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BACKGROUND: Walking aids such as walking frames offer support during walking, yet paradoxically, people who self-report using them remain more likely to fall than people who do not. Lifting of walking frames when crossing door thresholds or when turning has shown to reduce stability, and certain design features drive the need to lift (e.g. small, non-swivelling wheels at the front). To overcome shortfalls in design and provide better stability, biomechanists and industrial engineers engaged in a Knowledge Transfer Partnership to develop a novel walking frame that reduces the need for lifting during everyday tasks. This paper presents the results for the final prototype regarding stability, safety and other aspects of usability. METHODS: Four studies were conducted that explored the prototype in relation to the current standard frame: a detailed gait lab study of 9 healthy older adults performing repeated trials for a range of everyday tasks provided mechanical measures of stability, a real-world study that involved 9 users of walking frames provided measures of body weight transfer and lifting events, two interview studies (5 healthcare professionals and 7 users of walking frames) elicited stakeholder perceptions regarding stability, safety and usability. RESULTS: Analysis of healthy older adults using a standard walking frame and the prototype frame demonstrated that the prototype increases stability during performance of complex everyday tasks (p < 0.05). Similarly, gait assessments of walking frame users in their home environment showed that the prototype facilitated safer usage patterns and provided greater and more continuous body weight support. Interviews with healthcare professionals and users showed that the prototype was perceived to be safe and effective and hence more usable. CONCLUSIONS: The outcomes of the separate studies all support the same conclusion: the prototype is an improvement on the status quo, the typical front-wheeled Zimmer frame for indoor use which has not changed in design for decades. The significance of this work lies in the success of the Knowledge Transfer Partnership and in biomechanics-informed design leading to improvements, which in future may be applied to other walking aids, to benefit walking aid users by promoting safer, more stable use of their aid.
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Marcha , Caminata , Humanos , Anciano , Fenómenos Biomecánicos , Accidentes por Caídas , Peso CorporalRESUMEN
BACKGROUND: Walking aids are designed for structural support during walking, however, surprisingly self-reported use of a walking aid ("Yes, I use one.") has been identified as a risk factor for falling. Adjustment and design of walking aids may affect their usefulness in facilitating a stable walking pattern. We previously identified that increased body weight transfer onto a walking frame ('device loading') is associated with increased user stability. RESEARCH QUESTION: We asked: "Could adjustment of walking frame height to a lower height than clinically recommended serve as a mechanism to facilitate device loading and thereby increase stability? And: "Do ultra-narrow frames have an adverse effect on stability as compared to standard-width frames? METHODS: Ten older adults that were users of front-wheeled walking frames walked with walking frames of 1) 'standard width, standard height', 2)'standard width, low height', 3)'narrow width, standard height'. Smart Walker technology was used to record forces acting on the walking frame and inside the user's shoes, and cameras recorded relative position of the user's feet in relation to the frame's feet. Stability of the user-frame system and device loading (percent body weight transferred onto the frame) were calculated. A general linear mixed effects model was used for statistical analysis. RESULTS: A lower height setting did not increase device loading and stability, therefore adjusting the height to a lower setting proved to be an unsuccessful mechanism to increase stability. However, device loading was positively correlated with stability for all frame conditions (pâ¯<â¯0.05). Finally, stability was reduced when walking with the ultra-narrow, as compared to standard-width, frame (pâ¯=â¯0.002). SIGNIFICANCE: To increase stability in fall-prone users, active encouragement to transfer body weight onto the walking frame is needed. Considering the adverse effects of ultra-narrow frames on stability, such frames should be prescribed and used with caution.
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Bastones/provisión & distribución , Relación Cintura-Estatura , Caminata/fisiología , Anciano , Femenino , Humanos , MasculinoRESUMEN
The Fit4Purpose project aims to develop upper limb prosthetic devices which are suitable for deployment in lower- and middle-income countries (LMIC's). Open-frame trans-radial socket designs are being considered, formed of several, linked components, including pads which interface directly with the skin surface. A mechanical tool has been developed to aid the design of pad shapes, using an array of square brass bars of varying lengths (i.e. a pin-array) to apply a chosen normal pressure distribution to an area of tissue. The shape to which the tissue is displaced can then be captured by clamping the bars together to fix their relative positions. The device is described, then three short studies are used to demonstrate its use on the forearm of a single, anatomically intact subject. The first investigates the effect of array size on the measured surface stiffness, finding an inverse relationship with a similar characteristic to previous published results. The second tests the hypothesis that a pad with a shape which duplicates that captured by the device will generate a similar overall load to the original pins if applied to the same region of tissue. The results support the hypothesis, but also highlight the sensitivity of the interface loading to the underlying muscle activation. Finally, the tool is used to demonstrate that different tissue displacements are observed when the same pressure distribution is applied to different areas of the forearm. Whilst the tool itself is a simple device, and the techniques used are not sophisticated, the studies suggest that the approach could be useful in pad design. Although it is clearly not appropriate for clinical application in its current form, there may be potential to develop the concept into a more practical device. Other applications could include the design of other devices which interface with the skin, the generation of data for validation of finite element models, including the application of known pressure distributions and tissue deformations during Magnetic Resonance Imaging, and the assessment of matrix pressure sensing devices on compliant materials with complex geometries.
