you can find information regarding the new Ergonomics Standard. The last web site on the list provides an amusing look at a number of products that were poorly designed for human use. 

    Human Factors & Applied Cognitive Psychology at Texas Tech

















    MASTER'S THESES listed are only those related to Human Factors and Ergonomics



    (Revised September, 2000)


     June, 1963                                        Physiological Investigation Of Performance Rating For Repetitive Type Sedentary Work," Robert R. Manuel. Advisor: M.M. Ayoub

    June, 1963                                         “The Investigation Of Time, Distance, Weight Relationships For Certain Moves,” Billy P. Smith.  Advisor:  M.M. Ayoub

     May, 1964                                          “An Optimal Design For A Foot Activated Lever Mechanism,” John Ensdorff.  Advisor:  Richard A. Dudek

     May, 1964                                          “The Effect Of Vibration On Certain Psychomotor Responses,” David E. Clemens.  Advisor:  Richard A. Dudek

     May, 1964                                          “An Investigation Of The Interaction Of Light And Sound Variables On Reaction Time,” Raymond R. Medeiros.  Advisor:  M.M. Ayoub

     May, 1964                                          “Biomechanics Of Lever Operations,” Patrick F. Noud.  Advisor:  Richard A. Dudek

     May, 1964                                          “An Investigation Of The Metabolic Cost Of Tasks Involving Isometric Pull,” Michael J. Petruno.  Advisor:  Richard A. Dudek

     May, 1964                                          “Investigation Into The Effect Of Intermittent Noise Of Constant Periodicity vs. Random Periodicity On The Performance Of An Industrial Task,” Nevin E. Fornwalt.  Advisor:  M.M. Ayoub

     August, 1964                                     “The Determination Of An Optimal Work Area Envelope In The Horizontal Plane,” Harold M. Goodwin.  Advisor:  Richard A. Dudek

     May, 1965                                          “A Biomechanical Investigation Of Static Pull With Constant Shoulder Torques,” Morton B. Berman.  Advisor:  Richard A. Dudek

     May, 1965                                          “Optimal Three-Dimensional Work Place For The Seated Worker,” Richard H. Wyatt.  Advisor:  M.M. Ayoub

     May, 1966                                          “An Analysis Of The Center Of Gravity Of The Arm During Certain Simulated Industrial Moves,” Virgil B. McElhannon.  Advisor:  M.M. Ayoub

     May, 1966                                          “Effect Of Pace On Velocity And Acceleration Patterns Of Body Member Motions in Space,” Baldev G. Raheja.  Advisor:  M.M. Ayoub

     May, 1966                                          “Measurement Of The Incremental Volume Of The Upper Arm Under Dynamic Conditions,” George A. Schultz.  Advisor:  M.M. Ayoub

     May, 1966                                          “Experimental Determination Of An Optimal Foot Pedal Design,” Donald J. Trombley.  Advisor:  M.M. Ayoub

     May, 1966                                          “The Relative Placement of Control Stimulus-Display Panels With Respect To The Operator And Their Effect On Performance,” Sidney W. Vanloh.  Advisor:  M.M. Ayoub

     August, 1966                                     “The Effects Of Low-Level Vibration On The Performance Of A Sensory Input--Physical Response Task Requiring A Decision Factor,” Richard L. Bush.  Advisor:  E.R. Tichauer

     August, 1966                                     “The Sensitivity Of Sampling Inspection To Inspector Error,” Allan S. Davis.  Advisor:  M.M. Ayoub

     August, 1966                                     “An Investigation Of The Effect Of Work Surface Height And Operator Size On Physiological Cost In An Assembly Operation,” Robert D. Hastings.  Advisor:  E.R. Tichauer

     June, 1967                                         “A Kinesiological Evaluation Of The Performance Of The Gloved And Ungloved Upper Limb During Manipulative Handling Of Small Objects,” Robert C. Banasik.  Advisor:  E.R. Tichauer

    June, 1967                                         “Effects Of Lighting And Background With Common Signal Lights On Human Peripheral Color Vision,” George M. Colton.  Advisor:  Richard A. Dudek

