Repeated sprint ability and muscular responses according to the age category in elite youth soccer players

The aim of this study was to analyse the influence of age category on the performance and muscle response after a Repeated Sprint Ability (RSA) test in elite youth soccer players. 62 soccer players from three different age categories (Under 14 [n = 21], Under 16 [n = 20], and Under 18 [n = 21]) were selected to participate in this study. Players completed an RSA test (7 × 30 m) with a 20-s recovery between sprints. The muscular response to an electrical stimulus before and after the test of both the biceps femoris (BF) and the rectus femoris (RF) were evaluated using tensiomyography. A two-way ANOVA was used to analyse the differences in RSA parameters in each of the four distance-intervals (0–5; 5–25; 25–30; 0–30 m) between sprint and age category. The U14 age category (5.30 ± 0.30 s) showed higher mean sprint times than U16 (4.62 ± 0.20 s) and U18 (4.46 ± 0.17 s) throughout the entire test (p 0.05), although the delay time (Td) of the muscle was significantly lower after the RSA test in U16 players (−1.53 ms, CI95%: −2.607 to −0.452; ES: 0.38) and U18 players (−1.11 ms, CI95%: −2.10 to −0.12; ES: 0.22). In conclusion, this study revealed an increase in physical performance and muscle response variability after a repeated sprint ability test in the U16's and over. The fatigue induced by the RSA test did not show differences depending on the age of the players, although muscle mechanical properties were altered after the RSA test in U16 and U18 soccer players. Physical performance and muscle response can be complementary variables in managing fatigue according to the age category in soccer players.Sin financiación3.367 JCR (2019) Q1, 20/81 Physiology1.211 SJR (2019) Q2, 52/186 Physiology, 31/107 Physiology (medical)No data IDR 2019UE

Impact of harness attachment point on kinetics and kinematics during sled towing.

Resisted sprint training is performed in a horizontal direction, and involves similar muscles, velocities and ranges of motion (ROM) to those of normal sprinting. Generally, sleds are attached to the athletes via a lead (3m) and harness; the most common attachment points are the shoulder or waist. At present, it is not known how the different harness point's impact on the kinematics and kinetics associated with sled towing (ST). The aim of the current investigation was to examine the kinetics and kinematics of shoulder and waist harness attachment points in relation to the acceleration phase of ST. Fourteen trained males completed normal and ST trials, loaded at 10% reduction of sprint velocity. Sagittal plane kinematics from the trunk, hip, knee and ankle were measured, together with stance phase kinetics (third foot-strike). Kinetic and kinematic parameters were compared between harness attachments using one-way repeated measures analysis of variance. The results indicated that various kinetic differences were present between the normal and ST conditions. Significantly greater net horizontal mean force, net horizontal impulses, propulsive mean force and propulsive impulses were measured (p>0.05). Interestingly, the waist harness also led to greater net horizontal impulse when compared to the shoulder attachment (p = 0.000). In kinematic terms, ST conditions significantly increased peak flexion in hip, knee and ankle joints compared to the normal trials (p<0.05). Results highlighted that the shoulder harness had a greater impact on trunk and knee joint kinematics when compared to the waist harness (p<0.05). In summary, waist harnesses appear to be the most suitable attachment point for the acceleration phase of sprinting. Sled towing with these attachments resulted in fewer kinematic alterations and greater net horizontal impulse when compared to the shoulder harness. Future research is necessary, in order to explore the long-term adaptations of these acute changes

Antimicrobial Resistance profile of Staphylococcus aureus from dairy cows with mastitis in the Region of Central Macedonia over a five-month period (March-July 2021)

