scholarly journals Estimation of Transition Frequency during Continuous Translation Surface Perturbation

2019 ◽  
Vol 9 (22) ◽  
pp. 4891 ◽  
Author(s):  
Nur Fatin Fatina Mohd Ramli ◽  
Mohd Azuwan Mat Dzahir ◽  
Shin-Ichiroh Yamamoto

Depending on task requirements, a human is able to select distinct strategies such as the use of an ankle strategy and hip strategy to maintain their balance. Postural control actions often co-occur with other movements, and such movements may bring about a change from one type of postural coordination to another. The selection of a postural control strategy has typically been investigated by the transition of the center of mass (COM), center of pressure (COP), and in between angle joint motion along with their characteristics. In this paper, we proposed a method using the logistic function of the sigmoid model based on cross-correlation coefficient (CCF) data for investigating and observing the transition of postural control strategies of COM–COP and ankle-hip angles towards anterior–posterior (AP) continuous translation perturbation. Subjects were required to stand on the motion base platform where perturbations with an increasing frequency (0.2 Hz to 0.8 Hz) and decreasing frequency (0.8 Hz to 0.2 Hz) in steps of 0.02 Hz, were induced. As the frequency increased, the COM and COP displacements were decreased, with the opposite trend observable with decreasing frequency. This pattern was also observed at the head peak-to-peak amplitude. Meanwhile, ankle and hip angular displacements were increased during increasing frequency and decreased during decreasing frequency. In this paper, the proposed sigmoid model could identify the transition frequency of COM–COP and ankle–hip transition. The mean transition frequency of COM–COP during increasing frequency was 0.44 Hz, and the ankle–hip transition frequency was 0.42 Hz. Meanwhile, for decreasing frequency, the COM–COP transition frequency was 0.55 Hz, and for the ankle–hip transition the frequency was 0.56 Hz. With frequencies, both increasing and decreasing, the COM–COP and ankle–hip transition frequencies occurred almost at the same frequency. Furthermore, the transition occurred at a lower time scale during increasing frequency compared to decreasing frequency. In conclusion, the continuous translation surface perturbation provided information on the behavior of postural control strategies. A sudden change in ‘phase angle’ was observed, where either an ankle or hip strategy was implemented to maintain balance. Besides, the transition frequency of postural control strategies could be determined to occur between 0.4 Hz and 0.6 Hz, based on the average value, for healthy young subjects in the AP plane. Furthermore, the proposed sigmoid model was believed to be able to be used in the determination of transition frequency in postural control strategies.

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jooeun Song ◽  
Susan Sigward ◽  
Beth Fisher ◽  
George J. Salem

Persons withearly-stageParkinson’s disease (EPD) do not typically experience marked functional deficits but may have difficulty with turning tasks. Studies evaluating turning have focused on individuals in advanced stages of the disease. The purpose of this study was to compare postural control strategies adopted during turning in persons with EPD to those used by healthy control (HC) subjects. Fifteen persons with EPD, diagnosed within 3 years, and 10 HC participated. Participants walked 4 meters and then turned 90°. Dynamic postural control was quantified as the distance between the center of pressure (COP) and the extrapolated center of mass (eCOM). Individuals with EPD demonstrated significantly shorter COP-eCOM distances compared to HC. These findings suggest that dynamic postural control during turning is altered even in the early stages of PD.


2016 ◽  
Vol 21 (6) ◽  
pp. 33-39 ◽  
Author(s):  
Tyler R. Keith ◽  
Tara A. Condon ◽  
Ayana Phillips ◽  
Patrick O. McKeon ◽  
Deborah L. King

The Star Excursion Balance Test (SEBT) is a valid and reliable measure of dynamic postural control. Center of pressure (COP) behavior during the SEBT could provide additional information about direction-dependent SEBT balance strategies. The purpose of this study was to quantify spatiotemporal COP differences using COP area and velocity among three different SEBT reach directions (anterior, posteromedial, posterolateral). The anterior direction COP velocity was significantly lower than both posterior directions. However, the anterior COP area was significantly greater than posterior. Based on COP behavior, the anterior and posterior reach directions appear to use different postural control strategies on the SEBT.


