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Background and Objectives: The aim of this study was twofold: (i) to observe the individual results of fitness status [countermovement jump (CMJ)], hop test, linear sprinting time, stride frequency, stride distance, force-power-velocity, peak power maximal and maximal speed, and repeated sprint ability (RSA) and functional performance (overhead squat, single-leg squat test, dumbbell hip-hinge, Thomas test, hip extension, and internal and external hip rotators) and (ii) to analyze the relationship between anthropometrical measures and values of fitness status with % of difference in the Thomas test, hip extension, and internal and external hip rotators., Materials and Methods: The study followed a cohort design. Sixteen female soccer players competing in the second division of the Spanish league were monitored during the first days of the pre-season. These players were evaluated three times during the preseason of the cohort period. The dataset showed a negative moderate correlation between time and percentage of difference in hip angle and another positive moderate correlation between maximal sprint and percentage of difference in hip angle (r = -0.54, p = 0.02 and r = 0.53, p = 0.04), respectively. The correlations of stride time and distance with hip extension are interesting, as professional soccer players should have higher levels of hip flexor flexibility during the stride phase, recoil of the instep kick action.

The purpose of the study was to test the within-week variations of the internal and external training intensity outcomes organized by days of the week. An 8-month observational period was conducted during the 2020-2021 season. The training sessions and matches of an elite volleyball team were monitored daily. The data comes from 14 players (two setters, five middle blockers, five outside hitters, and two opposites) of an elite team from the Portuguese 1st League (age: 21.7 ± 4.19 years of age; experience: 6.2 ± 3.8 years; body mass: 85.7 ± 8.69 kg; height: 192.4 ± 6.25 cm; BMI: 23.1 ± 1.40 kg/m 2 ). The CR10 Borg scale was applied daily to measure the training intensity. The rate of perceived exertion (RPE) and the session-RPE were extracted as the internal outcomes. The external intensity was measured using an inertial measurement unit (IMU). The number of jumps, height average of jumps (JHA), minimum jump (MJ), maximal jump (MXJ), range jump (RJ), number of jumps (NJ), and training session density (D) were extracted as external intensity outcomes. The results showed that there was a difference between RPE and S-RPE (F (1.98) = 6.31, p = 0.01, η 2 = 0.36, and F (1.73) = 28.30, p = 0.001, η 2 = 0.72), as well as JHA and NJ (F (2.14) = 4.76, p = 0.02, η 2 = 0.30, and F (1.77) = 4.77, p = 0.02, η 2 = 0.30) within the microcycle. When analyzing the correlations between internal and external intensity, it was observed that there was a negative correlation between the Maximum Jump (4, 3, and 1 days before the Match day) (r 2 = 0.34, r 2 = 0.40, r 2 = 0.41, respectively) and the Range Jump (3 and 1 days before the Match day (r 2 = 0.33, r 2 = 0.38, respectively) with the RPE (4 days before the Match day) and Maximum Jump (5, 4, 3, and 1 days before the Match day (r 2 = 0.35, r 2 = 0.39, r 2 = 0.44, r 2 = 0.34, respectively) and Range Jump (5, 4, 3, and 1 days before the Match day) (r 2 = 0.34, r 2 = 0.35, r 2 = 0.40 and r 2 = 0.36, respectively) with S_RPE (4 days before the Match day). Such findings show that higher internal intensities are correlated with lower external intensities in sessions further away from the game day. Such results could be an important tool for coaches to reflect, plan, monitor, and execute the training unit according to the temporal distance to the competition.

This study investigated the effects of a coordinative in-water training. Total 26 young swimmers (16 boys) were divided in a training group (that performed two sets of 6 × 25-m front crawl, with manipulated speed and stroke frequency, two/week for eight weeks) and a control group. At the beginning and end of the training period, swimmers performed 50-m front crawl sprints recorded by seven land and six underwater Qualisys cameras. A linear mixed model regression was applied to investigate the training effects adjusted for sex. Differences between sex were registered in terms of speed, stroke length, and stroke index, highlighting that an adjustment for sex should be made in the subsequent analysis. Between moments, differences were noticed in coordinative variables (higher time spent in anti-phase and push, and lower out-of-phase and recovery for training group) and differences between sex were noticed in performance (stroke length and stroke index). Interactions (group * time) were found for the continuous relative phase, speed, stroke length, and stroke index. The sessions exerted a greater (indirect) influence on performance than on coordinative variables, thus, more sessions may be needed for a better understanding of coordinative changes since our swimmers, although not experts, are no longer in the early learning stages.