In Greece, a National Monitoring Plan for Antimicrobial Resistance in sick bovine animals was launched (2021). We aimed at surveying the antimicrobial resistance profiles of 118 pathogenic Staphylococcus aureus isolates obtained from dairy cows &gt;18 months with mastitis in the Region of Central Macedonia from 1st March to 31st July 2021, where 45% (Census 2020: 69.186/128.511) of dairy cows in Greece are concentrated. By using the disk diffusion method (according to the CLSI guidelines), we tested susceptibility of isolates to nine antimicrobials (penicillin, cefoxitin, cefquinome, gentamicin, tetracycline, marbofloxacin, erythromycin, clindamycin, enrofloxacin) selected following the marketing amounts of animal use in Greece. In the study, 62/11 Staphylococcus aureus isolates were found to be resistant 52,54% to penicillin; 57/118 were 48,31% resistant to erythromycin, 56/118 were resistant 47,46% to clindamycin; 29/118 were 24,58% resistant to tetracycline and cefquinome both, 27/118 were 22,88% resistant to cefoxitin, 20/118 were 16,95% resistant to gentamicin, 3/118 were 2,54% resistant to marbofloxacin and, 2/118 were 1,69% resistant to enrofloxacin. Regarding the surveillance on the antimicrobial resistance of the Staphylococcus aureus isolates, that cause mastitis in cattle (penicillin in combination with an aminoglycoside, is the most commonly applied therapeutic treatment scheme against mastitis in Greece), to the β-lactams (penicillin, cefoxitin) it is needed further investigation, under the ‘One Health’ approach in respect to the prudent use of antibiotics in staphylococcal infections in humans and in the veterinary medicine in Greece. However, it seems that several kinds of interventions at farm level led to the protection of quinolones. The study offers a thorough understanding of the antimicrobial resistance patterns among Staphylococcus aureus isolates. The significant resistance rates to various antibiotics highlight the need for responsible antibiotic usage and continuous monitoring of resistance trends. These insights are crucial in developing effective strategies to tackle the emergence and dissemination of resistant strains and ensuring better treatment and control of infections caused by this bacterium. The findings add valuable knowledge to our understanding of antibiotic resistance and its implications. Keywords: Antimicrobial Resistance; Staphylococcus aureus; mastitis; prudent use of antibiotics; One Healt

The differential hormonal milieu of morning versus evening, may have an impact on muscle hypertrophic potential

Substantial gains in muscle strength and hypertrophy are clearly associated with the routine performance of resistance training. What is less evident is the optimal timing of the resistance training stimulus to elicit these significant functional and structural skeletal muscle changes. Therefore, this investigation determined the impact of a single bout of resistance training performed either in the morning or evening upon acute anabolic signalling (insulin-like growth factor-binding protein-3 (IGFBP-3), myogenic index and differentiation) and catabolic processes (cortisol). Twenty-four male participants (age 21.4±1.9yrs, mass 83.7±13.7kg) with no sustained resistance training experience were allocated to a resistance exercise group (REP). Sixteen of the 24 participants were randomly selected to perform an additional non-exercising control group (CP) protocol. REP performed two bouts of resistance exercise (80% 1RM) in the morning (AM: 0800 hrs) and evening (PM: 1800 hrs), with the sessions separated by a minimum of 72 hours. Venous blood was collected immediately prior to, and 5 min after, each resistance exercise and control sessions. Serum cortisol and IGFBP-3 levels, myogenic index, myotube width, were determined at each sampling period. All data are reported as mean ± SEM, statistical significance was set at P≤0.05. As expected a significant reduction in evening cortisol concentration was observed at pre (AM: 98.4±10.5, PM: 49.8±4.4 ng/ml, P0.05). Timing of resistance training regimen in the evening appears to augment some markers of hypertrophic potential, with elevated IGFBP-3, suppressed cortisol and a superior cellular environment. Further investigation, to further elucidate the time course of peak anabolic signalling in morning vs evening training conditions, are timely

Cumulative Prognostic Score Predicting Mortality in Patients Older Than 80 Years Admitted to the ICU.

