ABSTRACT
Four-wheeled walkers or rollators are often used to assist older individuals in maintaining an independent life by compensating for muscle weakness and reduced movement stability. However, limited biomechanical studies have been performed to understand how rollator support affects posture and stability, especially when standing up and sitting down. Therefore, this study examined how stability and posture change with varying levels of rollator support and on an unstable floor. The aim was to collect comprehensive baseline data during standing up and sitting down in young participants. In this study, 20 able-bodied, young participants stood up and sat down both 1) unassisted and assisted using a custom-made robot rollator simulator under 2) full support and 3) touch support. Unassisted and assisted performances were analyzed on normal and unstable floors using balance pads with a compliant surface under each foot. Using 3D motion capturing and two ground-embedded force plates, we compared assistive support and floor conditions for movement duration, the relative timing of seat-off, movement stability (center of pressure (COP) path length and sway area), and posture after standing up (lower body sagittal joint angles) using ANOVA analysis. The relative event of seat-off was earliest under full support compared to touch and unassisted conditions under normal but not under unstable floor conditions. The duration of standing up and sitting down did not differ between support conditions on normal or unstable floors. COP path length and sway area during both standing up and sitting down were lowest under full support regardless of both floor conditions. Hip and knee joints were least flexed under full support, with no differences between touch and unassisted in both floor conditions. Hence, full rollator support led to increased movement stability, while not slowing down the movement, during both standing up and sitting down. During standing up, the full support led to an earlier seat-off and a more upright standing posture when reaching a stable stance. These results indicate that rollator support when handles are correctly aligned does not lead to the detrimental movement alterations of increased forward-leaning. Future research aims to verify these findings in older persons with stability and muscle weakness deficiencies.
ABSTRACT
OBJECTIVE: This study aims to assess the test-retest reproducibility of specific spatio-temporal (foot placement, foot contact time) and dynamic (resultant horizontal and vertical ground reaction force) gait parameters of three different, everyday occurring, turning conditions. The subjects were tested at two subsequent days. Out of this setting the purpose of this study is to clarify, if turning locomotion is stable when performed at different test occurrences. METHODS: Eight subjects completed three different daily occurring turning conditions along turns with a given walking velocity of 5 km/h (± 10%). Subjects had to complete the turns three times clockwise and counter clockwise. The measurements were recorded with a 3D motion analysis system (Vicon(®)) and two force sensitive platforms (AMTI(®)), connected to the motion analysis system. RESULTS: The analysis yields for most of the parameters and turning conditions ICCs from good (r = 0.72; p = .06) to high (r = 0.96; p < .01) magnitude for the measured spatio-temporal and dynamic parameters. CONCLUSIONS: Based on our findings it can be assumed that locomotion strategies, related to the measured gait parameters of common daily turning tasks, are stable and reproducible.
