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Evaluation of different hindfoot kinematics according to various shoe types during walking using biplanar fluoroscopy
No full textUnlike Skin marker-based models, biplanar fluoroscopy can evaluate the kinematic effects of various shoes. This study investigated foot and ankle kinematics across various shoe types during walking using a biplanar fluoroscopic system. Fifteen healthy participants were enrolled. All participants underwent three-dimensional (3D) computed tomography, and biplanar fluoroscopic images were captured during the stance phase of gait for barefoot and three different shoe types. 3D kinematic data of the ankle and subtalar joints were calculated using the anatomical coordinate system through the 3D/2D registration method. Running shoes (RS) significantly reduced maximum ankle dorsiflexion (p = 0.007), hindfoot dorsiflexion (p = 0.001) compared with barefoot. Rocker bottom shoes (RBS) reduced ankle and hindfoot DF-PF ROM (p < 0.001), and increased subtalar ROM by increasing subtalar plantarflexion(p = 0.047). Climbing shoes reduced the peak hindfoot dorsiflexion (p < 0.001), and ankle dorsiflexion (p = 0.013). High heels (HH) caused significant ankle (p < 0.001) and hindfoot (p <0.001) plantar flexion, along with increased hindfoot inversion (p = 0.008) and internal rotation (p = 0.003). In conclusion, Shoed walking reduced dorsiflexion compared with barefoot walking, potentially benefiting conditions such as anterior ankle impingement. RBSs may alleviate arthritis symptoms by limiting motion, whereas HHs increase hindfoot inversion, potentially increasing the risk of ankle injury and long-term joint damage.
Ein neues Modell der Mechanik des menschlichen Rumpfes beim Gehen
No full textAfter about 15 years of “dynamical” trunk studies, too many questions stay unexplained, and too many kinematical and dynamical aspects unexplored. We know from kinematical studies that trunk amplitudes, frequencies and phases are related to velocity. But we do not know how. In addition, can these amplitudes or phases be predicted? Are the changes in the amplitudes, frequencies or phases a function of anthropometry? Or something else? Why a person has its own individual gait? Could it be possible to find objective parameters in order to describe intra- and inter-individual variations of trunk amplitudes, frequencies and phases? The present work tries to find answers to these questions from a mechanical point of view. First expanding our kinematical knowledge and relating this to anthropometry, and then introducing a new model of the human trunk mechanics in walking.Beim menschlichen Gehen interagiert der Rumpf systematisch mit den
Extremitäten. Aus diesem Grund kann man Rumpfamplituden, Frequenzen und
Phasen als eine Funktion der Fortbewegungsgeschwindigkeit beobachten. Das
Bewegungsbild des Rumpfes aber ist individuell. Um die Ursachen der
intra- und interindividuellen Variation der Kinematik des Rumpfes zu
finden, wurden zwei Hypothesen geprüft: 1) die intra- und interindividuelle
Variation der Kinematik des Rumpfes ist eine Funktion der Massenverteilung,
2) hat man eine bestimmte Masseverteilung und eine gegebene
Geschwindigkeit, dann wird die intra- und interindividuelle Variation in
der Kinematik des Rumpfes durch die Änderungen in den visco-elastischen
Eigenschaften des Bewegungsapparates realisiert. Um Hypothese 1 zu testen,
wurde eine Studie mit 106 Probanden (50 w, 56 m) durchgeführt. Bei dieser
Studie wurde keine einfachen Zusammenhänge zwischen den 48
anthropometrischen und den kinematischen Parametern der Rumpfbewegung
(Freiheitsgrad 6) bei 4 km/h (energetische Optimalgeschwindigkeit nach
Cavagna) gefunden. Die in der vorliegenden Arbeit präsentierten
kinematischen Ergebnisse stellen dar, dass die Dämpfungsmechanismen (Dm) in
der Frontalebene betont sind, und auch, dass die Dm bei den Frauen stärker
ausgeprägt sind als bei den Männern. Außerdem zeigen die Ergebnisse, dass
die so genannten „Kompensationsmechanismen“ zwischen Kopfrotationen und
Schultertranslationen geschwindigkeitsabhängig sind, und auch, dass Frauen
und Männer unterschiedliche Strategien nutzen. Um die Hypothese 2 zu
testen, wurde ein Morpho-Funktionaelles Modell des Rumpfes mit
Freiheitsgrad 14, basierend auf den Hanavan Modell, vorgeschlagen. Die
Ergebnisse der Simulationen konnten nicht widerlegen, dass die
visco-elastischen Parameter, die bei der Simulation berechnet werden, eine
solide erklärende Kenngröße für die Änderungen der Amplituden, Frequenzen
und Phasen der verschiedenen Körpersegmenten des Rumpfes beim Gehen sind.
Sie sind auch in der Lage, die intra- und interindividuellen kinematischen
Variationen zu erklären. Die hier vorliegende Arbeit stellt zwei
unterschiedliche Anwendungsfelder für die visco-elastischen Parameter dar.
Das erste ist eine medizinisch orientierte Applikation, während sich das
zweite auf bionisch inspirierte Robotik oder morpho-funktionell Maschinen
bezieht.During human motion, the trunk systematically interacts with the
extremities. Changes of trunk amplitudes, frequencies and phases can be depicted as a function of gait’s velocity. These changes, however, vary among human beings. In order to find the causes of these intra and inter-individual variations, two possible hypotheses were tested: 1) intra and inter-individual variations of trunk kinematics are due to the segmental mass distribution represented by anthropometry, 2) For a defined mass distribution, and a given velocity, the variations of trunk kinematics are generated due to the changes in the visco-elastic properties of the locomotor system.To check hypothesis 1 a study on 106 volunteers (50 f, 56 m) was performed. No simple relations between 48 anthropometric parameters and the 6 DOF kinematic parameters of the trunk motion during walking at 4 km/h could be identified.Kinematical results of the present work show that the damping mechanisms towards the head (caudo-cranially) vary in dependence of anatomical planes and gender. In addition, the findings of this work display that the so called “compensation mechanism” between head rotations and body or shoulder translations are at first velocity dependent, but also that women and men use different strategies. In order to check hypothesis 2, a 14 DOF functional morphological model of the trunk based on Hanavan’s model was proposed. Results of the simulations could not disprove that visco-elastic parameters, which are obtained by the simulations, are a solid base to explain the change in amplitudes, phases and frequencies of the different body segments in normal walking. They also are able to explain inter and intra-individual kinematical variations. The present work introduces also two different application fields for the simulations and the visco-elastic parameters. The first one is a medically oriented application, while the second is oriented to bionically inspired robots or morphofunctional machines
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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