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Introduction. The aims of the present study were to determine the activity profiles of a large sample of Polish Premier League soccer players during elite-standard soccer matches depending on their position on the pitch and the intensity range of physical activity. Material and methods. The study sample comprised 1,178 players in 5 outfield positions: external defenders (ED, n = 289), central defenders (CD, n = 307), central midfield players (CM, n = 327), external midfield players (EM, n = 152), and forwards (F, n = 103). Altogether, 81 Polish League games held during four domestic seasons (2010-2011, 2011-2012, 2012-2013, and 2013-2014) were used in the analysis. A semi-automatic computerised player tracking system (Amisco Pro®, version 1.0.2, Nice, France) was applied to create the match activity profiles of the teams. Results. The results of statistical analysis revealed that the average total distance covered by all the players (n = 1,178) was 11,313 ± 852 m. With respect to the players’ position on the pitch, the central midfielders travelled the longest average distance (11,894 ± 765 m) during the game. The longest distance was covered in the V1 intensity range (62%), followed by V2 (15%), V3 (10%), V4 (8%), V5 (3%), and V6 (2%). Conclusions. The objective of this study was to verify the differences among playing positions and to quantify the demands placed on elite Polish soccer players in each individual position during match play. While analysing elite-level match play in terms of the overall distance covered in different categories of intensity, we found a number of statistically significant differences between different playing positions. The data presented in this study can be regarded as norms for elite soccer players, serve for present and future comparison, and represent the scientific basis for developing position-specific conditioning/training protocols in soccer.

The aim of the present study was to determine and characterize the activity of male Polish Premier League soccer players during elite-level matches, depending on playing position, activity intensity range, and match period. The study sample comprised 1178 players. Amisco Pro® was used to track the match activity players. Statistical analysis of the total distance covered by players revealed that the greatest distance was covered by central midfielders (11894 ± 765 m) and external midfielders (11751 ± 686 m). In terms of velocity, the greatest distance was covered by players in the V1 range (0 ≤ V1 11 km · h

This study presents a detailed analysis of sprinting activities and distance covered by professional soccer players in two seasons of the Europa League competition. The investigation considered such variables as the mean sprinting distance covered, duration of the rest pause between sprinting activities and maximal running speed recorded during the match. The study involved 147 soccer players participating in 10 matches played at one ground in the 2008–2009 and 2010–2011 Europa League seasons. Players' performance data were divided into two halves of matches and five playing positions. The study was carried out using data from Amisco Pro (version 1.0.2.). Results indicate wide variations in the analyzed variables, depending on the playing position on the pitch and tactical tasks. Individualization of training speed and endurance loads will help to optimize the training process of soccer players at different levels of their athletic skills.

Our aim was to verify whether running a marathon is associated with changes in irisin concentration in healthy, endurance-trained men. In an observational study, we assessed baseline biochemical and fitness parameters of 28 middle-aged runners (mean ± SD age, BMI, VO2max: 58 ± 8 years; 24.5 ± 3 kg/m2; 51.1 ± 1.7 ml/kg/min). We evaluated irisin before, immediately after, and 7 days after the marathon. Irisin concentration decreased from a baseline value of 639 ± 427 to 461 ± 255 ng/ml immediately after the marathon (p

Background This study aimed to investigate the effect of a 6-week plyometric exercise training program on the development of lower limb explosive power in terms of vertical jumping ability in university level volleyball players. The study involved 9 male volleyball players from the AWF Wroclaw University Sports Club, with a minimum of 5 years of training and competition experience. The program consisted of various bounds, hops, and jumps in vertical, horizontal, and mixed directions. During the program, a progressive overload of plyometric intervention was applied. Lower limb explosive power in the form of vertical jumping ability was developed and tested. Methods The jumping ability was evaluated via 5 types of maximum-effort vertical jumps, using the Opto Jump system. In addition, once each week, the heart rate was recorded using a heart rate monitor (Polar RS300X GPS). Results The only significant correlation was found between squat jump and number of jumps and between counter movement jump and heart rate. Conclusions From a practical standpoint, the improvement, which was noticed after 3 and 6 weeks, seems to optimal period for volleyball players adaptation to significant increased training load.

