Using a quantitative assessment of propulsion biomechanics in wheelchair racing to guide the design of personalized gloves: a case study.

This study with a T-52 class wheelchair racing athlete aimed to combine quantitative biomechanical measurements to the athlete's perception to design and test different prototypes of a new kind of rigid gloves. Three personalized rigid gloves with various, fixed wrist extension angles were prototyped and tested on a treadmill in a biomechanics laboratory. The prototype with 45° wrist extension was the athlete's favourite as it reduced his perception of effort. Biomechanical assessment and user-experience data indicated that his favourite prototype increased wrist stability throughout the propulsion cycle while maintaining a very similar propulsion technique to the athlete's prior soft gloves. Moreover, the inclusion of an innovative attachment system on the new gloves allowed the athlete to put his gloves on by himself, eliminating the need for external assistance and thus significantly increasing his autonomy. This multidisciplinary approach helped to prototype and develop a new rigid personalized gloves concept and is clearly a promising avenue to tailor adaptive sports equipment to an athlete's needs.

Inertial motion capture validation of 3D knee kinematics at various gait speed on the treadmill with a double-pose calibration.

BACKGROUND: Inertial motion capture (IMC) is rapidly gaining in popularity to evaluate gait in clinical settings. Previous examinations of IMC knee kinematics were often limited to the sagittal plane and IMC calibration has not been thoroughly investigated. RESEARCH QUESTION: The objective was to validate IMC 3D knee kinematics calibrated with a double-pose during gait with reference to optical motion capture (OMC). The hypotheses are that IMC can estimate adequately knee kinematics and that both systems will detect similarly the changes with gait speed. METHODS: Twenty-four healthy participants walked on the treadmill at gait speed of 0.6, 0.8, 1.0 and 1.2 m/s. Knee kinematics were obtained simultaneously with two magnetic and inertial measurement units and passive markers fixed on the KneeKG system. OMC was calibrated with a functional anatomical approach and the IMC with a double-pose. RESULTS: Root mean square differences of the two systems yielded 3-6° for knee flexion, adduction and external rotation. Knee kinematics were more similar during the stance phase than the swing phase. Gait speed showed a significant progressive effect on the three knee angles that was similarly detected by the two systems. SIGNIFICANCE: IMC 3D knee kinematics can be obtained independently with a simple calibration and only two magnetic and inertial measurement units at an acceptable level of error especially during stance.

Inmunodepresión e inmunorestauración en niños con desnutrición proteico energética grave / Inmunodepression and inmunorestauration on chidren with serious proteic energetic desnutrition

Ya es conocido que en niños desnutridos el sistemsa inmune disminuye sus funciones y provoca inmunodeperesión, la cual puede ser revertida con dietas .En el presente trabajo analizamos cuales dietas son más eficientes para este propósito. De 1500 niños desnutridos graves, 211 fueron seleccionados para constituir grupos estudio y control en 5 diferentes esquemas de tratamiento. Previo consentimiento de los padres, fueron aleatorizados, controlados, según criterios de inclusión: desnutridos graves, sin infección; con técnicas previamente validadas. Se controlaron; crecimiento, infecciones, respuesta inmunitaria (recuento de subpoblaciones linfocitarias / ecografía de tim o). Todos recibieron un aporte de calorías, proteínas, vitam inas: liposolubles e hidrosolubles. El Grupo I(G P L) recibió dieta inicial pobre en lactosa. El Grupo II(G Z) suplemento de zinc, el Grupo II I (G M A), megadosis de vitamina A + Z n . El Grupo IV (GZnFe)recibió zinc, hierro y vitamina A. El Grupo V: (G VM ) recibió dieta rica en Arginina, lisina, leucina, isoleucina y valina además de todos los nutrientes testados en los otros grupos. El Grupo I, mejoró el aporte de nutrientes con leche sin dilución y aporte de aceite vegetal, corrigiendo el aporte calórico, vitaminas liposolubles y ácidos grasos esenciales. En el G il se mejoró la respuesta inmunitaria, el crecimiento y control de patologías añadidas. El G U I (GM A) disminuyó la prevalencia de infecciones. El G IV (Z n F e ), optimizó sinérgicamente la recuperación inmunitaria y niveles de hemoglobina. EL G V (G VM ) mostró una mejor recuperación del timo y poblaciones linfocitarias en relación a los otros grupos ( p < 0 .0 0 0 1 ). El trabajo mostró secuencialmente que la inmunodepresión de niños desnutridos se puede vencer con un adecuado régimen alimentario rico en micronutrientes y aminoácidos inmunoestimulantes.

