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BACKGROUND AND PURPOSE: Energy variables, such as metabolic cost (MC) and energy expenditure (EE), are important characteristics of motor activities that can influence daily activity and have implications for health. In individuals poststroke, these variables have previously been described only for walking. Our goal was to characterize the MC and EE of typical motor activities among individuals in the chronic phase poststroke and compare them with those of able-bodied individuals. METHODS: Eleven individuals with poststroke and 8 able-bodied individuals participated in this study. Four activities were tested: sit-to-walk-to-sit, walking over an obstacle course, walking at a comfortable speed, and reaching for an object while in a standing position. Each activity was performed repeatedly for 8 minutes, while oxygen consumption was recorded. The MC of the activities was calculated by dividing the mean oxygen consumption by walking speed or the number of repetitions. The EE was represented by metabolic equivalents. RESULTS: There was a significant interaction effect of group and activity on MC and EE (P = 0.001 and P = 0.007, respectively). In the participants poststroke, the MC of mobility activities ranged from 0.24 (0.06) to 0.3 (0.06) mL/kg/m, and the MC of the standing activity was 0.1 (0.03) mL/kg/repetition. The MC was higher for the participants poststroke than for the able-bodied participants (P < 0.001). The EE of the participants poststroke ranged from 1.96 (0.4) to 3.83 (0.6) metabolic equivalents and was lower compared with the able-bodied participants (P = 0.001). DISCUSSION AND CONCLUSIONS: Individuals poststroke have high MC and low EE across various motor activities. These findings suggest that rehabilitation programs need to specifically address the energetic domain.Video Abstract available. See Video (Supplemental Digital Content 1, http://links.lww.com/JNPT/A75) for more insights from the authors.
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Metabolismo Energético/fisiología , Ejercicio Físico/fisiología , Consumo de Oxígeno/fisiología , Accidente Cerebrovascular/metabolismo , Caminata/fisiología , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Accidente Cerebrovascular/fisiopatología , Rehabilitación de Accidente CerebrovascularRESUMEN
BACKGROUND: Cycling has been used in the rehabilitation of individuals with both chronic and post-surgical conditions. Among the challenges with implementing bicycling for rehabilitation is the recruitment of both extremities, in particular when one is weaker or less coordinated. Feedback embedded in virtual reality (VR) augmented cycling may serve to address the requirement for efficacious cycling; specifically recruitment of both extremities and exercising at a high intensity. METHODS: In this paper a mechatronic rehabilitation bicycling system with an interactive virtual environment, called Virtual Reality Augmented Cycling Kit (VRACK), is presented. Novel hardware components embedded with sensors were implemented on a stationary exercise bicycle to monitor physiological and biomechanical parameters of participants while immersing them in an augmented reality simulation providing the user with visual, auditory and haptic feedback. This modular and adaptable system attaches to commercially-available stationary bicycle systems and interfaces with a personal computer for simulation and data acquisition processes. The complete bicycle system includes: a) handle bars based on hydraulic pressure sensors; b) pedals that monitor pedal kinematics with an inertial measurement unit (IMU) and forces on the pedals while providing vibratory feedback; c) off the shelf electronics to monitor heart rate and d) customized software for rehabilitation. Bench testing for the handle and pedal systems is presented for calibration of the sensors detecting force and angle. RESULTS: The modular mechatronic kit for exercise bicycles was tested in bench testing and human tests. Bench tests performed on the sensorized handle bars and the instrumented pedals validated the measurement accuracy of these components. Rider tests with the VRACK system focused on the pedal system and successfully monitored kinetic and kinematic parameters of the rider's lower extremities. CONCLUSIONS: The VRACK system, a virtual reality mechatronic bicycle rehabilitation modular system was designed to convert most bicycles in virtual reality (VR) cycles. Preliminary testing of the augmented reality bicycle system was successful in demonstrating that a modular mechatronic kit can monitor and record kinetic and kinematic parameters of several riders.
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Ciclismo , Diseño de Equipo , Neurorretroalimentación/instrumentación , Modalidades de Fisioterapia/instrumentación , Interfaz Usuario-Computador , Adulto , Fenómenos Biomecánicos/fisiología , Simulación por Computador , Humanos , Programas Informáticos , Terapia Asistida por Computador/instrumentación , Adulto JovenRESUMEN
BACKGROUND: Off-the-shelf activity-promoting video games (AVGs) are proposed as a tool for promoting regular physical activity among individuals poststroke. OBJECTIVE: To characterize the energy expenditure (EE), exercise intensity, and energy metabolism of individuals poststroke, while playing AVGs in different positions, from different consoles, and to compare the performance with comfortable walking and with able-bodied individuals. METHODS: Eleven poststroke and 8 able-bodied participants played in standing Wii-Boxing Xbox-Boxing, Wii-Run and Penguin, and also Wii-Boxing in sitting. EE (expressed as metabolic equivalents [METs]); exercise intensity (expressed as %predicted maximal heart rate [HR]), rate of perceived exertion (RPE), and respiratory exchange ratio (RER) were used to characterize the games. RESULTS: Participants' poststroke EE ranged from 1.81 ± 0.74 to 3.46 ± 1.3 METs and was lower compared with able-bodied participants for Xbox-Boxing (P = .001), Wii-Boxing in standing (P = .01), Run (P < .001), and Penguin (P = .001). Participants' poststroke exercise intensity ranged from 49.8 ± 9.3 to 64.7 ± 9.3 %predicted maximal HR and was lower compared with able-bodied participants for Xbox-Boxing (P = .007) and Run (P = .005). For participants poststroke, EE of walking at a comfortable did not differ from boxing games in standing or Run. For able-bodied participants only, the EE for Xbox-Boxing was higher than Wii-Boxing (6.5 ± 2.6 vs 4.4 ± 1.1, P = .02). EE was higher in standing versus sitting for poststroke (P = .04) and able-bodied (P = .03) participants. There were no significant group differences for RPEs. RER of playing in sitting approached anaerobic metabolism. CONCLUSIONS: Playing upper extremity (ie, Boxing) or mobility (ie, Run) AVGs in standing resulted in moderate EE and intensity for participants poststroke. EE was lower for poststroke than for able-bodied participants.