2018 ◽  
Vol 120 (2) ◽  
pp. 693-702 ◽  
Author(s):  
Luis Augusto Teixeira ◽  
Joane de Figueiredo Serpa Coutinho ◽  
Daniel Boari Coelho

In daily living activities, performance of spatially accurate manual movements in upright stance depends on postural stability. In the present investigation, we aimed to evaluate the effect of the required manual steadiness (task constraint) on the regulation of dynamic postural control. A single group of young participants ( n = 20) were evaluated in the performance of a dual posturo-manual task of balancing on a platform oscillating in sinusoidal translations at 0.4-Hz (low) or 1-Hz (high) frequencies while stabilizing a cylinder on a handheld tray. Manual task constraint was manipulated by comparing the conditions of keeping the cylinder stationary on its flat or round side, corresponding to low and high manual task constraints, respectively. Results showed that in the low oscillation frequency the high manual task constraint led to lower oscillation amplitudes of the head, center of mass, and tray, in addition to higher relative phase values between ankle/hip-shoulder oscillatory rotations and between center of mass/center of pressure-feet oscillations as compared with values observed in the low manual task constraint. Further analyses showed that the high manual task constraint also affected variables related to both postural (increased amplitudes of center of pressure oscillation) and manual (increased amplitude of shoulder rotations) task components in the high oscillation frequency. These results suggest that control of a dynamic posturo-manual task is modulated in distinct parameters to attend the required manual steadiness in a complex and flexible way. NEW & NOTEWORTHY We evaluated dynamic postural control on a platform oscillating in sinusoidal translations at different frequencies while performing a manual task with low or high steadiness constraints. Results showed that high manual task constraint led to modulation of metric and coordination variables associated with greater postural stability. Our findings suggest that motor control is regulated in an integrative mode at the posturo-manual task level, with reciprocal interplay between the postural and manual components.


2002 ◽  
Vol 82 (6) ◽  
pp. 566-577 ◽  
Author(s):  
Matthew Martin ◽  
Mindi Shinberg ◽  
Maggie Kuchibhatla ◽  
Laurie Ray ◽  
James J Carollo ◽  
...  

Abstract Background and Purpose. Initiation of gait requires transitions from relatively stationary positions to stability with movement and from double- to single-limb stances. These are deliberately destabilizing activities that may be difficult for people with early Parkinson disease (PD), even when they have no problems with level walking. We studied differences in postural stability during gait initiation between participants with early and middle stages of PD (characterized by Hoehn and Yahr as stages 1–3) and 2 other groups of participants without PD—older and younger adults. Subjects. The mean ages of the 3 groups of participants were as follows: subjects with PD, 69.3 years (SD=5.7, range=59–78); older subjects without PD, 69.0 years (SD=3.9, range=65–79); and younger subjects without PD, 27.5 (SD=3.9, range=22–35). Methods. A 3-dimensional motion analysis system was used with 2 force platforms to obtain data for center of mass (COM) and center of pressure (COP). The distance between the vertical projections of the COM and the COP (COM–COP distance) was used to reflect postural control during 5 events in gait initiation. Results. By use of multivariate analysis of variance, differences in COM–COP distance were found among the 3 groups. An analysis of variance indicated differences for 4 of the 5 events in gait initiation. A Scheffe post hoc analysis demonstrated differences in gait initiation between the subjects with PD and both groups of subjects without PD (2 events) and between the subjects with PD and the younger subjects without PD (2 events). Discussion and Conclusion. The COM–COP distance relationship was used to measure postural control during the transition from quiet standing to steady-state gait. Differences between groups indicated that individuals with impaired postural control allow less COM–COP distance than do individuals with no known neurologic problems. The method used could prove useful in the development and assessment of interventions to improve ambulation safety and enhance the independence of people with impaired postural control.


Healthcare ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 210
Author(s):  
Tadashi Ito ◽  
Yoshihito Sakai ◽  
Kazunori Yamazaki ◽  
Yohei Ito ◽  
Keitaro Kawai ◽  
...  

