Point prevalence audit surveys of respiratory tract infection consultations and antibiotic prescribing in primary care before and during the COVID-19 pandemic in Ireland.

BACKGROUND: Respiratory tract infections (RTIs) are the most common reason for prescribing antibiotics in general practice. The COVID-19 pandemic has impacted on antibiotic prescribing and delivery of primary care in Ireland. OBJECTIVES: To assess the quality of antibiotic prescribing, the impact of the COVID-19 pandemic and identify opportunities for antimicrobial stewardship (AMS) in Ireland. METHODS: Point prevalence audit surveys for RTI consultations were conducted as part of a European study at three time periods: January-February 2020, March-May 2020 and March-May 2021. Antibiotic prescribing was assessed and comparisons made between the three time periods. RESULTS: In total, 765 consultations were recorded, which were mainly face to face before the pandemic, but changed to predominantly remote consultations during the pandemic surveys in 2020 and 2021 (82% and 75%). Antibiotics were prescribed in 54% of RTI consultations before the pandemic. During pandemic surveys, this dropped to 23% in 2020 and 21% in 2021. There was a decrease in prescribing of Red (reserve) agents in 2021. Assessment against indication-specific quality indicators showed a high proportion of consultations for bronchitis and tonsillitis resulting in an antibiotic prescription (67% and 85%). Point-of-care testing (POCT) to aid diagnosis of RTIs were utilized in less than 1% of consultations. CONCLUSIONS: During the COVID-19 pandemic, there was a reduction in antibiotic prescribing. Opportunities identified to support AMS in primary care in Ireland are targeted initiatives to reduce antibiotic prescribing for bronchitis and tonsillitis and introducing POCT to support appropriate antibiotic prescribing.

Characterization of a DRC1 null variant associated with primary ciliary dyskinesia and female infertility.

PROPOSE: We here present a female case with primary ciliary dyskinesia (PCD) and infertility. In this report, we also present the evaluation of the patient family, including her twin sister, also with PCD and infertility. METHODS: Confirmation of the PCD clinical diagnosis was performed through assessment of cilia motility, by high-speed video microscopy (HSVM), axoneme ultrastructure, by transmission electron microscopy (TEM), and genetic characterization, by whole-exome sequence (WES). Gene expression studies used qPCR for mRNA expression and immunofluorescence to determine cell protein localization. RESULTS: We identified a homozygous nonsense variant in the DRC1 gene (NM 145038.5:c.352C>T (p.Gln118Ter)) in the female patient with PCD and infertility that fit the model of autosomal recessive genetic transmission. This variant eventually results in a dyskinetic ciliary beat with a lower frequency and a partial lack of both dynein arms as revealed by TEM analysis. Moreover, this variant implies a decrease in the expression of DRC1 mRNA and protein. Additionally, expression analysis suggested that DRC1 may interact with other DRC elements. CONCLUSIONS: Our findings suggest that the DRC1 null variant leads to PCD associated with infertility, likely caused by defects in axoneme from Fallopian tube cilia. Overall, our outcomes contribute to a better understanding of the genetic factors involved in the pathophysiology of PCD and infertility, and they highlight the interaction of different genes in the patient phenotype, which should be investigated further because it may explain the high heterogeneity observed in PCD patients.

Physical activity and long COVID: findings from the Prospective Study About Mental and Physical Health in Adults cohort.

