Auto-eficacia motriz, educación física y actividad física en adolescentes brasileños y españoles / Motor self-efficacy, physical education and physical activity in Brazilian and Spanish adolescents

La investigación estudia las relaciones entre la frecuencia de actividad física, la percepción de auto-eficacia motriz, y la satisfacción con la clase y con el profesorado de Educación Física, en dos culturas: Brasil y España. Se 632 aplicaron cuatro escalas a 2.017 adolescentes españoles y 1.119 brasileños (edad 14.22±1.73). Los resultados muestran: baja frecuencia de actividad física; y relaciones significativas entre las variables estudiadas (p<0.01). La autoeficacia motriz es el factor con mayor poder explicativo de la frecuencia de actividad física (R²=0.223 para Brasil y R²=0.226 para España). Los profesores de EF podrían mejorar la percepción de auto-eficacia aplicando adecuado feedback (AU)

The research studies the relationship among frequency of physical activity, perceived motor self-efficacy and satisfaction with PE lessons and teachers in two cultures: Brazil and Spain. Four scales were applied to 2,017 Spanish and 1,119 Brazilian adolescents (age 14.22±1.73). Results show low frequency of physical activity and significant relationships among the studied variables (p<0.01). Motor self-efficacy is the factor with the highest explanatory power of frequent physical activity (R²=0.223 for Brazil and R²=0.226 for Spain). PE teachers could raise perceived self-efficacy if they applied a suitable approach (AU)

Estimation of body fluids with bioimpedance spectroscopy: state of the art methods and proposal of novel methods.

Determination of body fluids is a useful common practice in determination of disease mechanisms and treatments. Bioimpedance spectroscopy (BIS) methods are non-invasive, inexpensive and rapid alternatives to reference methods such as tracer dilution. However, they are indirect and their robustness and validity are unclear. In this article, state of the art methods are reviewed, their drawbacks identified and new methods are proposed. All methods were tested on a clinical database of patients receiving growth hormone replacement therapy. Results indicated that most BIS methods are similarly accurate (e.g. < 0.5 ± 3.0% mean percentage difference for total body water) for estimation of body fluids. A new model for calculation is proposed that performs equally well for all fluid compartments (total body water, extra- and intracellular water). It is suggested that the main source of error in extracellular water estimation is due to anisotropy, in total body water estimation to the uncertainty associated with intracellular resistivity and in determination of intracellular water a combination of both.

Estudio preliminar con factores de crecimiento morfogenético humano en el tratamiento de la gonartrosis de rodilla / Preliminary study with human morphogenetic growth factors in the treatment of knee arthrosis

La gonartrosis es una enfermedad de elevada prevalencia, caracterizada por una afección articular crónica, degenerativa y progresiva cuyo tratamiento definitivo consiste en la artroplastia de rodilla, surgiendo como problema los estadios evolutivos precoces. Nuestro estudio consiste en la utilización intraarticular en rodilla de plasma rico en plaquetas con alto contenido de factores de crecimiento. Los factores de crecimiento son proteínas de síntesis propia capaces de regular el ciclo celular y otros procesos celulares, entre ellos la reparación y cicatrización de estructuras lesionadas. Nuestros resultados muestran que las infiltraciones con plasma rico en plaquetas es un método seguro y efectivo para obtener una mejoría clínica y funcional a corto plazo en los pacientes afectos de gonartrosis

Knee osteoarthritis is a highly prevalent disease, joint disease characterized by chronic, degenerative and progressive whose definitive treatment is knee arthroplasty, emerging as a problema early developmental stages. Our study is the use of intra-articular knee platelet rich plasma rich in growth factors. Growth factors are proteins own synthesis capable of regulating cell cycle and other celular processes, including repair and healing of injured structures. Our results show that injections of platelet-rich plasma is a safe and effective method for clinical and functional short-term improvement in patients with knee osteoarthritis

Robustness study of the different immittance spectra and frequency ranges in bioimpedance spectroscopy analysis for assessment of total body composition.