BACKGROUND The aim of the study was to examine the ways playing positions and match outcome (i.e. win, draw, loss) affect the sprint distance covered and the number of sprints performed by German Bundesliga soccer players. METHODS Match performance data were collected from 350 soccer players competing in the German Bundesliga during the 2014/2015 domestic season. A total of 4393 individual match observations were undertaken on outfield players. The analysis was carried using the Impire AG motion analysis system with records of all movements of players in all the 306 matches. The recorded variables included total sprint distance covered and the total number of sprints in offensive and defensive play. The conformity assessment was carried out with the Shapiro-Wilk test (P≤0.01). To compare mean values of the examined variables a two-way ANOVA was used. The differences between pairs of means were verified with Fisher's LSD. RESULTS The analysis of the covered sprint distance and the number of performed sprints showed that central defenders and full-backs covered shorter distances in won matches than in lost matches (P≤0.05). Furthermore, forwards and wide midfielders covered significantly longer sprint distances in won matches than in lost matches (P≤0.05). CONCLUSIONS The match outcome may be viewed as a measure of performance accomplishment and, hence, it may influence the sprinting efforts made by players.

The aim of this study was to investigate soccer players’ recovery by analyzing activity profiles of 11 Polish professional league soccer players over a period of three intense matches. Activity pro...

The aim of this study was a detailed physical and technical activities analysis of professional soccer players. The studied match performance variables included physical activity and technical acti...

The aim of this study was to determine relationships between repeated 1 &times, 1 small-sided games (SSGs) (variable duration, constant work-to-rest ratio) and the concentration of steroid hormones and characteristic fatigue markers in youth soccer players. Eighteen young male soccer players were assigned at random to two experimental groups: E1&mdash, undertaking a six 30 s one-on-one SSGs with a 2 min rest period, and E2&mdash, playing six 45 s SSGs with a 3 min rest interval. Capillary blood was collected from the players at rest, after the last game, and 15 and 30 min after the exercise protocol. The variables assessed included serum cortisol (C), free testosterone (FT) and total testosterone (TT). An effect was observed between the measurement times (TT (F = 15.26, p &le, 0.0001), FT (F = 6.86, p = 0.0006)). In terms of cortisol (C) levels, no interactions or effect between the studied groups were revealed, but an interaction was found (F = 4.01, p = 0.0126) and the effect appeared between the measurement times (F = 11.16, p &le, 0.0001). The study results show that in all likelihood, longer rest intervals in repeated 30 s 1 &times, 1 SSGs can reduce catabolic reactions and hence the risk of overtraining in youth soccer players.

The aim of the study was a detailed analysis of the sprinting activity of professional soccer players. The study involved 147 players who played in 10 matches of the 2008-09 and 2010-11 UEFA Europa League seasons. The number of performed sprints and total sprint distances covered by the players were examined using collected statistical material. Two types of sprints were distinguished based on their duration: S, short-duration sprint (below 5 seconds) and L, long-duration sprint (above 5 seconds). Additionally, sprints were classified according to their distance: 0-10, 10.1-20.0, and >20 m, respectively. The analysis of the sprinting activity of soccer players also involved their respective positions of play. The study was carried out using Amisco Pro (version. 1.0.2), one of the most comprehensive up-to-date computer systems for match analysis. The statistical analysis revealed that the mean total sprint distance covered by players (≥24 km·h) amounted to 237 ± 123 m. With regard to the position of play, the forwards covered the longest sprint distance (345 ± 129 m), that is, 9% longer than midfielders (313 ± 119 m) and over 100% longer than central midfielders (167 ± 87 m). The average number of sprints performed by the soccer players was 11.2 ± 5.3. It should also be emphasized that about 90% of sprints performed by professional soccer players were shorter than 5 seconds, whereas only 10% were longer than 5 seconds. Analysis of physical loads of soccer players during matches can be useful for individualization of training of soccer players' speed capabilities. It is an essential instrument of modern planning and application of training loads.