OBJECTIVES: The study investigated the longitudinal association between physical activity and the risk of long COVID in patients who recovered from COVID-19 infection. STUDY DESIGN: We analyzed longitudinal data of the Prospective Study About Mental and Physical Health cohort, a prospective cohort study with adults living in Southern Brazil. METHODS: Participants responded to an online, self-administered questionnaire in June 2020 (wave 1) and June 2022 (wave 4). Only participants who self-reported a positive test for COVID-19 were included. Physical activity was assessed before (wave 1, retrospectively) and during the pandemic (wave 1). Long COVID was assessed in wave 4 and defined as any post-COVID-19 symptoms that persisted for at least 3 months after infection. RESULTS: A total of 237 participants (75.1% women; mean age [standard deviation]: 37.1 [12.3]) were included in this study. The prevalence of physical inactivity in baseline was 71.7%, whereas 76.4% were classified with long COVID in wave 4. In the multivariate analysis, physical activity during the pandemic was associated with a reduced likelihood of long COVID (prevalence ratio [PR]: 0.83; 95% confidence interval [CI]: 0.69-0.99) and a reduced duration of long COVID symptoms (odds ratio: 0.44; 95% CI: 0.26-0.75). Participants who remained physically active from before to during the pandemic were less likely to report long COVID (PR: 0.74; 95% CI: 0.58-0.95), fatigue (PR: 0.49; 95% CI: 0.32-0.76), neurological complications (PR: 0.47; 95% CI: 0.27-0.80), cough (PR: 0.40; 95% CI: 0.22-0.71), and loss of sense of smell or taste (PR: 0.43; 95% CI: 0.21-0.87) as symptom-specific long COVID. CONCLUSION: Physical activity practice was associated with reduced risk of long COVID in adults.

Fusion of Tumor-Derived Exosomes with Long-Circulating and pH-Sensitive Liposomes Loaded with Doxorubicin for the Treatment of Breast Cancer.

Doxorubicin (DOX) is a chemotherapeutic agent that has been used in the treatment of breast cancer. However, serious toxic effects have limited its use, mainly cardiotoxicity. To minimize the adverse effects, liposomal preparations containing DOX have been developed. These preparations can reach the target in the tumor region as well as bypass the resistance-related problems. An alternative to increased therapeutic efficacy may be the fusion of liposomes with exosomes released from tumor cells to facilitate membrane and fusion interactions, achieving greater cell uptake. Thus, the purpose of this study was the fusion of exosomes derived from breast tumor cells with long-circulating and pH-sensitive liposomes loading DOX (ExoSpHL-DOX) for the treatment of breast cancer. The mean diameter of ExoSpHL-DOX was 100.8 ± 7.8 nm, the polydispersity index was 0.122 ± 0.004, and the encapsulated DOX content was equal to 83.5 ± 2.5%. The fusion of exosomes with long-circulating and pH-sensitive liposomes was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, and nano-flow cytometry. The physicochemical characteristics of ExoSpHL-DOX were maintained for 60 days, at 4 °C. The study of the release of DOX from ExoSpHL-DOX in dilution media with different pH values showed the pH sensitivity characteristic of the nanosystem, since 96.6 ± 0.2% of DOX was released from ExoSpHL-DOX at pH 5.0, while at pH 7.4, the release was 70.1 ± 1.7% in the medium. The cytotoxic study against the breast cancer cell line demonstrated that ExoSpHL-DOX treatment significantly reduced the cancer cell viability.

A systematic review of instruments measuring grief after perinatal loss and factors associated with grief reactions.

OBJECTIVE: Expectant parents who live through perinatal loss experience intense grief, which is not always acknowledged or accepted. A screening tool to detect bereaved parents' grief reactions can guide professionals, including perinatal palliative care teams, to provide follow-up for those in need. This review's goal is to identify and synthesize the international published literature on existent instruments specifically measuring the grieving process after any perinatal loss and to identify factors that could moderate grief reactions. METHOD: Systematic review (PROSPERO # CRD42018092555) with critical synthesis. PUBMED, Cochrane, and PsycINFO databases were searched in English language articles using the keywords "perinatal" AND ("grief" OR "bereavement" OR mourning) AND ("scale" OR "questionnaire" OR "measure" OR "assessment") up to May 2018. Eligibility criteria included every study using a measure to assess perinatal grief after all kinds of perinatal losses, including validations and translations to other languages and interventions designed to alleviate grief symptoms. RESULTS: A total of 67 papers met inclusion criteria. Seven instruments measuring perinatal grief published between 1984 and 2002 are described. The Perinatal Grief Scale (PGS) was used in 53 of the selected studies. Of those, 39 analyzed factors associated with grief reactions. Six articles used PGS scores to evaluate pre- and post-bereavement interventions. Studies in English language only might have limited the number of articles. SIGNIFICANCE OF RESULTS: The PGS is the most used standardized measures to assess grief after perinatal loss. All parents living through any kind of perinatal loss should be screened.