The aim of the present study was to compare electrical bioimpedance variables, blood markers and functional tests based on Body Mass Index (BMI) in older women. Associations between Phase Angle (PhA) with functional tests and blood markers were also analyzed. A total of 46 independent elderly people participated in the study, and they were divided into four groups according to BMI values: Group 1 (G1, BMI < 25 kg/m2); Group 2 (G2, BMI > 25−30 kg/m2); Group 3 (G3, BMI > 30−35 kg/m2); Group 4 (G4, BMI > 35 kg/m2). In addition to the weight and height used to calculate the BMI, the following body composition variables were collected: fat mass (FM), fat-free mass, intracellular water (ICW), extracellular water (ECW), total body water (TBW) and PhA (50 kHz) through InBody S10 equipment. Functional capacity was assessed using the Fullerton battery of tests: arm-curl; chair-stand; 6 min walking test (6MWT); time up-and-go test (TUG); standing on one leg (SOOL) and take 10 foot-lines (10FL). The main results showed differences between groups in the tests: 6MWT, SOOL and 10FL between G1 vs. G3 and G2 vs. G3 (p < 0.05); ACT, AIC and AEC between G1 vs. G4 (p < 0.05); FM among all groups (p < 0.05). Negative correlations were found between PhA and the agility test in G1 (r = −0.848; p = 0.008) and G4 (r = −0.909; p = 0.005); PhA and chair-stand in G3 (r = 0.527; p = 0.044); PhA and forearm flexion in G3 (r = 0.641; p = 0.010) and G4 (r = 0.943; p = 0.001); PhA and 6MWT in G4 (r = 0.771; p = 0.042). This study found that there is a clear trend towards better functional capacities with better parameters of body composition. Although there were no differences between groups in PhA, associations were found between different functional tests with PhA, which reveals the importance of this variable as a marker of health status.

This study aimed to analyse the impact of an 8-week core strength training (CST) programme in youth karate practitioners on core endurance, agility, flexibility, sprinting, jumping, and kick performance. This study followed a randomized parallel design. Twenty-nine participants (age: 12.86 ± 0.81 years old; height: 152.55 ± 10.37 cm; weight: 42.93 ± 8.85 kg) were allocated to a CST programme (n = 16) performed thrice weekly or to a control group (n = 13) only performing the sport-specific (karate) training. Participants were assessed three times (baseline, mid and post-intervention) for the following tests: (i) flexor endurance test (FET); (ii) back extensor test (BET); (iii) lateral musculature test (LMT); (iv) flexibility; (v) chance of direction (COD); (vi) countermovement jump (CMJ); (vii) back muscle strength (BMS); (viii) horizontal jump (LJ); (ix) sprint test; and (x) karate kick test (KKT). Between-group analysis revealed significant advantages for the CST group on the FET (p < 0.001), BET (p < 0.001), LMT (p < 0.001), 20 m sprint (p = 0.021) and KKT for right (p < 0.006) and left (p < 0.020) legs. No significant differences were found between groups in the remaining physical fitness variables (p > 0.05). The within-group changes revealed significant improvements in the CST group at flexibility (p = 0.002), COD (p < 0.001), CMJ (p < 0.001), BMS (p < 0.002), 20 m sprint (p = 0.033), and KKT (p < 0.001). In addition, within-group changes in the control group were also significant in flexibility (p = 0.024) and right kick (p < 0.042). We conclude that the CST programme improves core endurance and karate kick performance; however, it is not effective enough for other physical performance parameters in KR practitioners.