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Miembros Artificiales , Humanos , Diseño de Prótesis , Radio (Anatomía)RESUMEN
BACKGROUND: Walking aids are issued to older adults to prevent falls, however, paradoxically their use has been identified as a risk factor for falling. To prevent falls, walking aids must be used in a stable manner, but it remains unknown to what extent associated clinical guidance is adhered to at home, and whether following guidance facilitates a stable walking pattern. It was the aim of this study to investigate adherence to guidance on walking frame use, and to quantify user stability whilst using walking frames. Additionally, we explored the views of users and healthcare professionals on walking aid use, and regarding the instrumented walking frames ('Smart Walkers') utilized in this study. METHODS: This observational study used Smart Walkers and pressure-sensing insoles to investigate usage patterns of 17 older people in their home environment; corresponding video captured contextual information. Additionally, stability when following, or not, clinical guidance was quantified for a subset of users during walking in an Activities of Daily Living Flat and in a gait laboratory. Two focus groups (users, healthcare professionals) shared their experiences with walking aids and provided feedback on the Smart Walkers. RESULTS: Incorrect use was observed for 16% of single support periods and for 29% of dual support periods, and was associated with environmental constraints and a specific frame design feature. Incorrect use was associated with reduced stability. Participants and healthcare professionals perceived the Smart Walker technology positively. CONCLUSIONS: Clinical guidance cannot easily be adhered to and self-selected strategies reduce stability, hence are placing the user at risk. Current guidance needs to be improved to address environmental constraints whilst facilitating stable walking. The research is highly relevant considering the rising number of walking aid users, their increased falls-risk, and the costs of falls.
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Andadores , Caminata , Accidentes por Caídas/prevención & control , Actividades Cotidianas , Anciano , Anciano de 80 o más Años , Marcha , HumanosRESUMEN
With the advent of miniaturized sensing technology, which can be body-worn, it is now possible to collect and store data on different aspects of human movement under the conditions of free living. This technology has the potential to be used in automated activity profiling systems which produce a continuous record of activity patterns over extended periods of time. Such activity profiling systems are dependent on classification algorithms which can effectively interpret body-worn sensor data and identify different activities. This article reviews the different techniques which have been used to classify normal activities and/or identify falls from body-worn sensor data. The review is structured according to the different analytical techniques and illustrates the variety of approaches which have previously been applied in this field. Although significant progress has been made in this important area, there is still significant scope for further work, particularly in the application of advanced classification techniques to problems involving many different activities.
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Técnicas Biosensibles , Electrónica Médica , Actividad Motora/fisiología , HumanosRESUMEN
There is a common clinical belief that transverse plane tibial rotation is controlled by the rearfoot. Although distal structures may influence the motion of the tibia, transverse plane tibial rotation could be determined by the proximal hip musculature. Cadaver studies have identified gluteus maximus as having the largest capacity for external rotation of the hip. This study was therefore undertaken to investigate the effect of gluteus maximus on tibial motion. Kinematic data were collected from the foot and tibia along with EMG data from gluteus maximus for 17 male subjects during normal walking. A number of kinematic parameters were derived to characterise early stance phase. Gluteus maximus function was characterised using RMS EMG and EMG on/off times. No differences in muscle timing were found to be associated with any of the kinematic parameters. In addition, no differences in gluteal activation levels were found between groups of subjects who had different amounts of tibial rotation. However, there was a significant difference (p<0.001) in gluteus maximus activation when groups were defined by the time taken to decelerate the tibia (time to peak internal velocity). Specifically, subjects with greater gluteus maximus activity had a lower time to decelerate the tibia. We suggest that a high level of gluteus maximus activity results in a larger external torque being applied to the femur, which ultimately leads to a more rapid deceleration of the tibia.