Antibacterial activity of chitosan/collagen membranes containing red propolis extract.

In this study we developed a mucoadhesive polymeric membrane wound dressing incorporating red propolis extract (HERP). Membranes were made using a casting method employing collagen, chitosan, polyethylene glycol (15, 20, and 30v%), and hydroethanolic extract of EtOH-H2O 70v% - 30v% (v/v) of HERP (0.5, 1.0, and 1.5%). Membranes were extensively characterized to assess the thickness, pH, morphology using Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), mechanical properties, swelling, in vitro mucoadhesion, cytotoxicity, and minimum inhibitory concentration (MIC). Assessment of the thickness and mechanical properties of the membranes containing HERP revealed that the most significant thickness obtained was 40.7 µm; thermal analysis suggests suggesting the hydrogen bonds between hydroxyl groups of isoflavones and the free amine present in the region of chitosan. Cell viability decreased as the amount of HERP increased. Finally, the MICs were 7.8 and 1.9 µg.mL-1 for Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853, respectively. These results were suggesting that the 0.5 % HERP membrane has the potential for future studies for wound application.

Characterization of CCDC103 expression profiles: further insights in primary ciliary dyskinesia and in human reproduction.

PROPOSE: To study CCDC103 expression profiles and understand how pathogenic variants in CCDC103 affect its expression profile at mRNA and protein level. METHODS: To increase the knowledge about the CCDC103, we attempted genotype-phenotype correlations in two patients carrying novel homozygous (missense and frameshift) CCDC103 variants. Whole-exome sequencing, quantitative PCR, Western blot, electron microscopy, immunohistochemistry, immunocytochemistry, and immunogold labelling were performed to characterize CCDC103 expression profiles in reproductive and somatic cells. RESULTS: Our data demonstrate that pathogenic variants in CCDC103 gene negatively affect gene and protein expression in both patients who presented absence of DA on their axonemes. Further, we firstly report that CCDC103 is expressed at different levels in reproductive tissues and somatic cells and described that CCDC103 protein forms oligomers with tissue-specific sizes, which suggests that CCDC103 possibly undergoes post-translational modifications. Moreover, we reported that CCDC103 was restricted to the midpiece of sperm and is present at the cytoplasm of the other cells. CONCLUSIONS: Overall, our data support the CCDC103 involvement in PCD and suggest that CCDC103 may have different assemblies and roles in cilia and sperm flagella biology that are still unexplored.

Educational strategies and atraumatic restorative treatment effect on salivary characteristics: A controlled clinical trial.

OBJECTIVE: To evaluate educational strategies and atraumatic restorative treatment (ART)-restoration impact on salivary physicochemical and microbiological characteristics. DESIGN: Two groups of 6- to 7-year-old children were included: GART , with at least one decayed primary molar (n = 36), submitted to four sessions of oral health educational strategy (OHES) and ART restoration; GC , a paired caries-free group (n = 36), submitted to four sessions of OHES. Three evaluations were carried out: baseline, 1 week after OHES, and 1 month after OHES or ART, when biofilm and gingivitis frequencies, salivary flow, pH, buffer capacity, calcium and phosphorus concentrations were assessed. Total bacteria and Streptococcus mutans were quantified in unstimulated saliva (qPCR). RESULTS: Improvement in biofilm and gingivitis scores, salivary pH, and buffering capacity after OHES was observed in GC , with a decrease in total bacteria and S. mutans counts. GART also showed changes in salivary parameters, even before ART restoration was delivered, and total bacteria count remained lower than baseline 1 month after ART restoration, although a trend to increase the proportion of S. mutans was observed. CONCLUSION: Improvements in salivary physicochemical and microbiological characteristics were observed after educational strategies, thus reducing the caries risk of children with decayed teeth, although a trend to increase the S. mutans percentage was observed 1 month after ART restoration.