     June, 1967                                         “An Investigation Of The Effects Of Posture And Rest Periods On The Performance Of An Inspection And Positioning Task Performed Under Stereo Magnification,” John W. Douglass.  Advisor:  E.R. Tichauer

     June, 1967                                         “An Investigation Of The Effects Of Two Types Of Inspector Error On Sampling Inspection Plans,” Kenneth A. McKnight.  Advisor:  M.M. Ayoub

     June, 1967                                         “A Kinesiological Evaluation Of Parallel Versus Symmetrical Patterns In Simultaneous Hand And Arm Motions,” Fred G. Reichard.  Advisor:  E.R. Tichauer

     June, 1967                                         “A Study Of Factors Affecting The Move And Position Elements Of A Small Component Assembly Task,” Robert N. Roberts.  Advisor:  E.R. Tichauer

     June, 1967                                         “Peripheral Depth Perception At The Work Place,” Fred Rochez.  Advisor:  E.R. Tichauer

     June, 1967                                         “Kinesiological Analysis Of A Simple Assembly Task,” Willie R. Wall.  Advisor:  E.R. Tichauer

     August, 1967                                     “The Effects Of Noise Variables Of Reaction Time And On Sensorimotor Performance,” Walter L. Clark.  Advisor:  M.M. Ayoub

     June, 1968                                         “A Behavioral Analysis Of An Assembly-Line Inspection Task,” Richard V. Badalamente.  Advisor:  M.M. Ayoub

     June, 1968                                         “A Study Of Depth Perception Within The Binocular Peripheral Field Of Vision,” Richard H. Crockett, Jr.  Advisor:  M.M. Ayoub

     June, 1968                                         “A Biomechanical Investigation Of The Possibility Of Relating Static And Dynamic Work By Means Of A Common Parameter,” Tarek M. Khalil.  Advisor:  M.M. Ayoub

     June, 1968                                         “Electromyography And Optimum Handle Size,” Peter Lo Presti.  Advisor:  M.M. Ayoub

     June, 1968                                         “The Effects Of Noise Variables On Reaction Time,” James C. Scott.  Advisor:  Jerry D. Ramsey

     June, 1968                                         “An Elemental Component Decomposition Of A Simple Assembly Task,” John B. Sotman.  Advisor:  M.M. Ayoub

     June, 1968                                         “Numeral Identification In The Peripheral Field Of Vision As An Aid To Work Place Design,” Hirum E. West.  Advisor:  Jerry D. Ramsey

     August, 1968                                     “The Effects Of Colored Lighting, Illumination Intensity Level, And Color Of Workplace On A Fixed Inspection Task,” Robert W. Tedder.  Advisor:  Jerry D. Ramsey

     May, 1969                                          “Human Factors In The Design And Operation Of Handwheel Controls Used In A Dynamic Manual Task,” Larry B. Jordan.  Advisor:  Jerry D. Ramsey

     May, 1969                                          “Quantification Of Human Motion By Stereo-photogrammetric Technique,” Mahmoud A. Ayoub.  Advisor:  Jerry D. Ramsey

     May, 1969                                          “A Study Of The Effectiveness Of A Vibrotactile Warning Signal During Whole Body Vibration,” George A. Guthrie.  Advisor:  Jerry D. Ramsey

     June, 1969                                         “An Electromyographic Study Of A Rotary Task,” Edward Karnasiewicz.  Advisor:  Jerry D. Ramsey

     August, 1969                                     “The Effect Of Audio-Visual Loading On Vibrotactile Signal Detectability,” Gary D. Luker.  Advisor:  Jerry D. Ramsey

     August, 1969                                     “A Correlation Between Angular Impulse And Ventilation Rate During A Simple Movement Of The Upper Limb,” Amr K. Mortagy.  Advisor:  M.M. Ayoub

     December, 1969                             “An Investigation Of The Effect Of Inclination Of The Tilt Seat Stool On The Physiological Cost,” D.J. Vijayadeva Murthy.  Advisor:  M.M. Ayoub