This study aimed to assess differences in somatosensory control strategies between older patients with sagittal imbalance and young adults during postural tasks. The center of pressure displacement in 27 older patients with sagittal imbalance and 27 young adults was determined upon standing blindfolded on a balance board. Vibratory stimulation at 56 to 100 Hz was applied bilaterally to the gastrocnemius and soleus muscles (GS) and lumbar multifidus to evaluate the contributions of proprioceptive signals to postural control. Data of older patients and young adults were compared using the Mann–Whitney U-test or independent sample t-tests. Compared with the young adults, the older patients were significantly more reliant on the GS (p < 0.005) for their postural control and showed a higher relative proprioceptive weighting ratio (RPW) (p = 0.038). The postural strategy adopted by the older patients depended on the level of proprioceptive stimulation applied to the GS, and the postural control strategy of the ankle correlated with RPW. Overall, this study identifies RPW as a novel measure of postural strategy in older patients with sagittal imbalance and provides an understanding of strategies used to maintain balance, which may assist in developing preventative measures to reduce the risk of falls.


2022 ◽  
Vol 12 ◽  
Author(s):  
Daša Gorjan ◽  
Nejc Šarabon ◽  
Jan Babič

Understanding the relation between the motion of the center of mass (COM) and the center of pressure (COP) is important to understand the underlying mechanisms of maintaining body equilibrium. One way to investigate this is to stabilize COM by fixing the joints of the human and looking at the corresponding COP reactions. However, this approach constrains the natural motion of the human. To avoid this shortcoming, we stabilized COM without constraining the joint movements by using an external stabilization method based on inverted cart-pendulum system. Interestingly, this method only stabilized COM of a subgroup of participants and had a destabilizing effect for others which implies significant variability in inter-individual postural control. The aim of this work was to investigate the underlying causes of inter-individual variability by studying the postural parameters of quiet standing before the external stabilization. Eighteen volunteers took part in the experiment where they were standing on an actuated cart for 335 s. In the middle of this period we stabilized their COM in anteroposterior direction for 105 s. To stabilize the COM, we controlled the position of the cart using a double proportional–integral–derivative controller. We recorded COM position throughout the experiment, calculated its velocity, amplitude, and frequency during the quiet standing before the stabilization, and used these parameters as features in hierarchical clustering method. Clustering solution revealed that postural parameters of quiet standing before the stabilization cannot explain the inter-individual variability of postural responses during the external COM stabilization. COM was successfully stabilized for a group of participants but had a destabilizing effect on the others, showing a variability in individual postural control which cannot be explained by postural parameters of quiet-stance.


2000 ◽  
Vol 81 (1) ◽  
pp. 45-48 ◽  
Author(s):  
H[eacute]l[egrave]ne Corriveau ◽  
R[eacute]jean H[eacute]bert ◽  
Fran[ccedil]ois Prince ◽  
Michel Ra[icirc ]che

PLoS ONE ◽  
2019 ◽  
Vol 14 (7) ◽  
pp. e0219460 ◽  
Author(s):  
Krzysztof Piotr Michalak ◽  
Anna Przekoracka-Krawczyk ◽  
Ryszard Naskręcki

2015 ◽  
Vol 4 (3) ◽  
pp. 82-89
Author(s):  
Seyed Mojtaba Ojaghi ◽  
Fahimeh Kamali ◽  
Ali Ghanbari ◽  
Samaneh Ebrahimi ◽  
Ahmad Reza Nematollahi

Background: Patellofemoral pain syndrome (PFPS) is the most common overuse syndrome in athletes. The aim of this study was to compare the effects of taping and elastic bandage on postural control in athletes with PFPS. Materials and Methods: Fifteen males and 19 females with PFPS participated in this clinical trial study for more than 1 month and were randomly divided into two groups; group 1 was taped based on McConnell method and in group 2 elastic bandage was used. The static postural control in both groups was measured before and after interventions using the force- plate through measuring the center of pressure (COP) and estimation of differences between center of pressure and center of mass (COP-COM moment arms) in AP and ML directions. Moreover, dynamic postural control was measured by star excursion balance test (SEBT). Paired t-test and covariance analysis were used for analysis of the data. Results: Results indicated that after taping reach distances increased significantly (p< 0.05) in anterior, anterolateral, lateral and posterior directions but after elastic bandage reach distances increased in posterior, posteromedial and medial directions. After both taping and bandage, COP and COP-COM moment arm measures did not show significant differences. Conclusion: The findings of this investigation showed that in athletes with patellofemoral pain, taping and elastic bandage improved dynamic postural control. However, dynamic methods are successfully used to assess the effects of taping and bandage on postural control. Static variables compared with dynamic measures potentially lack the ability to detect subtle differences of postural control in athletes with PFPS. [GMJ. 2015;4(3):82-89]


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