Standing-up Motion Research Articles

Biomechanical Analysis of Hip Braces after Hip Arthroscopic Surgery for Femoroacetabular Impingement Syndrome: An Observational Study.

Currently, hip braces are recommended and typically worn by femoroacetabular impingement (FAI) patients after hip arthroscopic surgery. However, there is currently a lack of literature regarding the biomechanical effectiveness of hip braces. The purpose of this study was to investigate the biomechanical effect of hip braces after hip arthroscopic surgery for FAI. Overall, 11 patients who underwent arthroscopic FAI correction and labral preservation surgery were included in the study. Standing-up and walking tasks in unbraced and braced conditions were performed at 3 weeks postoperatively. For the standing-up task, videotaped images of the hip's sagittal plane were recorded while patients stood from a seated position. After each motion, the hip flexion-extension angle was calculated. For the walking task, acceleration of the greater trochanter was measured using a triaxial accelerometer. For the standing-up motion, the mean peak hip flexion angle was found to be significantly lower in the braced condition than in the unbraced condition. Furthermore, the mean peak acceleration of the greater trochanter was significantly lower in the braced condition than in the unbraced condition. Patients undergoing arthroscopic FAI correction surgery would benefit from usage of a hip brace in terms of protecting repaired tissues during early postoperative recovery.

Reliability and accuracy of 2D lower limb joint angles during a standing-up motion for markerless motion analysis software using deep learning

OpenPose (OP) and DeepLabCut (DLC) are applications that use deep learning to estimate posture, but there are few reports on the reliability, validity, and accuracy of their 2D lower limb joint motion analysis. This study compared OP and DLC estimates of lower extremity joint angles in standing movements with those of conventional software. A total of nine healthy men participated. The trial task was to stand up from a chair. The motion was recorded by a digital camera, and the joint angles of the hip and knee joints were calculated from the video using OP, DLC, and Kinovea. To confirm reliability and validity, ICC was calculated using the Kinovea value as the validity criterion and the correlation coefficient between OP and DLC. In addition, the agreement between those data was evaluated by the Bland-Altman plot. To evaluate the accuracy of the data, root means square error (RMSE) was calculated and compared for each joint. Although the correlation coefficients and ICC (2, 1) were in almost perfect agreement, fixed and proportional errors were found for most joints. The RMSE was smaller for OP than for DLC. Compared to Kinovea, OP and DLC can estimate the joint angles of the hip and knee joints during the stand-up movement with an estimation error of fewer than 10°, but since they are affected by the resolution of the analysis video and other factors, they need to be validated in a variety of environments and with a variety of movements.

A single-leg standing test evaluation system for fall prevention in workers

This paper developed a simple and quantitative evaluation system for a single-leg standing test. The proposed method represents the stand-up motion as a state transition model by quantitative measurement using a camera with a depth sensor (Azure Kinect) and a force plate. It objectively evaluates the movement of each state. In the experiment using the prototype, the evaluation results by the system and the skilled athletic trainer were the same for all subjects, and the shape of the radar chart was different among the subjects whose evaluation scores were the same. The results show that the proposed system can be quantitative evaluation even at worksites without skilled evaluators.

Optimal Design and Verification of Standing-up Motion Assistant Machine

Standing-up motion assistant machine is a new type of assistant device for the care and motion of the semi-disabled, which can replace the manual motion mode to a great extent and reduce the workload of the care-givers. After a detailed analysis of shortcomings of the structural design of the existing standing-up motion assistant machine in the practical application in elderly institutions, this paper proposes a design scheme and mechanical structure of the hanger. The optimized product is verified based on ergonomics theory. Results show that the design scheme and structure of the hanger of the motion assistant machine proposed in this paper can satisfy the requirements of occupant comfort on the premise of ensuring safety, as well as effectively expand the application of the standing-up motion assistant machine in elderly institutions of varied facility levels.

Current Status and Consideration of Support/Care Robots for Stand-Up Motion

In order to make robots, which are expected to play an active role in the medical and nursing care fields in the future, more practical for use in rehabilitation, it is necessary to evaluate the current status of the design of these robots. Therefore, this paper aims to investigate the existing literature on standing motion assistance robots developed and reported to date and investigate each existing design technique from the perspectives of “Functions and Effects” and “Assist form and control.” Then, we search and investigate papers written in English on standing motion assistance robots reported from 2008 to 2019 and organize the contents of the relevant papers into their different assistance modes and four categories related to design. As a result, the standing motion assistance robots are classified into three assist modes: partial assistance, total assistance, and both. The assistance forms are roughly divided into two types: a wearable type and a non-wearable type. It is also demonstrated that both the assistance forms adopt the same trends in terms of the control strategy design and system I/O relationships. On the other hand, power equipment tends to be different between the two forms.

