Isokinetic trunk flexion-extension protocol to assess trunk muscle strength and endurance: Reliability, learning effect, and sex differences.

PURPOSE: The purpose of this study was to examine the reliability and the learning effect of an isokinetic trunk flexion-extension protocol designed to simultaneously assess trunk muscle strength and endurance. In addition, the effect of the participants' sex on the reliability data was examined. METHODS: Fifty-seven healthy and physically active young men (n = 28) and women (n = 29) performed the isokinetic protocol 5 times, separated by a week between each of the first 4 sessions and by a month between the last 2 sessions. The protocol consisted of performing 4 trials of 15 maximum flexion-extension concentric exertions at 120°/s (range of trunk motion = 50°). The absolute and relative peak torque and total work were calculated to assess trunk flexion and extension strength. In addition, endurance ratio, modified endurance ratio, fatigue final ratio, recovery ratio, and modified recovery ratio variables were used for the assessment of trunk muscle endurance in both directions. RESULTS: Regarding the absolute reliability, no relevant changes were found between paired-comparison sessions for most strength and endurance variables, except for total work and relative total work variables in the flexion movement in both sexes. In addition, the typical error of the isokinetic variables was lower than 10% in both males and females, and minimum detectable changes ranged from 7% to 20%, with a tendency to be higher in females and in endurance variables. The strength variables showed high-to-excellent intraclass correlation coefficients (ICCs; >0.74); however, for the endurance variables only the endurance ratio and the modified endurance ratio obtained moderate-to-high ICC values (0.57 < ICC < 0.82). In addition, the analysis of the variance reported no significant differences between consecutive pairs of sessions for most variables in both sexes. CONCLUSION: Overall, these findings provide clinicians, trainers, and researchers with a 10-min single-session protocol to perform a reliable muscle strength and endurance evaluation of trunk flexor and extensor muscles, all within the same protocol.

Progressions of core stabilization exercises based on postural control challenge assessment.

PURPOSE: The intensity progression of core stabilization exercises (CSEs) is usually based on personal criteria rather than on objective parameters. To develop exercise progressions for four of the most common CSEs based on the postural control challenge imposed on the participants, and to analyze the effect of participants' sex and postural control level on these progressions. METHODS: Seventy-six males and females performed five variations of front bridge, back bridge, side bridge and bird-dog exercises on two force platforms. The mean velocity of the center of pressure displacement was calculated to assess exercise intensity through the measurement of the participants' body sway (PBS). RESULTS: In general, long bridges produced higher PBS than short bridges, bridging with single leg support produced higher PBS than bridging with double leg support and bridging on a hemisphere ball produced higher PBS than bridging on the floor. The most difficult bridging variations were those performed on a hemisphere ball with single leg support. Regarding the bird-dog, two-point positions produced higher PBS than three-point positions and the positions performed on a hemisphere ball produced higher PBS than those performed on the floor. CONCLUSION: The CSE progressions obtained by males and females were very similar. However, the participants with high trunk control showed less significant differences between exercise variations than the participants with low trunk control, which shows the need to individualize the progressions according to the participants' training level. Overall, this study provides useful information to guide the prescription of CSE progressions in young physically active individuals.

Training intensity quantification of core stability exercises based on a smartphone accelerometer.

Although core stability (CS) training is largely used to enhance motor performance and prevent musculoskeletal injuries, the lack of methods to quantify CS training intensity hinders the design of CS programs and the comparison and generalization of their effects. The aim of this study was to analyze the reliability of accelerometers integrated into smartphones to quantify the intensity of several CS isometric exercises. Additionally, this study analyzed to what extent the pelvic acceleration data represent the local stability of the core structures or the whole-body postural control. Twenty-three male and female physically-active individuals performed two testing-sessions spaced one week apart, each consisting of two 6-second trials of five variations of frontal bridge, back bridge, lateral bridge and bird-dog exercises. In order to assess load intensity based on the postural control challenge of CS exercises, a smartphone accelerometer and two force platforms were used to measure the mean pelvic linear acceleration and the mean velocity of the centre of pressure displacement, respectively. Reliability was assessed through the intra-class correlation coefficient (ICC3,1) and the standard error of measurement (SEM). In addition, Pearson coefficient was used to analyze the correlation between parameters. The reliability analysis showed that most CS exercise variations obtained moderate-to-high reliability scores for pelvic acceleration (0.71