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Metabolismo Energético/fisiología , Terapia por Ejercicio/métodos , Ejercicio Físico/fisiología , Rehabilitación de Accidente Cerebrovascular , Adulto , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Persona de Mediana Edad , Accidente Cerebrovascular/fisiopatología , Juegos de VideoRESUMEN
Ankle impairment and lower limb asymmetries in strength and coordination are common symptoms for individuals with selected musculoskeletal and neurological impairments. The virtual reality augmented cycling kit (VRACK) was designed as a compact mechatronics system for lower limb and mobility rehabilitation. The system measures interaction forces and cardiac activity during cycling in a virtual environment. The kinematics measurement was added to the system. Due to the constrained problem definition, the combination of inertial measurement unit (IMU) and Kalman filtering was recruited to compute the optimal pedal angular displacement during dynamic cycling exercise. Using a novel benchmarking method the accuracy of IMU-based kinematics measurement was evaluated. Relatively accurate angular measurements were achieved. The enhanced VRACK system can serve as a rehabilitation device to monitor biomechanical and physiological variables during cycling on a stationary bike.
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Ciclismo , Algoritmos , Fenómenos Biomecánicos , Humanos , MasculinoRESUMEN
Compared to static balance, dynamic balance requires a more complex strategy that goes beyond keeping the center of mass (COM) within the base of support, as established by the range of foot center of pressure (COP) displacement. Instead, neuromechanics must accommodate changing support conditions and inertial effects. Therefore, because they represent body's position and changes in applied moments, relative COM and COP displacements may also reveal dynamic postural strategies. To investigate this concept, kinetics and kinematics were recorded during three 12 cm, 1.25 Hz, sagittal perturbations. Forty-one individual trials were classified according to averaged cross-correlation lag between COM and COP displacement (lag(COM:COP)) and relative head-to-ankle displacement (Δ(head)/Δ(ankle)) using a k-means analysis. This process revealed two dominant patterns, one for which the lag(COM:COP) was positive (Group 1 (n=6)) and another for which it was negative (Group 2 (n=5)) . Group 1 (G1) absorbed power from the platform over most of the cycle, except during transitions in platform direction. Conversely, Group 2 (G2) participants applied power to the platform to maintain a larger margin between COM and COP position and also had larger knee flexion and ankle dorsiflexion, resulting in a lower stance. By the third repetition, the only kinematic differences were a slightly larger G2 linear knee displacement (p=0.008) and an antiphasic relationship of pelvis (linear) and trunk (angular) displacements. Therefore, it is likely that the strategy differences were detected by including COP in the initial screening method, because it reflects the pattern of force application that is not detectable by tracking body movements.
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Tobillo/fisiología , Rodilla/fisiología , Equilibrio Postural/fisiología , Adulto , Fenómenos Biomecánicos/fisiología , Femenino , Humanos , Cinética , Masculino , Movimiento/fisiología , PresiónRESUMEN
The objective of this study was to examine the combined electromyographic (EMG) and mechanical response to a rearward perturbation and to separate the response into three categories: preset properties of the muscle, reflex changes to the muscle, and active changes to the muscle. We hypothesized that an active response is required to maintain balance on a moving platform. Eleven healthy adult subjects stood on a platform oscillating at three frequencies (0.75, 1.0, and 1.25 Hz). Ankle extensor EMG activity and ankle moment were analyzed and compared for initial movement cycles. Timing of events in EMG and moment data were examined to separate observed changes into the three categories. Results showed an initial rise in ankle moment as the platform started to move backwards, followed by a more rapid reflex increase. After a slight drop, ankle moment again rose due to active response. By the third cycle of platform movement, the EMG and moment were synchronized with the platform movement, maintaining the body in a desired posture. Initial preset properties of the ankle extensor muscles combined with reflex activity were not sufficient to maintain balance. Following an initial reflex reaction, further active control was required to match the timing of the ankle moment and the platform motion and avoid a loss of balance. This study provides new insight for the rehabilitation of postural deficits.
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Adaptación Fisiológica , Articulación del Tobillo/fisiología , Movimiento/fisiología , Equilibrio Postural/fisiología , Adulto , Análisis de Varianza , Electromiografía , Femenino , Humanos , Masculino , Músculo Esquelético/fisiologíaRESUMEN
Proprioception plays an important role in appropriate sensation of spine position, movement, and stability. Previous research has demonstrated that position sense error in the lumbar spine is increased in flexed postures. This study investigated the change in position sense as a function of altered trunk flexion and moment loading independently. Reposition sense of lumbar angle in 17 subjects was assessed. Subjects were trained to assume specified lumbar angles using visual feedback. The ability of the subjects to reproduce this curvature without feedback was then assessed. This procedure was repeated for different torso flexion and moment loading conditions. These measurements demonstrated that position sense error increased significantly with the trunk flexion (40%, p < .05) but did not increase with moment load (p = .13). This increased error with flexion suggests a loss in the ability to appropriately sense and therefore control lumbar posture in flexed tasks. This loss in proprioceptive sense could lead to more variable lifting coordination and a loss in dynamic stability that could increase low back injury risk. This research suggests that it is advisable to avoid work in flexed postures.