Standing up is an important and common daily activity. It is essential for independence and a prerequisite for walking. Many elderly and many subjects with impairments have problems with transition from sitting to standing. The aim of the present study was to determine whether there was any difference between the characteristics of standing up in trans-femoral amputees and healthy subjects. Five young trans-femoral amputees and five healthy subjects were included in the study. They were asked to stand up. The body motion was recorded using an Optotrak contactless optical system. The force and moment vectors exerted on the seat were recorded by a JR3 six-axis robot wrist sensor. The force under the feet was recorded by two AMTI force plates. The trans-femoral amputees were found to stand up more slowly than the healthy subjects. The angles of the hip, knee, and ankle joints on the amputated side were different from the angles on the healthy side or in the healthy subjects. There was also a great difference in loading between the healthy and the prosthetic foot. It can be concluded that there are differences in standing up between the trans-femoral amputees and the healthy subjects. These differences may indicate a reason for problems many elderly trans-femoral amputees face when standing up.
The suitability of multichannel functional electrical stimulation (FES) during the standing-up manoeuvre for therapeutic home use was investigated. Two spinal cord-injured subjects (SCI) participated in the study. Ankle plantar flexors, knee extensors and hip extensors were stimulated. The amplitude of the stimulation pulses depended on the current phase of raising. The sit-to-stand process was divided into three phases by detecting characteristic events in the vertical handle reaction force. It was found that the multichannel FES did not contribute to the decrease of the arm support force when compared with stimulation of knee extensors only. However, stimulation of the hip extensors could speed up the raising process. Increased repeatability and faster standing up were observed when the stimulation began before the start of raising.
Abstract-Robot assisted standing-up manoeuver was tested in an intact person and a person after above-knee amputation. The subjects were asked to use as much leg activity as possible to lift their body while maintaining contact with the robot. The robot guided the subjects with three reference speeds. Kinematics and external forces acting on the body were recorded. The robot influence on the hip trajectory and the torques of the leg joints were studied. The subjects were able to track the robot movement. Thus, it is possible to use the robot to guide an impaired person along a desired trajectory during the standing-up process. In this way the impaired persons can be trained to accomplish an efficient sit-to-stand movement, while different trajectories of raising can be preprogrammed. Keywords -Standing-up, assistive robot, above-knee amputation I. INTRODUCTIONThe ability to stand up from a sitting position is essential for a person's independency. Successful raising is also the prerequisite for walking. However, the standing-up manoeuvre requires higher torque and larger ranges of motion in the joints of the lower limbs than walking. Standing-up is a frequent human activity. On average a healthy person stands up four times per hour [1]. Persons after the lower limb amputation are faced with the necessity to relearn standing-up in a different way than they were used to. Usually higher joint torques in the intact leg and improved balancing are required.A robot was built to assist disabled persons during the sit-to-stand transfer. The robot is meant to be used as a training device, an assessment tool and to study the rising manoeuvre. When training with the robot assistive device, a disabled person can safely approach limits of his/her capabilities without risking to fall. Using the robot to measure rising is more comfortable than placing sensors such as infrared markers or goniometers on the patient's body. The assistive device can be programmed to interact with a person's voluntary activity in order to gain information about the standing-up process. The suitability to support paraplegic patients rising by the help of functional electrical stimulation was evaluated in [2]. A similar passive device supporting part of a paraplegic patient's body weight was used to study the FES control strategies during standing-up [3]. We believe that other categories of disabled persons, such as amputees and aging population can benefit from robot assisted training of standing-up.The optimal trajectory of an amputee may differ from the optimal trajectory of an intact person. The present paper is a preliminary study mainly focused on the use of the robot as a device to guide a patient along a desired preprogrammed trajectory. Special attention was paid to interaction between the subject and the robot. II. METHODOLOGYThe assistive robot resembles to half of a seesaw construction and has one active and one passive degree of freedom (Fig. 1). A rotating segment is driven by a hydraulic cylinder. A commercially available bicycle seat s...
Abstruci -Raising from a chair by the help of open-loop electrical stimulation of knee extensors is well accepted in paralyzed persons. However, electrically stimulated knee extensors provide only low joint moments during raising. Thus, the effort of upper extremities during standing-up is extensive. The aim of the investigation was to study the influence of the stimulation of ankle plantar flexors and hip extensors on the efficiency of standing-up process.Spinal cord injuried subject performed raising from sitting to standing position with surface electrical stimulation. Different combinations of stimulated muscle groups were studied. The stimulation amplitude changed with respect to the current phase of the sit-to-stand process. The vertical arm support force was used to divide standing-up into three phases. The handle reaction force vector was assessed by a robot wrist sensor. The body movement was measured with a contactless optical system. The ground and seat reaction force vectors were determined with force plates. A 3-dimensional model of the human body was used to assess the joint torques.No considerable differences were observed between the different types of raising. Additional electrodes on hip extensors and ankle plantar flexors seem not to be justified for daily FES use. Standing-up is a realtively quick ballistic process. It appears that the patient cannot react in time in order to use his stimulated lower extremities to support the standing-up to a larger extent.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.