     May, 1970                                          “Strength Of Pronation And Supination At Selected Positions In Space,” Rajinder K. Chhabra.  Advisor:  M.M. Ayoub

     May, 1970                                          “Estimation Of Ventilation Transients Of Respiratory Control System,” Pradeep Sinha.  Advisor:  Jerry D. Ramsey

     May, 1970                                          “Optimal Skeletal Configuration Under Static Pushing And Pulling Tasks,” Grandai S. Srinivasan.  Advisor:  M.M. Ayoub

     August, 1971                                     “The Feasibility Of Utilizing Lateral Photocells In A System For Recording Human Motion,” Eugene N. Davidson.  Advisor:  M.M. Ayoub

     August, 1971                                     “Effects Of Interior Handle Design Parameters Upon Evacuation From Automobiles,” Eugene T. Dorneman.  Advisor:  Jerry D. Ramsey (Missing)

     August, 1971                                     “Development Of A Second-Order Model For Hand Motion,” Sanaa I. Taraman.  Advisor:  M.M. Ayoub

     August, 1972                                     *”A Study Of Man's Strength Relative To The Physical Requirements Of Lifting Tasks,” John W. Storment.  Advisor:  M.M. Ayoub

    March, 1973                                      *”The Problems Of The Man-Microscope Interface In The Industrial Environment,” Harvey C. Foushee.  Advisor:  M.M. Ayoub

     August, 1973                                     *”Lighting In Industry,” Horace Lehneis.  Advisor:  Richard A. Dudek

                                                                 *These are reports, not Theses

    August, 1974                                     “Lifting Capacity As A Function Of Operator And Task Variables,” Fereydoun Aghazadeh.  Advisor:  M.M. Ayoub

     December, 1974                             “An Evaluation Of Existing Occupational Noise Standards,” Kenneth M. Bisbee.  Advisor:  Jerry D. Ramsey

     December, 1974                             “Sedentary Job Performance Within The Thermal Comfort Zone,” Seelam P. Reddy.  Advisor:  Jerry D. Ramsey

     December, 1975                             “Work Place Design Approach With Ergonomic Emphasis,” Robert W. Kutter.  Advisor:  M.M. Ayoub

     May, 1976                                          “Temperature-Time Effects On Female Performance Of Sedentary Tasks,” Sadashiv B. Pai.  Advisor:  Jerry D. Ramsey

     May, 1981                                          “The Assessment Of The Ability Of Various Heat Stress Indices To Predict Safe Work Behavior,” Chi-Ping Chai.  Advisor:  Jerry D. Ramsey

     December, 1981                             “A Manual Materials Handling Study Of Bag Lifting,” Bernard Chen-Chun Jiang.  Advisor:  James L. Smith

     May, 1982                                          “Effect Of Temperature, Age And Experience On Safety-Behavior,” Ekambaresway R. Agastya.  Advisor:  Jerry D. Ramsey


    August, 1982                                     “Effects Of Fatigue On The Kinematics Of Sagittal Lifting,” Ruthan Lewis.  Advisor:  M.M. Ayoub

     August, 1982                                     “Predicting Oxygen Consumption From Pulmonary Ventilation Under Low To Moderate Work Loads,” George W. Calisto.  Advisor:  M.M. Ayoub

     December, 1982                                “A Psychophysical Study Of Bi-Manual Lifting,” Robert R. Fox.  Advisor:  James L. Smith

     December, 1983                             “Alternative Strength Testing Methods For Employee Screening,” Christopher C. Plott.  Advisor:  James L. Smith

     May, 1984                                          “Design And Evaluation Of A Mailbag For Mailcarriers,” Nina A. Ashton.  Advisor:  M.M. Ayoub

     August, 1985                                     “Measurements Of VDT Workload As A Function Of Work/Rest Cycles,” Yung-Hui Terrence Lee.  Advisor:  James L. Smith

     December, 1985                             “A Workplace Design Expert System,” Thomas B. DeGreve.  Advisor:  M.M. Ayoub

    December, 1986                             “Grip Strength Of Telecommunication Workers Thirty To Forty Years Of Age,” Freddy N. McKenzie.  Advisor:  James L. Smith

