Ahead of the Curve

September 30, 2005

Innovation has always been the watchword for Curves Inc., so it's no surprise that founder Gary Heavin has partnered with Baylor researchers to take the women's fitness giant to the next level of technology and design.

Ahead of the Curve

Heavin, who located Curves headquarters in Waco, opened the first Curves for Women in 1992. The concept is to provide 30-minute fitness, strength training and weight-loss guidance in a woman-friendly environment. The first franchise opened in 1995, and within three years, there were 1,000 locations. This year, more than 9,000 Curves fitness centers operate around the world, and the company has been ranked as the world's fastest-growing franchise by Entrepreneur magazine two years in a row.

While meeting about a different project in 2003, Heavin asked Walter Bradley, Distinguished Professor of Engineering and associate dean for research at Baylor, if he would consider designing upgrades to the Curves resistance machines. The multidisciplinary undertaking encompasses mechanical and electrical engineering, materials, science, computer science and art, as well as emerging hybrid fields like mechatronics and biomechanics. "Since we were already acquainted, and he knew I was interested in exploring the possibility of an engineering research project, he contacted me about his vision for Curves," Bradley says.

"The project was interesting in its own right. But Gary piqued my interest by his passionate vision for serving our mothers, grandmothers, sisters and daughters to achieve the best possible health," he says. "I brainstormed with my principal co-investigators, Ian Gravagne and Brian Garner, and we came up with some exciting possibilities, which, if successfully developed, could significantly enhance the exercise experience of women who are served by Curves." The project is being conducted in three phases. Phase one consisted of plans Bradley drew up for the project and presented to Heavin, who liked what he saw. Bradley assembled his team and began phase two -- the development process of designing and building prototypes for the new machines. Phase three will be the manufacturing stage. After producing the first few machines, the team will test for reliability and customer satisfaction. Gravagne, assistant professor of electrical engineering, has worked on the project since it began and oversees a busy lab developing and building prototypes of the enhanced equipment. His team includes faculty, graduate students and undergraduates.

"We have an egalitarian system of contribution," he says. "I value the students' input -- they have come up with excellent design ideas I hadn't thought of. They don't necessarily have the expertise to make it happen, but the professors have that knowledge, so we use everyone in the same capacity. We just go into the shop and talk. We can't point to a single person responsible for the design -- the project is truly collaborative," he says. One of Gravagne's roles in the project is mechatronics -- the interface between mechanical and electrical engineering. Unlike many engineers, especially electrical engineers, Gravagne is hands-on in the machine shop, personally constructing and overseeing fabrication. It's an interest he developed as a child at his father's knee. "My father was a master piano technician, and I used to go into his workshop and putter around. That's how I learned to use these machines," he says.

Another robotics expert on the team is biomechanics researcher Brian Garner. The assistant professor of mechanical engineering says the key is to design for a proper resistance response at different points through the range of the user's muscle extension. "For example, when you flex your elbow, it's strongest about halfway and weakest at its full extension," he says.

Garner began his process by measuring women's performance on the existing machines. "We measured the force they applied to the machine and the speed they used. We then developed mathematic models and reproduced those results in our computer model. Now that we have the computer model, we can make changes on the computer and design the machine to give the performance we want." Gravagne uses Garner's modified design to build a prototype for human testers to practice on while the team observes to see if the machines are giving the desired performance. Garner and his students also match the resistance of body movement to the machines and the time scale to make sure the user is exercising at the right speed for maximum benefit.

They also must design machines that can be adapted easily for use by women of all body types and weights. "Another consideration is ergonomics -- designing so the machines will fit people of different sizes," Garner says. The first prototypes were tested this summer with "load cells" and a four-camera video motion-capture system. The load cells measure force, and the motion system allowed them to track movement by applying reflective markers to, say, a shoulder, elbow and wrist.

"If at least two markers are scanned, we can triangulate to get a position; it allows us to study and quantify the motion," Garner says. "We want the equipment to be effective for the largest range of sizes and shapes of people."

Merging Two worlds

Like truth and beauty, engineering and art can enhance one another. As the designs progressed, it became obvious that this interface needed to happen. Robbie Barber, assistant art professor at Baylor and sculptor, was brought onto the team to provide artistic design for the new machines. "Ian sought me out," says Barber, who teaches sculpture and three-dimensional (3-D) design classes. "They had taken the design so far, and he saw that they needed

an artist's perspective. I had never worked on an industrial project, so I've enjoyed it."

Collaborating across the two disciplines was a first for both Gravagne and Barber, and it took a short period of adjustment. "Last year when I first sat down with the team, it was a little awkward, but not in a bad way," Barber says. "I felt a little like I was out of my element. It was like dancing; we had to get synchronized. At first, I wondered what they thought of what I was saying, like two people who don't speak the same language."