The bench press is performed in parapowerlifting with the back, shoulders, buttocks, legs and heels extended over the bench, and the use of straps to secure the athlete to the bench is optional. Thus, the study evaluated muscle activation, surface electromyography (sEMG), maximum velocity (MaxV) and mean propulsive velocity (MPV), and power in paralympic powerlifting athletes under conditions tied or untied to the bench. Fifteen experienced Paralympic powerlifting male athletes (22.27 ± 10.30 years, 78.5 ± 21.6 kg) took part in the research. The sEMG measurement was performed in the sternal portion of the pectoralis major (PMES), anterior deltoid (AD), long head of the triceps brachii (TRI) and clavicular portion of the pectoralis major (PMCL). The MaxV, MPV and power were evaluated using an encoder. Loads of 40%, 60%, 80% and 100% 1RM were analyzed under untied and tied conditions. No differences were found in muscle activation between the tied and untied conditions; however, sEMG showed differences in the untied condition between AD and TRI (F (3112) = 4.484; p = 0.005) in the 100% 1RM load, between PMCL and AD (F (3112) = 3.743; p = 0.013) in 60% 1RM load and in the tied condition, between the PMES and the AD (F (3112) = 4.067; p = 0.009). There were differences in MaxV (F (3112) = 213.3; p < 0.001), and MPV (F (3112) = 248.2; p < 0.001), between all loads in the tied and untied condition. In power, the load of 100% 1RM differed from all other relative loads (F (3112) = 36.54; p < 0.001) in both conditions. The tied condition seems to favor muscle activation, sEMG, and velocity over the untied condition.

This study aimed to: (i) analyze fat mass and physical fitness variations among age-groups and playing positions, and (ii) explore the relationship between fat mass and physical fitness in youth male soccer players. A total of 66 players from under-16, under-17, and under-19 were tested. Body mass, skinfolds, countermovement jump (CMJ), single-leg triple hop jump (SLTH), bilateral triple hop jump (BTH), and yo-yo intermittent recovery Level 2 (YYIR-2) were assessed. A two- and one-way ANOVA were conducted, and the effect size was measured. Interactions were found in skin folds and fat mass. The under-19 group was taller, heavier, with a greater BMI and muscle mass than the under-16 group. They also exceeded the under-16 and under-17 in SLTH, BTH, and YYIRT-2. The under-17 group jumped higher and longer than under-16 group. Goalkeepers were taller and heavier than the midfielders. Central defenders were taller and had more muscle mass than midfielders and were heavier than the midfielders and wingers. The wingers jumped higher than the midfielders and showed better YYIRT-2. BMI was small correlated with YYIRT-2 and moderately with CMJ. Fat mass had a moderate negative correlation with CMJ and YYIRT-2. Muscle mass largely correlated with CMJ, UTH, very large with BTH and moderate with YYIRT-2. Summarily, with increasing age, better performances and body compositions were registered. Muscle mass better influences performance than body fat. Body composition can distinguish players positions.

The aim of this study was two-fold: (i) analyze the weekly variations of well-being and training/match intensity measures in youth soccer players, and (ii) test relations between well-being and training intensity outcomes. The study followed a descriptive case study design. Twenty-seven under-17 male soccer players were monitored for well-being and training intensity parameters over seventeen consecutive weeks. An adjusted version of the Hooper questionnaire was used to monitor the perceptive sleep quality, readiness, fatigue, and delayed onset muscle soreness (DOMS) early in the morning. The CR-10 Borg’s scale was also used for monitoring the rate of perceived exertion (RPE) of players after training sessions. Repeated-measures analysis of variance was executed to test the between-week variations of both well-being and training intensity outcomes. Moreover, Pearson product moment correlation was used to test the relations between well-being and training intensity outcomes. Repeated measures ANOVA revealed significant differences between weeks in the sleep quality (F = 0.422; p < 0.001; ηp2 = 0.140), readiness (F = 0.8.734; p < 0.001; ηp2 = 0.251), fatigue (F = 4.484; p < 0.001; ηp2 = 0.147), DOMS (F = 3.775; p = 0.001; ηp2 = 0.127), RPE (F = 7.301; p < 0.001; ηp2 = 0.219), and session-RPE (F = 17.708; p < 0.001; ηp2 = 0.405). Correlations between well-being and training intensity outcomes in the same week revealed moderate correlations between fatigue and session-RPE (r = 0.325). As conclusions, it was found that well-being and training intensity fluctuates over the season, while well-being outcomes seems to be related with training intensity, although with a small magnitude.