Phenylephrine increases near-infrared spectroscopy determined muscle oxygenation in men.

Phenylephrine increases mean arterial pressure (MAP) by enhanced total peripheral resistance (TPR) but near-infrared spectroscopy (NIRS) determined muscle oxygenation (SmO2) increases. We addressed that apparent paradox during supine rest and head-up tilt (HUT). Variables were determined ± phenylephrine in males during supine rest (n = 17) and 40° HUT (n = 7). MAP, stroke volume (SV), heart rate (HR), and TPR were derived by Modelflow® and NIRS determined biceps SmO2 and (tibial) bone oxygenation (StibialO2). For ten subjects, cardiac filling and the diameter of the inferior caval vein (ICV collapsibility index: ((ICVexpiration - ICVinspiration)/ICVexpiration) × 100) were assessed by ultrasound. Pancreatic polypeptide (PP) and atrial natriuretic peptide (proANP) in plasma were determined by immunoassay. Brachial artery blood flow was assessed by ultrasound and skin oxygenation (SskinO2) monitored by white light spectroscopy. Phenylephrine increased MAP by 34% and TPR (62%; P < 0.001) during supine rest. The ICV collapsibility index decreased (24%; P < 0.001) indicating augmented cardiac preload although volume of the left atrium and ventricle did not change. SV increased (18%; P < 0.001) as HR decreased (24%; P < 0.001). ProANP increased by 9% (P = 0.002) with unaffected PP. Brachial artery blood flow tended to decrease while SskinO2 together with StibialO2 decreased by 11% (P = 0.026) and 20% (P < 0.001), respectively. Conversely, phenylephrine increased SmO2 (9%) and restored the HUT elicited decrease in SmO2 (by 19%) along with SV (P = 0.02). Phenylephrine reduces skin and bone oxygenation and tends to reduce arm blood flow, suggesting that the increase in SmO2 reflects veno-constriction with consequent centralization of the blood volume.

Assessment of quality of life, anxiety, socio-economic factors and caries experience in Brazilian children with overweight and obesity.

PURPOSE: This study evaluated the association between excess weight and quality of life (QoL), symptoms of anxiety, caries experience and socio-economic factors in a representative sample of 8- to 10-year-old children from three public schools of Piracicaba (SP, Brazil). MATERIALS AND METHODS: The Autoquestionnaire Qualité de Vie Enfant Image was applied to explore family and social relations, activities, health, body functions and separation domains, and, by means of the Multidimensional Anxiety Scale for Children, symptoms of anxiety were screened. Clinical examination was performed using DMFT/dmft indexes to assess oral health and caries experience. Medical and nutritional history, parents' schooling, monthly income and ownership of household goods and services were also evaluated. RESULTS: Of the 313 subjects included, four subjects were underweight, 188 normal weight, 67 overweight and 54 presented obesity (38.7% with excess weight). Measures of QoL, anxiety scores and caries experience did not differ between groups. The regression model showed a significant association between excess weight and the ownership of household goods and services (OR = 5.4/CI = 1.6-18.3). CONCLUSIONS: High prevalence of excess weight was observed among prepubertal children, emphasizing the need for continued health programmes to limit risk factors for obesity. QoL, anxiety scores and caries experience did not differ between subjects with different body weights, although children from public schools with higher ownership of goods and services were more likely to present excess weight.

Catechol-O-methyltransferase activity in erythrocytes from patients with eating disorders.

