EFFECT OF AGE ON HIGH JUMP TAKEOFF BIOMECHANICS

The aim of the study was to analyse the differences in critical features of high jump take-off in different ages. 3D photogrammetry was used to analyse the best jump of the participants of 3 Spanish Indoor Championships (2009) (13-15 y, 17-18 y, and 18-34 y). The variables measured were horizontal velocity of the centre of mass (CM) at touchdown (VH0), knee angle at touchdown (K0), leg angle at touchdown (L0); height of the CM at touchdown (H0); and take-off angle (TOA). The three groups were compared with ANOVA and each variable was correlated with the maximum CM height. Statistical differences were found in VH0 and H0, but not in the variables directly related to the take-off technique. It is concluded that younger athletes use similar techniques than older ones. This might be a wrong strategy, as they should adapt it to their maturity limitations

Kinematic, strength, and stiffness adaptations after a short-term sled towing training in athletes

One of the most frequently used methods for training the sprint‐specific strength is the sled towing. To date, no studies have been conducted to explore the effects of this method after a training period in well‐trained athletes. The purpose of this study was to determine the effects of 4 weeks of resisted sprint training with sled towing. Twenty‐two trained athletes experienced in the use of weighted sled (WS) participated in the study. They conducted the same 3‐week training to level their initial condition. After that they were distributed in two groups, unresisted (UR) and WS training. They carried out the same 4‐week, 2 days/week sprint‐specific training, only differing in that the experimental group performed sprints with a (WS) which caused a reduction of 7.5% of their maximum velocity. Pre‐ and posttest were conducted which included the measurement of sprint kinematics, muscular strength (including isoinertial, isokinetic, and jump measurements), and sprinting stiffness (leg and vertical). Results show different adaptations in the groups although no interaction effect was found. The WS group improved the velocity in the transition phase, while the UR group improved the velocity in the maximum velocity phase. No improvements in the height of the jump tests were found.Actividad Física y Deport

Trapping and patterning of biological objects using photovoltaic tweezers

Photovoltaic tweezers are a recently proposed technique for manipulation and patterning of micro- and nano-objects. It is based in the dielectrophoretic forces associated to the electric fields induced by illumination of certain ferroelectrics due to the bulk photovoltaic effect. The technique has been applied to the patterning of dielectric and metal micro- and nano-particles. In this work, we report the use of photovoltaic tweezers to pattern biological objects on LiNbO3:Fe. Specifically, spores and pollen grains and their nanometric fragments have been trapped and patterned. 1D and 2D arrangements have been achieved by deposition in air or from a hexane suspension. The quality of patterns obtained with nanometric fragments is even better than previous results using photovoltaic tweezers with inorganic micro- and nano-particles. In fact, 1D patterns with a period of 2 μm, almost half of the minimum reported period achieved with photovoltaic tweezers, have been obtained with pollen fragmentsThis work was supported by Spanish projects MAT2011-28379-C03 and MAT2014-57704-C0

Characteristics and effects of resisted sprint training methods

Para la mejora del rendimiento en el sprint se utilizan distintos métodos de entrenamiento, entre los más populares se encuentran los métodos resistidos. Un método resistido para el sprint se caracteriza por utilizar sprints con una sobrecarga o resistencia añadida. Dependiendo de las características del dispositivo, tanto la magnitud como la dirección de la resistencia va a ser diferente. Así, existen distintos tipos de métodos resistidos, estos son: arrastres de trineos o ruedas, lastres de chalecos o cinturones, arrastres de paracaídas, carreras cuesta arriba, e incluso carreras sobre la arena de la playa. El principal objetivo al usar métodos resistidos es mejorar la fuerza específica de los deportistas sin producir una modificación significativa de la técnica del deportista. En el presente trabajo se revisan las características y efectos de los métodos resistidos tanto de forma aguda, como sus efectos a corto, medio y largo plazo.Actividad Física y Deport

Prevalence, Risk Factors and Burnout Levels in Intensive Care Unit Nurses: A Systematic Review and Meta-Analysis

Nursing is considered to be an at-risk profession of burnout due to daily exposure to difficult situations such as death and pain care. In addition, some units such as the intensive care unit (ICU), can be stressful due to high levels of morbidity and mortality and ethical dilemmas. Burnout causes a deterioration in quality of care, increasing the risk of mortality in patients due to poor performance and errors in the healthcare environment. The aim of this study was to analyse the levels, prevalence and related factors of burnout in ICU nurses. A systematic review and metaanalysis were carried out in the Medline, Scopus and CINAHL databases. Fifteen articles were found for the systematic review and four for the meta-analysis. With a sample of n = 1986 nurses, the meta-analytic estimate prevalence for high emotional exhaustion was 31% (95% CI, 8–59%), for high depersonalization was 18% (95% CI, 8–30%), and for low personal accomplishment was 46% (95% CI, 20–74%). Within the dimensions of burnout, emotional exhaustion had a significant relationship with depression and personality factors. Both sociodemographic factors (being younger, single marital status, and having less professional experience in ICU) and working conditions (workload and working longer hours) influence the risk of burnout syndrome