Evaluation of Standing-Up Motion from a Forward-Sloping Toilet Seat for Older People

(1) Background: In-home assistive systems to help people with physical disabilities stand up from toilets are necessary, and the ease of the standing-up motion should be evaluated. (2) Methods: This study investigated the ease of the standing-up motion using objective and subjective data from healthy participants to facilitate the development of a toilet-seat-tilting system. Participants were divided into younger and older age groups. Objective data concerning muscle activity (EMG), three-dimensional (3D) body motion, and center of pressure distribution (COP) were collected. The participants also provided subjective data related to standing up from a toilet tilted at three different angles. (3) Results: All participants repeated the motion 25 times for each angle and provided feedback regarding their standing-up experience under each condition. Objective EMG, COP, and 3D body motion analysis results varied across individuals and age groups. The older group exhibited a consistent pattern of head motion while standing up. Thus, older individuals prefer a forward trunk-inclination motion. (4) Conclusions: According to the collected subjective data, all participants found it easier to stand when the seat angle was 5° or 10°; objective data on the ankle dorsiflexion angle, muscle activity, and head motion may be related to the subjective ease of the standing-up motion.

Development of an Exoskeleton-Type Assist Suit Utilizing Variable Stiffness Control Devices Based on Human Joint Characteristics

In this paper, the prototype of the assistive suit for lower limbs was developed. The prototype was based on an assist method with joint stiffness and antagonized angle control. The assist method comprises a system consisting of a pneumatic artificial muscle and a pull spring, which changes the joint stiffness and the antagonized angle to correspond to the movement phase and aims at coordinated motion assistance with the wearer. First, the characteristics of the developed prototype were tested. It was confirmed that the measured value of the prototype followed the target value in the relationship between torque and angle. In addition, there was hysteresis in the measured value, but it did not affect the assist. Next, the evaluation of standing-up and gait assist by measuring electromyography (EMG) of the knee extensor muscle was conducted using the prototype. In all subjects, a decrease in EMG due to the assist was confirmed. In one subject, the maximum decrease rate at the peak of the EMG was about 50% for standing-up motion and about 75% for gait motion. From the results of these assist evaluations, the effectiveness of the assist method based on the joint stiffness and antagonistic angle control using the prototype was confirmed.

Standing, Walking, and Sitting Support Robot Based on User State Estimation Using a Small Number of Sensors

With the aging of the population and the consequent severe shortage of caregivers, the demand for care robots to assist the elderly is increasing. However, care robots have yet to be widely adopted owing to cost constraints and anxiety issues due to several factors. For instance, care robots are required to have higher functionality than general care devices. It is important to provide both massive power and the appropriate support for the user’s state. However, this requires more sensors to obtain detailed information for user-state estimation and more actuators for physical support, increasing the cost and risk of failure. In a system that has many sensors and operates based on detailed data, the problem of user privacy also emerges. The risk of personal information leakage and the feeling of being monitored increase user discomfort. To support standing up and prevent falling during walking, care robots are required to apply power to the user according to the user state. The position of the center of gravity (CoG) has been used for such state estimation; however, many sensors are required to determine the accurate CoG position. To reduce the number of sensors required for user state estimation, we proposed a method for calculating CoG candidates, and validated the proposed method via experiments. Previous studies have focused solely on normal standing-up motion. However, in daily activities, standing up, walking, and sitting down are a set of motions. In addition, it is not always true that the care robot user can move normally; hence, anomaly detection is beneficial in care robots. Therefore, it is important to estimate the user state considering not only standing-up motion, but also walking and sitting down, as well as any anomaly that may occur during these motions. In this study, we develop an elderly support system that can assist in standing, walking, and sitting based on user state estimation. The CoG candidate calculation method is improved for walking and stand-to-sit movements, and an anomaly detection method using CoG candidates is also proposed. The care robot is designed to be user-driven and provide support for persons with insufficient strength based on state estimation. The experiments verify that the developed system can constantly monitor the user’s state and support a series of movements, such as standing up, walking, and sitting down, with a single robot.