The estimation of body fluids is a useful and common practice for assessment of disease status and therapy outcomes. Electrical bioimpedance spectroscopy (EBIS) methods are noninvasive, inexpensive and efficient alternatives for determination of body fluids. One of the main source of errors in EBIS measurements in the estimation of body fluids is capacitive coupling. In this paper an analysis of capacitive coupling in EBIS measurements was performed and the robustness of the different immittance spectra against it tested. On simulations the conductance (G) spectrum presented the smallest overall error, among all immittance spectra, in the estimation of the impedance parameters used to estimate body fluids. Afterwards the frequency range of 10-500 kHz showed to be the most robust band of the G spectrum. The accuracy of body fluid estimations from the resulting parameters that utilized G spectrum and parameters provided by the measuring device were tested on EBIS clinical measurements from growth hormone replacement therapy patients against estimations performed with dilution methods. Regarding extracellular fluid, the correlation between each EBIS method and dilution was 0.93 with limits of agreement of 1.06 ± 2.95 l for the device, 1.10 ± 2.94 l for G [10-500 kHz] and 1.04 ± 2.94 l for G [5-1000 kHz]. Regarding intracellular fluid, the correlation between dilution and the device was 0.91, same as for G [10-500 kHz] and 0.92 for G [5-1000 kHz]. Limits of agreement were 0.12 ± 4.46 l for the device, 0.09 ± 4.45 for G [10-500 kHz] and 0.04 ± 4.58 for G [5-1000 kHz]. Such close results between the EBIS methods validate the proposed approach of using G spectrum for initial Cole characterization and posterior clinical estimation of body fluids status.

Adaptive frequency distribution for electrical bioimpedance spectroscopy measurements.

This paper presents a novel frequency distribution scheme intended to provide more accurate estimations of Cole parameters. Nowadays a logarithmic frequency distribution is mostly used in Electrical Bioimpedance Spectroscopy (EBIS) applications. However it is not optimized following any criterion. Our hypothesis is that an EBIS signal contains more information where the variation of the measurement regarding the frequency is larger; and that there ought to be more measuring frequencies where there is more information. Results show that for EBIS data with characteristic frequencies up to 200 kHz the error obtained with both frequency distribution schemes is similar. However, for EBIS data with higher values of characteristic frequency the error produced when estimating the values from EBIS measurements using an adaptive frequency distribution is smaller. Thus it may useful for EBIS applications with high values of characteristic frequency, e.g. cerebral bioimpedance.

Cole function and conductance-based parasitic capacitance compensation for cerebral electrical bioimpedance measurements.

One of the most common measurement artifacts present in Electrical Bioimpedance Spectroscopy measurements (EBIS) comes from the capacitive leakage effect resulting from parasitic stray capacitances. This artifact produces a deviation in the measured impedance spectrum that is most noticeable at higher frequencies. The artifact taints the spectroscopy measurement increasing the difficulty of producing reliable EBIS measurements at high frequencies. In this work, an approach for removing such capacitive influence from the spectral measurement is presented making use of a novel method to estimate the value of the parasitic capacitance equivalent that causes the measurement artifact. The proposed method has been tested and validated theoretically and experimentally and it gives a more accurate estimation of the value of the parasitic capacitance than the previous methods. Once a reliable value of parasitic capacitance has been estimated the capacitive influence can be easily compensated in the EBIS measured data. Thus enabling analysis of EBIS data at higher frequencies, i.e. in the range of 300-500 kHz like measurements intended for cerebral monitoring, where the characteristic frequency is remarkably higher than EBIS measurements i.e. within the range 30 to 50 kHz, intended for body composition assessment.

Textile electrode straps for wrist-to-ankle bioimpedance measurements for Body Composition Analysis. Initial validation & experimental results.

Electrical Bioimpedance (EBI) is one of the non-invasive monitoring technologies that could benefit from the emerging textile based measurement systems. If reliable and reproducible EBI measurements could be done with textile electrodes, that would facilitate the utilization of EBI-based personalized healthcare monitoring applications. In this work the performance of a custom-made dry-textile electrode prototype is tested. Four-electrodes ankle-to-wrist EBI measurements have been taken on healthy subjects with the Impedimed spectrometer SFB7 in the frequency range 5 kHz to 1 MHz. The EBI spectroscopy measurements taken with dry electrodes were analyzed via the Cole and Body Composition Analysis (BCA) parameters, which were compared with EBI measurements obtained with standard electrolytic electrodes. The analysis of the obtained results indicate that even when dry textile electrodes may be used for EBI spectroscopy measurements, the measurements present remarkable differences that influence in the Cole parameter estimation process and in the final production of the BCA parameters. These initial results indicate that more research work must be done to in order to obtain a textile-based electrode that ensures reliable and reproducible EBI spectroscopy measurements.

Biocompression external fixation. Sliding external osteosynthesis.

Biocompression is a term applied to the stresses that have their origin in the elastic deformation of a diaphyseal bone, under the loads of functional activities. Its significance is the osteogenic response that biocompression stress induces in the cells of the healthy bone. The Biocompression Theory assumes that biocompression is as essential as osteogenic factors in the repair of a fracture. Thus, fracture healing requires not only stability, which is not osteogenic in itself, but physiologic biocompression. An external fixator that provides good stability and enables local biocompression has been used in the tibia of 127 patients, and healing with callus formation has been achieved in all.