This study aimed to investigate the effects of the 6-week small-sided games training (SSGs) vs. high-intensity interval training (HIIT) on the psychophysiological and performance responses, and technical skills of young basketball players. Thirty-two male players (age: 14.5 ± 0.5 years of age) were randomly divided into SSGs group ( n = 16) and HIIT group ( n = 16) training methods thrice per week for 6 weeks. The players in the SSGs group performed two 5-8 min of 2 vs. 2 with 2 min rest periods, while the players in HIIT performed 12-18 min of runs at intensities (90 to 95%) related to the velocity obtained in the 30-15 intermittent fitness test (IFT). Pre-testing and post-testing sessions involved assessments of Yo-Yo Intermittent Recovery Test level 1, 30-15 intermittent fitness test, 5 and 30 m sprint times, vertical jump height, repeated sprint ability, defensive and offensive agility, and technical skills. The SSGs group demonstrated significantly higher agility-based technical responses in terms of the control dribbling and shooting skills ( d = 1.71 vs. 0.20, d = 1.41 vs. 0.35, respectively) compared with the HIIT group. Conversely, the HIIT induced greater improvements in 30 m sprint times ( d = 3.15 vs. 0.68). These findings provided that SSGs in youth basketball players may allow similar positive physical adaptations to HIIT, with an extra advantage of improving technical skills while improving enjoyability.

The aim of this study is to examine how physical performance has changed after 15 weeks (109 days) long-term absence of organized training in youth soccer players imposed by the stay at home orders. A total of sixty-eight young male soccer players from different age categories (U15, U16, U17 and U19) voluntarily participated in the prospective cohort study. Body fat percentage (BF%), counter-movement jump (CMJ), 30 m sprint, change-of-direction (COD) and yo-yo intermittent recovery test level-1 (YYIRTL-1) were evaluated twice (before and after the detraining period). Subsequently, 2 × 2 repeated measures ANOVA was used to investigate group and time differences in repeated measurements. A significance level of p < 0.05 was implemented. CV and SWC values were calculated to test the reliability of the tests performed at different times. Statistical analysis was performed using the IBM SPSS statistics software (v.25, IBM, New York, NY, USA). Significant increments in BF%, 30 m sprint, and COD (left and right), and also significant decrements in CMJ and YYIRTL-1, were found after the detraining period. A long-term detraining period due to the stay at home orders has a detrimental effect on body composition, neuromuscular performances, and aerobic capacity in youth soccer players.

The purpose of this study was two-fold: (i) analyze the variations of locomotor profile, sprinting, change-of-direction (COD) and jumping performances between different youth age-groups; and (ii) test the interaction effect of athletic performance with playing positions. A cross-sectional study design was followed. A total of 124 youth soccer players from five age-groups were analyzed once in a time. Players were classified based on their typical playing position. The following measures were obtained: (i) body composition (fat mass); (ii) jump height (measured in the countermovement jump; CMJ); (iii) sprinting time at 5-, 10-, 15-, 20-, 25- and 30-m; (iv) maximal sprint speed (measured in the best split time; MSS); (v) COD asymmetry index percentage); (vi) final velocity at 30-15 Intermittent Fitness Test (V IFT ); and (vii) anaerobic speed reserve (ASR = MSS - V IFT ). A two-way ANOVA was used for establishing the interactions between age-groups and playing positions. Significant differences were found between age-groups in CMJ ( p < 0.001), 5-m ( p < 0.001), 10-m ( p < 0.001), 15-m ( p < 0.001), 20-m ( p < 0.001), 25-m ( p < 0.001), 30-m ( p < 0.001), V IFT ( p < 0.001), ASR ( p = 0.003), MSS ( p < 0.001), COD ( p < 0.001). Regarding variations between playing positions no significant differences were found. In conclusion, it was found that the main factor influencing changes in physical fitness was the age group while playing positions had no influence on the variations in the assessed parameters. In particular, as older the age group, as better was in jumping, sprinting, COD, and locomotor profile.