The aim of the study is to compare the level of exercise capacities to the loads occurring at the lactate threshold among soccer players representing different levels of sport mastery. The research included 51 soccer players representing different levels of sport mastery. The research was conducted at the beginning of the preparatory period for the spring season. A field exercise test of increasing intensity was performed to check the players’ exercise capacities on the soccer pitch. The test enabled us to determine the 4 millimolar lactate threshold (TLA 4 mmol · l-1) on the basis of lactate concentration in blood (LA), and to define the threshold running speed and the threshold heart rate (HR). The lactate level in blood was measured using a Lactate Scout photometer with the enzyme-amperometric method from capillary blood for 20 seconds after each load. The threshold running speed at the level of the 4 millimolar lactate threshold was marked using the two-point form of the equation of a straight line. The conducted tests showed significant differentiation of the threshold running speed among individual teams. The soccer players of a leading first league club were expected to achieve the best result. The conducted tests did not confirm this assumption. Juniors reached the highest threshold running speed of 3.61 m · s-1. Lower values of the analysed indicator were acquired by players of the first league team (3.50 m · s-1) and the lowest by players of the second league team (3.28 m · s-1). Statistically significant differences were noted between the junior group and second league team (p≤ 0.01) and between the first and the second league soccer players (p

The aim of this study was to evaluate the changes in pressure pain sensitivity maps in untrained subjects over 2 subsequent sessions of eccentric exercise (ECC) expected to result in (a) delayed onset muscle soreness (DOMS) and (b) adaptation/recovery, respectively. Eleven healthy male subjects participated in this study. Pressure pain threshold (PPT), rate of perceived exertion (RPE), pain intensity, soreness area drawing, maximal voluntary contraction (MVC), and shoulder range of motion were assessed in session 1 before, immediately after, and 24 hours after ECC. The ECC protocol that was used to induce DOMS consisted of 50 eccentric contractions of the right shoulder that were divided into 5 bouts, including 10 contractions at MVC level separated by a 2-minute resting period. Session 2 was identical to session 1 and performed exactly 1 week later. There was only a significant increase in the RPE assessed before the exercise and 24 hours after the exercise in session 1 (p = 0.001). The average PPT only decreased significantly from before the exercise (660.2 ± 76.2 kPa) to 24 hours after the exercise (435.6 ± 59.3 kPa) in session 1 (p = 0.016). The present study confirmed a heterogeneous distribution of mechanical sensitivity before and after sessions of ECC. The first session of ECC underlined increased mechanical sensitivity because of DOMS, whereas the second session reflected an adaptation process. Our results support the potential role of ECC bouts in training regimens.

The objective of this study was to determine the distance covered by professional soccer players during matches with the use of the computerized match analysis system Amisco Pro® (version 1.0.2, Nice, France). Kinematic examination included the specification of the distance covered by 31 players participating in 4 matches in the Union of European Football Association Cup competitions during the 2008-2009 season. Data were analyzed based on players' positions on the pitch, changes in the players' motor activity intensity level, and match period (first or second half). The results of statistical analysis revealed that the average total distance covered by all players (n = 31) was 11,288 ± 734 m. With respect to the player's position on the pitch, the midfielders traveled the longest average distance (11,770 ± 554 m) during the game. This was 3% longer than the distance achieved by the attackers at 11,377 ± 584 m, and 7% longer than that achieved by the defenders 10,932 ± 728 m. The analysis of physical loads on soccer players during a match is highly useful for training individualization. It provides a tool for effective planning and for recording the loads on players, which is an indispensable element of modern coaching.

Eleven healthy volunteers took part in three sessions where computer work was performed for 10 min in each session. The recordings were made on two consecutive days. After the first session, the subjects underwent a series of high intensity eccentric exercises of shoulder elevation to induce muscle soreness. The second session was performed immediately after the exercises and third session 24 hours after the exercise. Surface electromyography (EMG) of descending and ascending trapezius, deltoideus anterior and serratus anterior was recorded. Exposure variation analysis (EVA) centroid and marginal distribution was computed. Principle component analysis (PCA) was performed on both cases. Describing more than 80% of variance, first eight components for EVA marginal distributions and first four ones for EVA centroid were picked to be investigated. The sole EVA amplitude levels played a practically significant role to describe the variation in EVA marginal distribution. However, a significant pattern of load redistribution to superficial muscles was not found. This may suggest investigating the role of deep muscles in redistribution of load during computer work in response to high level eccentric contractions.