PURPOSE: Abnormal feeding has been linked to disruptions in brain dopaminergic activity and recent studies have assessed the role of catechol-O-methyltransferase (COMT) in eating disorders. This is the first study to quantify the soluble catechol-O-methyltransferase (S-COMT) activity in erythrocytes from patients with anorexia nervosa (AN), bulimia nervosa (BN) and binge-eating disorder (BED) and the first study at all to evaluate the COMT on patients with BED. METHODS: Forty blood samples from patients with AN, BN and BED and healthy controls were drawn to evaluate S-COMT activity in erythrocytes by high-performance liquid chromatography and mass spectrometry. Since several patients were being treated with fluoxetine 20 mg, they were included in a different group (BN MED and BED MED). Liver homogenates from rats were used to evaluate baseline S-COMT activity in the presence of fluoxetine by the same in vitro procedures and assays. RESULTS: Erythrocyte S-COMT activity (pmol/mg prt/h) was significantly increased in patients with BN and BED (41.3 ± 6.8 and 41.4 ± 14, respectively) compared to control group (25.3 ± 9.7). In fluoxetine-treated patients with BN, S-COMT activity (15.9 ± 8.8) was decreased compared to the other BN group; however, in BED group, the difference between BED MED and BED was not observed. In patients with AN, no significant difference was found compared to controls. CONCLUSION: Patients with BN and BED presented higher S-COMT activity in erythrocytes, which is in agreement with previous studies on the literature addressing the high-activity COMT allele, Val158, as risk factor for eating disorders. Although in fluoxetine-treated patients with BN the activity of S-COMT was similar to the controls, this is not explained by a direct interaction between fluoxetine and S-COMT as verified in in vitro assays.

Hydrodynamic profile of young swimmers: changes over a competitive season.

The aim of this study was to analyze the changes in the hydrodynamic profile of young swimmers over a competitive season and to compare the variations according to a well-designed training periodization. Twenty-five swimmers (13 boys and 12 girls) were evaluated in (a) October (M1); (b) March (M2); and (c) June (M3). Inertial and anthropometrical measures included body mass, swimmer's added water mass, height, and trunk transverse surface area. Swimming efficiency was estimated by the speed fluctuation, stroke index, and approximate entropy. Active drag was estimated with the velocity perturbation method and the passive drag with the gliding decay method. Hydrodynamic dimensionless numbers (Froude and Reynolds numbers) and hull velocity (i.e., speed at Froude number = 0.42) were also calculated. No variable presented a significant gender effect. Anthropometrics and inertial parameters plus dimensionless numbers increased over time. Swimming efficiency improved between M1 and M3. There was a trend for both passive and active drag increase from M1 to M2, but being lower at M3 than at M1. Intra-individual changes between evaluation moments suggest high between- and within-subject variations. Therefore, hydrodynamic changes over a season occur in a non-linear fashion way, where the interplay between growth and training periodization explain the unique path flow selected by each young swimmer.

Remote ischemic preconditioning delays fatigue development during handgrip exercise.

Ischemic preconditioning (IPC) of one or two limbs improves performance of exercise that recruits the same limb(s). However, it is unclear whether IPC application to another limb than that in exercise is also effective and which mechanisms are involved. We investigated the effect of remote IPC (RIPC) on muscle fatigue, time to task failure, forearm hemodynamics, and deoxygenation during handgrip exercise. Thirteen men underwent RIPC in the lower limbs or a control intervention (CON), in random order, and then performed a constant load rhythmic handgrip protocol until task failure. Rates of contraction and relaxation (ΔForce/ΔTime) were used as indices of fatigue. Brachial artery blood flow and conductance, besides forearm microvascular deoxygenation, were assessed during exercise. RIPC attenuated the slowing of contraction and relaxation throughout exercise (P < 0.05 vs CON) and increased time to task failure by 11.2% (95% confidence interval: 0.7-21.7%, P <0.05 vs CON). There was no significant difference in blood flow, conductance, and deoxygenation between conditions throughout exercise (P > 0.05). In conclusion, RIPC applied to the lower limbs delayed the development of fatigue during handgrip exercise, prolonged time to task failure, but was not accompanied by changes in forearm hemodynamics and deoxygenation.

Associations between psychological factors and the presence of deleterious oral habits in children and adolescents.

