Effect Of External Lateral Stabilization Research Articles

The effect of external lateral stabilization on ankle moment control during steady-state walking

External lateral stabilization can help identify stability control mechanisms during steady-state walking. The degree of step-by-step foot placement control and step width are known to decrease when walking with external lateral stabilization. Here, we investigated the effect of external lateral stabilization on ankle moment control in healthy participants. Ankle moment control complements foot placement, by allowing a corrective center-of-pressure shift once the foot has been placed. This is reflected by a model predicting this center-of-pressure shift based on the preceding foot placement error. Here, the absolute explained variance accounted for by this model decreased when walking with external lateral stabilization. In other words, we found a reduction in the contribution of step-by-step ankle moment control to mediolateral gait stability when externally stabilized. Concurrently, foot placement error and the average center-of-pressure shift remained unchanged.

How does external lateral stabilization constrain normal gait, apart from improving medio-lateral gait stability?

Background: The effect of external lateral stabilization on medio-lateral gait stability has been investigated previously. However, existing lateral stabilization devices not only constrain lateral motions but also transverse and frontal pelvis rotations. This study aimed to investigate the effect of external lateral stabilization with and without constrained transverse pelvis rotation on mechanical and metabolic gait features. Methods: We undertook two experiments with 11 and 10 young adult subjects, respectively. Kinematic, kinetic and breath-by-breath oxygen consumption data were recorded during three walking conditions (normal walking (Normal), lateral stabilization with (Free) and without transverse pelvis rotation (Restricted)) and at three speeds (0.83, 1.25 and 1.66 m s−1) for each condition. In the second experiment, we reduced the weight of the frame, and allowed for longer habituation time to the stabilized conditions. Results: External lateral stabilization significantly reduced the amplitudes of the transverse and frontal pelvis rotations, in addition to medio-lateral, anterior–posterior, and vertical pelvis displacements, transverse thorax rotation, arm swing, step length and step width. The amplitudes of free vertical moment, anterior–posterior drift over a trial, and energy cost were not significantly influenced by external lateral stabilization. The removal of pelvic rotation restrictions by our experimental set-ups resulted in normal frontal pelvis rotation in Experiment 1 and significantly higher transverse pelvis rotation in Experiment 2, although transverse pelvis rotation still remained significantly less than in the Normal condition. Step length increased with the increased transverse pelvis rotation. Conclusion: Existing lateral stabilization set-ups not only constrain medio-lateral motions (i.e. medio-lateral pelvis displacement) but also constrain other movements such as transverse and frontal pelvis rotations, which leads to several other gait changes such as reduced transverse thorax rotation, and arm swing. Our new set-ups allowed for normal frontal pelvis rotation and more transverse pelvis rotation (yet less than normal). However, this did not result in more normal thorax rotation and arm swing. Hence, to provide medio-lateral support without constraining other gait variables, more elaborate set-ups are needed.

The effect of external lateral stabilization on the use of foot placement to control mediolateral stability in walking and running.

It is still unclear how humans control mediolateral (ML) stability in walking and even more so for running. Here, foot placement strategy as a main mechanism to control ML stability was compared between walking and running. Moreover, to verify the role of foot placement as a means to control ML stability in both modes of locomotion, this study investigated the effect of external lateral stabilization on foot placement control. Ten young adults participated in this study. Kinematic data of the trunk (T6) and feet were recorded during walking and running on a treadmill in normal and stabilized conditions. Correlation between ML trunk CoM state and subsequent ML foot placement, step width, and step width variability were assessed. Paired t-tests (either SPM1d or normal) were used to compare aforementioned parameters between normal walking and running. Two-way repeated measures ANOVAs (either SPM1d or normal) were used to test for effects of walking vs. running and of normal vs. stabilized condition. We found a stronger correlation between ML trunk CoM state and ML foot placement and significantly higher step width variability in walking than in running. The correlation between ML trunk CoM state and ML foot placement, step width, and step width variability were significantly decreased by external lateral stabilization in walking and running, and this reduction was stronger in walking than in running. We conclude that ML foot placement is coordinated to ML trunk CoM state to stabilize both walking and running and this coordination is stronger in walking than in running.

The effect of external lateral stabilization on the control of mediolateral stability in walking and running.

Development of scaffolds from naturally available biomaterials for bone tissue engineering is an interesting research area. Among the different scaffolds established for this purpose, biogenic silica nanostructure (BSN) serves as a promising naturally available inorganic and biocompatible material. A few studies have demonstrated the intrinsic biological activity of synthetic silica nanoparticles. The virtually infinite promising applications of these structures rely on their erratic physicochemical properties. We have derived BSNs from Sorghum bicolor seed head using a progressive approach. The intrinsic biological activities were analyzed using human mesenchymal stem cells (hMSCs) as an in vitro model with MTT assay and acridine orange/ethidium bromide staining. We also studied the role of BSNs in the osteogenic differentiation of hMSCs using alkaline phosphatase staining, alizarin red staining, and gene expression analysis. BSNs increased the formation of calcium nodules and stimulated alkaline phosphatase (ALP) activity. Significant changes and/or upregulation in the expression of osteogenic prominent markers such as ALP, bone morphogenetic protein-2 (BMP-2), BMP-4, bone sialoprotein (BSP), collagen-1 (Col-1), and Runt-related transcription factor 2 (RUNX2) genes were observed. Taken together, these results suggest that BSNs exhibited biocompatibility and induced osteogenic differentiation of hMSCs, indicative of their potential applications for bone tissue engineering.