     May, 1988                                          “Physiological Evaluation Of The NIOSH Work Practices Guide For Lifting,” Michael Reyna.  Advisor:  James L. Smith

     May, 1988                                          “Assembly Line Balancing Utilizing Fatigue Constraints And Task Grouping,” David Rentschler.  Advisor:  James L. Smith

     May, 1988                                          “Determination Of Forces Applied On A Calculator Keypad Through A Computer Interface,” Robert L. Carr.  Advisor:  James L. Smith

     December, 1988                             “Isokinetic Strength Testing Of The Elbow Joint Using The Cybex II Dynamometer,” Marilyn A. Rowell.  Advisor:  James L. Smith

     May, 1993                                          “Human Factors For Expert Systems,” Esin O. Kiris.  Advisor:  Mica R. Endsley

     August, 1993                                     “Assessing Aerobic Capacity:  A Comparison Of Five Step-Test Methods,” Leanne M. Druskins.  Advisor:  James L. Smith

     December, 1993                             “The Influence Of Certain Variables On Pinch Strength,” Patrick G. Dempsey.  Advisor:  M.M. Ayoub

     December, 1993                             “A Neural Network Approach To Model Decision Processes,” Muralidharan Sundararajan.  Advisors:  Mica R. Endsley and Thomas M. English

     May, 1997                                          “A Biomechanical Analysis Of The Revised NIOSH Equation,” Patricia A. Seeley.  Advisor:  James L. Smith

     August, 1997                                     “Biomechanics Of Slips And Falls In The Elderly,” Thurmon E. Lockhart.  Advisor:  Jeffrey C. Woldstad

     August, 1997                                     “The Effect Of Unit Task Granularity On Performance In Teleoperations,” Emrah Onal.  Advisor:  Mica R. Endsley

     December, 1997                             “Toward An Alternate Method to Empirical Usability Testing For Intranet Applications,” Laura E. Blanchard.  Advisor:  James L. Smith


    Dissertations listed are only those related to Human Factors and Ergonomics



    (Revised September, 2000)

      August, 1967                                     “A Comparative Study Of Some Physiological Parameters Of Static And Dynamic Work Performed By The Upper Limb,” Jerry L. Purswell.  Advisor:  E.R. Tichauer

     August, 1967                                     “The Quantification Of Human Effort And Motion For The Upper Limbs By Means Of An Exoskeletal Kinematometer,” Jerry D. Ramsey.  Advisor:  M.M. Ayoub

     May, 1969                                          “An Investigation Of The Effects Of Low-Frequency Vibration On Whole-Body Orientation,” Waymon L. Johnson.  Advisor:  M.M. Ayoub

     August, 1969                                     “Performance And Recovery Under Prolonged Vibration,” Tarek M. Khalil.  Advisor:  M.M. Ayoub

     May, 1971                                          “A Biomechanical Model For The Upper Extremity Using Optimization Techniques,” Mahmoud A. Ayoub.  Advisor:  M.M. Ayoub

     August, 1971                                     “Crew Performance In Extended Operation Under Vibrational Stress,” Mohamed A. El-Nawawi.  Advisor:  Richard A. Dudek

     August, 1971                                     “Effects Of Work/Rest Schedules On Monitoring Performance In The Heat,” Amr K. Mortagy.  Advisor:  Jerry D. Ramsey

     December, 1972                             “A Predictive Model For Motions Of The Arm In Three-Dimensional Space,” Michael J. Petruno.  Advisor:  M.M. Ayoub

     December, 1972                             “Prediction Of Acceptable Lift Capacity,” Joe W. McDaniel.  Advisor:  M.M. Ayoub

     May, 1973                                          “Prediction Of Endurance Time Limit For Muscular Work Under Alternating Work Load Conditions,” Subramaniam Deivanayagam.  Advisor:  M.M. Ayoub


    August, 1973                                     “A Predictive Model For The Maximum Permissible Weight Of Lift From Knuckle To Shoulder Height,” Robert D. Dryden.  Advisor:  M.M. Ayoub

     August, 1973                                     “Measurement Of Muscle Fatigue Using Electromyography,” Ching-Hsaung Wu.  Advisor:  M.M. Ayoub

     August, 1973                                     “Protective Capability Of Contemporary Football Helmets,” Thomas E. Rogers.  Advisor:  M.M. Ayoub

     August, 1973                                     “The Relation Of Personal Characteristics And Whole Body Vibration,” Richard J. Wolf.  Advisor:  Harry F. Martz, Jr.

