THEORETICAL MODEL VALIDATION OF MUSCLE FORCES DURING EXTREME MOVEMENTS

Introduction: The validation of the involved muscular forces for a computer model of the human body, which allows simulation of internal forces in patients, was achieved by inverse-dynamic analysis. Methods: Beginning with an extreme vertical jump, joint moments were extracted from high-speed film data and eventually subdivided into muscular forces. The muscle groups responsible for movements were determined by electromyography. A squat jump with both legs and maximum strength was filmed in the sagittal plane with a frequency of 200 Hz. Moments in the hip, knee and ankle joints were determined from the film data. Using surface electrodes of a Neuraxon Myosoft 2008 system and an amplifier system from Multichannel Systems, the muscle groups responsible for movements were electromyographically determined. The muscle insertions and muscle paths were extracted from MRI pictures of patients. Results: With this information joint moments can be subdivided into single muscle forces. Depending on the jump demands, the muscle groups responsible for movements can be divided and analyzed in six extensor groups. Conclusion: Inverse-dynamic muscle force analysis is a basis which can be expanded for the validation of complex movements under extreme internal loads in patients

INTERNAL LOAD ESTIMATION FOR CLINICAL PROGNOSIS

Introduction: In therapy and rehabilitation it is important to know the ranges of the expected loads in the human body resulting from different movements. Because of the difficulty of measuring experimental dynamic loads (hip loads, Bergmann, Taylor), the loads created under these dynamic conditions are estimated by theoretical models and computer simulation. The method will be presented considering a squat jump. Methods: A squat jump performed with both legs, maximum strength and without counter-movement was modeled by a two-dimensional multi-body system with four segments. The movement-generating muscles were implemented taking into account the muscle insertions and paths, as well as Hill’s force-velocity-relation. The data were extracted from MR images and the literature. The muscles were excited by Hatze’s stimulation model. To obtain maximal jump height, the muscles were excited coordinately by optimization algorithms. Results: In the case of a vertical jump, the loads reached maximum values of 4250 N, 4750 N and 4800 N in hip, knee and ankle joints, respectively. The mean values of the hip, knee and ankle joint loads were 3100 N, 3650 N and 2600 N, respectively. Comparing the calculated values with those of Bassey et al. (1997), who measured the hip load during a fast jump, a good agreement of the load values was found. Conclusion: With this vertical jump it was proved that an estimation of joint loads is possible. A multitude of movements can be examined with this model in order to compile data for a joint load database which can be used for clinical prognosis. References: Bassey, E.J., Littlewood, J.J., Taylor, S.J.G. (1997). Relations Between Compressive Axial Forces in an Instrumented Massive Femoral Implant, Ground Reaction Forces, and Integrated Electromyographs From Vastus Lateralis During Various Ostogenic Exercies. J. Biomechanics 30, 213-223. Bergmann, G., Graichen, F., Rohlmann, A. (1993). Hip Joint Loading During Walking and Running, Measured in Two Patients. J. Biomechanics 26, 969-990

Обучение креативной деятельности как одно из направлений современного зарубежного образования (на примере Великобритании)

Представлен анализ зарубежной психолого-педагогической литературы, а также правительственных документов Великобритании, посвященных проблемам обучения креативной деятельности. Выявлено, что креативная деятельность характеризуется целенаправленностью, ориентирована на создание нового продукта, связана с вовлечением воображения и ориентирована на развитие мышления учащихся и формирование у них навыков решения проблемных задач. Выявлены условия успешности обучения креативной деятельности, к которым относятся обучение учащихся критическому мышлению; учет индивидуальных особенностей учащихся; предоставление адекватной оценки деятельности учащихся; рациональное распределение времени и уровня нагрузки; положительная мотивация учащихся; активное вовлечение положительных эмоций учащихся; предоставление учащимся адекватного уровня свободы действий; соблюдение баланса между традиционными и инновационными методами обучения; совместная работа учащихся; наличие у учащихся навыков решения проблемных задач. Исследование показало, что обучение креативной деятельности является одним из основных направлений процесса реорганизации системы образования за рубежом