During aerobic exercise with increasing intensities choice reaction time (CRT) progressively shortens up to 60-80% of maximal workload, and then it rapidly increases. The aim of this study was to determine whether workload associated with the shortest CRT operationally called "the psychomotor fatigue threshold" is related to the metabolic response to exercise. Thirteen male soccer players (aged 23.3 + or - 1.0 yrs) participated in this study. Before and after 6 weeks of training in the pre-competition period they underwent treadmill test at 0 grade with running speed increasing every 3 min by 2 km/h starting from 6 km/h until exhaustion. At each stage of exercise CRT, heart rate, respiratory gas exchange and blood lactate [LA] were measured and the workload corresponding to [LA] of 4 mmol/l (OBLA) was recorded. After training, CRT was significantly shortened at rest (from m + or - SEM = 345 + or - 12 to 317 + or - 12 ms) and during exercise (from 304 + or - 10 to 285 + or - 11 ms at the psychomotor fatigue threshold and from 359 + or - 13 to 331 + or - 13 ms, p

Aerobic capacity and sprint velocity of Leagues I and IV football players Study aim: To assess the aerobic capacity, sprint velocity and changes in biochemical variables in football players preparing for the spring round of matches. Material and methods: Football players from League I (n = 19) and League IV (n = 15) were subjected twice to a graded running tests at the beginning and at the end of the pre-season preparation period. The following variables were recorded: maximum running velocity (km/h), O2max (ml/kg/min), pulmonary ventilation (VE), load at the lactate threshold (LT) expressed as the threshold velocity (LTV; km/h) or %O2max, activities of enzymes in plasma - creatine kinase (CK) and lactate dehydrogenase (LDH), concentrations of lactate (La), ammonia (NH3) and of glucose (Gl) in plasma. At the end of the study the players were also subjected to a 30-m sprint test. Results: In League I players, LT significantly (p3 and Gl significantly (p Conclusions: The negligible differences between football players from Leagues I and IV in their aerobic capacity and speed abilities, and the marked distance from world elite players in those indices, call for substantial changes in training strategies and schedules.

Individualization of Physical Loads and Speed Abilities of Young Soccer Players in a Six-Month Training Macrocycle The aim of this paper was to address the issue of individualized training loads and its influence on speed development among speed-type and endurance-type players during a six-month training macrocycle. The research was conducted in a group of 36 young male soccer players from for two sport clubs: Lech Poznań and Warta Poznań. The stages of the study undertaken resulted from the time structure of sport training and were carried out during a six-month macrocycle. The players of Lech Poznań took part in a test which involved applying three series' (six repetitions each) of speed-type exercises, with regard to the player's motor type in each of the three training units comprising the weekly macrocycle. During each stage of data collection, the players were subjected to a stress test for stretches of 10, 20 and 30 m. The study has shown a significant impact of individualization of training loads on development of speed abilities in the examined players. An increase of speed during the tests of 10 and 20 m was noted in both speed and endurance-type players. This was probably an effect of adapting individual training loads to motor predispositions of the players during the six months of the experiment. It can be also assumed that the increase in speed among the subjects is a result of rising phosphagen potential and enzymatic activity (especially creatine kinase), as well as improved motor units recruitment.

