Monitoring training load in youth soccer players: effects of a six-week preparatory training program and the association between external and internal loads

This study examined the effects of a six-week preparatory training program on physical performance and physiological adaptations in junior soccer players. Additionally, we investigated whether a relationship existed between external and internal loads. Youth soccer players (aged 16 years old) from a youth football academy participated in six weeks of pre-conditioning training. Wireless Polar Team Pro and Polar heart rate sensors (H10) were used to monitor physical performance indicators (sprint and acceleration scores, covered distance, maximum and average speed and duration), physiological responses (maximum and average heart rate [HR] and R-R interval, time in HR zones 4+5, and heart rate variability [HRV]), and training load score. Additionally, muscle status and rating of perceived exertion (RPE) scores were measured using digital questionnaires. Significant increases were observed in the majority of physical performance indicators [i.e., sprints (p = 0.015, ES = 1.02), acceleration (p = 0.014, ES = 1), total distance (p = 0.02, ES = 0.87), as well as maximum speed (p = 0.02, ES = 0.87)]. A trend towards improvement was observed in the remaining performance indicators (i.e., distance/min and avg speed; ES = 0.6), training load (ES = 0.2), muscle status (ES = 0.3)), and all physiological responses parameters (ES = 0.1 to 0.6). Significant correlations were found between the majority of external load parameters (i.e., performance indicators) and objective (i.e., physiological responses) and subjective (i.e., RPE, muscle status) internal load parameters (p < 0.001). The highest number of moderate-large correlations were registered between performance indicators and time in HR zone 4+5 (0.58 < r < 0.82), training load (0.53 < r < 0.83), average HR (0.50 < r < 0.87), maximal HR (0.51 < r < 0.54) and average R-R interval (0.58 < r < 0.76). HR zone 4+5, average and maximal HR, average R-R interval, and training load score may help control training parameters and reduce the risk of under- or over-training in youth soccer players. However, these conclusions should be confirmed and replicated in future studies with more diverse subject populations.     

Aspects cliniques et biologiques de l’azoospermie chez l’homme infertile en Tunisie

Objective

It is now very important to investigate azoospermia because the introduction of the intracytoplasmic sperm injection technique during the last decade has allowed many infertile men to achieve their dreams of fatherhood. The purpose of this study was to define the characteristics of infertile men with azoospermia, and to analyse the clinical and laboratory features and the causes of infertility in Tunisia. The authors also discuss various aspects that they consider to be very important in the diagnosis of male fertility.

Material and Methods

This retrospective study analysed the parameters of physical examination, laboratory tests, semen analysis, radiographic examinations, testicular biopsy, karyotype and AZF microdeletions.

Results

Based on the results of endocrinological and cytogenetic examinations, the aetiology of azoospermia was considered to be secretory in 43 cases of azoospermia. Physical examination revealed a high percentage of hypotrophic/atrophic testes (43.9%). Serum follicle stimulating hormone levels were high in 58.5% of cases. The overall incidence of chromosomal abnormalities was 31.4%. The most frequent anomaly was Klinefelter syndrome (9 cases). Seven out of 28 patients (25%) with nonobstructive azoospermia had AZF deletions. None of the patients with excretory azoospermia and severe oligospermia had an abnormal karyotype or AZF microdeletions. 48.8% of patients presented a varicocele, 13.9% had cryptorchidism and 13.0% had a history of genital tract infection.

Conclusion

In line with the literature, genetic abmormalities are the main causes of severe forms of impaired spermatogenesis in the Tunisian population.     

Skewed X-chromosome inactivation pattern in SRY positive XX maleness: a case report and review of literature

XX maleness is the most common condition in which testes develop in the absence of a cytogenetically detectable Y chromosome. Using fluorescence in situ hybridization (FISH) or PCR, it was possible to detect the transfer of Yp fragments including SRY gene to the terminal part of X chromosome in the majority of XX males. We report a 32-year-old-male in whom a seminal analysis showed azoospermia, an X chromatin analysis showed 44% of Barr body positive nuclei and a chromosomal analysis revealed a 46,XX karyotype. Physical examination showed a normal sexual development and bilateral small testes. Hormonal studies revealed hypergonadotropic hypogonadism. Testis histological examination showed a profile of Sertoli Only Cell Syndrome. FISH study ruled out the presence of a Y-bearing cell line, and confirmed translocation of SRY to Xp terminal part. In order to confirm that the complete masculinized phenotype was related to a preferential inactivation of the no rearranged X chromosome, X-chromosome inactivation patterns (XCIP) were studied by analysis of methylation status of the androgen receptor gene. Highly skewed XCIP was observed by greater than 90% preferential inactivation involving one of the two X chromosomes, suggesting that the SRY-bearing X chromosome was the preferentially active X allowing for sufficient SRY expression for complete masculinization.     