This study aimed to analyze the variations of fitness status, as well as test the relationships between accumulated training load and fitness changes in women soccer players. This study followed an observational analytic cohort design. Observations were conducted over 23 consecutive weeks (from the preseason to the midseason). Twenty-two women soccer players from the same first Portuguese league team (22.7 ± 5.21 years old) took part in the study. The fitness assessment included anthropometry, hip adductor and abductor strength, vertical jump, change of direction, linear speed, repeated sprint ability, and the Yo-Yo intermittent recovery test. The training load was monitored daily using session rating of perceived exertion (s-RPE). A one-way repeated ANOVA revealed no significant differences for any of the variables analyzed across the three moments of fitness assessments ( p > 0.05). The t -test also revealed no differences in the training load across the moments of the season ( t = 1.216; p = 0.235). No significant correlations were found between fitness levels and accumulated training load (range: r = 0.023 to -0.447; p > 0.05). This study revealed no differences in the fitness status during the analyzed season, and the fitness status had no significant relationship with accumulated training load.

This study aimed to investigate the relationship between health perception and health predictors among the elderly. In this study, 376 older adults from four different countries (Hungary, n = 86; Italy, n = 133; Portugal, n = 95; and Spain, n = 62) were analyzed. All subjects completed the EQ-5D-5L to assess their quality-adjusted life years and were assessed in handgrip (HG) and in Timed Up and Go (TUG) tests. A three-way MANOVA was conducted to analyze the groups based on their age, sex, and country. The interaction effects in all included variables were also considered. The Bonferroni test was also executed as a post hoc test. Any interaction results were noticed. Regarding age, lower perceived quality of life scores and higher TUG results were registered in the oldest group, and greater values of left and right HG results were registered in the second-oldest group. Males showed greater left and right HG values than women. Spain showed lower perceived quality of life scores. Portugal and Italy showed greater HG left values, while Portugal had better HG right values. Hungary produced the greatest TUG scores. Quality of life is dependent on the subject's age and physical fitness, as increasing age was associated with decreased values of HG and TUG. Only strength was different between sexes.

The purpose of this study was to test the relationships between training workload (WL) parameters with variations in anaerobic power and change of direction (COD) in under-16 soccer players. Twenty-three elite players under 16 years were daily monitored for their WL across 20 weeks during the competition soccer season. Additionally, players were assessed three times for anthropometric, body composition, COD, and anaerobic power. A correlational analysis between the mean differences between assessments and accumulated WL parameters were conducted. Moreover, a regression analysis was executed to explain the variations in the percentage of change in fitness levels considering the accumulated WL parameters and peak height velocity. The accumulated daily loads during one week showed a large and a moderate correlation with peak power and COD at different periods of the season. Regression analysis showed no significant predictions for COD ( F (12, 10) = 1.2, p = 0.41) prediction, acute load ( F (12, 10) = 0.63, p = 0.78), or chronic load ( F (12, 10) = 0.59, p = 0.81). In conclusion, it may be assumed that the values of the chronic workload and the accumulated training monotony can be used to better explain the physical capacities of young soccer players, suggesting the importance of psychophysiological instruments to identify the effects of the training process in this population.

The aim of this systematic review conducted in the topic of youth team-sports players was three-fold: (i) Analyze the variations of decision-making processes between low- and high-level youth players; (ii) analyze the variations of decision-making processes between different age groups; and (iii) analyze the effects of decision-making training-based programs on youth players. Following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, this systematic review searched for studies on PubMed, ScienceDirect, Academic Search Complete, SPORTDiscus, and Taylor & Francis Online. The search returned 6215 papers. After screening the records against set criteria, 26 articles were fully reviewed. From the included studies, 9 were focused on comparing the decision-making process between low- and high-level players, 6 compared the decisions made by players from different age categories, and 11 analyzed the effects of decision-making-based training programs on youth players. Comparisons between high- and low-level players suggested that high-level and most talented players present a greater accuracy in the cognitive and executive answers to the game as well as being more adjustable to more complex situations. Considering the comparisons between age groups, a tendency of older players to execute more accurate decisions in the game and to have better tactical knowledge and behavior was observed. Finally, the effects of decision-making training programs suggest a beneficial effect employing practical scenarios (mainly based on small-sided and conditioned games), primarily improving passing decisions and execution. However, the benefits of interventions using videos are not clear., Competing Interests: The authors declare no conflict of interest.

