Wearable inertial sensors for human movement analysis

Introduction: The present review aims to provide an overview of the most common uses of wearable inertial sensors in the field of clinical human movement analysis.Areas covered: Six main areas of application are analysed: gait analysis, stabilometry, instrumented clinical tests, upper body mobility assessment, daily-life activity monitoring and tremor assessment. Each area is analyzed both from a methodological and applicative point of view. The focus on the methodological approaches is meant to provide an idea of the computational complexity behind a variable/parameter/index of interest so that the reader is aware of the reliability of the approach. The focus on the application is meant to provide a practical guide for advising clinicians on how inertial sensors can help them in their clinical practice.Expert commentary: Less expensive and more easy to use than other systems used in human movement analysis, wearable sensors have evolved to the point that they can be considered ready for being part of routine clinical routine

Postural threat during walking:Effects on energy cost and accompanying gait changes

Background: Balance control during walking has been shown to involve a metabolic cost in healthy subjects, but it is unclear how this cost changes as a function of postural threat. The aim of the present study was to determine the influence of postural threat on the energy cost of walking, as well as on concomitant changes in spatiotemporal gait parameters, muscle activity and perturbation responses. In addition, we examined if and how these effects are dependent on walking speed. Methods: Healthy subjects walked on a treadmill under four conditions of varying postural threat. Each condition was performed at 7 walking speeds ranging from 60-140% of preferred speed. Postural threat was induced by applying unexpected sideward pulls to the pelvis and varied experimentally by manipulating the width of the path subjects had to walk on. Results: Results showed that the energy cost of walking increased by 6-13% in the two conditions with the largest postural threat. This increase in metabolic demand was accompanied by adaptations in spatiotemporal gait parameters and increases in muscle activity, which likely served to arm the participants against a potential loss of balance in the face of the postural threat. Perturbation responses exhibited a slower rate of recovery in high threat conditions, probably reflecting a change in strategy to cope with the imposed constraints. The observed changes occurred independent of changes in walking speed, suggesting that walking speed is not a major determinant influencing gait stability in healthy young adults. Conclusions: The current study shows that in healthy adults, increasing postural threat leads to a decrease in gait economy, independent of walking speed. This could be an important factor in the elevated energy costs of pathological gait

What are the differences between subjects with and without flatfoot condition, with the aid of ultrasonography, kinematics, and kinetics in posture and gait?

O complexo do pé tem um papel importante na postura, equilíbrio, estabilidade e movimento, durante as posições estáticas e nos padrões gerais de movimento. Alterações estruturais ou funcionais no complexo do pé e no seu posicionamento podem afetar a postura e o movimento das estruturas distais e proximais. Comumente, indivíduos com pé plano desenvolvem restrições neurológicas ou musculares, frouxidão ligamentar ou articular, movimento excessivo e atividade muscular. Essa condição leva a maiores riscos de desenvolver lesões por sobrecarga mecânica nas articulações dos membros inferiores adjacentes. O objetivo é determinar se existem diferenças entre indivíduos com pé plano em comparação com indivíduos com pé neutro, em relação à postura e à análise do padrão de marcha. A amostra foi constituída por sujeitos com pé plano e neutro, alocados em dois grupos. Todos os sujeitos foram submetidos a procedimentos de avaliação para serem alocados em um dos grupos. Cada participante foi submetido à avaliação do padrão de marcha e postura, com auxílio de sistema MOCAP, e à avaliação da rigidez muscular com Ultrassonografia e, por fim, à avaliação da pressão plantar com uma plataforma de pressões. Os sujeitos com pé plano mostraram várias alterações e diferenças quando comparados aos participantes com pé neutro, de acordo com os principais resultados da análise da postura e do padrão de marcha. Considerando todos os estudos realizados e incluídos nesta tese, várias diferenças foram encontradas em indivíduos de pé plano. Porém, a maioria desses resultados são contraditórios com os resultados presentes na literatura, dando um crescimento da evidência científica sobre a condição de pé plano e a sua influência na postura, e no padrão de marcha. No entanto, em relação à falta de consenso sobre os resultados e condições de avaliação, vários estudos necessitam ser realizados para criar uma maior robustez da evidência científica. Porém, no que se refere ao rigor metodológico em relação a diferentes parâmetros, novos estudos precisam de abranger variáveis que foquem a avaliação geral da condição e não apenas do complexo do pé. Palavras-chave: POSTURA DE PÉ, PADRÕES DE MOVIMENTO, PÈ PLANO, BIOMECÂNICA.The foot complex has an important role in posture, balance, stability, and movement, during the static positions and in overall movements' patterns. Structural or functional alteration in the foot complex and foot posture may have an impact on posture and movement on distal and proximal structures. Commonly, subjects with flatfoot develop neurological or muscular restrictions, ligament or joint laxity, excessive motion, and muscle activity. This condition leads to higher risks of developing mechanical overloading injuries on adjacent lower-limb joints. The aim of this study is to determine if there are differences between flatfoot subjects compared to neutral foot subjects, regarding posture and gait pattern analysis. The sample was constituted by subjects with a flat and neutral foot, allocated in two groups. All subjects were submitted to assessment procedures to be allocated in one of the groups. Therefore, each participant was submitted to gait pattern and posture assessment, with the aid of a MOCAP system, and to muscle stiffness assessment with an ultrasound-based Shear- Wave Elastography and, finally to plantar pressure assessment with a baropodometric platform. Flatfoot subjects showed several alterations and differences when compared to neutral foot participants considering all principal outcomes along with posture and gait pattern. Considering all studies realized and included in this thesis, several differences were found in flatfoot subjects. Thus, most of those results are contradictory to those found in the literature, giving a growth of evidence relatively to foot posture condition and influence in posture and gait pattern. However, regarding the lack of consensus about the outcomes and assessment conditions, further studies need to be performed to create a more robust body of evidence. Although, regarding methodological deficiency regarding influencing aspects, further studies need to encompass methodological variables handling to focus on an overall evaluation of the condition and not only on the foot complex