Development of Standing-up Motion Training Device Which Users Step into from the Side

Development of Standing-up Motion Training Device Which Users Step into from the Side

Regression Equation between Required Force and Lumbar Load of Caregiver in Supporting Standing-up Motion via Computational Musculoskeletal Simulation

Caregivers experience low back pain because of patient handling such as supporting standing-up. The lumbar load of a caregiver depends on the required force for patient handling motions. If the relationship between the required force and the lumbar load is quantitatively clarified, it may be useful for preventing low back pain in caregivers. In this study, we investigated the quantitative relationships between the required force and lumbar loads such as vertebral stress and muscle activity in supporting standing-up by computational musculoskeletal simulation. First, a musculoskeletal model of a caregiver was prepared, and then the model performed simulated supporting standing-up motions. The vertical load used as the required force was placed on the upper limb of the model. The compressive/shear stress of the vertebral (L4–L5) and muscle activities of spinae erector muscle group were recorded as the lumbar load. The results showed that there are highly significant correlations between the required force (r > 0.9, p < 0.01). In addition, regression equations for predicting each lumbar load by the required force with highly determination coefficients (R2 > 0.9) were obtained from these relationships. Furthermore, we found that when the required force was more than 120 N, the compression stresses of the vertebral exceeded injury threshold (3400 N) by the regression equation. These regression equations contribute to quantitatively consider lumbar loads of caregiver during patient handling based on injury thresholds and the required force.

MUSCULOSKELETAL SIMULATION OF THE RELATIONSHIP BETWEEN FOOT POSITION AND STRESS OF THE L4–L5 JOINT IN SUPPORTING STANDING-UP MOTION TO PREVENT LOW BACK PAIN AMONG CAREGIVERS

Most caregivers have low back pain which results from frequent care activities such as assistance motion that supports transfer and standing-up. Various parameters are associated with the caregiver’s lumbar load. In this study, we focus on the foot position of the caregiver as one of the subjective adjustable parameters. This study aimed to analyze the relationship between foot position and stresses of the L4–L5 joint as lumbar load during supporting standing-up via musculoskeletal simulation. The musculoskeletal model was tasked with simulating supported standing-up motions based on a specific pelvic position and angular variation of each joint. The anterior foot (left foot) was fixed, and the posterior foot (right foot) was moved to three backward positions and three rightward positions, thus obtaining nine posterior foot positions. Compressive, anteroposterior shear, and lateral shear stresses of the L4–L5 joint were compared for nine foot positions. The results showed that as the anteroposterior distance and lateral widths between both feet increased, the average value of compressive/shear stress of the L4–L5 joint during motions decreased. From our findings, we hypothesized that the foot position may reduce the lumbar load and prevent low back pain.

Relationship between surface electromyography of the spinae erector muscles and subjectively adjusted step length in the supporting standing-up motion.

[Purpose] Caregivers experience low back pain owing to frequent patient handling motions such as supporting the body while standing up. To prevent low back pain in caregivers, low load posture while engaging in patient handling motions is required. We determined the relationship between surface electromyography of the erector spinae muscles and subjective step length as “long” and “short” during the supporting standing-up motions of caregivers. [Participants and Methods] Ten young male participants were asked to perform supporting standing-up motion 10 times using two-step lengths comprised of subjective long and short steps. During supporting standing-up motion, we measured surface electromyograms of the erector spinae muscles and calculated the integral electromyographic values. [Results] The subjective long/short-step length normalized by body height did not differ across the participants. In addition, the subjective long-step length was longer than the subjective short-step length in all the participants. Integral electromyographic values for both the left and right erector spinae muscles in the short-step length were significantly lower than those in the long-step length when the data obtained from all the participants were used. [Conclusion] We considered that the load of the erector spinae muscle will be reduced if the short-step instead of the long-step instruction is given. In the future, instructions based on the subjective step-length variation in caregivers must be considered.

Muscle Synergy Analysis of Standing-up Motion with Differing Load Conditions

Muscle Synergy Analysis of Standing-up Motion with Differing Load Conditions

Effect of Physical Therapy on Muscle Synergy Structure During Standing-Up Motion of Hemiplegic Patients

Stroke patients suffer from declined physical ability, and it is important to analyze rehabilitation intervention and clarify its effect on the motion of patients. In this study, the effect of intervention on the standing-up motion of stroke patients is investigated. First, the intervention timing of a physical therapist (PT) is analyzed quantitatively from the muscle activity of upper limbs during therapy. Next, the intervention effect is evaluated based on body kinematics and muscle synergy. In this study, twenty trials are conducted, in which the standing-up motion of hemiplegic patients (n=12) is measured with and without the intervention by a PT. The results show that PTs teach hemiplegic patients the timing of lifting their buttocks during standing-up motion. Furthermore, it has been found that this intervention could improve the standing-up motion, although stroke patients had inadequate muscle synergy structure. In particular, some patients had delayed activation of the synergy and they could only stood up after they moved their center of mass toward their feet. However, the intervention by PTs could induce earlier activation of the synergy. Moreover, the intervention could properly shorten the activation duration of muscle synergy for those who had unusually inappropriate longer activation of synergy. These results imply that disordered and inadequate muscle synergy structure can be improved by proper intervention, and this study contributes to the further development of new rehabilitation methodologies.

