Association between polymorphism rs6295 of HTR1A serotonin receptor gene and personality traits among athletes of combat sport.

HTR1A (5-hydroxytryptamine receptor 1A) and its polymorphic variants are highly important for athletes in different aspects, allowing us to hypothesize their biological influences. Hence, to investigate at least part of the relationship mentioned in the case literature, it was decided to study the association of the selected HTR1A polymorphism with personality traits measured by the Temperament and Character Inventory (TCI). The participants consisted of 250 mixed martial arts (combat sport) athletes and 209 healthy male participants (control group). The personality traits were measured for the Revised Temperament and Character Inventory (TCI-R). Genetic material was isolated from whole blood collected from patients, and then all samples were genotyped using the real-time PCR method. Statistical analysis was performed using a 2 × 3 factorial ANOVA. The research revealed a statistically significant effect of a complex factor of rs6295 of the HTR1A serotonin receptor gene with combat sport/control and with Novelty Seeking (F2,453 = 6.126; p = 0.0024; η2 = 0.026) and Harm Avoidance (F2,453 = 3.709; p = 0.0252; η2 = 0.016). The presence of the HTR1A GG genotype (rs6295) was found to be associated with higher scores in self-management and lower scores in harm avoidance, indicating genetic predispositions in the strength group towards better results in combat sports.

Association Between the rs4680 Polymorphism of the COMT Gene and Personality Traits among Combat Sports Athletes.

Physical performance has been the focus of studies examining genetic influences in martial arts. There has been little quantitative analysis of the interaction between psychological traits and gene variants in athletes. This study aimed to determine whether the rs4680 polymorphism of the COMT gene (catechol-O-methyltransferase) was linked to other sports phenotypes such as temperament, mental toughness, and stress tolerance. In our study, we concentrated on the case-control analysis of athletes in the aspect of their personality traits in association with the COMT gene polymorphism. Participants comprised 258 combat sports athletes and 278 healthy male individuals as a control group. Psychometric properties were assessed with the Revised Temperament and Character Inventory (TCI-R). COMT polymorphism testing was performed using real-time PCR. We found a statistically significant effect of a complex factor COMT rs4680 genotype with combat athletes/controls and novelty seeking (F2,530 = 5.958, p = 0.0028, η2 = 0.022), self-management (F2,530 = 6.772, p = 0.0012, η2 = 0.025), and with self-transcendence skills (F2,530 = 9.387, p = 0.00009, η2 = 0.034). The results are important for encouraging further studies on the genetic makeup of athletes in conjunction with personality traits. Due to the multigene and multifactorial nature of determinants of sports predispositions, we propose to take into account also other features, especially when studying genes related to cerebral neurotransmission. It is a holistic departure, and it clearly illustrates the relationship between the given characteristics of an athlete.

Preliminary Development of a Brainwave Model for K1 Kickboxers Using Quantitative Electroencephalography (QEEG) with Open Eyes.