OBJECTIVES: To develop a scoring system model that predicts mortality within 30 days of admission of patients older than 80 years admitted to intensive care units (ICUs). DESIGN: Prospective cohort study. SETTING: A total of 306 ICUs from 24 European countries. PARTICIPANTS: Older adults admitted to European ICUs (N = 3730; median age = 84 years [interquartile range = 81-87 y]; 51.8% male). MEASUREMENTS: Overall, 24 variables available during ICU admission were included as potential predictive variables. Multivariable logistic regression was used to identify independent predictors of 30-day mortality. Model sensitivity, specificity, and accuracy were evaluated with receiver operating characteristic curves. RESULTS: The 30-day-mortality was 1562 (41.9%). In multivariable analysis, these variables were selected as independent predictors of mortality: age, sex, ICU admission diagnosis, Clinical Frailty Scale, Sequential Organ Failure Score, invasive mechanical ventilation, and renal replacement therapy. The discrimination, accuracy, and calibration of the model were good: the area under the curve for a score of 10 or higher was .80, and the Brier score was .18. At a cut point of 10 or higher (75% of all patients), the model predicts 30-day mortality in 91.1% of all patients who die. CONCLUSION: A predictive model of cumulative events predicts 30-day mortality in patients older than 80 years admitted to ICUs. Future studies should include other potential predictor variables including functional status, presence of advance care plans, and assessment of each patient's decision-making capacity

Physiological and Performance Impacts After Field Supramaximal High-Intensity Interval Training With Different Work-Recovery Duration

High-intensity interval training (HIIT) has numerous external load control variables. The management of these variables makes the physiological responses and performance presented by athletes also modify. The present study aimed to assess the activity of CK and LDH enzymes, performance and metabolic responses caused by two HIIT protocols above the maximum in male recreational runners. Fifteen recreational male runners performed two HIIT protocols in randomized order with multiple conditions: 1) H15 (n= 15), with a HIIT protocol of 15:15 work-recovery duration, and 2) H30 (n= 15) with a HIIT protocol of 30:30 work-recovery duration. Both protocols were performed at similar intensity (130% vV?O-2max), one set until voluntary exhaustion. Blood samples were collected and used to capture the levels and activities of blood lactate (BLac: mmol.L-1), glucose (GLU: mg.dL(-1)), creatine kinase (CK: U.L-1), and lactate dehydrogenase (LDH: U.L-1). BLac and GLU were collected at pre, five, and ten minutes after the H15 and H30 protocols were performed. Blood samples were used to measure the activities of CK and LDH enzymes, which were verified 24 h before and 48 h after the protocols. The distance traveled (m), total time (s), and bouts performed (rep) were also registered. Significant differences between conditions H15 and H30 were observed in the bouts performed (p= 0.001; ES = 1.19). Several statistical differences were found over time for BLac [pre vs. post 5 (both conditions:p= 0.001), pre vs. post 10 (both conditions:p= 0.001), and post 5 vs. post 10 (H30:p= 0.004)], CK [pre vs. post 24 (H15:p< 0.001; ES = 0.97 and H30:p= 0.001; ES = 0.74) post 24 vs. post 48 (H30:p= 0.03; ES = 0.56)], and LDH [pre vs. post24 (H15:p= 0.008; ES = 1.07 and H30:p= 0.022; ES = 0.85). No statistical differences between conditions were observed for any blood parameter. Thus, the volunteers exhibited equal performance in both protocols, which resulted in a similar physiological response. Despite this similarity, in comparison to H15, the H30 protocol presented lower CK activity post 48 and lactate levels after 10 min post protocol

Vrabas. The Effect of Natural and Artificial Grass on Sprinting Performance in Young Soccer Players

Abstract: The sprint performance on natural and artificial grass of 5 th generation was assessed. Sixty eight young male soccer players, which were divided in two groups according to their age [children (n=36; 12.1±0.5y) and adolescents (n=32; 14.2±0.4y)], performed 30-m sprint tests with and without handling the ball on natural and artificial grass. The performance was recorded during 0-10m, 10-30m, and 0-30m running distances. It was found that children were significantly faster during 0-10m running distance on the artificial compared to natural grass when handling the ball while adolescents revealed no differences in sprint performance between the surfaces irrespectively of the ball condition. In running distances 10-30m and 0-30m, children were significant faster in the artificial compared to the natural grass either with or without ball, while the adolescents were significantly faster in the artificial grass only without handling the ball. Children run faster on artificial than natural grass while adolescent soccer players are faster in artificial grass when they do not have to handle the ball. It is clear that children should be more careful when play soccer on artificial grass because the ball is moving faster and greater skill is needed in order to avoid injuries