     December, 1973                             “Systems Approach To The Design Of A Progressive Patient Care System,” Jayanta K. Bandyopadhyay.  Advisor:  Arun G. Walvekar

     May, 1974                                          “An Index For Assessing Heat Stress In Terms Of Physiological Strain,” Deepak Dayal.  Advisor:  Jerry D. Ramsey

    August, 1974                                     “Predictive Models For The Maximum Acceptable Weight Of Lift,” Ronald E. Knipfer.  Advisor:  M.M. Ayoub

     August, 1974                                     “A Biomechanical Dynamic Model For Lifting In The Sagittal Plan,” Moustafa M. El-Bassoussi.  Advisor:  M.M. Ayoub

     August, 1974                                     “An Approach To The Incorporation Of Social Psychological Factors In Work Design,” Richard V. Badalamente.  Advisor:  Jerry D. Ramsey

     December, 1978                             “Determination Of Efficient Methods Of Lift By Comparing Trained And Untrained Male And Female Lifters,” Richard H. Shannon.  Advisor:  M.M. Ayoub

     May, 1980                                          “Effect Of Task Variable Interactions In Lifting And Lowering,” Anil Mital.  Advisor:  M.M. Ayoub

     December 1980                             “Energy Cost Prediction Models For Manual Lifting And Lowering Tasks,” Shihab S. Asfour.  Advisor:  M.M. Ayoub

     December, 1980                             “A Simulation Of Selected Low Coal Mining Tasks,” Stephen J. Morrissey.  Advisor:  Charles L. Burford

     December, 1982                             “A Fuzzy Sets Based Model Of The Interaction Between Stresses Involved In Manual Lifting Tasks,” Waldemar Karwowski.  Advisor:  M.M. Ayoub

     May, 1983                                          “Simulated Dynamic Lifting Strength Models For Manual Lifting,” Fereydoun Aghazadeh.  Advisor:  M.M. Ayoub

     August, 1983                                     “Lifting Capacity Determination As A Function Of Task Variables,” Gary M. Bakken.  Advisor:  M.M. Ayoub

     August, 1983                                     “Design And Evaluation Of A Neutral Posture Chair,” Jerome J. Congleton.  Advisor:  M.M. Ayoub

     December, 1983                             “Evaluation Of Anaerobic Threshold For Lifting Tasks,” Kitti Intaranont.  Advisor:  M.M. Ayoub

     December, 1983                             “Modelling Isokinetic Strength Of The Upper Extremity,” Sheik N. Imrhan.  Advisor:  M.M. Ayoub

     May, 1984                                          “An Investigation Of Biomechanical, Physiological And Environmental Heat Stresses Associated With Manual Lifting In Hot Environments,” Hala A. Hafez.  Advisor:  M.M. Ayoub

     August, 1984                                     “Psychophysical Capacity Modeling Of Individual And Combined Manual Materials Handling Activities,” Bernard Chen-Chun Jiang.  Advisor:  James L. Smith

     August, 1985                                     “Reaction Time And Strength In Pregnant And Nonpregnant Employed Women,” W. Yondell Masten.  Advisor:  James L. Smith

     May, 1986                                          “Design And Evaluation Of A Micro-Climate Cooling System Using A Vest With Ice Bags,” Fariborz Tayyari.  Advisor:  Charles L. Burford

     May, 1986                                          “Effects Of Wick Contamination And Thermal Component Variation On Thermal Indices,” Chin H. Lee.  Advisor:  Jerry D. Ramsey

     December, 1986                             “Psychophysical Lifting Capacity Over Extended Periods,” Jeffrey E. Fernandez.  Advisor:  M.M. Ayoub