K1 kickboxing fighting is characterised by high injury rates due to the low restrictions of fighting rules. In recent years, much attention has been paid to research on changes in brain function among athletes, including those in combat sports. One of the tools that are likely to help diagnose and assess brain function is quantitative electroencephalography (QEEG). Therefore, the aim of the present study was an attempt to develop a brainwave model using quantitative electroencephalography in competitive K1 kickboxers. A total of thirty-six male individuals were purposefully selected and then comparatively divided into two groups. The first group consisted of specialised K1 kickboxing athletes exhibiting a high level of sports performance (experimental group, n = 18, mean age: 29.83 ± 3.43), while the second group comprised healthy individuals not training competitively (control group, n = 18, mean age: 26.72 ± 1.77). Body composition assessment was performed in all participants before the main measurement process. Measurements were taken for kickboxers during the de-training period, after the sports competition phase. Quantitative electroencephalography of Delta, Theta, Alpha, sensimotor rhytm (SMR), Beta1 and Beta2 waves was performed using electrodes placed on nine measurement points (frontal: FzF3F4, central: CzC3C4, and parietal: PzP3P4) with open eyes. In the course of the analyses, it was found that the level of brain activity among the study population significantly differentiated the K1 formula competitors compared with the reference standards and the control group in selected measurement areas. For kickboxers, all results of the Delta amplitude activity in the area of the frontal lobe were significantly above the normative values for this wave. The highest value was recorded for the average value of the F3 electrode (left frontal lobe), exceeding the norm by 95.65%, for F4 by 74.45% and Fz by 50.6%, respectively. In addition, the Alpha wave standard value for the F4 electrode was exceeded by 14.6%. Normative values were found for the remaining wave amplitudes. Statistically significant differentiation of results, with a strong effect (d = 1.52-8.41), was shown for the activity of Delta waves of the frontal area and the central part of the parietal area (Fz,F3,F4,Cz-p < 0.001), Theta for the frontal area as well as the central and left parietal lobes (Fz,F3,F4-p < 0.001, Cz-p = 0.001, C3-p = 0.018; d = 1.05-3.18), Alpha for the frontal, parietal and occipital areas (for: Fz,F3-p < 0.001, F4-p = 0.036, Cz-p < 0.001, C3-p = 0.001, C4-p = 0.025, Pz-p = 0.010, P3-p < 0.001, P4-p = 0.038; d = 0.90-1.66), SMR for the central parietal and left occipital lobes (Cz-p = 0.043; d = 0.69, P3-p < 0.001; d = 1.62), Beta for the frontal area, occipital and central lobes and left parietal segment (Fz,F3-p < 0.001, F4-p = 0.008, Cz, C3, Pz, P3,P4-p < 0.001; d = 1.27-2.85) and Beta 2 for all measurement areas (Fz, F3, F4, Cz, C3, C4, Pz, P3, P4-p < 0.001; d = 1.90-3.35) among the study groups. Significantly higher results were shown in the kickboxer group compared to the control. In addition to problems with concentration or over-stimulation of neural structures, high Delta waves, with elevated Alpha, Theta and Beta 2 waves, can cause disorders in the limbic system and problems in the cerebral cortex.

Acute Effects of Isometric Conditioning Activity on the Viscoelastic Properties of Muscles and Sprint and Jumping Performance in Handball Players.

ABSTRACT: Krzysztofik, M, Spieszny, M, Trybulski, R, Wilk, M, Pisz, A, Kolinger, D, Filip-Stachnik, A, and Stastny, P. Acute effects of isometric conditioning activity on the viscoelastic properties of muscles and sprint and jumping performance in handball players. J Strength Cond Res 37(7): 1486-1494, 2023-The effects of conditioning activity (CA) on muscle stiffness are currently unknown, suggesting that maximum CA effort can increase or decrease the stiffness of involved muscle groups. Therefore, this study aimed to investigate the effect of maximal isometric half-squats on the viscoelastic properties of muscles and postactivation performance enhancement (PAPE) in sprints and jumps. Twelve handball players underwent a standard warm-up and baseline assessment of muscle stiffness and tone of vastus lateralis and gastrocnemius medialis muscle, followed by 20-m sprint with intermediate measures at 5 and 10 m and countermovement jump. The PAPE was assessed by repeating the tests (at 4th, 8th, and 12th minute post-CA) after a CA protocol consisting of 3 sets of 3-second maximal isometric half-squats (EXP) or a control condition (CTRL) without any CA. The vastus lateralis stiffness in the 4th and 12th minute and muscle tone in the 4th minute post-CA significantly decreased compared with baseline ( p = 0.041, ES = 0.57; p = 0.013, ES = 0.52; p = 0.004, ES = 0.81, respectively) in the EXP condition. The 20-m sprint time significantly decreased at all post-CA time points compared with the baseline for the EXP condition ( p < 0.033) and the after values in the CTRL condition ( p < 0.036). In comparison to baseline, the 10-m sprint time decreased in the eighth minute post-CA ( p = 0.021; ES = 0.82) in the EXP condition. Moreover, it was significantly lower at the 8th and 12th minute post-CA ( p = 0.038; ES = 0.71 and p = 0.005; ES = 1.26) compared with that time points in the CTRL condition. The maximal isometric half-squats effectively improved sprint performance and significantly decreased vastus lateralis tone and stiffness. These findings offer new insights into the assessment of viscoelastic properties for evaluating the fatigue or potentiation state, which requires further investigation.

Acute Effects of Caffeinated Chewing Gum on Volleyball Performance in High-Performance Female Players.