It's known that the inmune system of malnouruished children has a worst performance , and it can be reverted with an improved diet. About 1500 severe malnourished children, 211 were selected to form study groups and control in 5 different treatment schemes. Prior parental consent, were randomized, controlled, according to inclusión criteria: severe malnourished, without infection, using techniques previously validated. Were monitored: growth, infections, immune response (lymphocyte subpopulations count / ultrasound th ym us). Th e y received a supply of calories, protein, vitam ins: fat soluble and water soluble. Group I (LPG ) has received initial diet low in lactose. Group II (G Z ) Zincsupplementation. Group III (G M A), megadoses of vitamin A + Z n . Group IV (Z n F e) received zinc, ¡ron and vitam in A. Group V: (G VM ) received a diet rich in arginine, lysine, leucine, isoleucine and valine, plus all the nutrients tested in other groups. Group I, improved nutrient raw milk and vegetable oil supply, correcting the calories, fat soluble vitamins and essential fatty acids. In Group II improved the immune response, growth and control of diseases added. Group II I (GM A) decreased the prevalence of infections. Th e G IV (Z n F e ) synergistically optimize immune recovery and levéis of hemoglobin. Group V (GM V) showed better recovery of the thym us and lymphocyte populations in relation to the other groups. The study showed that sequential immunosuppression of malnourished children can be overeóme with a properdiet rich in nutrients and am ino acid immunostimulants.

A simple and rapid method for electromagnetic field distortion correction when using two Fastrak sensors for biomechanical studies.

The article presents a simple and rapid method for the correction of electromagnetic distortions when using electromagnetic Fastrak (Polhemus, USA) sensors. It is based on the minimization of objective functions composed of derivative polynomial functions, hence estimating the distortion of the electromagnetic field. The polynomial functions composing the objective function each contain 35 deformation coefficients. These coefficients are then used to correct the electromagnetic measures in position and orientation. Preliminary results on the efficacy of the method are presented for two subjects who walked on a treadmill, and for whom relative movement of the lower leg with respect to the thigh was recorded using two Fastrak sensors. The corrected Fastrak measurements were compared with optoelectronic measurements (Vicon, USA), which are not affected by distortions as electromagnetic sensors are. Results showed that after 3 min of calibrating a volume of approximately 1m(3), the method proved to be efficient in correcting errors in orientation (56% (2.72-1.12 degrees ), 78% (4.4-0.89 degrees ), and 56% (2.25-0.90 degrees ) of error reduction in the respective flexion/extension, ab/adduction and tibial internal/external rotation) and position (53% (18.9-8.9 mm), 21% (6.6-4.6mm), and 48% (15.9-8.1mm) of error reduction in the respective medial/lateral, anterior/posterior and proximal/distal translations) (values are overall means for two subjects and four calibration procedures). That amount of correction compared favorably with values presented in the literature.

Gesture standardization increases the reproducibility of 3D kinematic measurements of the knee joint.

BACKGROUND: The literature on the 3D kinematics of the knee suggests that the gesture accomplished during kinematic assessment might play a significant role in the values measured. The purpose of this study is to demonstrate that a standardized gesture leads to an increased reproducibility in 3D kinematic measurements of the knee. METHODS: Seventeen healthy male subjects performed series of knee-bends in standardized and unconstrained conditions while their left knee's 3D kinematics were recorded using an optical motion-recording system. Standardized knee-bends were performed in a specially designed structure stabilizing the shoulders, pelvis and feet. Coefficient of multiple correlation were calculated for the ascent and the descent phases of the knee-bends for the tibial rotation and abduction/adduction components of the knee movement. FINDINGS: Comparisons between coefficient of multiple correlation of the different gesture conditions showed a statistically significant increase in reproducibility for the tibial rotation during the standardized knee-bends. INTERPRETATION: It appears that gesture standardization is an interesting option to consider for precise kinematic assessment of the living human knee.

A reproducible method for studying three-dimensional knee kinematics.

The methods used in movement analysis often rely on the definition of joint coordinate systems permitting three-dimensional (3D) kinematics. The first aim of this research project was to present a functional and postural method (FP method) to define a bone-embedded anatomical frame (BAF) on the femur and tibia, and, subsequently, a knee joint coordinate system. The repeatability of the proposed method was also assessed. Using FP method to define the BAFs, 4 kinematic parameters (flexion/extension, abduction/adduction, tibial internal/external rotation, and antero-posterior translation) were computed for 15 subjects walking on a treadmill. The repeatability for all four kinematic parameters was then assessed, using intra- and inter-observer settings. After pooling the results for all observers, the mean repeatability value ranged between 0.4 degrees and 0.8 degrees for rotation angles and between 0.8 and 2.2 mm for translation.