September 16, 2025
By Mikey Fuller

As people age, walking often becomes slower and less efficient, limiting mobility and independence. 

To address these challenges, three Georgia Tech researchers have received a $3.2 million Research Project Grant (R01) from the National Institutes of Health's (NIH) National Institute on Aging (NIA).

Leading the study is Gregory Sawicki, Joseph Anderer Faculty Fellow and professor in the George W. Woodruff School of Mechanical Engineering and School of Biological Sciences. He is joined by Woodruff School colleagues Aaron Young, associate professor, and Kinsey Herrin, principal research scientist, along with partners at the Institute for Human & Machine Cognition (IHMC) and Northeastern University. Together, they will study how aging impacts lower-limb joint mechanics, muscle function, and the energy cost of walking.

“Aging touches every one of us—our families, our communities, and ourselves,” Herrin said. “This work represents both an important opportunity and a responsibility to try to improve mobility, dignity, and independence over the lifespan.”

Sawicki and his colleagues ultimately hope their findings will help guide the development of improved exercise therapy programs and wearable technology that can expand health over one’s lifespan.

The researchers hypothesize that most older adults walk at a slower pace than younger adults to prioritize stability and avoid falls. However, slower walking speeds combined with declining neuromuscular efficiency can result in a “lose-lose” effect that can elevate the metabolic cost of walking, or overall energy consumption.

After a 2021 study by the NIH on mobility impairments, it was discovered that there was a foundational age-related difference in walking functionality. Older walkers relied more on hip movement rather than ankle muscle-tendons, which results in a slower, safer method for getting around. With this grant, Sawicki and his team aim to improve mobility and safety for older adults, promoting independence in daily life.

To do this, they will use a sensor suit that uses custom-trained, machine-learning algorithms to track how younger adults move compared to older, less active adults when walking. The suit will analyze mechanical efficiency in the ankles and hips. Hip and ankle exoskeletons will also be used as tools to estimate the efficiency of muscle-tendon mechanical work at each joint.

Young said that understanding the mechanisms behind the lowered efficiency in aging mobility is key to unlocking new therapeutic approaches that can target improved mobility.

“By understanding how older adults’ musculoskeletal systems are changing, we can provide targeted interventions at the joint level with specialized control to support independence and mobility late into life,” Young said.

A collaborative team of muscle biologists at IHMC, led by research scientist Zachary Graham, will recruit a cohort matched to Georgia Tech’s study participants. The team will collect muscle biopsies to study mitochondrial function, myofiber, and mitochondrial/metabolic molecular analyses. They will also use task-based assignments to see how these muscle-level changes influence the metabolic cost of walking.

Finally, a team of computational neuromechanics researchers at Northeastern University, led by Assistant Professor Seungmoon Song, will pool the data collected at Georgia Tech and IHMC to drive "digital human" models of young and older adults to understand how priorities for balance versus efficiency might change with age.