Análise clínica da marcha exemplo de aplicação em laboratório de movimento

Neste artigo pretende-se introduzir os conceitos principais da análise quantitativa da marcha como uma ferramenta de apoio à prática clínica. Assim, para as várias áreas de estudo, cinemática, cinética, pressões, actividade muscular, apresenta-se a respectiva importância para a avaliação clínica, abordam-se meios e métodos para aquisição, tratamento e apresentação das diversas variáveis biomecânicas. Neste artigo dá-se ainda a indicação da aplicação da análise quantitativa da marcha no caso concreto do laboratório do movimento do CRPG Centro de Reabilitação Profissional de Gaia

The effects of shoe traction and obstacle height on lower extremity coordination dynamics during walking.

This study aims to investigate the effects of shoe traction and obstacle height on lower extremity relative phase dynamics (analysis of intralimb coordination) during walking to better understand the mechanisms employed to avoid slippage following obstacle clearance. Ten participants walked at a self-selected pace during eight conditions: four obstacle heights (0%, 10%, 20%, and 40% of limb length) while wearing two pairs of shoes (low and high traction). A coordination analysis was used and phasing relationships between lower extremity segments were examined. The results demonstrated that significant behavioral changes were elicited under varied obstacle heights and frictional conditions. Both decreasing shoe traction and increasing obstacle height resulted in a more in-phase relationship between the interacting lower limb segments. The higher the obstacle and the lower the shoe traction, the more unstable the system became. These changes in phasing relationship and variability are indicators of alterations in coordinative behavior, which if pushed further may have lead to falling

Master of Science

thesisStabilization of the head is critical for running. Homo sapiens possess several anatomical features that are useful for head stabilization. In order to test the functional value of some of these features, namely the location of the center of mass and the muscular connection between the skull and shoulder girdle, mechanical models are created. These mechanical models are representative of Homo sapiens and their ancestors. These models are subject to the kinematics and dynamics of a complete running gait cycle. The results show that the location of the center of mass for the Homo sapiens is superior to that of its ancestors for the purposes of head stabilization. Furthermore, the results show that the muscular connection between the skull and the shoulder girdle of Homo sapiens permit the counter rotation of the shoulders to reduce the energy needed to stabilize the head during running

Development and validation of biomechanical models to quantify horse back forces at the walk in three horse breeds

Therapeutic horseback riding is a common component of physical therapy programs. Quantification of the horse back forces will provide vital information to match therapeutic riders with equine partners. To meet this medical need, a model to quantify the horse back forces from ground reaction forces was developed to test the hypothesis that the forces transferred to a static weight on the horse’s back can be predicted given horse breed and weight. Simultaneous, real time kinetic, kinematic, and back force data on a static weight were collected from 7 adult horses: 3 thoroughbreds, 3 quarter horses, and 1 paso fino. An integrated system consisting of a force platform, an active motion detection system and wireless force transducers were used. Data was collected from a minimum of four successful trials from all horses at a walk (1.3-2.0 m/s). Inverse dynamic analysis was used to calculate the fore and hind limb joint forces to the shoulder and hip, taking into consideration all 4 limbs’ motion per stride cycle. Virtual segments were created to model the equine back as a series of springs and dampers and joined to the limbs. Calculated forces from the inverse dynamics analysis were then input to the spring-damper model sequentially and at the same frequency as data collection. The energy absorption coefficients were derived by aligning the model output forces of the fore- and hind limb data with measured back forces. Horse back forces were simulated with different coefficients for each breed, and specifically for each horse. . Simulated results had a significant positive correlation (r = 0.81±0.04, p \u3c0.001) with forces measured directly on the back. The data from this investigation will contribute to mechanisms to predict forces experienced by the rider during horse motion to advance the science of therapeutic riding

Comparison of Assistive Mobility Devices with Axillary Supports

Assistive ambulatory devices with axillary supports are compared using a multidisciplinary approach. Axillary supports are commonly referred to as "shoulder supports" on standard crutches. A framework is presented that compares axillary supports based on loading characteristics during initial contact and during a stride. The underlying goal of this research is to lay the foundation for an axillary support design that is safe. The force normal to the axillary support of two types of assistive devices, axillary crutches and the Strutter, is found experimentally for 2-point gait and 2-point gait with no hands. A dynamic model is developed to estimate the force tangential to the axillary support required for axillary crutches and the Strutter to have the same stride time. Models for the Strutter are also developed to study the response of the axillary support to impact loads due to initial contact