The effect of strength training at the same time of the day on the diurnal fluctuations of muscular anaerobic performances

The aim of this study was to examine the effects of training at the same time of the day on the diurnal variations of anaerobic performances to provide some recommendations to adjust training hours with the time of the day of competitive events. Thirty participants underwent 8 weeks of lower-extremity progressive resistance training performed 3 times per week designed to promote muscular strength and power. These subjects were randomly assigned to a morning training group (MTG, 07:00-08:00 hours, n = 10), an evening training group (ETG, 17:00-18:00 hours, n = 10), and a control group (CG, completed all tests but did not train, n = 10). Performance in the squat jump, the countermovement jump, the Wingate and 1 repetition maximum (1RM) during leg extension, leg curl, and squat tests was recorded just before and 2 weeks after an 8-week course of regular training. For all the subjects, the morning and evening tests were scheduled at the same time of the day as for the morning and evening training sessions. Before training, the results indicated a significant increase in performance from morning to evening tests (ca. 2.84-17.55% for all tests) for all groups. After training, the diurnal variations in anaerobic performances were blunted in the MTG. In fact, there was no significant difference in muscular power or strength between morning and evening tests. However, these intradaily variations in anaerobic performances persisted in the ETG and CG. From a practical point of view, adaptation to strength training is greater at the time of the day at which training was scheduled than at other times.     

Immunocytochemical localization of scorpion digestive lipase

The scorpion hepatopancreas consists of digestive diverticula and interstitial tissue. A digestive diverticulum is composed of two differentiated cell types: the secretory zymogene-like cells and the digestive cells which are the most abundant. The scorpion digestive lipase (SDL) has been previously purified from scorpion hepatopancreas, but its cellular localization has not yet been established. Polyclonal antibodies specific to SDL were prepared and used in immunofluorescence and immunogold techniques to determine the cellular location of SDL. Our results clearly established that SDL was detected intracellularly in specific vesicles tentatively named (SDL+) granules of the digestive cells. No immunolabelling was observed in secretory zymogene-like cells. This immunocytolocalization indicates that lipid digestion might occur in specific granules inside the digestive cells, as suggested by previous studies on the scorpion digestive process.     

Salinity tolerance of hydroponically grown <Emphasis Type="Italic">Pinus pinea</Emphasis> L. seedlings

The salinity tolerance and ion transport of 2-month-old seedlings of stone pine (Pinus pinea L.) grown in hydroponic solution containing various concentrations of NaCl (0–100 mM) were studied. The presence of salt of up to 100 mM did not significantly reduce growth. Seedling hydration was insensitive to salinity. High salt concentrations reduced K⁺ and Ca²⁺ uptake, root accumulation, and export to shoots. Na⁺ and Cl⁻ ions, representing the major part of the ionic uptake, were effectively compartmentalized in vacuoles. We concluded that seedlings of stone pine cultivated hydroponically were highly tolerant to salt concentrations of up to 100 mM for a culture period of 38 days. This tolerance was associated with the accumulation of Na⁺ and Cl⁻ ions in the shoots.     

Cytogenetics and fluorescence in situ hybridization assessment of sex-chromosome mosaicism in Klinefelter's syndrome

A retrospective study was carried out in 152 infertile men to determine the prevalence of sex chromosome abnormalities among non-obstructive azoospermic and severe oligospermic men (n = 51) and to evaluate the feasibility of fluorescence in situ hybridization (FISH) techniques to assess mosaicism in Klinefelter's patients in comparison with conventional cytogenetics. Cytogenetic analysis were performed for 51 infertile men and among 14 chromosomal abnormalities found, nine were compatible with Klinefelter's syndrome. FISH staining with a CEP X/CEP Y probes were performed for Klinefelter's patients and for five of them; testes were biopsied for histopathologic examination. Six Klinefelter's patients showed a non-mosaic 47,XXY and three showed a 47,XXY/46,XY mosaic by G or R banding analysis of 20 cells with a ratio of 17%, 20% and 33%, respectively. FISH analysis confirmed mosaicism in only one patient (the first) in whom a third cells population was found. There was no relationship between the ratios of mosaicism by banding and FISH analysis. Conventional histopathologic findings in five non-mosaic Klinefelter's patients confirm the diagnosis of Sertoli Only Cells syndrome. FISH is recommended in Klinefelter's syndrome to define exactly the cytogenetic statute as mosaic or non-mosaic and then discussing prognosis and decision regarding fertility counseling.     