To date, no investigation has studied the effect of acute intake of caffeinated chewing gum on volleyball performance. Therefore, the aim of this investigation was to establish the impact of caffeinated chewing gum ingestion on physical performance in female volleyball players. Twelve high-performance volleyball female athletes participated in a randomized, crossover, placebo-controlled, and double-blind experiment. Each athlete performed two identical experimental sessions after a) ingestion of ~6.4 mg/kg of caffeine via caffeinated chewing gum, b) ingestion of non-caffeinated chewing gum as a placebo. After the ingestion of gum, athletes performed a volleyball game, and performance was assessed by a notational analysis. Just before and after the game, jump performance during block and attack actions was evaluated. The number of points obtained and the number of errors committed during serve, reception, attacking, and blocking actions were unaffected by the ingestion of caffeinated chewing gum (p from 0.066 to 0.890). However, caffeinated chewing gum increased jump attack height in comparison to the placebo (pre-game 46.0 ± 7.2 vs. 47.2 ± 6.7 cm, p = 0.032; post-game 46.3 ± 7.6 vs. 47.5 ± 6.9 cm, p = 0.022, respectively). Caffeinated chewing gum did not modify block jump height (pre-game 32.7 ± 5.5 and 33.0 ± 4.3 cm, p = 0.829; post-game: 34.8 ± 6.1, 35.4 ± 6.1 cm, p = 0.993, respectively). The ingestion of ~6.4 mg/kg of caffeine via caffeinated chewing gum was effective for improving jump attack performance in women volleyball athletes. However, this effect was not translated into better volleyball performance during a game.

Acute Effects of Percussive Massage Treatment on Drop Jump Performance and Achilles Tendon Stiffness.

This study aimed to investigate the impact of Achilles tendon (AT) mechanical percussion massage (PM) on the passive stiffness of that tendon and subsequent drop jump kinematics. Eleven physically active participants performed two conditions in random order: (i) 60 s of PM applied to each AT (EXP) and (ii) no PM (CTRL). Measurements were performed 5 min before, immediately after, and 5 min following the completion of the PM. In the CTRL, measurements were performed at the same time point but no massage was applied. The two-way ANOVA indicated that there was no statistically significant interaction effect on contact time (p = 0.786), reactive strength index (p = 0.914), and relative peak power (p = 0.896). However, a statistically significant interaction on peak velocity (p = 0.046) and jump height (p = 0.03) was found. Despite that, there was no significant post-hoc comparisons for jump height, it slightly decreased 5 min post-PM (p = 0.136; ES = -0.25; Δ = -3.1%) compared with the CTRL condition (p = 1.00; ES = 0.11; Δ = +1.5%). Friedman's test did not show significant differences in dominant (p = 0.073) and non-dominant limb (p = 0.091) AT stiffness. Although not significant, numerically, the dominant limb AT (p = 0.126; ES = -0.64; Δ = -7.8%) had a larger reduction in stiffness immediately post-PM compared with the non-dominant limb (p = 0.294; ES = -0.26; Δ = -3.6%). The results of this study indicated the temporary effect of PM on the reduction in tissue stiffness. Moreover, these findings show that a mechanical PM might slightly hinder subsequent explosive athletic performance.

Post-Isometric Back Squat Performance Enhancement of Squat and Countermovement Jump.

The effectiveness of isometric conditioning activity (CA) is not well described in terms of the level of performance enhancement and the presence of a stretch and shortening cycle in subsequent explosive tasks. Therefore, the aim of this study was to evaluate the effect of a maximum isometric squat as the CA and a subsequent squat jump (SJ) and countermovement jump (CMJ) height. A total of 31 semi-professional handball and soccer players were randomly assigned to two different conditions: (i) 3 sets of 3 repetitions (each lasting 3 s) of maximum isometric back squats (EXP), and (ii) no CA (CTRL). The jump height measurements were performed 5 min before the CA and approximately at the 4th and 8th minute following the completion of the CA. Due to the high inter-individual variability in the potentiation responses, the best value obtained post-CA was also analyzed. The SJ height significantly increased from baseline to the 8th minute post-CA (p = 0.004; ES = 0.31; Δ = +3.1 ± 5.0%) in the EXP condition. On the other hand, the CMJ height was significantly higher in the 4th (p = 0.001; ES = 0.23; Δ = +2.7 ± 3.7%) and 8th minute post-CA (p = 0.005; ES = 0.32; Δ = +3.6 ± 5.7%) in comparison to baseline during the EXP condition. Furthermore, SJ height significantly increased from baseline to the best time-point during the EXP (p < 0.001; ES = 0.47; Δ = +4.9 ± 4.9%) and CTRL (p = 0.038; ES = 0.21; Δ = +2.5 ± 5.8%) condition. Moreover, the CMJ height was significantly higher at the best time-points than at the baseline during EXP (p < 0.001; ES = 0.53; Δ = +5.6 ± 4.7%) and CTRL (p = 0.002; ES = 0.38; Δ = +3.1 ± 5.2%) condition. The findings from this study indicate that a maximum isometric squat, used as a CA, effectively improved SJ and CMJ height. This suggests that the presence or absence of a stretch and shortening cycle in both CA and post-CA tasks does not significantly impact the post-activation performance enhancement response.