Clinical assessment of stand-up and sit-down motion assist by personal standing mobility QoLo in people with spinal cord injury

We developed Qolo, a new personal mobility device for those with motor disability in their lower limbs It assists sit-to-stand and stand-to-sit postural transitions, as well as navigation in standing posture with hands-free operation Its mechanism to assist postural transition is implemented with passive gas springs without using electric actuators, making it compact, light-weight and low cost The purpose of this study is to report a clinical assessment of the device with people with spinal cord injury (SCI), and investigate plausibility of the device and discuss further technical improvements. Four participants with SCI (age: 31–52y, 3 males and one female, neurological level: T10-L3, AIS: A-C, MMT Hip Ext: 0-1, Knee Ext: 1–5) were asked to conduct stand-up and sit-down postural transitions using the device ( Fig. 1 ) Feasibility and duration of the assisted motions were evaluated. Two of the participants conducted stand-up motion by themselves using the device (duration: 14 and 16 s) The other two needed external posture support The main factor that differed in relation to the ability of performing stand-up motion using the device was MMT Knee Ext; greater than 2 for the group that was able to perform, and 1 for the other All participants conducted sit-down motion by themselves using the device without external support (10–15 s). Capability of the device to assist posture transition was shown for some SCI people through the experiment At the same time, greater assistance on the knee joint was found to be necessary Because the device utilizes voluntary control of the trunk to induce assisted motion of knee and ankle joints for posture transition, we considered that assistance for trunk motion would be helpful for them For the next step, we plan to introduce a mechanism for lumbar posture stabilization that can support motion of hip in coordination with knee.

Assessment and handling skills of seated posture and standing-up motion

Assessment and handling skills of seated posture and standing-up motion

Analysis of the Handling Technique for the Standing-up Motion

Analysis of the Handling Technique for the Standing-up Motion

Clarification of muscle synergy structure during standing-up motion of healthy young, elderly and post-stroke patients.

Standing-up motion is an important daily activity. It has been known that elderly and post-stroke patients have difficulty in performing standing-up motion. The standing-up motion is retrained by therapists to maximize independence of the elderly and post-stroke patients, but it is not clear how the elderly and post-stroke patients control their redundant muscles to achieve standing-up motion. This study employed the concept of muscle synergy to analyze how healthy young adults, healthy elderly people and post-stroke patients control their muscles. Experimental result verified that four muscle synergies can represent human standing-up motion. In addition, it indicated that the post-stroke patients shift the weights of muscle synergies to finish standing-up motion comparing to healthy subjects. Moreover, different muscle synergy structures were associated with the CoM and joint kinematics.

An estimation of knee and ankle joint angles during extension phase of standing up motion performed using an inertial sensor.

[Purpose] Motion capture system is difficult to use in daily life. The aim of this study was to propose an estimation model for knee and ankle joint angle measurements and locate body center of gravity (COG) of the extension phase during standing-up motion. [Subjects and Methods] Seven healthy male volunteers were enrolled. An estimation model was proposed for the knee and ankle joint angle measurements by combining the angle and acceleration of the trunk, based on readings from the inertial sensor attachment on the subject’s chest, during the extension phase. Joint angles and COG position were compared to those obtained by a motion capture system. [Results] The joint angles and COG position demonstrated high correlation coefficients which represent strong correlation between the proposed model and the motion capture system. The proposed model could estimate the joint angle during extension phase, with a maximum error of 4.58 degrees, as well as COG position in the horizontal and vertical directions with maximum errors of 4.48 cm and 3.19 cm, respectively. [Conclusion] The proposed system could be used instead of motion capture system to estimate knee and ankle joint angles; however, the estimation of the COG position was insufficient because of lacked accuracy.

A Preliminary Numerical Simulation Study of Developing Ankle Foot Orthosis to Support Sit-To-Stand Movement in Children with Cerebral Palsy

The purpose of this study is to identify an effective method of support for the standing-up motion of children with cerebral palsy (CP). Experiments revealed remarkable differences in the shank and upper-body motions of children with CP compared with normally developed (ND) children. Shank tilt angles of CP children were smaller and their upper-body tilt angles were larger than those of ND children. The large upper-body tilt compensates for the smaller shank tilt but will cause back pain and/or deformation of the hip joint as they grow. It is therefore imperative to find a method of support to help CP children realize more natural motions (similar to those of ND children) to prevent these problems. The standing-up motion of ND children was adopted as the goal. Experiments identified a similarity in the angular variation between ND children’s upper bodies and shanks; the standing-up motion of children with CP under that condition was then simulated using a two-dimensional four-link model of the human body. As a result of the numerical simulation, shank angles of CP children increased and their upper-body angles decreased from those measured during the experiments, which indicates that the proposed method of support is qualitatively effective at allowing CP children to realize a more natural standing-up motion.