Evaluation of the Blood Antioxidant Capacity in Two Selected Phases of the Training Cycle in Professional Soccer Players The aim of this study was to evaluate the effects of a regular pre-season training on the aerobic performance and the blood antioxidant defense capacity in soccer players from the Polish Premier League club (n=19) and IVth League team (n=15). The players participated in an incremental treadmill running exercise to volitional fatigue twice (i.e., at the beginning (Trial A) and the end (Trial B) of the pre-season spring training). In venous blood samples, taken at rest and 3 min post-test, the activities of antioxidant enzymes (SOD, GSH-Px, CAT, GR) and concentrations of non-enzymatic antioxidants (GSH, tocopherols, retinol, uric acid) and malondialdehyde as a lipid peroxidation biomarker were measured. With the aim of between-group comparisons and possible conclusions on training-induced changes in the capacity of the blood antioxidant defense, the POTAX index was calculated as a sum of standardized activities of antioxidant enzymes and concentrations of non-enzymatic antioxidants. The results of the present study indicate that the players from the Premier League club were characterized by only slightly higher maximal oxygen uptake rates, the differences compared to IVth League team, as assessed in both trials, were statistically insignificant. Participation in the pre-season training resulted in a moderate improvement of aerobic performance, although only a few players were characterized by VO2max comparable to the international-class elite performers. No distinct differences were observed in the level of aerobic performance between higher- and lower-classified players. Pre-season training led to an improvement in the global blood antioxidant capacity expressed in terms of POTAOX indices, although the changes in the activities and concentrations of individual components of the antioxidant system were less pronounced. Training-induced level of antioxidant conditioning was higher among the Premier League players, which may be related to differences in the training schedule and nutritional preparation of the athletes.

The aim of the study was to investigate the effects of breath-hold diving on divers' psychomotor performance and blood adrenaline, noradrenaline and lactate concentrations. Four male divers took part in the experiment. During the study the divers' choice reaction time as well as plasma concentration of adrenaline, noradrenaline and lactate were measured. The measurements were carried out before immersion (before a warm-up), three minutes after the dive, and 60 minutes after the dive. A reduction in the reaction time to audiovisual stimuli was found in three divers, three minutes after the dive. Diver 4, who broke his personal best record, had a longer choice reaction time at three minutes after the dive. The adrenaline concentration was lowered in Diver 1 and Diver 2, at three minutes after the dive. The adrenaline level in Diver 3 was relatively steady at all test measurements. In Diver 4, who broke his personal best, a twofold increase in adrenaline concentration was noted at three minutes after the dive. All examined divers revealed an increase in noradrenaline blood level at three minutes after the dive. The results of the study are of great practical value since disturbed reactions during freediving can put the diver at the risk of serious barotraumas.

Rationale: The effects of caffeine on psychomotor performance have been evaluated under resting conditions and in a thermoneutral environment. Our hypothesis was that these effects could be modified by factors enhancing the level of alertness, such as exercise and cold exposure. Objective: The purpose of this study was to follow up changes in the multiple choice reaction time (RT) during exercise at room and low ambient temperatures after caffeine or placebo administered in a double blind manner. Methods: Nine soccer players performed multistage, incremental exercise until volitional exhaustion on a bicycle ergometer at 22°C or 4°C, 1 h after ingestion of coffee with caffeine (CAF) or without it (PL). Immediately before exercise and at the end of each workload, RT and blood lactate (LA) were measured. Oxygen uptake (VO2) and heart rate (HR) were recorded continuously. Blood LA threshold and the workload associated with the shortest RT were determined. Results: During exercise at 22°C, RT was significantly shorter in CAF than in the PL test, while at 4°C there were no differences in RT between CAF and PL trials. Cold exposure did not affect RT either at rest or during exercise. Neither caffeine nor cold exposure influenced the maximal VO2, the maximal HR and LA threshold. Conclusion: In the thermoneutral environment, caffeine ingestion improved psychomotor performance during exercise, whilst at low ambient temperature this effect was blunted. These findings suggest that the stimulating action of caffeine depends on the level and source of arousal.

This study was designed to determine the effect of ginseng treatment on multiple choice reaction time (RT) during exercise. Fifteen soccer players (age 19.07 ± 0.62 yrs) were placed in a double-blind manner into one of two groups: ginseng (n = 7), receiving 350 mg of ginseng daily for 6 weeks, or placebo (n = 8), receiving a placebo daily for 6 weeks. Before and after the treatment all the subjects performed an incremental bicycle ergometer exercise with intensity increasing 50 W every 3 min until volitional exhaustion. RT was measured before exercise, and then in the last 2 min of each exercise load. Maximal oxygen uptake (VO2max) and lactate threshold (LAT) were also determined from the exercise test. Ginseng treatment was found to shorten RT at rest and during exercise, shifting the exercise load associated with the shortest RT toward higher exercise loads. Neither ginseng nor placebo influenced VO2 max and LAT. In conclusion, ginseng extract does improve psychomotor performance during exercise without affecting exercise capacity.

