scholarly journals Evaluation and Fault Classification for Service Robot during Sit- to-Stand Movement through Center of Mass

2018 ◽  
Author(s):  
Tianyi Wang ◽  
Hieyong Jeong ◽  
Yuko Ohno
Keyword(s):  
Center Of Mass ◽  
Fault Classification ◽  
Service Robot ◽  
Sit To Stand

scholarly journals Fault classification with discriminant analysis during sit-to-stand movement assisted by a nursing care robot

2018 ◽  
Vol 113 ◽  
pp. 90-101 ◽  
Author(s):  
Tianyi Wang ◽  
Hieyong Jeong ◽  
Mikio Watanabe ◽  
Yoshinori Iwatani ◽  
Yuko Ohno
Keyword(s):  
Discriminant Analysis ◽  
Nursing Care ◽  
Fault Classification ◽  
Sit To Stand

scholarly journals Coordinated Ground Forces Exerted by Buttocks and Feet are Adequately Programmed for Weight Transfer During Sit-to-Stand

1999 ◽  
Vol 82 (6) ◽  
pp. 3021-3029 ◽  
Author(s):  
Helga Hirschfeld ◽  
Maria Thorsteinsdottir ◽  
Elisabeth Olsson
Keyword(s):  
Center Of Mass ◽  
Three Dimensional ◽  
The Body ◽  
Whole Body ◽  
Sit To Stand ◽  
Preparatory Phase ◽  
Base Distance ◽  
Left And Right ◽  
Hip Flexion ◽  
Weight Transfer

The purpose of this study was to test the hypothesis whether weight transfer during sit-to-stand (STS) is the result of coordinated ground forces exerted by buttocks and feet before seat-off. Whole-body kinematics and three-dimensional ground forces from left and right buttock as well as from left and right foot were recorded for seven adults during STS. We defined a preparatory phase from onset of the first detectable anterior/posterior (A/P) force to seat-off (buttock forces fell to 0) and a rising phase from seat-off to the decrease of center of mass (CoM) vertical velocity to zero. STS was induced by an increase of vertical and backward directed ground forces exerted by the buttocks that significantly preceded the onset of any trunk movement. All ground forces peaked before or around the moment of seat-off, whereas all kinematic variables, except trunk forward rotation and hip flexion, peaked after seat-off, during or after the rising phase. The present study suggests that the weight transfer from sit to stand is induced by ground forces exerted by buttocks and feet before seat-off, i.e., during the preparatory phase. The buttocks generate the isometric “rising forces,” e.g., the propulsive impulse for the forward acceleration of the body, while the feet apply adequate damping control before seat-off. This indicates that the rising movement is a result of these coordinated forces, targeted to match the subject's weight and support base distance between buttocks and feet. The single peaked, bell-shaped profiles peaking before seat-off, were seen beneath buttocks for the “rising drive,” i.e., between the time of peak backward directed force and seat-off, as well as beneath the feet for the “damping drive,” i.e., from onset to the peak of forward-directed force and for CoM A/P velocity. This suggests that both beginning and end of the weight transfer process are programmed before seat-off. The peak deceleration of A/P CoM took place shortly (∼100 ms) after CoM peak velocity, resulting in a well controlled CoM deceleration before seat-off. In contrast to the view of other authors, this suggests that body equilibrium is controlled during weight transfer.

Influence of Moving Visual Environment on Sit-to-Stand Kinematics in Children and Adults

2009 ◽  
Vol 109 (1) ◽  
pp. 121-132 ◽  
Author(s):  
Jill C. Slaboda ◽  
Joseph E. Barton ◽  
Emily A. Keshner
Keyword(s):  
Visual Motion ◽  
Center Of Mass ◽  
Visual Input ◽  
Time Dependent ◽  
Visual Environment ◽  
Sit To Stand ◽  
Immersion Period ◽  
Angular Velocities ◽  
Adults And Children ◽  
Time Dependent Effect

The effect of visual field motion on the sit-to-stand kinematics of adults and children was investigated. Children (8 tol2 years of age) and adults (21 to 49 years of age) were seated in a virtual environment that rotated in the pitch and roll directions. Participants stood up either (1) concurrent with onset of visual motion or (2) after an immersion period in the moving visual environment, and (3) without visual input. Angular velocities of the head with respect to the trunk, and trunk with respect to the environment, were calculated as was head and trunk center of mass. Both adults and children reduced head and trunk angular velocity after immersion in the moving visual environment. Unlike adults, children demonstrated significant differences in displacement of the head center of mass during the immersion and concurrent trials when compared to trials without visual input. Results suggest a time-dependent effect of vision on sit-to-stand kinematics in adults, whereas children are influenced by the immediate presence or absence of vision.

scholarly journals Effect of Externally Cued Training on Dynamic Stability Control During the Sit-to-Stand Task in People With Parkinson Disease