Inhibitory effects of estrogens on digestive enzymes,insulin deficiency,and pancreas toxicity in diabetic rats

Diabetes mellitus, with its attendant disorders and dysfunctional behaviors, constitutes a growing concern to the population of the world. With this concern in mind, the present study investigated the anti-diabetic and hypolipedimic potential of 17β-estradiol (called E2), particularly in terms of its inhibitory effects on maltase, sucrase, lactase, and lipase activities in the intestine of surviving diabetic rats. The findings revealed that this supplement helped protect the β cells of the rats from death and damage. Interestingly, E2 induced considerable decreases of 29%, 46%, 42%, and 84% in the activities of intestinal maltase, lactase, sucrase, and lipase, respectively. The E2 extract also decreased the glucose, triglyceride, and total cholesterol rates in the plasma of diabetic rats by 39%, 27%, and 53%, respectively, and increased the HDL–cholesterol level by 74%, which helped maintain the homeostasis of blood lipid. When compared to those of the untreated diabetic rats, the superoxide dismutase, catalase, and glutathione peroxidase levels in the pancreas of the rats treated with this supplement were also enhanced by 330%, 170%, and 301%, respectively. A significant decrease was also observed in the lipid peroxidation level and lactate dehydrogenase activity in the pancreas of diabetic rats after E2 administration. Overall, the findings presented in this study demonstrate that E2 has both a promising potential with regard to the inhibition of intestinal maltase, sucrase, lactase, and lipase activities, and a valuable hypoglycemic and hypolipidemic function, which make it a potential strong candidate for industrial application as apharmacological agent for the treatment and prevention of hyperlipidemia, obesity, and cardiovascular diseases.     

Biochemical characterization,cloning and molecular modeling of a digestive lipase from red seabream (Pagrus major): Structural explanation of the interaction deficiency with colipase and lipidic interface

Red seabream digestive lipase (RsDL) was purified from fresh pyloric caeca. Pure RsDL has an apparent molecular mass of 50 kDa. The RsDL is more active on short‐chain triacylglycerols (TC₄), and enzymatic activity decreases when medium (TC₈) or long‐chain (olive oil) triacylglycerols were used as substrates. The specific activities of RsDL are very weak as compared to those obtained with classical pancreatic lipases. No colipase was detected in the red seabream pyloric caeca. Furthermore, the RsDL was not activated by a mammal colipase. Similar results were reported for annular seabream lipase. In order to explain structurally the discrepancies between sparidae and mammal lipases, genes encoding mature RsDL and five other lipases from sparidae fish species were cloned and sequenced. Phylogenetic studies indicated the closest homology of sparidae lipases to bird pancreatic ones. Structural models were built for annular seabream and RsDL under their closed and open forms using mammal pancreatic lipases as templates. Several differences were noticed when analyzing the amino acids corresponding to those involved in HPL binding to colipase. This is likely to prevent interaction between the fish lipase and the mammalian colipase and may explain the fact that mammalian colipase is not effective in activating sparidae lipases. In addition, several hydrophobic residues, playing a key role in anchoring pancreatic lipase onto the lipid interface, are replaced by polar residues in fish lipases. This might explain the reason why the latter enzymes display weak activity levels when compared to mammalian pancreatic lipases.     

Potential of doubled-haploid lines and localization of quantitative trait loci (QTL) for partial resistance to bacterial leaf streak (Xanthomonas campestris pv. hordei) in barley

 Genetic variability for partial resistance to bacterial leaf streak in barley, caused by Xanthomonas campestris pv. hordei, was investigated in 119 doubled-haploid lines (DH) developed by the Hordeum bulbosum method from the F₁ progeny of the cross between two cultivars, ‘Morex’ (resistant) and ‘Steptoe’ (susceptible). Two experiments were undertaken in a randomized complete block design with three replicates, in a controlled growth chamber. Twenty seeds per replicate were planted in plastic containers (60×40×8 cm) containing moistened vermiculite. At the two-leaf stage seedlings were inoculated with an Iranian strain of the pathogen. Genetic variability was observed among the 119 DH lines for partial resistance to the disease. Some DH lines were significantly more resistant than ‘Morex’ (resistant parent) to bacterial leaf streak. Genetic gain in percentage of resistant parent for 5% of the selected DH lines was significant (47.70% and 33.72% in the first and the second experiment, respectively). A QTL analysis of bacterial leaf streak resistance showed that three QTLs were detected on chromosomes 3 and 7. Multilocus allelic effects of the three QTLs account for almost 54% of the mean difference between the parents and nearly 30% of the phenotypic variation of the trait in the mean experiment. The resistance locus on chromosome 3, near ABG377, apprears to be a major gene. Received: 15 July 1997 / Accepted: 4 August 1997