Effects of different vibration frequencies, amplitudes and contraction levels on lower limb muscles during graded isometric contractions superimposed on whole body vibration stimulation

Background: Indirect vibration stimulation, i.e., whole body vibration or upper limb vibration, has been investigated increasingly as an exercise intervention for rehabilitation applications. However, there is a lack of evidence regarding the effects of graded isometric contractions superimposed on whole body vibration stimulation. Hence, the objective of this study was to quantify and analyse the effects of variations in the vibration parameters and contraction levels on the neuromuscular responses to isometric exercise superimposed on whole body vibration stimulation. Methods: In this study, we assessed the 'neuromuscular effects' of graded isometric contractions, of 20%, 40%, 60%, 80% and 100% of maximum voluntary contraction, superimposed on whole body vibration stimulation (V) and control (C), i.e., no-vibration in 12 healthy volunteers. Vibration stimuli tested were 30 Hz and 50 Hz frequencies and 0.5 mm and 1.5 mm amplitude. Surface electromyographic activity of the vastus lateralis, vastus medialis and biceps femoris were measured during V and C conditions with electromyographic root mean square and electromyographic mean frequency values used to quantify muscle activity and their fatigue levels, respectively. Results: Both the prime mover (vastus lateralis) and the antagonist (biceps femoris) displayed significantly higher (P < 0.05) electromyographic activity with the V than the C condition with varying percentage increases in EMG root-mean-square (EMGrms) values ranging from 20% to 200%. For both the vastus lateralis and biceps femoris, the increase in mean EMGrms values depended on the frequency, amplitude and muscle contraction level with 50 Hz-0.5 mm stimulation inducing the largest neuromuscular activity. Conclusions: These results show that the isometric contraction superimposed on vibration stimulation leads to higher neuromuscular activity compared to isometric contraction alone in the lower limbs. The combination of the vibration frequency with the amplitude and the muscle tension together grades the final neuromuscular output.Peer reviewe

Modelling, Simulation and Testing of a Reconfigurable Cable-Based Parallel Manipulator as Motion Aiding System

This paper presents results on the modelling, simulation and experimental tests of a cable-based parallel manipulator to be used as an aiding or guiding system for people with motion disabilities. There is a high level of motivation for people with a motion disability or the elderly to perform basic daily-living activities independently. Therefore, it is of great interest to design and implement safe and reliable motion assisting and guiding devices that are able to help end-users. In general, a robot for a medical application should be able to interact with a patient in safety conditions, i.e. it must not damage people or surroundings; it must be designed to guarantee high accuracy and low acceleration during the operation. Furthermore, it should not be too bulky and it should exert limited wrenches after close interaction with people. It can be advisable to have a portable system which can be easily brought into and assembled in a hospital or a domestic environment. Cable-based robotic structures can fulfil those requirements because of their main characteristics that make them light and intrinsically safe. In this paper, a reconfigurable four-cable-based parallel manipulator has been proposed as a motion assisting and guiding device to help people to accomplish a number of tasks, such as an aiding or guiding system to move the upper and lower limbs or the whole body. Modelling and simulation are presented in the ADAMS environment. Moreover, experimental tests are reported as based on an available laboratory prototype

Rehabilitation Engineering

Population ageing has major consequences and implications in all areas of our daily life as well as other important aspects, such as economic growth, savings, investment and consumption, labour markets, pensions, property and care from one generation to another. Additionally, health and related care, family composition and life-style, housing and migration are also affected. Given the rapid increase in the aging of the population and the further increase that is expected in the coming years, an important problem that has to be faced is the corresponding increase in chronic illness, disabilities, and loss of functional independence endemic to the elderly (WHO 2008). For this reason, novel methods of rehabilitation and care management are urgently needed. This book covers many rehabilitation support systems and robots developed for upper limbs, lower limbs as well as visually impaired condition. Other than upper limbs, the lower limb research works are also discussed like motorized foot rest for electric powered wheelchair and standing assistance device

