We are thrilled to congratulate Aubrey Gray for successfully defending her PhD dissertation, titled “Mechanical leverage of the foot and ankle: aging, balance, and the future of super shoes”. We also thank the wonderful support of her committee members, Jacque Cole (UNC/NC State), Kate Saul (NC State), Eric Ryan (UNC), and Kota Takahashi (Utah). Fantastic job, Aubrey!
Congratulations to 4th-year PhD candidate Emily Eichenlaub for receiving a 2024/2025 Award for Research Achievement from the Lampe Joint Department of Biomedical Engineering. The awards committee noted Emily’s NIH Fellowship “The Proactive and Reactive Neuromechanics of Instability in Aging and Dementia with Lewy Bodies”, industry internship experience in wearable sensing and movement biomechanics, and impressive scholarship and productivity as reasons for her selection.
An interdisciplinary team spanning Biomedical Engineering, Exercise and Sports Science, Biostatistics and the Thurston Arthritis Research Center has received a new 5-year, $3M R01 Grant from the National Institutes of Health titled “Discovering the Mechanisms Linking Gait to Osteoarthritis Onset and Progression.”
The project will be led by Co-Principal Investigators Dr. Jason Franz (Associate Professor in BME) and Dr. Brian Pietrosimone (Professor in Exercise and Sport Science) and will see pivotal contributions from BME Associate Professors Dr. Brian Diekman and Dr. David Lalush as well as from Dr. Todd Schwartz (Professor of Biostatistics) and Dr. Lara Longobardi (Associate Professor of Medicine).
Together, the research team will investigate the underlying mechanistic pathway to explain how aberrant knee joint loading in walking alters the mechanical, biophysical and biological properties of tibiofemoral articular cartilage in individuals at risk for knee osteoarthritis. The researchers noted “Establishing this mechanistic pathway is the single most important milestone toward advancing precision gait retraining as an effective strategy for preventing knee osteoarthritis.”
From the UNC/NC State Joint BME News announcements: https://bme.unc.edu/2024/01/dr-jason-franz-receives-two-awards-to-accelerate-wearable-sensing-to-optimize-knee-joint-health/
BME Associate Professor Dr. Jason Franz has established a highly productive and collaborative line of research that integrates wearable sensing and machine learning for precision rehabilitation of individuals with knee osteoarthritis. That research, in close partnership with Dr. Brian Pietrosimone from the UNC Department of Exercise and Sports Science, was recently recognized with two awards to accelerate their path from scientific discovery to commercialization and genuine translational impact.
The first, a 2-year $110k translational research grant from the North Carolina Biotechnology Center, will generate patient data to demonstrate proof-of-concept and feasibility of a novel wearable sensing and machine learning prediction technology for detecting, treating and monitoring aberrant forces during walking relevant to the onset and progression of knee osteoarthritis.
The second, a $50k commercialization grant from UNC Kickstart Venture Services, was awarded to VETTA Solutions – the start-up company inspired by these research discoveries and co-founded by Drs. Franz and Pietrosimone.
Commercialization and entrepreneurship are cornerstones of our mission here in BME, and we want to congratulate Dr. Franz and his entire team for their recent success.”
Exploring the Functional Boundaries and Metabolic Consequences of Triceps Surae Force-Length Relations during Walking (2021 Journal of Biomechanics Award Winner, American Society of Biomechanics)
Abstract. The relationship between individual muscle dynamics and whole-body metabolic cost is not well established. Here we use biofeedback to modulate triceps surae (TS) activity during walking. We hypothesized: (1) increased TS activity would increase metabolic cost via shorter muscle fascicle lengths and thus reduced force capacity and (2) decreased TS activity would decrease metabolic cost via longer muscle fascicle lengths and thus increased force capacity. 23 young adults walked on an instrumented treadmill at 1.25 m/s using electromyographic (EMG) biofeedback to match targets corresponding to ±20 and ±40% TS activity during push-off (late stance). B-mode ultrasound imaged the medial gastrocnemius (MG). Participants increased net metabolic power up to 85% and 21% when targeting increased and decreased TS activity, respectively (p < 0.001). At the instant of peak gastrocnemius force, MG fascicle length was 7% shorter (p < 0.001) and gastrocnemius force was 6% larger (p < 0.001) when targeting +40% TS activity. Fascicle length was 3% shorter (p = 0.004) and force was 7% lower (p = 0.004) when targeting -40% TS activity. Participants were unable to achieve decreased activation targets. MG fascicle length and activity mediated 11.7% (p = 0.036) and 57.2% (p = 0.006) of the changes in net metabolic power, respectively. MG force did not mediate changes in net metabolic power (p = 0.948). These findings suggest that changes in the functional operating length of muscle, induced by volitional changes in TS activity, mediate the metabolic cost of walking, relatively independently of force. Thus, shifts to shorter fascicle lengths may mediate activity-induced increases in metabolic cost.
