Jon Irazusta

Physiological and anthropometric characteristics of young soccer players according to their playing position: relevance for the selection process.

The aim of this study was to establish the anthropometric and physiological profiles of young nonelite soccer players according to their playing position, and to determine their relevance for the selection process. Two hundred forty-one male soccer players who were members of the Getxo Arenas Club (Bizkaia) participated in this study. Players, age 17.31 (± 2.64) years, range 14–21 years, were classified into the following groups: forwards (n = 56), midfielders (n = 79), defenders (n = 77), and goalkeepers (n = 29). Anthropometric variables of participants (height, weight, body mass index, 6 skinfolds, 4 diameters, and 3 perimeters) were measured. Also, their somatotype and body composition (weights and percentages of fat, bone, and muscle) were calculated. Participants performed the Astrand test to estimate their absolute and relative &OV0312;O2max, an endurance test, sprint tests (30 meters flat and 30 meters with 10 cones) and 3 jump tests (squat jump, counter movement jump and drop jump). Forwards were the leanest, presenting the highest percentage of muscle. They were the best performers in all the physiological tests, including endurance, velocity, agility, and power. In contrast, goalkeepers were found to be the tallest and the heaviest players. They also had the largest fat skinfolds and the highest fat percentage, but their aerobic capacity was the lowest. In the selection process, agility and the jump tests were the most discriminating for forwards. In contrast, agility, height, and endurance were the key factors for midfielders. The defenders group was characterized by a lower quantity of fat. Thus, we may conclude that anthropometric and physiological differences exist among soccer players who play in different positions. These differences fit with their different workload in a game. Therefore, training programs should include specific sessions for each positional role.

ANTHROPOMETRIC AND PHYSIOLOGICAL DIFFERENCES BETWEEN FIRST TEAM AND RESERVE SOCCER PLAYERS AGED 10-14 YEARS AT THE BEGINNING AND END OF THE SEASON

Gravina, L, Gil, SM, Ruiz, F, Zubero, J, Gil, J, and Irazusta, J. Anthropometric and physiological differences between first team and reserve soccer players aged 10-14 years at the beginning and end of the season. J Strength Cond Res 22: 1308-1314, 2008-The aim of this article was to identify differences in the anthropometric and physiological characteristics of first team and reserve young soccer players (10-14 years old) at both the beginning and end of the soccer season. Body composition was calculated by measuring weight, height, skinfold, limb circumference, and joint diameter. &OV0312;o2max was estimated by Astrands test. Sprint and jump tests were also performed. In general, first team players (FTPs) were taller and leaner. However, the most relevant difference that we found at the beginning of the season was that FTPs had shorter sprint times than reserves in the 30-m test (both flat and with 10 cones). Moreover, these differences in sprint time were more marked at the end of the season. In addition, jump test performance by the reserves declined from the beginning to the end of the season. These results indicate that sprint time is an important factor associated with selection as an FTP between the ages of 10 and 14 years. The progression of the FTPs during the course of the season is better than that of the reserves and is associated with a different degree of growth and maturity. These findings should be taken into account by trainers and coaches to avoid a bias against late maturing or younger soccer players.

Reduced antioxidant defense in early onset first-episode psychosis: a case-control study

BackgroundOur objective is to determine the activity of the antioxidant defense system at admission in patients with early onset first psychotic episodes compared with a control group.MethodsTotal antioxidant status (TAS) and lipid peroxidation (LOOH) were determined in plasma. Enzyme activities and total glutathione levels were determined in erythrocytes in 102 children and adolescents with a first psychotic episode and 98 healthy controls.ResultsA decrease in antioxidant defense was found in patients, measured as decreased TAS and glutathione levels. Lipid damage (LOOH) and glutathione peroxidase activity was higher in patients than controls. Our study shows a decrease in the antioxidant defense system in early onset first episode psychotic patients.ConclusionsGlutathione deficit seems to be implicated in psychosis, and may be an important indirect biomarker of oxidative stress in early-onset schizophrenia. Oxidative damage is present in these patients, and may contribute to its pathophysiology.