Cuestionario de frecuencia de consumo de alimentos para valorar la calidad de la dieta en la prevención de la deficiencia de hierro / A food frequency questionnaire to assess diet quality in the prevention of iron deficiency

Introducción: a pesar del amplio conocimiento sobre la biodisponibilidad del hierro, no se ha implementado aún un cuestionario de frecuencia de consumo de alimentos (CFCA) para su aplicación en grupos poblacionales con predisposición a anemia. Objetivos: diseñar un CFCA basado en los potenciadores e inhibidores de la absorción del hierro y valorar su aplicabilidad en un grupo de mujeres en edad fértil. Métodos: se elaboró un CFCA específico de 28 preguntas, 10 de ellas con indicación del momento de consumo de alimentos, en el desayuno (D) y en comida/cena (CC). Se seleccionaron 179 mujeres sanas jóvenes que se distribuyeron en tres grupos en función de su estado de hierro, ferritina sérica 30 ng/mL. Resultados: la reproducibilidad del CFCA fue muy alta ( 0,500, p < 0,001 para todas las variables). El consumo de carnes rojas y bebidas alcohólicas se asoció positivamente con la ferritina, mientras que el de frutas cítricas-CC y frutos secos-CC se asoció negativamente (p 0,05). El consumo de frutas cítricas-CC se asoció negativamente con el de carne roja (p < 0,05) y positivamente con el de legumbres, pescado, ensalada, vegetales, alimentos enriquecidos con fibra, otras frutas (p < 0,001) y pan integral (p < 0,05). El consumo de zumos de frutas con el desayuno fue menor en las mujeres de ferritina (AU)

Introduction: despite the extensive knowledge on iron bioavailability, a Food Frequency Questionnaire (FFQ) for application in population groups predisposed to iron deficiency anaemia has not been implemented. Objectives: to design a FFQ based on enhancers and inhibitors of iron absorption and to assess its applicability in a group of women at childbearing age. Methods: the FFQ included 28 items and the time of consumption for 10 of them, breakfast (B) and lunch/dinner (LD). One hundred and seventy nine healthy young women were selected and distributed into three groups according to their iron status measured by serum ferritin: 30 ng/mL. Results: the reproducibility of this FFQ was very high (Spearman coefficient > 0.500, p < 0.001 for all variables). Red meat and alcoholic beverages consumption was positively associated with ferritin, while citric fruits LD and nuts-LD were negatively associated (p 0.05). Citric fruits-LD was negatively associated with red meat (p < 0.05) and positively with legumes, fish, salad, vegetables, foods fortified with fiber, other fruits (p < 0.001) and brown bread (p < 0.05). The consumption of fruit juices with breakfast was lower in women with ferritin < 15 ng/ml compared to ferritin 15-30 ng/ml. Conclusion: this questionnaire is simple and reproducible. Red meat is the main dietary factor related with higher iron status in young women, thus its influence on iron absorption compared to other enhancers and inhibitors is highlighted (AU)

[A FOOD FREQUENCY QUESTIONNAIRE TO ASSESS DIET QUALITY IN THE PREVENTION OF IRON DEFICIENCY]. / CUESTIONARIO DE FRECUENCIA DE CONSUMO DE ALIMENTOS PARA VALORAR LA CALIDAD DE LA DIETA EN LA PREVENCIÓN DE LA DEFICIENCIA DE HIERRO.

INTRODUCTION: Despite the extensive knowledge on iron bioavailability, a Food Frequency Questionnaire (FFQ) for application in population groups predisposed to iron deficiency anaemia has not been implemented. OBJECTIVES: To design a FFQ based on enhancers and inhibitors of iron absorption and to assess its applicability in a group of women at childbearing age. METHODS: the FFQ included 28 items and the time of consumption for 10 of them, breakfast (B) and lunch/dinner(LD). One hundred and seventy nine healthy young women were selected and distributed into three groups according to their iron status measured by serum ferritin:< 15, 15-30 or > 30 ng/mL. RESULTS: the reproducibility of this FFQ was very high(Spearman coefficient > 0.500, p < 0.001 for all variables). Red meat and alcoholic beverages consumption was positively associated with ferritin, while citric fruits-LD and nuts-LD were negatively associated (p < 0.05). Citric fruits-LD was negatively associated with red meat (p < 0.05) and positively with legumes, fish, salad, vegetables,foods fortified with fiber, other fruits (p < 0.001)and brown bread (p < 0.05). The consumption of fruit juices with breakfast was lower in women with ferritin <15 ng/ml compared to ferritin 15-30 ng/ml. CONCLUSION: this questionnaire is simple and reproducible.Red meat is the main dietary factor related with higher iron status in young women, thus its influence on iron absorption compared to other enhancers and inhibitors is highlighted.