     December, 1988                             “An Optimization Approach To Determine Manual Lifting Motion,” Yung-Hui Terrence Lee.  Advisors:  M.M. Ayoub and Eric L. Blair

     December, 1988                             “The Effects Of Rigid Container Height And Shape On Maximum Acceptable Weight Of Lift,” Lee T. Ostrom.  Advisor:  James L. Smith

     December, 1988                             “Biomechanical Stresses During Asymmetric Lifting -- A Dynamic Three-Dimensional Approach,” Hong-Chang Chen.  Advisor:  M.M. Ayoub

     December, 1989                             “A Study Of Spatial Perception Using An Ultrasonic Guidance System,” Young-Kil Kim.  Advisor:  James L. Smith

     May, 1990                                          “The Effect Of Postural Changes On Slip And Fall Accidents,” Dal Ho Son.  Advisor:  Tom B. Leamon

     December, 1990                             “Development Of A Simple Apparent Temperature Model In Hot And Cold Outdoor Work Environments,” Yeong-Guk Kwon.  Advisor:  Jerry D. Ramsey

     December, 1990                             “Development Of A Model For Combined Ergonomic Approaches In Manual Materials Handling Tasks,” Hong-Ki Kim.  Advisor:  M.M. Ayoub

     May, 1991                                          “Measured And Modeled Hand Forces And Resulting Forces At The Low Back During The Pull Phase Of A Lifting Task,” Mary E. Danz.  Advisor:  M.M. Ayoub

     December, 1991                             “A Biomechanical Study Of Slipping Accidents With Load Carriage,” Kai Way Li.  Advisor:  Tom B. Leamon

     December, 1992                             “Simulation Of Manual Materials Handling,” Mong Simon Hsiang.  Advisor:  M.M. Ayoub

     August, 1993                                     “A Psychophysical Study Of High-Frequency Lifting,” Robert R. Fox.  Advisor:  James L. Smith

     August, 1993                                     “An Investigation Of Changes In Biomechanical Strategies Over Extended Lifting Periods,” Maxwell T. Fogleman.  Advisor:  James L. Smith

     August, 1993                                     “Floor Slipperiness And Load Carrying Effects On The Biomechanical Study Of Slips And Falls,” Rohae Myung.  Advisor:  James L. Smith

     August, 1995                                     “A Computerized Dynamic Biomechanical Simulation Model For Sagittal Plane Lifting Activities,” Chiuhsiang Joe Lin.  Advisor:  M.M. Ayoub

     December, 1995                             “An Empirical Study On The Knowledge Acquisition Process For Expert Systems,” Esin O. Kiris.  Advisor:  Mica R. Endsley

     December, 1995                             “Computerized Dynamic Biomechanical Simulation Of Lifting Versus Inverse Dynamics Model:  Effects Of Task Variables,” Tracey M. Bernard.  Advisor:  M.M. Ayoub

     May, 1996                                          “Power As A Predictor Of Lifting Capacity,” Patrick G. Dempsey.  Advisor:  M.M. Ayoub

     May, 1996                                          “Psychophysical And Physiological Study Of One-Handed And Two-Handed Combined Tasks,” Hoonyong Yoon.  Advisor:  James L. Smith

     August, 1996                                     “The Effect Of Level Of Automation And Adaptive Automation On Performance In Dynamic Control Environments,” David B. Kaber.  Advisor:  Mica R. Endsley

     December, 1996                             “Effect Of cue Type On Situation Awareness,” Debra G. Jones.  Advisor:  Mica R. Endsley

     May, 1997                                          “An Analysis Of The Effect Of Confirmation Bias On Industrial Radiography,” Henry A. Romero.  Advisor:  James L. Smith

    May, 1998                                          “The Effects Of Display Format And Visual Enhancement Cues On Performance Of Three-Dimensional Teleoperational Tasks,” Sung Ha Park.  Advisor:  Jeffrey C. Woldstad

     May, 2000                                          “Effects Of Musculoskeletal And Sensory Degradation Due To Aging On The Biomechanics Of Slips And Falls,” Thurmon E. Lockhart.  Advisors:  Jeffrey C. Woldstad and James L. Smith

     August, 2000                                     “Evaluation Of An Automated Three-Dimensional Compensation Algorithm For Visual-Display Misalignment And Effects Of Display Formats In Three-Dimensional Telerobot Manipulation,” Seonwan Myung.  Advisor:  James L. Smith



    This web site was created and is being maintained by Jeff Brewer
    The last update occurred on 04/15/2003 .