The present study aims to assess motor activity of volleyball players using an original video recording method developed by the authors. Twenty-eight volleyball players taking part in 4 matches of the Polish Volleyball League were examined. The recorded data were analyzed in view of the mean total distance covered by volleyball players on different court positions during a match, set, and rally. The results showed that volleyball players cover the mean total distance of 1221 ± 327 m (mean ± SD) in a 3-set match, and 1757 ± 462 m in a 4-set match. A statistically significant difference (p ≤ 0.005) was found between the distance covered by the middle blockers and setters, defenders, spikers, and libero players in a match and in a set. The study revealed a tendency to lengthen the distance by the players in the final sets, which is indicative of the extended time of individual rallies. The mean distance covered in a single rally amounted to 10.92 ± 0.9 m in 4 matches (between 9.12 and 12.56 m). Considering the limited size of the field of play, volleyball players cover relatively long distances during a match and individual sets, with the shortest distance covered by middle blockers, and the longest by setters. From a practical application point of view, detailed topographic analysis of a player's movements on the court as well as precise data on the time of activity and rest breaks provide the coach with valuable information on the ways of development of arrhythmic, changing and dynamic training loads.

Previous investigations from this laboratory have demonstrated that during graded exercise with exercise intensities increasing every 3 min until exhaustion the multiple choice reaction time (RT) decreased until the intensity exceeded the lactate threshold (LT) by approximately 25%, and then rapidly increased. The aim of this study was to follow up changes in RT during prolonged exercise at constant intensities above and below LT and to relate these changes to changes in venous blood lactate [La−]b, and plasma catecholamine [CA]pl concentration responses to the exercise. For this purpose eight young soccer players exercised for 20-min on a cycle ergometer at 10% above LT, and nine exercised for 60 min at an intensity 30% below LT. During both tests RT, heart rate (HR), as well as [La−]b, and [CA]pl were measured. Above LT, RT decreased from the 5th min until the end of exercise, whilst HR, [La−]b, and [CA]pl increased progressively. Significant inverse correlations were ascertained between RT and plasma adrenaline (r = − 0.651) and noradrenaline concentrations (r = − 0.678). During exercise below LT, RT decreased up to approximately 40 min, then it reached a nadir, and stabilized at this level. This was accompanied by only small changes in [La−]b and [CA]pl. The present findings would indicate that young athletes are able to maintain for a relatively long time, or even increase, their psychomotor performance during endurance exercise both below and above the LT.

Endurance and Speed Capacity of the Korea Republic Football National Team During the World Cup of 2010 The aim of the study was to characterize selected indices of endurance and speed of the Korea Republic team with reference to the four best teams during the World Cup of 2010. Five hundred and ninety-nine football players from thirty-two teams participated in the study. All teams played in the 2010 World Cup in South Africa. For the assessment of the players' motor activity during matches common kinematic test results were recorded using the Castrol Performance Index. The following variables were analysed: total distance covered by the team, distance covered by individual players, maximum running speed and average match running speed for the team and individual players, as well as with division with regard to playing position: defenders, midfielders, strikers. In comparison to the four best teams at the football World Cup of 2010, the Korea Republic players achieved the highest running speed (p≤0.05), and similar levels of covered distance and average match running speed.

