Stepping toward understanding: Gait analysis to advance neuroscience and cancer survivorship

In the Human Performance Lab (HPL) at St. Jude, Joshua Burns, PhD, Department of Epidemiology & Cancer Control — a self-described “six-foot guy from Australia” — is on the floor, immersed in play with a young patient. For 17 years, the HPL has studied physical function in cancer survivors and patients currently receiving treatment for cancer and other diseases. While these treatments save lives, their toxicities often lead to short- and long-term side effects. By understanding how treatments impact physical performance, the HPL aims to improve the quality of life for patients under active treatment for cancer and survivors alike.

With the addition of Burns as Director of the HPL in 2024, the ongoing work to prevent disability in cancer survivors is now expanding to include studying mobility issues in children with rare neurological disorders. Burns is a global expert in gait analysis and the rare neurological disorder Charcot-Marie-Tooth disease. By spearheading a new 3D Gait & Mobility Lab (GML) alongside the HPL, Burns and his colleagues aim to develop targeted interventions to improve mobility and quality of life by capturing precision measurements via cutting-edge technology. For Burns, “rolling around on the floor,” as he puts it, is key to these efforts. 

“Children are special people that don’t necessarily like being poked and prodded and walking in the gait lab for three hours,” said Burns. “Sometimes, to truly connect, you have to get down on their level.”

Giving back quality of life

Founded by Kirsten Ness, PT, PhD, FAPTA, Principal Investigator of the HPL and co-leader of the Cancer Control and Survivorship Program, the HPL initially focused on the late effects of cancer treatment, such as chemotherapy-induced peripheral neuropathy. It now supports a broader range of pediatric diseases, including sickle cell anemia and neurological conditions. 

Under Burns’ leadership, the GML assesses gait (the manner with which someone walks), balance, muscle function, coordination and endurance — key measures for evaluating both disease severity and treatment effects. To accurately and reliably understand disability among children with cancer, and survivors of childhood cancer and genetic neurologic disorders, the GML uses the most advanced biomechanical instrumentation and wearable inertial sensors. This effort is anticipated to be at the leading edge of digital health technology globally. 

The HPL currently serves 50 participants weekly, from infancy to late adulthood, across diagnoses ranging from leukemia to hereditary neuropathies. Assessments take place at various stages of care, generating longitudinal data used in both clinical practice and trials. In addition to assessment, the HPL offers interventions such as exercise programs and neuromuscular re-education to help prevent functional decline. Burns aims to shift these efforts earlier in the care continuum. 

“Dr. Burns will be overseeing the most advanced gait lab in the world to extend the lifespan and health span of children with cancer and catastrophic neurological disease,” said Gregory Armstrong, MD, MSCE, Department of Epidemiology and Cancer Control chair. “This important work will expand our understanding of these patients and how St. Jude can best support them.” 

Reflecting on the role of the HPL and GML within St. Jude overall, Burns says the incredible work of St. Jude doctors gives back decades of life to children with catastrophic illnesses, and the HPL and GML give back quality of life. “Not only do we measure the outcomes, but we also intervene along the way,” explained Burns. “And in the perfect world, we bring that measurement and those interventions much, much earlier. That’s the next frontier.”

“There’s kind of a juggernaut happening”

Burns’ path to St. Jude began through a long-standing collaboration with Richard Finkel, MD, Center for Experimental Neurotherapeutics (CENT) director within the St. Jude Pediatric Translational Neuroscience Initiative (PTNI). Finkel is a world leader in pediatric neuromuscular disorders, and the two worked together for more than 15 years developing outcome measures to track disease progression and treatment response in catastrophic neurological conditions such as Charcot-Marie-Tooth disease, Duchenne muscular dystrophy, spinal muscular atrophy and Friedreich’s ataxia. Finkel, who joined St. Jude in 2020, invited Burns to visit campus, a trip that sparked his eventual move to St. Jude.

“I was blown away with the level of focus,” Burns said. “There are very few institutions in the world that are so effectively focused and using their resources at St. Jude. That’s why the impact potential here is enormous.”

As a PTNI collaborator, Burns is already working with CENT, using the HPL and GML’s growing precision measurement capabilities to help establish biomarkers for precision treatment. “There’s kind of a juggernaut happening that’s so important and will continue,” he said. “The potential for miraculous outcomes, such as what Dr. Finkel is showing with spinal muscular atrophy, is a serious endeavor that we think is translatable to other diseases. So many people who work at St. Jude are really in the business of hope. And hope, in this field, is a strategy.”

Turning movement into meaningful data

In the GML, technology originally developed for Hollywood animation studios now helps researchers map the mechanics of pediatric movement disorders. The process starts with placing reflective markers on key joints of a child’s body. As the patient walks down a special walkway, 18 infrared cameras track each marker’s position from multiple angles, capturing motion in all three anatomical planes. The data are then compared to normative reference ranges to detect abnormalities and guide interventions.

For more detailed insight, researchers can overlay wireless electromyography (EMG) sensors to capture real-time muscle activity — critical for diagnosing and managing spasticity and similar conditions. For children too young or medically fragile for full gait analysis, the “magic carpet” — a mat embedded with over 16,000 sensors — offers another option. It records movement patterns even when children stumble or play. Together, these tools help determine whether treatments are working and how to personalize care.

Another technological leap for the HPL and GML, for both cancer survivors and patients with neuromuscular disorders, is the use of wearable technology. Wearable inertial sensors offer advantages beyond convenience. They allow researchers to capture how children function in their natural environments and reduce the need for long journeys or repeated hospital visits.

“If researchers and clinicians are looking to improve the real lives of children, we need to measure them in real life,” said Burns. “But wearable technology also has the huge benefit of reducing the burden on families.”

Over time, this real-world data could act as an early warning system, prompting action when function declines or offering reassurance when progress holds steady. With this vision, the HPL and GML aim to remain a global leader — not just in understanding how children move — but in transforming how that movement data is used to guide care and recovery.

The HPL and GML stride into a bold future

Burns is excited about the future of this work at St. Jude, bringing in new technologies and advanced deep phenotyping tools while continuing to expand the program. He’s particularly excited to harness the full power of St. Jude to do for neurological conditions what the research, clinical care and support of the HPL has done for so many years for children with cancer and for cancer survivors. 

“The potential for life-changing breakthroughs is very real,” said Burns. “So, I’m here. I’ve got 20 years at least or more of rolling around on the floor with the kids and will be really excited to see what we can achieve.”