Before long, though, they were enjoying a free-ranging exchange of ideas. Barber says Gravagne "has a strong appreciation for the arts," and Gravagne adds that "the marriage of these two efforts has been exciting. I've never worked with an artist, and he's never worked with engineers before."

Barber, who describes himself as a research-oriented artist, uses the principles he teaches in his 3-D design class, starting with the fundamentals of how to work out an idea, experimenting with elements and principles of design, plane, texture and how to organize, using repetition and variety. "For the Curves project, I started looking at bones -- they are the structure of things. The machines reminded me of a skeleton, like the way a rib is shaped. A wishbone was my inspiration for one of the first machines we did. The cool thing about bones is how they go from thick to thin, round to flat."

The name Curves itself inspired Barber, and he used it as his launching point. "The word 'curves' fits my idea because bones do have curves. I wanted every aspect of the design to have a curve to it," he says. "When I was forming the idea, I sat there with a compass and drew a big arc. I've tried to avoid any flat or straight element, so every surface would have a flow to it, so curves would dominate the forms. The funny thing about it is, once you figure out that sort of thing, the guidelines are set and you are just along for the ride."

The models are made out of wood and clay. Barber says he begins by taking images of existing Curves machines, doing rough sketches on top of them, transferring those to a piece of wood and then adding clay. "It's an intuitive thing, and the shape emerges as you play with the clay," he says. "It's all about hands-on experience."

Barber doesn't use computers as a designer, so he has enjoyed watching the engineers do the computer modeling of his designs. "There is a tendency to think computer modeling is all we need, but there is a lot of information you can't get unless you build a 3-D model," he says.

Student enthusiasm

Even though they don't have an abundance of experience, the students' problem-solving ideas are valued. "Working your way through a problem is a team effort with everybody contributing and discussing," says biomechanics engineer Garner. "It's helpful to have fresh eyes on things. If you don't look at their ideas, you may miss a great solution. Sometimes an idea can't be used, but it spawns another idea. We try to encourage thinking outside the box, and it's helpful to have ideas coming from people who haven't gotten into the box yet," he says. "A Curves employee attending a meeting of [our Baylor] group told me he'd never seen the most junior and the most senior collaborating freely like we do," Gravagne says.

The input of students on such a project is unusual, but they are enthusiastic about the opportunity. Yasaman Shirazi-Fard, a sophomore who worked on the team in the spring, says she enjoyed using her creativity on the project, rising to the challenge to come up with a simple, fast and adjustable design and build it with the existing material.

"My main task was building prototypes with a few other people in the robotics lab in the engineering building. I also worked closely with Dr. Garner on the ergonomic aspects to make recommendations on the various dimensions of the machines," she says. Garner called her "the resident go-to person for making decisions about dimensions."

She especially enjoyed the collaboration. "Working next to skilled instructors and brilliant upper classmates and graduate students made me more enthusiastic to learn and work on the project."

David Webster, BS '05, a first-year master's student in mechanical engineering, says the broad scope of the project is gratifying, describing it as "the progression from initial research phases to machining and testing, and then to assembly. Every person involved has their own 'specialty,' or area of focus, so it's exciting to see everyone's contributions come together for the overall design."

Webster is looking at the fatigue properties of different aluminum castings, providing accurate material properties for the machines. "For my daily work, I'm performing computer-based analyses of the various machine parts using SolidWorks [a computer-assisted design program] to determine if the parts can withstand the expected loads."

Scott Wilson, a senior in mechanical engineering, says working on the Curves project has enhanced his education, much like an internship. He has worked on design and construction of the new prototypes, with some data analysis of motion-capture data. "This is my first real job using my education and engineering background," he says. "It put me in a real business environment in which I have a certain amount of time to finish a project and have my boss test it out." Before the Curves project began, Wilson says he hadn't considered going to graduate school, but now may change his mind. He's delighted at the experience he's gaining as part of the research team, including learning the technical aspects and language used in the machine shop. "I consider it invaluable information for a mechanical engineer, because now I know how a machinist constructs a piece. This knowledge may change how I design a certain piece, because I know what can and cannot be machined easily," he says.

By the end of summer, the project was about halfway through phase two of the development process with seven of the 13 machines researched, redesigned and prototypes built and tested. Phase three, the manufacturing stage, is about to begin. If progress continues at the current pace, women around the world will enjoy the inspired beauty of this enhanced equipment in less than two years.

And that's the other benefit one of the students is excited about. "My mother goes to Curves back in my hometown of Houston," Wilson says, "and I like knowing that one day she may be using a machine I helped design."