Slip and Fall Risks: Pre-Slip Gait Contributions and Post-Slip Response Effects

This thesis describes analysis methods and results from slip-perturbed gait experiments. The risk for falls was related both to the conditions present at heel strike and to the nature of the response. Gait analysis was performed using the Human Movement and Balance Laboratory (HMBL) model, a fifteen segment, fourteen joint model of the human body that was developed as part of this thesis effort. Resulting kinematics and kinetics included three-dimensional angles describing relative segment rotations, segmental and whole-body centers-of-mass, and joint actuation torques for the entire body.The relationship between pre-slip gait characteristics and the magnitude of slips was explored for both younger and older adults. Slip severity, either hazardous or non-hazardous, was determined using a 1.0 m/s peak slip velocity threshold. Hazardous slips were associated with greater step lengths normalized by leg length, larger and more rapidly changing foot-floor angles at heel strike, and increased cadence across the two subject groups. These results suggest that gait characteristics play an important role in the severity of slips. Older adults were found to walk with shorter step lengths and with smaller and more slowly changing foot-floor angles at heel strike compared to younger subjects, suggesting that age effects also impact slip severity.The effects of slipping and trailing leg response on slip outcome (falls or recoveries) were explored. Slip severity was found to be the most significant parameter related to outcome. Response strategies were classified, based on trailing leg dynamics, as either minimal, foot-flat, mid-flight, or toe-down. Slipping and trailing leg hip and knee torques were determined using the HMBL model and timing and magnitude parameters from these torques were then identified. Relationships between these parameters, age group (younger/older), response strategy, and outcome were then explored. Age was not found to be significantly related to response strategy or outcome, nor was response strategy found to be related to outcome. Slipping leg knee torque timing and magnitude parameters were related to slip severity and to outcome for hazardous slips. These results suggest that slip responses, coupled with slip severity, determine fall or recovery outcomes

Seguimento do movimento humano usando visão computacional : aplicação na análise da marcha

Tese de mestrado. Engenharia Electrotécnica e de computadores (área de especialização em Informática e Automação). Faculdade de Engenharia. Universidade do Porto. 200

Quantification of knee extensor muscle forces: a multimodality approach

Given the growing interest of using musculoskeletal (MSK) models in a large number of clinical applications for quantifying the internal loading of the human MSK system, verification and validation of the model’s predictions, especially at the knee joint, have remained as one of the biggest challenges in the use of the models as clinical tools. This thesis proposes a methodology for more accurate quantification of knee extensor forces by exploring different experimental and modelling techniques that can be used to enhance the process of verification and validation of the knee joint model within the MSK models for transforming the models to a viable clinical tool. In this methodology, an experimental protocol was developed for simultaneous measurement of the knee joint motion, torques, external forces and muscular activation during an isolated knee extension exercise. This experimental protocol was tested on a cohort of 11 male subjects and the measurements were used to quantify knee extensor forces using two different MSK models representing a simplified model of the knee extensor mechanism and a previously-developed three-dimensional MSK model of the lower limb. The quantified knee extensor forces from the MSK models were then compared to evaluate the performance of the models for quantifying knee extensor forces. The MSK models were also used to investigate the sensitivity of the calculated knee extensor forces to key modelling parameters of the knee including the method of quantifying the knee centre of rotation and the effect of joint translation during motion. In addition, the feasibility of an emerging ultrasound-based imaging technique (shear wave elastography) for direct quantification of the physiologically-relevant musculotendon forces was investigated. The results in this thesis showed that a simplified model of the knee can be reliably used during a controlled planar activity as a computationally-fast and effective tool for hierarchical verification of the knee joint model in optimisation-based large-scale MSK models to provide more confidence in the outputs of the models. Furthermore, the calculation of knee extensor muscle forces has been found to be sensitive to knee joint translation (moving centre of rotation of the knee), highlighting the importance of this modelling parameter for quantifying physiologically-realistic knee muscle forces in the MSK models. It was also demonstrated how the movement of the knee axis of rotation during motion can be used as an intuitive tool for understanding the functional anatomy of the knee joint. Moreover, the findings in this thesis indicated that the shear wave elastography technique can be potentially used as a novel method for direct quantification of the physiologically-relevant musculotendon forces for independent validation of the predictions of musculotendon forces from the MSK models.Open Acces