Increased Brain Reward Responsivity to Food-Related Odors in Obesity

Objective Food odors serve as powerful stimuli signaling the food quality and energy density and direct food-specific appetite and consumption. This study explored obesity-related brain activation in response to odors related to high- or low-energy-dense foods. Methods Seventeen participants with obesity (BMI > 30 kg/m2 ; 4 males and 13 females) and twenty-one with normal weight (BMI < 25 kg/m2 ; 9 males and 12 females) underwent a functional magnetic resonance imaging scan in which they received chocolate (high-energy-dense food) and cucumber (low-energy-dense food) odor stimuli. Participants' olfactory and gustatory functions were assessed by the "Sniffin' Sticks" and "Taste Strips" tests, respectively. Results Compared with normal-weight controls, participants with obesity had lower odor sensitivity (phenylethyl alcohol) and decreased odor discrimination ability. However, participants with obesity demonstrated greater brain activation in response to chocolate compared with cucumber odors in the bilateral inferior frontal operculum and cerebellar vermis, right ventral anterior insula extending to putamen, right middle temporal gyrus, and right supramarginal areas. Conclusions The present study provides preliminary evidence that obesity is associated with heightened brain activation of the reward and flavor processing areas in response to chocolate versus cucumber odors, possibly because of the higher energy density and reinforcing value of chocolate compared with cucumber.Peer reviewe

The Aetiology of Olfactory Dysfunction and Its Relationship to Diet Quality

People with olfactory loss may choose foods rich in sugar, salt and fat to compensate their loss—foods that constitute a Western-style diet (WSD). However, olfactory dysfunction has not been consistently linked to any particular type of dietary change. Here we considered whether the aetiology of olfactory dysfunction may affect consumption of a WSD. Two-hundred and twenty-two people with olfactory dysfunction of varying cause, were tested for chemosensory performance and their frequency of consumption of a WSD. There was no evidence of a link between a WSD and olfactory dysfunction at the aggregate level, but an aetiology-based approach revealed various patterns, showing both positive and negative associations between olfactory performance and consumption of a WSD. We suggest a number of reasons why, in certain cases, greater olfactory dysfunction may be linked to lower intakes of a WSD, and the role that different aetiologies may have in affecting choices for foods that may appeal following olfactory impairment

Verbesserung einer Kreuzkorrelationsanalyse mit ungünstiger Quellverteilung durch Slant Stack und Migrationsanalyse

Aufgrund des nicht isotropen seismischen Hintergrundsignals, das im Stadtgebiet von Bukarest aufgezeichnet wurde, können die Wellengruppen in den Kreuzkorrelogrammen nicht als Impulsantwort des Untergrundes interpretiert werden. Die dominanten Wellengruppen konnten aber mit Hilfe einer Migrationsanalyse einer Punktquelle im Stadtgebiet zugeordnet werden. Die extrem kurze Länge der Ausgangszeitreihen, die zum Lokalisieren der Punktquelle in der Migrationsanalyse benötigt werden, ermöglicht eine Abbildung ihrer zeitlichen Variationen. Mit Hilfe eines Slant Stacks konnten die Wellengruppen in den Kreuzkorrelogrammen, die auf dem diffusen Anteil im seismischen Hintergrundsignal basieren, durch Stapelung verstärkt werden, während die dominanten Wellengruppen der Punktquelle in der Stapelung nicht verstärkt wurden. Auf diese Weise konnten das Signal-Stör-Verhältnis wesentlich verbessert und Dispersionskurven gewonnen werden. Diese konnten zu einem einfachen Untergrundmodell invertiert werden, das eine Lücke in den vorhandenen Modellen für die Struktur in den ersten 400 m unter Bukarest schließt