ExoBike : mechanical component development

Muitas das vezes o processo de reabilitação é monótono e desmotivador devido à repetibilidade dos exercícios e falta de feedback ou ferramentas que permitam avaliar o progresso. Assim, tendo em conta que o exercício de bicicleta é muito utilizado para a reabilitação dos membros inferiores, foi criado o projeto ExoBike. De modo a combater tais fatores, a ExoBike consiste numa bicicleta equipada com sensores de força nos principais pontos de interação entre bicicleta e paciente. Assim é possível adquirir dados importantes para avaliar o progresso do paciente, bem como estabelecer metas e ajustar os exercícios conforme as necessidades do paciente. Alem desta componente de aquisição de dados, o projeto ExoBike engloba ainda uma vertente de realidade virtual, que junta com a componente de aquisição de dados, proporciona ao paciente uma experiência mais imersiva, tornando assim a prática de exercício para reabilitação mais divertida e motivadora. Este documento foca-se no desenvolvimento dos dispositivos mecânicos instalados na bicicleta para a aquisição dos dados do paciente. Para tal foi desenvolvido um selim capaz de analisar a postura do paciente, um guiador que caracteriza a força que o paciente realiza com os membros superiores, uns pedais capazes de analisar o movimento de pedalada e uns punhos que adquirem a força de preensão que o paciente é capaz de efetuar. Sendo que as metodologias de aquisição de dados dos dispositivos se baseiam em células de carga, extensometria elétrica por resistência e inteligência artificial. Os dispositivos foram desenvolvidos e otimizados com recurso a programas de desenho computacional, analisados através de métodos numéricos e analíticos, ensaiados através de prototipagem rápida com impressão 3D e produzidos com recurso a máquinas de fabrico subtrativo com controlo numérico. De modo a garantir o correto funcionamento dos dispositivos, estes foram sujeitos a uma serie de calibrações e testes funcionais com grupos de 3, 5 e 31 voluntários para corroborar as metodologias adotadas e avaliar as capacidades das mesmas. Sendo que os dipositivos indicaram uma correlação de 0.7, entre a postura do voluntario e a sua altura, e uma correlação elevada de 0.9 entre a massa do voluntario e a força exercida pelos membros inferiores. Entre outro tipo de correlações, os dipositivos foram ainda capazes de determinar, com uma fiabilidade 95%, o efeito de recalcamento psicológico quando os voluntários foram sujeitos a uma reação de defesa induzida nos membros inferiores. Considerando assim, que as metodologias e dispositivos desenvolvidos se encontram mais do que aptos para o objetivo pretendido de avaliação e monitorização do processo de reabilitação dos membros inferiores com recurso a bicicleta estátic

Southwest Research Institute assistance to NASA in biomedical areas of the technology

Significant applications of aerospace technology were achieved. These applications include: a miniaturized, noninvasive system to telemeter electrocardiographic signals of heart transplant patients during their recuperative period as graded situations are introduced; and economical vital signs monitor for use in nursing homes and rehabilitation hospitals to indicate the onset of respiratory arrest; an implantable telemetry system to indicate the onset of the rejection phenomenon in animals undergoing cardiac transplants; an exceptionally accurate current proportional temperature controller for pollution studies; an automatic, atraumatic blood pressure measurement device; materials for protecting burned areas in contact with joint bender splints; a detector to signal the passage of animals by a given point during ecology studies; and special cushioning for use with below-knee amputees to protect the integrity of the skin at the stump/prosthesis interface

BIOMECHANICS IN EQUINE REHABILITATION: A WEIGHT-REDUCTION SYSTEM AND MOVEMENT TRACKING DEVICE

Equine musculoskeletal conditions can be challenging to treat and career-ending or result in euthanasia in severe cases. Often it is the secondary complications (weight and immobility related) that develop while treating the initial injury that carries the poor prognosis. For this reason, many attempts have been made to reduce the horse’s weight during recovery. This study aimed to design and test a chest support (breastplate) for use with a rehabilitation lift and test a movement tracking device for monitoring rehabilitation progress. By focusing on the horse's biomechanics, support can be directed to load-bearing structures, minimizing the risk of compromised breathing or restricted blood flow. Tracking movement could assist in early detection of changes in movement patterns that may be indicative of the onset of complications, such as supporting limb laminitis, in horses with ambulatory difficulties. A breastplate was developed to facilitate front limb support, attempting to minimize the risk of complications, such as pressure ulcers. Design testing included strength tests (to 227 kg) for safety, fit tests to minimize discomfort, and weight compensation trials using a computer-controlled rehabilitation lift to reduce load. The goal was to reach a 50% weight reduction of the forelimbs. Weight reduction was incrementally increased, observing the horse’s behaviour and respiratory rate, indicating discomfort and directing design modifications. A 50% weight reduction was achieved after a series of design iterations. To aid in the objective assessment of movement of horses during stall confinement, a readily available motion sensor (inertial measurement unit = IMU) was tested. The IMU was placed at three different locations (withers, right forelimb, and hindlimb) to determine the best location to quantify step count when compared to a video-based step count criterion. Data was recorded in five-minute intervals for three movements (free movement, circles, and figure-eight). An intra-class correlation (ICC) analysis determined that the IMU placement on the limbs was the most accurate using the vertical axis to determine step count with the current algorithm, while the withers location was the least accurate. The movement analysis demonstrated the potential of a limb-mounted IMU to quantify movement during stall confinement