Congratulations to all our lab members that attended and presented at the 2023 Annual Meeting of the American Society of Biomechanics!
Emily Eichenlaub, a third-year BME Ph.D. student, has received a National Research Service Award (NIH F31) from the National Institute of Aging. The award will fund her project titled “The Proactive and Reactive Neuromechanics of Instability in Aging and Dementia with Lewy Bodies.” The research will establish the effects of age and dementia on proactive and reactive neuromechanics underlying vulnerability to balance challenges. Emily will be sponsored by Dr. Jason Franz, Associate Professor in BME, and a mentoring committee that spans Engineering, Physical Therapy, Neurology and Biostatistics. Her research in the BME Applied Biomechanics Lab will pave the way for clinical translation in prescription of personalized interventions, wearable sensor monitoring to mitigate falls, and development of assistive devices with onboard monitoring of muscle neuromechanics to deliver assistance in the face of a balance challenge. Congratulations, Emily!!
The Metabolic Cost of Walking Balance Control and Adaptation in Young Adults.
Shawn Ahuja and Jason R. Franz
Background: Our aim was to quantify the role of metabolic energy cost in governing neuromuscular adaptation to prolonged exposure to optical flow walking balance perturbations in young adults. Research Question: We hypothesized that metabolic cost would increase at the onset of balance perturbations in a manner consistent with wider and shorter steps and increased step-to-step variability. We also hypothesized that metabolic cost would decrease with prolonged exposure in a manner consistent with a return of step width and step length to values seen during normal, unperturbed walking. Methods: Healthy young adults (n=18) walked on a treadmill while viewing a virtual hallway. Optical flow balance perturbations were introduced over a 10-minute interval during a 20-minute walking bout while measuring step kinematics and metabolic energy cost. For all outcome measures, we computed average values during the following four time periods of interest: Pre (minutes 3-5), Early Perturbation (minutes 5-7), Late Perturbation (minutes 13-15), and Post (minutes 18-20). A repeated-measures ANOVA tested for main effects of time, following by post-hoc pairwise comparisons. Results: With the onset of perturbations, participants walked with 3% shorter, 17% wider, and 53-73% more variable steps. These changes were accompanied by a significant 12% increase in net metabolic power compared to walking normally. With prolonged exposure to perturbations, step width and step length tended toward values seen during normal, unperturbed walking – changes accompanied by a 5% reduction in metabolic power (p-values≤0.05). Significance: Our study reveals that the adoption of generalized anticipatory control at the onset of optical flow balance perturbations and the subsequent shift to task-specific reactive control following prolonged exposure have meaningful metabolic consequences. Moreover, our findings suggest that metabolic energy cost may shape the strategies we use to adapt walking balance in response to perturbations.
Our lab had a wonderful time attending our regional ASB meeting here at UNC Chapel Hill. Really inclusive meeting with especially great opportunities for undergraduate biomechanists. Our triangle-area ASB student chapter was well represented as well! Congratulations to Ricky Pimentel, Andy Shelton, Mandy Munsch, Jordan Feldman, and Ellie McTaggart for their terrific presentations.
Our laboratory was recently awarded two pilot grants from the UNC Thurston Arthritis Research Center (TARC). The awards will accelerate new interdisciplinary lines of research into: (i) the association between muscle action, inflammatory biomarkers, and cartilage loading during walking in people with osteoarthritis, and (ii) precision medicine approaches for individualized gait retraining to mitigate osteoarthritis. Our team science approach formally integrates biomedical engineering, exercise and sport science, orthopaedics, and rheumatology, allergy and immunology. Thanks for the support!