    Below is an additional discussion of the 'backpack vs. flexible poles' project results:

    This experiment provided an excellent opportunity for the researchers to gain experience designing and preparing an experiment using complex equipment such as the instrumented treadmill, and metabolic measuring cart along with the force transducer, goniometer, and machine weight equipment to study the biomechanical parameters of human subjects running in both an unloaded an loaded condition. Of special interest has been the difference in load carrying between a rigidly attached backpack and three lengths of compliant poles. Ideally, an experiment using human subjects running on a treadmill should involve a number of familiarization sessions to ensure that each subject has adapted to running while breathing through the oxygen consumption measuring equipment and with the various loads. A familiarization process involving four or five repetitions of each loading condition would ensure a much better assessment of steady state conditions and allow for repeatable performance values. The lengthy familiarization process would have allowed subjects to go through the learning curve and reach a level of performance governed by a normal distribution of metrics. Complete standardization of footwear could also have been an improvement to the methodology.


    Of course, despite the methodological weakness of a short familiarization process and the fact that only ten seconds of force profile data was gathered for each subject during each experimental trial, the researchers feel confident that the results presented provide good insight into the biomechanical differences between backpack vs. pole load carrying techniques. This confidence results from the observation that each subject was in reasonably good physical condition (S5 and S6 were in excellent physical condition) and the fact that all subjects were familiar (to some degree) with treadmill running. Another factor promoting general confidence in the results is that the activity performed (running) involved steady state performance of a repetitious task – video analysis suggests that each subject quickly found, and then maintained, a steady state gait pattern. A couple of slight deviations to the steady state nature of the gait pattern were observed, but these were temporary and typically due to the compliant poles shifting on the shoulders (S5 – harness did not fit tightly enough).


    Therefore, acknowledging the above methodological limitations, here are the important results from this study:

    1. Energy consumption (as implied from oxygen consumption), did increase in a manner that supports the hypothesis that energy expenditure increases in direct proportion to the load carried. In this case, as the load increased by 15% of body mass, the oxygen consumption values increased from 11-20% depending upon the subject. Also, the greater overall VO2 values and VO2 per body mass values for subjects 5 and 6 indicate that they are better able to deliver oxygen to working muscles – they are shown to be in better aerobic shape than subjects 1 and 2.

    2. Peak shoulder forces were not definitively shown to be higher for the backpack load carrying than the compliant pole carrying methods (as implied from maximum vertical force profiles) as was suggested by previous research in which the back pack was assumed to be ‘rigidly attached’ to the subject (Kram 1991) . It is the impression by the subjects that peak shoulder forces were higher when using the backpack method, but it is also noted that the complex movement of the backpack and the way in which the pack was supported by both shoulder straps and a waist belt enabled impact forces to be distributed in non-vertical directions. Of course, improved collection of tension data at the point of contact between the backpack straps and the shoulder (or gathering kinematic data) would have been ideal for resolving the peak force issue.

    3. There were noticeable differences in preference between load carrying methods and these preferences (from subjective data, pg. 42) correspond well to the quantitative measurements made of the average vertical forces applied to the treadmill belt. Subjects 1, 5 and 6 all reflected this relationship well while subject 2 showed the originally expected relationship of nearly constant average vertical forces for all of the loading trials. It may be said that if a much larger data set was gathered (>> than 10 seconds), then all of the averages may have looked very similar, but the rest of the data suggests that these ten second profiles were an accurate reflection of the steady state locomotion dynamics (see figures19 and 21). Subjects 1 and 2 preferred the short poles while subjects 5 and 6 preferred the medium poles. It may be true that the difference in these preferences had to do with differences between the natural frequencies of subjects 1,2 and 5,6. Physical differences in musculature may help explain effects on the person’s natural frequency, but that is highly speculative at this point.