Distribution of prolyl endopeptidase activities in rat and human brain

Prolyl endopeptidase is a proteolytic enzyme which could have a neuropeptide catabolising role in the central nervous system. Although prolyl endopeptidase has been described as a cytosolic enzyme, it has become clear that it can also be found in particulate form. The regional and subcellular distribution of this enzyme was evaluated in rat and human brain. The activity of the enzyme was higher in the human than in the rat brain. In the human brain, the activity levels of both soluble and particulate prolyl endopeptidase were the highest in frontal, parietal and occipital cortices and the lowest in the cerebellum. In the rat brain, the regional distribution of the enzyme was more homogeneous. The activity in all the areas of the central nervous system is higher than in peripheral tissues. Subcellular distribution of the enzyme in the brain indicates that prolyl endopeptidase was higher in the cytosolic fraction than in the particulate fractions. The particulate form was enriched in the synaptosomal and the myelinic membranes. The high activity of prolyl endopeptidase in the human cortex suggests that prolyl endopeptidase could play a role in the functions of this brain area.

Nutritional intake in soccer players of different ages.

The purpose of this study was to evaluate the dietary practices of soccer players of different ages. The diets of the members of four soccer teams (mean ages of 14.0, 15.0, 16.6 and 20.9 years, respectively) were examined. Our results show that the caloric intake per kilogram of body mass was significantly higher among the youngest players when compared with the adult players (P  < 0.05). The contribution of carbohydrates to total energy intake was lower than that recommended for athletes. This contribution decreased with age from 47.4% of total energy intake for the 14-year-olds to 44.6% for the adult players. No significant differences in protein or total fat intake were detected among the teams examined. Overall, our results show that the nutritional intake of the soccer players was not optimal, and that this intake was poorer among the adult players than among the adolescents. On the basis of our results, we recommended that nutritional education should be given to soccer players at an early age and should continue throughout adolescence, not only with a view to improving performance but also to promoting more healthy dietary practices in the long term.

Peptidase activities in human semen.

Enkephalins are one of the opioids present in human semen and to date their function in this tissue remains unknown. The present work studies enkephalin-degrading enzyme activities, puromycin-sensitive alanyl aminopeptidase (AAP-S), puromycin-insensitive alanyl aminopeptidase N (Ap N) and neprilysin (NEP) in human seminal fractions. AAP-S activity was not detected in any fractions, whereas Ap N appeared in soluble and particulate sperm fractions in seminal fluid and in prostasome fraction. With regard to NEP activity, this was exclusively located in prostasome membranes. The high activity values observed in the prostasome fraction suggested that these peptidases and their substrates could be involved in seminal physiology.

Exercise, Physical Fitness, and Dietary Habits of First-Year Female Nursing Students

The objective of the present study was to evaluate the practice of regular physical exercise, the anthropometrical and physiological characteristics, and the dietary habits of a group of female nursing students (n = 46) and of a control group of female students from other disciplines (n = 58) attending the University of the Basque Country. To this end, diets and leisure-time physical exercise were analyzed and the following variables were measured: body mass index, body composition, blood pressure, maximal oxygen consumption (VO 2 max), and explosive muscle strength. Results show that the percentage of sedentary students was higher among first-year nursing students (50%) than among other matched students (43.6%). Regular physical exercise in nursing students was found to be positively correlated with higher absolute (p < .01) and relative VO 2 max (p < 0.05) and with lower diastolic blood pressure (p < 0.05). Analysis of the diets of the nursing students showed that their energetic intake was deficient and was very low in carbohydrates and very high in fat and protein. Statistically significant differences between the two groups in anthropometric indices were not observed. The competence to provide adequate nutritional and preventive physical exercise recommendations was higher among active final-year nursing students than among sedentary final-year nursing students. Overall, the results of the present study highlight the need for a greater emphasis on the benefits of regular physical exercise and an adequate nutritional education early in the nursing educational program to encourage students to adopt healthier behaviors and to provide more effective preventive physical exercise and nutritional counseling for their future patients.

