The dancing baby is trapped in a single, spellbinding routine; and Lara, Buzz and the rest of the video gang are forced to recycle a time-worn set of basic maneuvers. Over and over, they repeat the same steps in walking, twist in the same way to turn around, and trace the same circle in each somersault. They are exciting to watch, but far from realistic.

"The gaming industry is only interested in flashy action for entertainment purposes," Chaffin says. "These are bold, repetitive, sports-related actions. It's the antithesis of what we are all about."

In Chaffin's virtual world, hominoids are free to move as if they have a life of their own. The gaming glitz is gone, but hominoid animation is so lifelike that researchers can use it to predict real human movements necessary for daily activities. With this knowledge it is possible to design safer and more effective workstations, automobile interiors, office layouts, and any other environment where people reach, grasp and move things.

"The car interior is a big issue," says Chaffin, Ph.D., professor of biomedical engineering and ergonomics at the University of Michigan. "We are simulating reaching movements to the glove box, or the passenger door, or behind the passenger seat to get the baby bottle that was thrown on the floor.

"Drivers don't just sit there and look straight ahead. Any movements required while driving should be unimpeded to the fullest extent possible. This can be made possible through changes in interior car designs."

To study human motion, Chaffin's group at the University of Michigan has created a company of virtual characters---hominoids, young and old, large and small, short and tall, each endowed with a vast range of realistic motion. A reaching hominoid draws upon a database of 8,000 different reaching movements, and there are similar numbers of corresponding head movements.

Chaffin's animations are realistic because they are based on digital recordings of dozens of male and female volunteers of various ages and sizes at Michigan's Laboratory for Human Motion Simulation. Motion sensors taped to their bodies record the details of their activity. The data are then averaged using mathematical models developed by Chaffin and statistician Julian Faraway, Ph.D.

These data give life to Chaffin's hominoids. And programmed variations on the data extend the hominoids' range of motion beyond the limits of the original recordings. By watching the hominoids in action, researchers can pinpoint and predict stress and strain on joints, such as the spine and shoulder, and zero in on areas of physical discomfort.

A hominoid can sit in a virtual driver's seat, for example, and reach for the glove box in a simulation that can assess whether a change in the dashboard design could make the reach easier for a real driver.

Chaffin's current research is an outgrowth of static, 3-D studies of human motion that he undertook in 1975 for the National Aeronautics and Space Administration. NASA used the research to design Skylab and plan lunar surface activities during the Apollo missions. Ford Motor Co. and General Motors Corp. have used Chaffin's software to refit assembly line workstations. The refitting has fueled a new industry that manufactures hoists and other devices to make reaching and lifting easier on workers. The software is also a teaching aidžits original purposežfor biomechanics students across the country.

In his current work, Chaffin has uncovered some surprises. For example, the movements of an active younger person are statistically different by a few degrees from those of an active older person.

"That may be insignificant for video action figures, but for a worker on the job, it could mean the difference between comfort and the illness of cumulative trauma," Chaffin says.

The researchers have also caught a glimpse of something that could have an impact on psychiatry. The hominoid software may be able to detect and quantify differences between the body movements of depressed patients and those of healthy individuals.

"This is very speculative right now," Chaffin says. "The first studies are just starting. But one thing that depression does is change the way people move when walking or reaching or getting up from a chair. It's quite different from normal movement. They are less energetic and more lethargic."

Michigan psychiatry professor Norman Alessi, M.D., who is working with Chaffin on the study, says the ability to quantify physical differences between depressed patients and healthy individuals could lead to improved treatments, such as the use of drugs that would not impair movement.

The foundation supports Chaffin's work through a Development Award to consolidate biomedical engineering at University of Michigan's engineering college and medical school, and through fellowships to students in his laboratory.