2013 ◽  
Vol 93 (4) ◽  
pp. 492-503 ◽  
Author(s):  
Tanvi Bhatt ◽  
Feng Yang ◽  
Margaret K.Y. Mak ◽  
Christina W-Y. Hui-Chan ◽  
Yi-Chung Pai
Keyword(s):  
Dynamic Stability ◽  
Center Of Mass ◽  
Stability Control ◽  
Sit To Stand ◽  
Backward Stability ◽  
Stability Limits ◽  
Balance Loss ◽  
Mass Position ◽  
Dynamic Stability Control ◽  
Forward Stability

Background Previous studies have shown that people with Parkinson disease (PD) have difficulty performing the sit-to-stand task because of mobility and stability-related impairments. Despite its importance, literature on the quantification of dynamic stability control in people with PD during this task is limited. Objective The study objective was to examine differences in dynamic stability control between people with PD and people who were healthy and the extent to which externally cued training could improve such control during the sit-to-stand task in people with PD. Design This was a quasi-experimental controlled trial. Methods The performance of 21 people with PD was compared with that of 12 older adults who dwelled in the community. People with PD were randomly assigned to 2 groups: a group that did not receive training and a group that received audiovisually cued training (3 times per week for 4 weeks) for speeding up performance on the sit-to-stand task. Outcome measures recorded at baseline and after 4 weeks included center-of-mass position, center-of-mass velocity, and stability against either backward or forward balance loss (backward or forward stability) at seat-off and movement termination. Results Compared with people who were healthy, people with PD had greater backward stability resulting from a more anterior center-of-mass position at seat-off. This feature, combined with decreased forward stability at movement termination, increased their risk of forward balance loss at movement termination. After training, people with PD achieved greater backward stability through increased forward center-of-mass velocity at seat-off and reduced the likelihood of forward balance loss at movement termination through a posterior shift in the center-of-mass position. Limitations The study applied stability limits derived from adults who were healthy to people with PD, and the suggested impact on the risk of balance loss and falling is based on these theoretical stability limits. Conclusions For people with PD, postural stability against backward balance loss at task initiation was increased at the expense of possible forward balance loss at task termination. Task-specific training with preparatory audiovisual cues resulted in improved overall dynamic stability against both forward and backward balance loss.

Dynamic Optimization of the Sit-to-Stand Movement

2011 ◽  
Vol 27 (4) ◽  
pp. 306-313 ◽  
Author(s):  
Hiroshi R. Yamasaki ◽  
Hiroyuki Kambara ◽  
Yasuharu Koike
Keyword(s):  
Motion Analysis ◽  
Dynamic Optimization ◽  
Center Of Mass ◽  
Optimal Trajectories ◽  
Change Model ◽  
Change Models ◽  
Sit To Stand ◽  
Minimum Jerk ◽  
Ankle Joints ◽  
Minimum Torque

The purpose of this study was to clarify criteria that can predict trajectories during the sit-to-stand movement. In particular, the minimum jerk and minimum torque-change models were examined. Three patterns of sit-to-stand movement from a chair, i.e., upright, natural, and leaning forward, were measured in five young participants using a 3-D motion analysis device (200 Hz). The trajectory of the center of mass and its smoothness were examined, and the optimal trajectories predicted by both models were evaluated. Trajectories of the center of mass predicted by the minimum torque-change model, rather than the minimum jerk model, resembled the measured movements in all rising movement patterns. The upright pattern required greater extension torque of the knee and ankle joints at the instant of seat-off. The leaning-forward pattern required greater extension hip torque and higher movement cost than the natural and upright patterns. These results indicate that the natural sit-to-stand movement might be a result of dynamic optimization.

scholarly journals Neuromechanical Differences Between Successful and Failed Sit-to-Stand Movements and Response to Rehabilitation Early After Stroke

2019 ◽  
Vol 33 (5) ◽  
pp. 395-403 ◽  
Author(s):  
Andy Kerr ◽  
Allan Clark ◽  
Valerie M. Pomeroy
Keyword(s):  
Body Position ◽  
Center Of Mass ◽  
Onset Time ◽  
Time Difference ◽  
Therapy Targets ◽  
Sit To Stand ◽  
Before And After ◽  
Temporal Coupling ◽  
Improved Performance ◽  
Evidence Based Therapy

Background. Recovery of the sit-to-stand (StS) movement early after stroke could be improved by targeting physical therapy at the underlying movement deficits in those people likely to respond. Aim. To compare the movement characteristics of successful and failed StS movements in people early after stroke and identify which characteristics change in people recovering their ability to perform this movement independently following rehabilitation. Methods. Muscle activity and kinematic (including center of mass, CoM) data were recorded from 91 participants (mean 35 days after stroke) performing the StS movement before (baseline), immediately after (outcome), and 3 months after (follow-up) rehabilitation. Three subgroups (never-able [n = 19], always-able [n = 51], and able-after-baseline [n = 21]) were compared at baseline with the able-after-baseline subgroup compared before and after rehabilitation. Results. The subgroups differed at baseline for quadriceps onset time ( P = .009) and forward body position when quadriceps peaked ( P = .038). Following rehabilitation, the able-after-baseline subgroup increased their forward position ( P < .001), decreased the time difference between bilateral quadriceps peaks ( P < .001) and between quadriceps and hamstrings peaks on the nonhemiplegic side ( P = .007). An improved performance in the always-able subgroup was associated with a number of baseline factors, including forward positioning ( P = .002) and time difference between peak activity of bilateral quadriceps ( P = .001). Conclusions. This neuromechanical study of StS before and after rehabilitation in a sample of people early after stroke identified the importance of temporal coupling between forward trunk movement and quadriceps and hamstrings’ activity. These findings advance the science of stroke rehabilitation by providing evidence-based therapy targets to promote recovery of the StS movement.