OBJECTIVES: This study aimed to evaluate the associations between psychological factors and the presence of deleterious oral habits in children and adolescents. STUDY DESIGN: 147 students aged 8 to 14-years-old were divided in two groups concerning the presence and absence of DOH Habit group (HG) and Habit free group (HFG). Participants were asked about the presence of DOH using the domain III (Oral Habits) of the Nordic Orofacial Test-Screening (NOT-S). Symptoms of anxiety and depression were evaluated using the Brazilian Portuguese versions of the Revised Children's Manifest Anxiety Scale (RCMAS) and the Children's Depression Inventory (CDI), respectively. Saliva was collected 30 min after waking and at night to determine the diurnal decline in salivary cortisol (DDSC). Data were analyzed using the Chi-squared, Mann-Whitney, Spearman's correlation and logistic regression. RESULTS: The prevalence of DOH was higher in females than males (65.1 vs 34.9; p < 0.05). The most frequent DOH was nail biting (58.7%). HG presented more depressive symptoms than HFG (p < 0.05). There was positive correlation between salivary cortisol levels and age (p < 0.01). Logistic regression analysis found association between symptoms of anxiety and the presence of DOH (OR = 2.35; p < 0.05). CONCLUSIONS: In conclusion, children and adolescents with DOH presented more symptoms of depression than their counterparts. Moreover, they were more likely to report symptoms of anxiety.

Changes in the oral-health-related quality of life of Brazilian children after an educational preventive programme: an 1-month longitudinal evaluation.

OBJECTIVE: This 1-month longitudinal study assessed whether the oral status and the oral-health-related quality of life (OHRQoL) of children changed after four sessions of an educational preventive programme. STUDY POPULATION AND METHODS: Fifty Brazilian students (11-12 year old) were examined for signs and symptoms of gingivitis using the Community Periodontal Index and two questions about gingival bleeding. The OHRQoL was measured using the Brazilian Portuguese version of the Child Oral Impacts on Daily Performances (Child-OIDP). Higher scores indicated worse OHRQoL. The results were analysed using the Shapiro-Wilk, Chi-square, Wilcoxon signed-rank and Mann-Whitney tests. The magnitude of the mean change was calculated using the effect size. RESULTS: Twenty-four percentage of children had more than six sites with bleeding at follow-up compared with 58% at baseline. There was a significant decline in the intensity and extension of impacts at follow-up. A significant improvement in the clinical status and oral hygiene was observed for both transitional categories. There was a significant decline in the Child-OIDP scores of those reporting 'much improved'. A significant improvement in the global ratings of oral health was observed at follow-up. CONCLUSIONS: In the studied sample, an improvement occurred with respect to the severity of disease, intensity and extension of impacts and global ratings of oral health after 1-month follow-up. These results suggest that improving the global transition in health by enhancing coping and management skills while inducing slight changes in the clinical status and the specific aspects of health compromised by the disease is possible.

Morita-Baylis-Hillman adduct shows in vitro activity against Leishmania (Viannia) braziliensis associated with a reduction in IL-6 and IL-10 but independent of nitric oxide.

Current treatments for different clinical forms of leishmaniasis are unsatisfactory, highly toxic and associated with increasing failure rates resulting from the emergence of resistant parasites. Leishmania (Viannia) braziliensis is the main aetiological agent of different clinical forms of American tegumentary leishmaniasis, including the mucosal form for which treatment has high failure rates. The aim of this work was to investigate the activity of the Morita-Baylis-Hillman adduct, methyl 2-{2-[hydroxy(2-nitrophenyl)methyl])acryloyloxy} benzoate in vitro against isolates of L. (V.) braziliensis obtained from patients with different clinical manifestations of tegumentary leishmaniasis: localized cutaneous leishmaniasis, mucosal leishmaniasis and disseminated cutaneous leishmaniasis. The adduct effectively inhibited the growth of promastigotes of the different isolates of L. (V.) braziliensis (IC(50) ≤ 7·77 µg/ml), as well as reduced the infection rate of macrophages infected with these parasites (EC(50) ≤ 1·37 µg/ml). It is remarkable to state that the adduct was more effective against intracellular amastigotes (P ≤ 0·0045). The anti-amastigote activity correlated with an immunomodulatory effect, since the adduct was able to decrease the production of IL-6 and IL-10 by the infected macrophages. However, its effect was independent of nitric oxide production. This work demonstrates the anti-leishmanial activity of methyl 2-{2-[hydroxy(2-nitrophenyl)methyl])acryloyloxy} benzoate and suggests its potential in the treatment of human infections caused by L. (V.) braziliensis.

