TURNING BIOMECHANICS
Balance and momenta control during turns
Turns are ubiquitous in daily mobility and challenge balance, especially in fall-risk populations. In the first objective of the CAREER project, we are focused on understanding person-specific balance and momenta control strategies used during turns of varied environmental contexts across the lifespan.
Publications:
Tillman, M., Molino, J. & Zaferiou, A.M. Healthy older adults generate transverse-plane momenta required for 90° turns while walking during the same phases of gait as used in straight-line gait. Journal of NeuroEngineering and Rehabilitation (2024) https://doi.org/10.1186/s12984-024-01437-3
Tillman, M., Molino, J. & Zaferiou, A.M. Gait-phase specific transverse-plane momenta generation during pre-planned and late-cued 90 degree turns while walking. Sci Rep 13, 6846 (2023). https://doi.org/10.1038/s41598-023-33667-1
Tillman M, Molino J, Zaferiou AM. Frontal plane balance during pre-planned and late-cued 90 degree turns while walking. J Biomech. 2022 Aug;141:111206. doi: 10.1016/j.jbiomech.2022.111206. Epub 2022 Jun 20. PMID: 35772242.
First-person point of view in the two turn conditions and one “catch trial” where the cue to turn was not present, so the participant continued walking straight.
We are currently studying how balance is regulated during planned and late-cued turns. In the late-cued turns, participants know that there is a 50% chance that the monitor will display the grocery item of interest (green broccoli), as a cue to turn, or a “NO” symbol (red circle with a line through it), as a cue to continuing to walk straight.
The videos below are from the same exemplar participant during pre-planned and late-cued turns. Each participant either started walking with their left or right foot (e.g., “Start Left”) which led to different footfall strategies adopted when they reached the aisle.
Our newest discovery relates to understanding how the body generates the requisite changes in horizontal plane angular and linear momentum. We are finding that regardless of the footfall strategy used, transverse-plane dynamics previously established during straight-line gait are used or leveraged during pre-planned and late-cued turns.
During straight-line gait, the body generates the most leftward angular momentum about a vertical axis immediately following left heel strike, during left double support. Likewise, during straight-line gait, the body generates the most leftward linear momentum during right foot single support. During pre-planned and late-cued leftward turns, we have found the same two strategies.