Footedness but not dominance influences force steadiness during isometric dorsiflexion in young men.

The aim of the study was to assess the potential influence of footedness and dominance on maximal force, force fluctuations and neural drive during dorsiflexion. Fifteen left-footed (LF) and fifteen right-footed (RF) young adults performed 2 maximal voluntary contractions (MVC) and 3 steady submaximal isometric contractions at five target forces (5, 10, 20, 40 and 60% MVC) with the dorsiflexors of both legs. High-density electromyography (EMG) was used to record the discharge characteristics of motor units (MUs) of Tibialis Anterior. MVC force and EMG amplitude (root mean square) were similar between the two legs and groups (p > 0.05). Force fluctuations (Coefficient of Variation, CoV for force), mean discharge rate of MUs, discharge variability (CoV of interspike interval), and variability in neural drive (standard deviation of filtered cumulative spike train) were greater (p < 0.05) and the input-output gain of the MUs (ΔDR/ΔF) was lower (p < 0.05) for the LF relative to the RF group. The differences in force fluctuations during steady contractions with the dorsiflexors were associated with footedness but not with dominance. They reflect greater variability in motor neuron output, as suggested by coefficient of variation for interspike interval (independent input) and the standard deviation of the smoothed discharge times (common input).

Biochemical profile of Serbian youth national soccer teams / Perfil bioquímico de equipos juveniles de fútbol serbios

The aim of the present study was to determine biochemical profile of youth national soccer teams and to compare the values of nine biochemical parameters between three Serbian youth national teams (under 14, 15 and 16 years old), as well as between soccer players and non-athletes. Eighty young soccer players and thirty non-athletes participated in the study. Nine biochemical parameters (glucose, cholesterol, triglycerides, urea, creatinine, total bilirubin, AST (SGOT), ALT (SGPT), iron) were measured. In order to determine the significance of differences between the groups on a multivariate level a multivariate analysis of variance (MANOVA) was administered, and to test the differences between the groups on an univariate level a univariate analysis of variance (ANOVA) was applied. Statistically significant differences were found between groups (soccer players up to 14, 15 and 16 years of age) on a multivariate level of the applied biochemical variables (MANOVA, p= 0.00). ANOVA also revealed significant differences in Creatinine (p= 0.00), Total bilirubin (p= 0.00) and ALT (SGPT) (p= 0.02). Statistically significant differences in the applied variables were found between soccer players and non-athletes on a multivariate level (MANOVA p= 0.00). ANOVA also revealed significant differences in Glucose, Cholesterol, Triglycerides, Creatinine, Total bilirubin, ALT (SGPT) and Iron (p= 0.00) between soccer players and non-athletes, but there were no statistically significant differences in other variables (AST (SGOT) and Urea). It was concluded that there is significant difference in almost all variables (glucose, cholesterol, triglycerides, etc.), except AST (SGOT) and Urea between soccer players and non-athletes. From a practical point of view, the clinician has to take into account not only age, but also training status of individuals when evaluating their blood tests.

El objetivo fue determinar el perfil bioquímico de los equipos juveniles de fútbol nacional y comparar los valores de nueve parámetros bioquímicos entre tres equipos nacionales serbios (menores de 14, 15 y 16 años de edad), así como entre los jugadores de fútbol y no atletas. Ochenta jóvenes jugadores de fútbol y treinta no atletas participaron en el estudio. Se midieron nueve parámetros bioquímicos (glucosa, colesterol, triglicéridos, urea, creatinina, bilirrubina total, AST (SGOT), ALT (SGPT), hierro). Con el fin de determinar la significación de las diferencias entre los grupos en un nivel multivariado se administró un análisis multivariado de varianza (MANOVA), y para poner a prueba las diferencias entre los grupos en un nivel univariado se aplicó un análisis univariado de la varianza (ANOVA). Se encontraron diferencias estadísticamente significativas entre los grupos (jugadores de fútbol hasta 14, 15 y 16 años de edad) en un nivel multivariado de las variables bioquímicas (MANOVA, p= 0,00). ANOVA también reveló diferencias significativas en creatina (p= 0,00), la bilirrubina total (p= 0,00) y ALT (SGPT) (p= 0,02). Se encontraron diferencias estadísticamente significativas en las variables aplicadas entre los jugadores de fútbol y no atletas a nivel multivariado (MANOVA p= 0,00). ANOVA también reveló diferencias significativas en glucosa, colesterol, triglicéridos, creatinina, bilirrubina total, ALT (SGPT) y hierro (p= 0,00) entre los jugadores de fútbol y no atletas. Sin embargo no hubo diferencias estadísticamente significativas en otras variables (AST (SGOT) y urea). Se concluyó que a excepción de la AST (SGOT) y urea no existe diferencia significativa en casi todas las variables (glucosa, colesterol, triglicéridos, etc.) entre los jugadores de fútbol y no atletas. Desde un punto de vista práctico, el médico debe tener en cuenta no solamente la edad, sino también la formación de estado de los individuos en la evaluación de sus análisis de sangre.