Effects of concurrent training on explosive strength and VO(2max) in prepubescent children.

The purpose of this study was to compare the effects of an 8-weeks training period of resistance training alone (GR), combined resistance and endurance training (GCON) and a control group (GC) on explosive strength and V(O2max) in a large sample of prepubescent boys and girls. 125 healthy children (58 boys, 67 girls), aged 10-11 years old (10.8±0.4 years) were assigned into 2 training groups to train twice a week for 8 weeks: GR (19 boys, 22 girls), GCON (21 boys, 24 girls) and a control group (GC: 18 boys, 21 girls; no training program). A significant but medium-sized increase from pre- to the post-training in the vertical jump (Effect size=0.22, F=34.44, p<0.01) and V(O2max) (Effect size=0.19, F=32.89, p<0.01) was observed. A significant large increase in the 1 kg (Effect size=0.53, F=202.17, p<0.01) and 3 kg (Effect size=0.48, F=132.1, p<0.01) ball throwing, standing long jump (Effect size=0.53, F=72.93, p<0.01) and running speed (Effect size=0.45, F=122.21, p<0.01) was also observed. The training group (GR and GCON) and sex factors did not significantly influence the evolution of strength variables from pre- to the post-training. The V(O2max) increased significantly only in GCON. Concurrent training is equally effective on training-induced explosive strength, and more efficient than resistance training only for V(O2max), in prepubescent boys and girls. This should be taken into consideration in order to optimize strength training school-based programs.

The interaction between intra-cyclic variation of the velocity and mean swimming velocity in young competitive swimmers.

The aim of this study was to assess the relationship between the intra-cyclic variation of the horizontal velocity (dv) and the velocity of the 4 competitive swimming techniques in young swimmers. 45 young swimmers performed a set of maximal 4 × 25 m (freestyle, backstroke, breaststroke and butterfly stroke) swims with in water start. A speed-meter cable was attached to the swimmer's hip. The dv and the swimming velocity were analyzed. Within-subject tests presented significant variations in the dv based on the swimming technique. Post-hoc test revealed significant differences across all pair-wised swimming techniques (P<0.001), except for the comparison between freestyle and backstroke (P=0.98). The dv was higher in the breaststroke, followed by the butterfly, the backstroke and the freestyle. The quadratic models had the best goodness-of-fit and the lower error of estimation for the relationship between the dv and the swimming velocity in all swimming techniques (0.24 ≤ R(2) ≤ 0.51). As a conclusion, there is a non-linear relationship where the increase of swimming velocity leads to a decrease of dv in young competitive swimmers.

Effects of swim training on energetics and performance.

The aim of this study was to determine the effect of several months of training on performance and energetic profile of elite swimmers. 9 elite swimmers were evaluated at 3 different time periods during the 2010-2011 calendar. Swimming performance was assessed based on lists of times for the 200 m freestyle event. An incremental set of 7×200 m swims was applied to obtain the energetic data. Measurements and/or estimations were made for the: velocity at 4 mmol l(-1) of lactate concentrations, highest value of lactate concentrations, maximal oxygen consumption, minimum swimming velocity where the maximal oxygen consumption is reached and total energy expenditure (Etot). The performance and most of the energetic variables assessed presented no significant variations during the study period. The only exception was the Etot with significant differences between all measurements. Correlation coefficients suggested a high stability for all variables. Cohen's Kappa tracking index demonstrated high variability in the individual adaptations to training. It is concluded that elite swimmers demonstrate a slight improvement in performance and energetic profile in response to several months of training. Each subject has an individual way of adapting to the training load, combining the different energetic confounders to enhance performance.