The aim of this study was two-fold: (1) to analyze the within-week variations of heart rate, session-rated of perceived exertion (sRPE), total distance, distance in 8.0-11.99 km/h -1 , recovery distance in 12.0-17.99 km/h -1 , distance in >18.0 km/h -1 , maximum speed, number of sprints, heart rate variability, delayed onset muscle soreness (DOMS), and fatigue during training camps of a national futsal team; and (2) to analyze the relationships between load and the well-being. Twenty-eight men from the Chinese Taipei U-20 national futsal team were analyzed. Comparisons of training days revealed that the total distance was significantly smaller on day 1 (d = -1.22) and day 6 (d = -1.95) than on day 3. The sRPE values were significantly lower on day 1 than days 4 (d = -1.53), 5 (d = -2.07), and 6 (d = -2.59). The relationships between training load and recovery parameters revealed moderate correlations between the DOMS and the sRPE recorded one ( r = -0.321) and two days before training ( r = -0.289). It is possible conclude that first day imposed a smaller external load and internal load, and that the internal load had a greater dependent relationship with reported DOMS and fatigue during the training camps.

Volleyball is considered a very explosive and fast-paced sport in which plyometric training is widely used. Our purpose was to review the effects of plyometric training on volleyball players' performance. A systematic search was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines using PubMed, SciELO, SPORTDiscus, Medline, Scopus, Academic Search Complete, CINAHL and Web Science for articles published no later than December 2018. Any criteria were imposed for the included sample. The search focus was on interventional studies in which athletes underwent a plyometric program. To the 1831 articles found, another five were added, identified through other sources. Duplicated files were removed, titles and abstracts were screened, which left 21 remaining studies for extensive analysis. Results showed that the vertical jump (15 studies) was the major ability studied in plyometric training interventions, followed by strength (four studies), horizontal jump (four studies), flexibility (four studies) and agility/speed (three studies). In addition, it was observed that young (under 18 years old) female athletes were the most studied. The included studies indicated that plyometric training seems to increase vertical jump performance, strength, horizontal jump performance, flexibility and agility/speed in volleyball players. However, more studies are needed to better understand the benefits of plyometric training in volleyball players' performance.

Aluminum absorption leads to deposits in several tissues. In this study, we have investigated, to our knowledge for the first time, aluminum deposition in the salivary glands in addition to the resultant cellular changes in the parotid and submandibular salivary glands in a model of chronic intoxication with aluminum citrate in rats. Aluminum deposits were observed in the parotid and submandibular glands. Immunohistochemical evaluation of cytokeratin-18 revealed a decreased expression in the parotid gland with no changes in the submandibular gland. A decreased expression of α-smooth muscle actin was observed in the myoepithelial cells of both glands. The expression of metallothionein I and II (MT-I/II), a group of metal-binding proteins, which are useful indicators for detecting physiological responses to metal exposure, was higher in both glands. In conclusion, we have shown that at a certain time and quantity of dosage, aluminum citrate promotes aluminum deposition in the parotid and submandibular glands, leads to an increased expression of MT-I/II in both the glands, damages the cytoskeleton of the myoepithelial cells in both glands, and damages the cytoskeleton of the acinar/ductal cells of the parotid glands, with the submandibular glands showing resistance to the toxicity of the latter.

The aims of this study were to evaluate whether chronic intoxication with mercury chloride (HgCl2), in a low concentration over a long time, can be deposited in the central nervous tissue and to determine if this exposure induces motor and cognitive impairments. Twenty animals were intoxicated for 45 days at a dose of 0.375 mg/kg/day. After this period, the animals underwent a battery of behavioral tests, in a sequence of open field, social recognition, elevated T maze and rotarod tests. They were then sacrificed, their brains collected and the motor cortex and hippocampus dissected for quantification of mercury deposited. This study demonstrates that long-term chronic HgCl2 intoxication in rats promotes functional damage. Exposure to HgCl2 induced anxiety-related responses, short- and long-term memory impairments and motor deficits. Additionally, HgCl2 accumulated in both the hippocampus and cortex of the brain with a higher affinity for the cortex.