Neuromuscular control and adaptations during perturbed locomotion

Human locomotion faces various perturbations to stability that provoke neuromotor adjustments and adaptations to maintain postural integrity and avoid falls. It has been suggested that the central nervous system monitors and corrects motor responses based on predicting sensory consequences of perturbations. However, this must accurately reflect the nature of the perturbation, and hence, motor control is constantly refined based on error-feedback information. Task-specific assessment of gait stability, adaptability, and fall risk during irregular and perturbed locomotion, in addition to potential training-induced improvements in the reactive stepping behavior, constitutes an interesting experimental approach to assess and influence mechanisms that may affect the safety of human gait. By implementing unpredictable trip-based perturbations during walking, our recent findings support the hypothesis that the neuro-motor system can facilitate reactive balance responses by enhancing its neuromuscular coordination and retaining those balance improvements over several years, which may reduce the risk of falling. In this research theme, we primarily investigate how gait stability and adaptability during walking with horizontal perturbations (e.g., following trip- or slip-based perturbations) are affected by ageing, neuromuscular properties, and pathology to understand better the underlying mechanisms of the decline in locomotor function in aging and due to neuromuscular dysfunction.
In collaboration with the University of Applied Sciences Koblenz, Campus Remagen, and the biomechanics research team at London South Bank University (United Kingdom), we employ advanced techniques to study and perturb human gait. One key tool is a custom-built, pneumatically driven mechanical perturbation device, which uses a break-and-release mechanism to apply controlled perturbations to the ankle, simulating trip-like events for participants walking on a treadmill. The device is also capable of applying pulling forces to the hip, inducing perturbations in both anterior and medio-lateral directions. In addition to mechanical-based perturbations to gait, we explore virtual and augmented reality environments to create visual perturbations and provide erroneous visual feedback information to affect body dynamics during walking and standing.
To assess locomotion mechanics, neuromuscular control and adaptation to mechanical and virtual-based perturbations, we analyze joint kinetics via inverse dynamics using an instrumented treadmill or force plates during overground walking in combination with optical motion capture systems and by considering electromyographic and ultrasonographic recordings of the muscles at the lower extremity. The state-of-the-art laboratory furthermore features a 15-meter mechatronic walkway system equipped with hidden mechanisms that can induce unpredictable slips, trips, and missteps, providing standardized environment conditions for studying neuromuscular control and adaptations during perturbed locomotion across the adult lifespan.

Mechanical-based perturbations

Virtual-based perturbations

Publications (selected)

Gießler, M., Werth, J., Waltersberger, B., & Karamanidis, K. (2024). A wearable sensor and framework for accurate remote monitoring of human motion. Communications Engineering, 3(1), 20.

Weber, A., Hartmann, U., Werth, J., Epro, G., Seeley, J., Nickel, P., & Karamanidis, K. (2022). Limited transfer and retention of locomotor adaptations from virtual reality obstacle avoidance to the physical world. Scientific Reports, 12(1), 19655.

Werth, J., Epro, G., König, M., Santuz, A., Seeley, J., Arampatzis, A., & Karamanidis, K. (2022). Differences in motor response to stability perturbations limit fall-resisting skill transfer. Scientific Reports, 12(1), 21901.

McCrum, C., Bhatt, T. S., Gerards, M. H., Karamanidis, K., Rogers, M. W., Lord, S. R., & Okubo, Y. (2022). Perturbation-based balance training: principles, mechanisms and implementation in clinical practice. Frontiers in Sports and Active Living, 4, 1015394.

König, M., Santuz, A., Epro, G., Werth, J., Arampatzis, A., & Karamanidis, K. (2022). Differences in muscle synergies among recovery responses limit inter-task generalisation of stability performance. Human Movement Science, 82, 102937.

Weber, A., Friemert, D., Hartmann, U., Epro, G., Seeley, J., Werth, J., ... & Karamanidis, K. (2021). Obstacle avoidance training in virtual environments leads to limb-specific locomotor adaptations but not to interlimb transfer in healthy young adults. Journal of Biomechanics, 120:110357

Karamanidis K., Epro G., McCrum C. & König M. (2020). Improving Trip-and Slip-Resisting Skills in Older People: Perturbation Dose Matters. Exercise and Sport Sciences Reviews, 48;1:40-47

McCrum C., Lucieer F., van de Berg R., Willems P., Fornos A.P., Guinand N., Karamanidis K., Kingma H. & Meijer K. (2019). The walking speed-dependency of gait variability in bilateral vestibulopathy and its association with clinical tests of vestibular function. Scientific Reports, 9;1:1-12

König M., Epro G., Seeley J., Potthast W. & Karamanidis K. (2019). Retention and generalizability of balance recovery response adaptations from trip perturbations across the adult life span. Journal of Neurophysiology, 122;5:1884-1893

Epro G., Mierau A., McCrum C., Leyendecker M., Brüggemann G.-P. & Karamanidis K. (2018). Retention of gait stability improvements over 1.5 years in older adults: effects of perturbation exposure and triceps surae neuromuscular exercise. Journal of Neurophysiology, 119;6:2229-2240

McCrum C., Karamanidis K., Willems P., Zijlstra W. & Meijer K. (2018). Retention, savings and interlimb transfer of reactive gait adaptations in humans following unexpected perturbations. Communications Biology, 1:230

Epro G., McCrum C., Mierau A., Leyendecker M., Brüggemann G.-P. & Karamanidis K. (2018). Effects of triceps surae muscle strength and tendon stiffness on the reactive dynamic stability and adaptability of older female adults during perturbed walking. Journal of Applied Physiology, 124;6:1541-1549

McCrum C., Epro G., Meijer K., Zijlstra W., Brüggemann G.-P. & Karamanidis K. (2016). Locomotor stability and adaptation during perturbed walking across the adult female lifespan. Journal of Biomechanics, 49;7:1244-1247

McCrum C., Eysel-Gosepath K., Epro G., Meijer K., Savelberg H.H.C.M., Brüggemann G.-P- & Karamanidis K. (2014). Deficient recovery response and adaptive feedback potential in dynamic gait stability in unilateral peripheral vestibular disorder patients. Physiological Reports, 2;12:e12222

Arampatzis A., Karamanidis K. & Mademli L. (2008). Deficits in the way to achieve balance related to mechanisms of dynamic stability control in the elderly. Journal of Biomechanics, 41;8:1754-1761

Karamanidis K., Arampatzis A. & Mademli L. (2008). Age-related deficit in dynamic stability control after forward falls is affected by muscle strength and tendon stiffness. Journal of Electromyography and Kinesiology, 18;6:980-989