Purpose. The aim of this study was to examine the body tissue composition and functional traits of young football players. Methods. Analysis was performed on 23 junior football players. body mass and height were measured. bioelectrical impedance was used to assess the players’ body composition (fat mass, muscle mass, body cell mass and extracellular mass). The body mass index, body cell mass index and the extracellular mass/body cell mass ratio were also calculated. Functional traits were assessed by a one-on-one football game in an enclosed space with the objective to score the highest number of goals in a timed setting. Measurements of Hrrest, Hrmax and heart rate reserve were used to evaluate the efficiency of the subjects’ cardiovascular systems. Results. Insignificant differences in body tissue composition and cardiovascular efficiency were found regardless of what position was played. Overall, forwards were characterised by having the greatest height, the highest level of active body tissue development and the most efficient cardiovascular systems. Defenders were characterised by having larger body build, while midfielders displayed a significantly greater percentage of extracellular mass and EMc in relation to bcM. Conclusions. The results reveal that trends exist in the body tissue composition and cardiovascular efficiency of football players depending on which position they play. These differences reflect the varied physical efforts players perform during a match and should be taken into consideration when designing training programmes.

Breath-hold diving (freediving) is a discipline that makes considerable demands on sportsmen, which can amount to extreme distress. It is also known that psychological and physical strain affects hormonal milieus. We wanted to assess the impact of a stressful event (such as breath-hold diving) on the androgen status of men.We evaluated serum gonadotropins and androgen concentrations in four divers before diving, immediately post, and 60 minutes after diving.We found that neither gonadotropins nor total testosterone, free testosterone, calculated free testosterone or bioavailable testosterone concentrations changed significantly during diving practice.We conclude that the acute distress associated with breath-hold diving does not impact upon gonadotropins or androgen concentrations.

The present study was designed to determine changes in the multiple-choice reaction time (MRT) during treadmill running simulating locomotor activity during a soccer game and to examine the effect of branched chain amino acids (BCAA) ingestion on psychomotor performance during the effort. Ten male soccer players were submitted to BCAA and placebo trials at 1-week intervals in a randomized order. BCAA (7 g) or placebo were given 1 h before exercise in a double blind manner. The running test consisted of two 45 min exercise bouts separated by a 15-min passive rest period and the whole test ended with 20-min active recovery. Running–walking speed changed from 0 to 6.4 m·s–1 according to the time-motion analysis of soccer match. During the test, blood samples were taken for lactate, glucose, free fatty acid, and catecholamine determination. Following placebo treatment, MRT shortened from 320 ± 18 to 271 ± 11 ms (p < 0.001) during the first exercise bout then it increased during the resting break to 303 ± 138 ms (p < 0.05). During the second bout, MRT decreased to 280 ± 13 ms (p < 0.001). During active recovery, further shortening of MRT was noted. During BCAA trial, MRT was shorter than during placebo trial by ~10% (p < 0.05) before and during exercise. No significant differences were found between BCAA and placebo trials in biochemical indices. It is concluded that BCAA supplementation might be recommended in sport activities that change in intensity and require quick responses to external signals (e.g., soccer and other team games).

The aim of this study was to analyze the influence of individualized training (IT) as a function of motor type and effort status on changes of in specific physiological parameters among young soccer competitors. Blood pH and lactate concentrations, and lactate dehydrogenase (LDH), and creatine kinase (CK) activities were measured at the beginning of a preparation period, a match season, and a recuperation period of a 6-month macrocycle. The differences among specific physiological parameters as a function of the preparation phase for a defined motor type were analyzed by means of a 1-way generalized linear model (GLM) for repeated measurements. The differences in physiological parameters among defined motor types for a defined preparation phase were analyzed by means of the GLM for independent data. The differences in specific parameters before and after short time effort were analyzed by means of a t-test for matched pairs. Applied experimental and analytical approaches have revealed that IT administered to specific motor types differentiates players with respect to the pH, lactate concentration, and LDH activity. Obtained results indicate also that the dynamics of these parameters reflects the player's fitness level. Analysis of CK activity as a function of a preparation phase may serve as a prognostic tool for both overtraining and physical exhaustion.

The aim of this study was to analyze the influence of individualized training (IT) on psychomotor performance of young soccer players. Psychomotor performance was measured by means of differential response time and number of correct responses to audio and visual stimuli. Kinematic analysis allowing assessment of both the distances and the average speeds of young players during consecutive matches was also performed. For the data analysis, one-way analysis of variance, Friedman test, and t-test for dependent samples were used. The obtained results clearly indicate that IT during the preparation period increases specific psychomotor performance among young soccer players.