Fall 2010
The Next Big Step

The moment Betty came in to the Biomechanics Lab, I knew she was an athlete. She moved with confidence and speed, reaching easily across the steel platforms in the floor that measure a body’s force. She grasped my hand, shook it firmly and said, “I’m ready to walk when you are.” I was struck by the way she moved, how strong her voice was. Even though I planned to formally interview her later for my walking study, I was too curious to wait, so I jumped in and started asking questions. It turns out that between her senior group, walking the dog and hiking on weekends, she walked almost 24 miles a week. Betty was an elite athlete by any standard. And to top it all off, she was 90 years of age.

Betty came to my lab that day to help me understand the effects of aging on the energy cost of walking, a primary focus of my research. It has long been known that older adults over the age of 70 use about 30 percent more energy to walk the same distance as a young adult. But the reasons are not well understood. Possibly as a result, most older adults walk less and more slowly as they age, often leading to a complete loss of mobility. My goal is to understand if there is a link between the loss of mobility and the higher cost of walking in older adults, determine the causes, and ultimately learn whether exercises such as walking, strength training and even Tai Chi can improve mobility among the most senior members of our society.

My work in biomechanics all started here at HSU. I was a pre-med student wandering the halls of the Science B building, unsure if I should be a biology or physics major. I loved the math in physics but was fascinated by the most incredible machine I had ever seen: the human body. Based on a suggestion from a physics instructor, I took a course in kinesiology called Biomechanics, which is essentially the physics of human movement. The professor of the course, Richard Stull, fascinated me with colorful descriptions of how the body works. I was hooked. After that class, I switched majors to Kinesiology and never looked back. Professor Stull continued to nurture my passion for biomechanics, letting me help him with projects and lab experiments. Working with Professor Stull at Humboldt State gave me the skills I needed to get into graduate school at the University of Colorado, earn my Ph.D., and ultimately return to HSU to continue the cycle of turning students on to the field of Biomechanics.

So what’s the next step (pun intended)? In the Biomechanics Lab, located in the new Kinesiology & Athletics building (please come and visit), I have two teams of graduate and undergraduate students working to answer the question “Why do older adults have a greater cost of walking?” One team is looking at how muscles are activated when elderly adults walk and whether they use more muscle than is actually needed. For example, older adults might contract their hamstring when only the quadriceps is needed. This “co-contraction” of antagonist muscles has been shown to increase the cost of walking in other populations such as cerebral palsy or post-stroke patients.

The second team of students is quantifying the energy cost of generating force to support body weight. Over the last year and a half the team built a weight-support device that allows us to measure changes in energy consumption at different levels of weight support. How does it work? As weight support increases, the energy cost of walking decreases. If older adults have a greater cost of supporting body weight we should see a greater drop in energy consumption as a result of weight support.

The results of these studies should help us to develop exercise programs for improving walking efficiency and keeping older adults mobile longer in life. We know it is possible. After all, Betty who is now 93, is still walking more than 20 miles a week.

SEE JUSTUS ORTEGA at “Classes without Quizzes”
during Homecoming & Family Weekend.