MUSCLE ACTIVITY OF THREE SUBJECTS DIFFERING IN WEIGHT AND HEIGHT DURING A VERTICAL JUMP

Introduction: The first measurement was done to evaluate changes of potentials of surface electromyography with different locations of electrode sites and different resistors between the electrodes. The objective of the second was to investigate the activity of muscles in their stimulation sequence, the quantitative participation of the single muscle and cinematic study of vertical jumps. This work is part of a project to determine the internal forces of the human motional apparatus with an anatomical model of muscles. Methods: For each measurement we chose a Noraxon EMG, ECG electrodes from Medicotest, and the electrodes were placed following the description of D.A. Winter. At first we chose the M. gastro. med., M. gastro. lat., and M. soleus of male subject and did a measurement while the subject moved ten times from a ‘standing at attention’ posture to standing on the tips of his toes with a resistor between the electrodes higher than 60 Ohm and one with a resistor lower than 5 Ohm. Then we moved the electrodes 2 cm and 4 cm in the vertical and horizontal directions (resistor of lower than 5 Ohm). Secondly, we chose eight muscles (M. glut. max., M. semitend., M. biceps femoris, M. rectus femoris, M. vastus lat., M. vastus med., M. gastro. med., M. soleus) of three male subjects differing in weight and height and did the measurements while the subjects jumped ten times from a squatting position on a force plate, filmed by a high-speed camera. Results: The measurements with a 60 Ohm resistor and a 5 Ohm resistor differed, as well as the measurements with different locations of electrode sites. The second measurements showed that the M. gas. med. seemed to be the muscle with the highest response, followed by the M. sol. The M. vast. med., M. vast. lat., M. bic. fem. and M. rec. fem. had the same type of reaction. In one case the M. glut. max. seemed to be important while jumping. In an second case the M. semit. showed a high response. The muscles of the tallest subject had the longest activity, and the muscles of the shortest one had the shortest activity. The timedependent angles of knee, hip and foot joints of every subject were nearly identical. Like the EMG, the acceleration phases of the tallest subject took the longest time, while the acceleration phase of the shortest subject took the least time. Conclusions: Firstly, it is possible to see how important the placement and resistor of the electrodes is. Secondly, there is a possible relationship between the beginning of the activity of the muscles and the size of the subjects, as well as a correlation of the angles and the size of the subjects. This effect should be considered in using such calculations of the internal forces of the human motional apparatus in the development of protheses and in sports science

THREE DIMENSIONAL MEASUREMENT OF THE GEOMETRY OF THE HUMAN MOTION APPARATUS

INTRODUCTION: This work is part of a project of the Department for Sports Medicine to calculate the internal stresses arising when jumping from a squat position. The goal of the project is to facilitate individual calculations by establishing a biomechanical model whose parameters are the major anatomical-geometrical and physiological quantities, gained by electromyogram (EMG) and radiological measurement. Procedures for acquiring the latter data are described here. METHODS: As the study did not involve pathologies, ionizing radiation was ruled out, and magnetic resonance imaging (MRI) was used. The biomechanical model required geometrical parameters from joint positions beyond those occurring during the squat-vault, so the Siemens Magnetom Open device was chosen. It has the disadvantage of relatively low magnetic field strength (0.2 T), but allows for almost unlimited movement in the table plane. Different measurement parameters were evaluated. As the length of the field of view was about 25 cm, the different joints had to be scanned separately. A positioning table was used to serve three purposes: 1. Positioning with defined joint angles, so the morphology could be related to the EMG measurements. 2. Exertion of force, to measure the geometry of muscles and tendons under strain. 3. Placement of markers with high MRI contrast, to relate the relative position of the scans of the different joints. [delete line space]. The evaluation of the images was done using the ‘Tübinger Medstation’ software developed by the Department of Computer Science at the University of Tübingen. RESULTS: Although the use of T2 weighted sequences resulted in better soft tissue contrast, the T1 weighted spin echo sequence was preferred because of shorter acquisition time, which was an important factor because measurements had to be made under strain. Bones and tendons, with their low hydrogen content, produce weak signals in MRI and thus contrast with the adjacent soft tissue. Even shorter acquisition times by use of a gradient sequence were ruled out because of their low signal/noise ratio, which rendered the fascies undetectable. Automatic segmentation of these fascies is extremely hard to achieve. The ‘Medstation’ software was used to extract coordinates of muscle and tendon insertions by hand and combine them in a common frame of reference. CONCLUSIONS: A procedure has been established to extract the geometrical data of muscles, tendons and osseous structures important for the biomechanical model. For this model, extended muscle and tendon insertions have to be reduced to a point by calculation of the center of mass of the insertion area. A table for the positioning of the probationer enabled positioning with reproducible joint angles under exertion of strain. To define the relative position of different scans a screen of markers was integrated into this plate