scholarly journals Functional movement compensations persist in individuals with hip osteoarthritis performing the five times sit-to-stand test 1 year after total hip arthroplasty

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Anna-Clara Esbjörnsson ◽  
Josefine E. Naili
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Center Of Mass ◽  
Area Under The Curve ◽  
Hip Osteoarthritis ◽  
Functional Movement ◽  
Stand Test ◽  
Total Hip ◽  
Sit To Stand ◽  
Anterior Posterior

Abstract Background Methods to quantify and evaluate function are important for development of specific rehabilitation interventions. This study aimed to evaluate functional movement compensation in individuals with hip osteoarthritis performing the five times sit-to-stand test and change following total hip arthroplasty. To this end, trajectories of the body’s center of mass in the medial-lateral and anterior-posterior dimensions were quantified prior to and 1 year after total hip arthroplasty and compared to a healthy control group. Methods Twenty-eight individuals with hip osteoarthritis and 21 matched healthy controls were enrolled in this prospective study. Within 1 month prior to and 1 year after total hip arthroplasty, performance on the five times sit-to-stand test was evaluated using three-dimensional motion analysis and perceived pain using a visual analog scale. The center of mass trajectories for the medial-lateral and the anterior-posterior dimensions were identified, and the area under the curve was calculated, respectively. Repeated measures ANOVA were used to evaluate differences in the area under the curve, between pre- and postoperative performance, and between participants with hip osteoarthritis and controls. Results Preoperatively, individuals with hip osteoarthritis displayed a larger contralateral shift (p < 0.001) and forward displacement of the center of mass (p = 0.022) compared to controls. After surgery, deviations in both dimensions were reduced (medial-lateral p = 0.013; anterior-posterior p = 0.009). However, as compared to controls, the contralateral shift of the center of mass remained larger (p = 0.010), indicative of persistent asymmetric limb loading. Perceived pain was significantly reduced postoperatively (p < 0.001). Conclusions By quantifying the center of mass trajectory during five times sit-to-stand test performance, functional movement compensations could be detected and evaluated over time. Prior to total hip arthroplasty, individuals with hip osteoarthritis presented with an increased contralateral shift and forward displacement of the center of mass, representing a strategy to reduce pain by unloading the affected hip and reducing required hip and knee extension moments. After surgery, individuals with total hip arthroplasty displayed a persistent increased contralateral shift as compared to controls. This finding has implications for rehabilitation, where more focus must be directed towards normalizing loading of the limbs.

scholarly journals Discover Your Potential: The Influence of Kinematics on a Muscle’s Ability to Contribute to the Sit-to-Stand Transfer

2021 ◽  
Author(s):  
Sarah A. Roelker ◽  
Laura C. Schmitt ◽  
Ajit M.W. Chaudhari ◽  
Robert A. Siston
Keyword(s):  
Young Adults ◽  
Center Of Mass ◽  
Joint Kinematics ◽  
New Method ◽  
Whole Body ◽  
Muscle Strengthening ◽  
Sit To Stand ◽  
Vertical Support ◽  
Anterior Pelvic Tilt ◽  
Body Center

AbstractExisting methods for estimating how individual muscles contribute to a movement require extensive time and experimental resources. In this study we developed an efficient method for determining how changes to lower extremity joint kinematics affect the potential of individual muscles to contribute to whole-body center-of-mass vertical (support) and anteroposterior (progression) accelerations. A 4-link 2-dimensional model was used to assess the effect of kinematic changes on muscle function. Joint kinematics were systematically varied throughout ranges observed during the momentum transfer phase of the sit-to-stand transfer. Each muscle’s potential to contribute to support and progression was computed and compared to simulated potentials estimated by traditional dynamic simulation methods for young adults and individuals with knee osteoarthritis (KOA). The new method required 4-10s to compute muscle potentials per kinematic state and computed potentials were consistent with simulated potentials. The new method identified differences in muscle potentials between groups due to kinematic differences, particularly decreased anterior pelvic tilt in young adults, and revealed kinematic and muscle strengthening modifications to increase support. The methods presented provide an efficient, systematic approach to evaluate how joint kinematic adjustments alter a muscle’s ability to contribute to movement and can identify potential sources of pathologic movement and rehabilitation strategies.

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