Juegos motores Una alternativa para fortalecer los músculos del abdomen

El objetivo del estudio fue comparar la amplitud de la electromiografía (EMG) y el modo en que fueron coactivados los músculos abdominales durante la ejecución del ejercicio de encorvamiento del tronco y dos juegos motores tradicionales: la carretilla y el hula hop. Para ello, se registró la EMG de los músculos rectus, obliquus externus y obliquus internus abdominis durante la ejecución de cada una de las tareas. En el estudio participaron nueve voluntarios sanos sin antecedentes de cirugía abdominal, lesiones raquídeas o síndrome de dolor lumbar. La amplitud de la EMG fue promediada y normalizada respecto a la contracción voluntaria máxima. Se realizó un ANOVA de dos factores (músculo/tarea) y un post hoc Tukey para examinar las diferencias en la actividad eléctrica de cada músculo entre las tareas y en cada tarea entre los músculos. Los juegos analizados produjeron niveles de actividad eléctrica superiores a los generados por el encorvamiento del tronco, por lo que deben ser considerados como un complemento o una alternativa a los ejercicios de fortalecimiento abdominal. La carretilla generó un importante nivel de coactivación abdominal, aunque activó principalmente al obliquus externus abdominis. En el hula hop, las diferencias entre los músculos no fueron estadísticamente significativas

Jocs motors Una alternativa per enfortir els músculs de l’abdomen

L’objectiu de l’estudi va ser comparar l’amplitud de l’electromiografia (EMG) i la forma en què van ser coactivats els músculs abdominals durant l’execució de l’exercici d’encorbament del tronc i dos jocs motors tradicionals: el carretó i l’hula-hop. Per fer-ho, es va enregistrar l’EMG dels músculs recte, oblic extern i oblic intern de l’abdomen, durant l’execució de cada una de les tasques. A l’estudi hi van participar nou voluntaris sans, sense antecedents de cirurgia abdominal, lesions raquídies o síndrome de dolor lumbar. L’amplitud de l’EMG va ser amitjanada i normalitzada respecte a la contracció voluntària màxima. Es va realitzar un ANOVA de dos factors (múscul/tasca) i un post hoc Tukey per examinar les diferències en l’activitat elèctrica de cada múscul entre les tasques i en cada tasca entre els músculs. Els jocs analitzats van produir nivells d’activitat elèctrica superiors als generats per l’encorbament del tronc, i en conseqüència, han de ser considerats com un complement o una alternativa als exercicis d’enfortiment abdominal. El carretó va generar un important nivell de coactivació abdominal, encara que va activar principalment l’oblic extern de l’abdomen. A l’hula-hop, les diferències entre els músculs no van ser estadísticament significatives

Kinetic behavior of Desulfovibrio gigas aldehyde oxidoreductase encapsulated in reverse micelles

Biochemical and Biophysical Research Communications 308 (2003) 73–78We report the kinetic behavior of the enzyme aldehyde oxidoreductase (AOR) from the sulfate reducing bacterium Desulfovibrio gigas (Dg) encapsulated in reverse micelles of sodium bis-(2-ethylhexyl) sulfosuccinate in isooctane using benzaldehyde, octaldehyde, and decylaldehyde as substrates. Dg AOR is a 200-kDa homodimeric protein that catalyzes the conversion of aldehydes to carboxylic acids. Ultrasedimentation analysis of Dg AOR-containing micelles showed the presence of 100-kDa molecular weight species, confirming that the Dg AOR subunits can be dissociated. UV–visible spectra of encapsulated Dg AOR are indistinguishable from the enzyme spectrum in solution, suggesting that both protein fold and metal cofactor are kept intact upon encapsulation. The catalytic constant (kcat) profile as a function of the micelle size W0 (W0 ¼ ½H2O /[AOT]) using benzaldehyde as substrate showed two bell-shaped activity peaks at W0 ¼ 20 and 26. Furthermore, enzymatic activity for octaldehyde and decylaldehyde was detected only in reverse micelles. Like for the benzaldehyde kinetics, two peaks with both similar kcat values and W0 positions were obtained. EPR studies using spin-labeled reverse micelles indicated that octaldehyde and benzaldehyde are intercalated in the micelle membrane. This suggests that, though Dg AOR is found in the cytoplasm of bacterial cells, the enzyme may catalyze the reaction of substrates incorporated into a cell membrane

Detection of cannabinoid receptors CB1 and CB2 within basal ganglia output neurons in macaques: changes following experimental parkinsonism

Abstract Although type 1 cannabinoid receptors (CB1- Rs) are expressed abundantly throughout the brain, the presence of type 2 cannabinoid receptors (CB2Rs) in neurons is still somewhat controversial. Taking advantage of newly designed CB1R and CB2R mRNA riboprobes, we demonstrate by PCR and in situ hybridization that transcripts for both cannabinoid receptors are present within labeled pallidothalamic-projecting neurons of control and MPTP-treated macaques, whereas the expression is markedly reduced in dyskinetic animals. Moreover, an in situ proximity ligation assay was used to qualitatively assess the presence of CB1Rs and CB2Rs, as well as CB1R–CB2R heteromers within basal ganglia output neurons in all animal groups (control, parkinsonian and dyskinetic macaques). A marked reduction in the number of CB1Rs, CB2Rs and CB1R–CB2R heteromers was found in dyskinetic animals, mimicking the observed reduction in CB1R and CB2R mRNA expression levels. The fact that chronic levodopa treatment disrupted CB1R–CB2R heteromeric complexes should be taken into consideration when designing new drugs acting on cannabinoid receptor heteromers

Transverse ratchet effect and superconducting vortices: simulation and experiment

A transverse ratchet effect has been measured in magnetic/ superconducting hybrid films fabricated by electron beam lithography and magnetron sputtering techniques. The samples are Nb films grown on top of an array of Ni nanotriangles. Injecting an ac current parallel to the triangle reflection symmetry axis yields an output dc voltage perpendicular to the current, due to a net motion of flux vortices in the superconductor. The effect is reproduced by numerical simulations of vortices as Langevin particles with realistic parameters. Simulations provide an intuitive picture of the ratchet mechanism, revealing the fundamental role played by the random intrinsic pinning of the superconductor