The CB2 cannabinoid receptor regulates human sperm cell motility

OBJECTIVE To analyze the expression and distribution of cannabinoid receptors in human sperm cells and evaluate the effects of activation of receptors by specific agonists and antagonists, with a special emphasis on the CB(2) receptor. DESIGN We performed expression assays for CB(1) and CB(2) by reverse transcriptase PCR, Western blot, and immunofluorescence techniques in spermatozoa and performed motility analysis after incubation of semen samples with cannabinoid agonists and CB(2) antagonist SR144528. SETTING Academic research laboratory. PATIENT(S) Semen from 50 normozoospermic, healthy human donors. INTERVENTION(S) Spermatozoa isolated from semen by two consecutive swim-ups were used for all techniques. MAIN OUTCOME MEASURE(S) Reverse transcriptase PCR amplification gels, immunoblots, indirect immunofluorescence antibody assays, and percentage of motile sperm. RESULT(S) We have verified the presence of CB(1) and CB(2) receptors in human spermatozoa. The distribution of both of these receptors was distinct. Incubation with selective cannabinoid receptor agonists induced a significant reduction in the proportion of rapidly progressive motile spermatozoa, and whereas the CB(1) agonist increased the proportion of immobile sperm cells, the CB(2) receptor agonist increased the slow/sluggish progressive sperm cell population. The effect of the CB(2) agonist was antagonized by the CB(2)-specific antagonist. CONCLUSION(S) The functional CB(2) cannabinoid receptor is present in human spermatozoa and regulates the sperm motility in a more distinct manner than CB(1).

Anthropometric, physiological and maturational characteristics in selected elite and non-elite male adolescent basketball players

Abstract We investigated the anthropometric, physiological and maturation characteristics of young players (13–14 years old) associated with being successful in basketball. Body parameters were measured (stature, total body mass, skinfolds and lengths) and physiological capacities were assessed by endurance, sprint (20 m), jump and dribbling tests. Chronological age (CA) was recorded and maturity estimated using predicted age at peak height velocity (APHV). Anthropometric analysis indicated that elite players were taller, heavier and had a higher percentage of muscle. Further, physiological testing showed that these elite players perform better in jump, endurance, speed and agility tests (especially in the agility and ball tests). In addition, these skills are correlated with point average during the regular season. More basketball players born in the first semester of the year are selected and there is a predominance of early-maturing boys among those selected for the elite team. Those who are more mature have advantages in anthropometric characteristics and physiological test results. In conclusion, around puberty, physical and physiological parameters associated with maturity and CA are important in determining the success of basketball players. These findings should be taken into account by trainers and coaches, to avoid artificial bias in their selection choices.

Anthropometrical characteristics and somatotype of young soccer players and their comparison with the general population

In soccer, most studies have been conducted on elite adult players and there is less information about young, non-elite players. The objectives of this project were twofold: to evaluate the changes in the anthropometric characteristics and the somatotype of soccer players across different ages and to compare these characteristics to those of the general population (Basque and U.S.A. standards).The study population was formed of 203 soccer players, aged 14 to 19 years. Height, weight, B.M.I., skinfolds, diameters and circumferences were measured in order to calculate the body composition and somatotype. Boys aged 14 and 15 were shorter and leaner than the remainder of players. From age 16 onwards there was no differences in the measurements, implying that the subjects attained adult stature at age 16. The trunk-to-limb-fat ratio increased across the age groups, as happens in the general population; however, in soccer players this was due to a decrease in limb fat rather than an increase in the truncal fat.Soccer players showed a mainly mesomorphic somatotype, with the exception of the 14 year-old individuals who presented a greater ectomorphy compared to the adult players.The comparison with the general population showed that soccer players were taller and heavier, though this may due to a selection process favoring boys with these characteristics. Young soccer players were taller and bigger than boys of the same age in the general population; this may be due to a selection process towards larger and stronger boys.