    4. In general, the stride length went down (cadence went up) as subjects moved from the backpack condition to the pole conditions. This was expected due to the even loading (anterior-posterior) and greater stability created by the lagged movement of the suspended weights (providing more constant vertical force to the shoulders). Interestingly, individual differences due not appear to be related to stature height, leg length, or flexibility. It is still very much open to debate whether muscular conditioning or certain strategic parameters played a significant role in the stride length differences. From table one, it may be seen that the comfortable walking speed for subject one is noticeably higher than those for subjects 2,5 and 6. Could this mean that subject one is accustomed to taking larger strides? It is hard to tell, kinematic analysis may have helped with speculation regarding this point. One interesting additional finding regarding stride length is that there might be a connection between body mass and stride length. Looking at page 27 you can see that there is roughly a seven percent difference between stride lengths of S1 and S6. There is also an eight percent difference between S1 and S6 in body mass (note that overall stature and leg length are nearly identical). Subjects 2 and 5 do not show such a clear relationship of course there are more confounding factors (different leg lengths, and possibly different mass composition). Does this imply that stride length corresponds closely with lean body mass? More research is needed to investigate this possibility.

    5. Weight acceptance rates generally increased as the stride length decreased when the subjects moved from backpack load carrying to pole carrying (figure 22). This is an expected result as it takes less time for the body to fully load the supporting leg.

    6. Push-off rates were much higher for subjects 2,5 and 6 than for subject 1. It is suspected that this may be due to greater gastrocnemius and soleus strength in S2, S5, and S6 per body mass, of course calf strength measurements were not taken – further research should investigate this possibility.

    7. Regardless of the noticeable differences in running effort that were reported by subjects between long, medium, and short pole running – all of the subjects preferred the shorter pole lengths in terms of energy expenditure and ability to control movement of the loads. Of course, subjects 1 and 2 apparently did not like the control characteristics of the medium poles so that implies that the short poles would be the ideal compliant pole length for people who decide that carrying loads with flexible poles suits the tasks to be performed. An additional detailed analysis of how to fit the poles to the subject should be conducted by examining the frequency characteristics of the poles, taking a closer look at anthropometric characteristics and continuing to use subjective assessment techniques. VO2 data would not be necessary for this new experiment. At this point, it appears that the timing of the forcing function (vertical movement of the person) and the magnitude of the suspended loads are critical for establishing the proper compliant pole length. The authors suspect that pole characteristics should be individual and task specific.

    8. General subjective comments and observations revealed that even when the long poles were deemed ‘comfortable’ for carrying loads with regard to average force values – they were not deemed ‘easy to control’ with regard to the suspended load. Therefore, when designing/selecting compliant poles for load carrying, it is highly recommended that pole length be in the short to medium ranges shown here. If the pole length becomes to short, there is a risk of impact between the load and the person if horizontal perturbations occur. Also, the pole carrying method is especially recommended in situations where load levels are high, terrain elevation does not change rapidly (suspended loads would hit the ground) and the person will not be traveling down hallways or natural constrictions which prevent turning the person pole system around. Of course, lowering the loads and reversing the direction of the person could partially circumvent the ‘hallway’ problem. Three other important factors to consider regarding the choice between carrying methods include:

      1. Fragility of the load (newborn baby, glass items, etc.) – the backpack method provides less chance of loosing control of load position.

      2. Flexibility required (military soldier on patrol, pedestrian trying to navigate crowded streets, etc.) – the small size and secure connection of the backpack to the body allows for rapid change of direction, orientation, speed and also protection if the person falls to the ground on their back.

      3. Conditioning – subject 5 in this study was very much accustomed to running and cycling with a backpack, therefore she felt much more comfortable and efficient moving with a backpack load. This further emphasizes the task specific nature of load carrying techniques and the need to gradually be introduced or conditioned to use the compliant pole method if the functional aspects of the task encourage it.


     This web site was created and is being maintained by Jeff Brewer
    The last update occurred on 04/15/2003 .