Introducción: A pesar del amplio conocimiento sobre la biodisponibilidad del hierro, no se ha implementado aún un cuestionario de frecuencia de consumo de alimentos (CFCA) para su aplicación en grupos poblacionales con predisposición a anemia. Objetivos: Diseñar un CFCA basado en los potenciadores e inhibidores de la absorción del hierro y valorar su aplicabilidad en un grupo de mujeres en edad fértil. Métodos: Se elaboró un CFCA específico de 28 preguntas, 10 de ellas con indicación del momento de consumo de alimentos, en el desayuno y en comida/cena (CC). Se seleccionaron 179 mujeres sanas jóvenes que se distribuyeron en 3 grupos en función de su estado del hierro, ferritina sérica 30 ng/mL. Resultados: La reproducibilidad del CFCA fue muy alta (coeficiente de Spearman>0.500, p.

Safety assessment of chronic oral exposure to iron oxide nanoparticles.

Iron oxide nanoparticles with engineered physical and biochemical properties are finding a rapidly increasing number of biomedical applications. However, a wide variety of safety concerns, especially those related to oral exposure, still need to be addressed for iron oxide nanoparticles in order to reach clinical practice. Here, we report on the effects of chronic oral exposure to low doses of γ-Fe2O3 nanoparticles in growing chickens. Animal observation, weight, and diet intake reveal no adverse signs, symptoms, or mortality. No nanoparticle accumulation was observed in liver, spleen, and duodenum, with feces as the main excretion route. Liver iron level and duodenal villi morphology reflect the bioavailability of the iron released from the partial transformation of γ-Fe2O3 nanoparticles in the acid gastric environment. Duodenal gene expression studies related to the absorption of iron from γ-Fe2O3 nanoparticles indicate the enhancement of a ferric over ferrous pathway supporting the role of mucins. Our findings reveal that oral administration of iron oxide nanoparticles is a safe route for drug delivery at low nanoparticle doses.

Trunk muscle activation during stabilization exercises with single and double leg support.

The aim of this study was to analyze trunk muscle activity during bridge style stabilization exercises, when combined with single and double leg support strategies. Twenty-nine healthy volunteers performed bridge exercises in 3 different positions (back, front and side bridges), with and without an elevated leg, and a quadruped exercise with contralateral arm and leg raise ("bird-dog"). Surface EMG was bilaterally recorded from rectus abdominis (RA), external and internal oblique (EO, IO), and erector spinae (ES). Back, front and side bridges primarily activated the ES (approximately 17% MVC), RA (approximately 30% MVC) and muscles required to support the lateral moment (mostly obliques), respectively. Compared with conventional bridge exercises, single leg support produced higher levels of trunk activation, predominantly in the oblique muscles. The bird-dog exercise produced greatest activity in IO on the side of the elevated arm and in the contralateral ES. In conclusion, during a common bridge with double leg support, the antigravity muscles were the most active. When performed with an elevated leg, however, rotation torques increased the activation of the trunk rotators, especially IO. This information may be useful for clinicians and rehabilitation specialists in determining appropriate exercise progression for the trunk stabilizers.

A novel SNaPshot assay to detect genetic mutations related to iron metabolism.

The minisequencing method is a cost-effective tool to study single-nucleotide polymorphisms in human disease. For this reason, a novel polymerase chain reaction multiplex SNaPshot reaction has been developed that targets 10 autosomal mutations in genes, or regions near to them, reported to be involved in iron metabolism: TMPRSS6, TF, and HFE. To validate this multiplex, 284 samples from unrelated women from the Spanish population were tested at a fertile age. The novel polymerase chain reaction multiplex SNaPshot reaction developed is a very simple, sensitive, and low-cost approach, and therefore will be useful as a tool of clinic diagnosis in iron metabolism alterations and to replicate results obtained from genome-wide linkage analysis.

Agua mineral natural y riesgo cardiovascular / Agua mineral natural y riesgo cardiovascular

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