Cognitive Factors in Elite Handball: Do Players' Positions Determine Their Cognitive Processes?

For an athlete to be successful at the professional level, he or she should be characterized by extraordinary preparation in four areas: physical, technical, cognitive (related to game strategy, perception, and decision-making), and emotional (coping, emotional control). This study aimed to determine the level of selected cognitive traits in handball players while considering their sports level and assigned position on the court. Fifty handball players participated in the study. Participants consisted of 35 national team players, six first-division players, and nine second-division players. There were no significant differences between players from the elite (national team) and the sub-elite (I and II divisions) group. The results identified major differences in selective attention and short-term memory between handball players assigned to different positions (goalkeepers, compared to players in other positions, had lower attention and short-term memory). Thus, it is possible to develop a more effective psychological training program. However, it must be remembered that the results showed great variability among handball players. With this in mind, individual differences should be taken into account when planning psychological interventions.

Effect of High-Intensity Strength and Endurance Training in the Form of Small Circuits on Changes in Lipid Levels in Men Aged 35-40 Years.

BACKGROUND: Blood lipid profiles consist of total cholesterol (TC) and its fractions, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), non-high-density lipoprotein cholesterol (non-HDL), and triglycerides (TG). For several decades, studies have examined the effects of various factors on lipid status and its association with the risk of developing arteriosclerosis and cardiovascular disease. The beneficial effects of increased physical activity on cardiovascular health have been demonstrated by appropriate modulation of lipid profiles. For individuals with low physical activity, the literature recommends engaging in various forms of training that can improve physical fitness and resting lipid status. The aim of the study was to examine whether a specific original training program improves lipid profiles to the levels recommended for the male population. METHODS: The study involved two equal (n = 15) groups of men (experimental and control groups, aged 35-40 years). The experimental group performed 60-min training sessions for 8 weeks (3 times a week) including a set of strength and endurance exercises. Before and after the training program, blood was drawn from both groups for serum determination of TC, HDL, LDL non-HDL, and TG, and a battery of four field physical performance tests was administered. RESULTS: Statistically significant decreases (TC by 19.3%, TG by 23.7%, LDL by 15%), a non-significant decrease (10% for non-HDL), and no change for HDL were found in the experimental group. Control group showed a statistically significant decrease, by 7.4% for TC. The results confirm the effectiveness of the proposed training in improving health indices. CONCLUSIONS: The 8-week training program met the health-related fitness paradigm recommended for physical activity in men aged 35-40 years. After the completion of the program, all the participants expressed their satisfaction from participating in a health-promoting experiment.

Does caffeine ingestion affect the lower-body post-activation performance enhancement in female volleyball players?

BACKGROUND: Post-activation performance enhancement (PAPE) is a physiological phenomenon that acutely improves voluntary muscular performance following a conditioning activity. A large and growing body of literature has investigated different strategies to induce a PAPE stimulus; however, little attention has been given to whether acute caffeine ingestion could augment the effect of PAPE on subsequent performance. This study evaluated the acute effects of caffeine ingestion and back squat conditioning activity on subsequent countermovement jump (CMJ) performance in female semi-professional volleyball players. METHODS: Fourteen resistance-trained female volleyball players (26 ± 3 years) performed 3 different testing conditions in randomized order: where each ingested 6 mg/kg of caffeine (CAF) or placebo (PLAC) and performed a single set of back squats at 80%1RM until mean movement velocity dropped by 10% as the conditioning activity or a control (CTRL) condition where participants did not ingest any supplement and did not perform the conditioning activity. CMJ height was examined at baseline and in 2 min intervals until 10 min postconditioning activity. Furthermore, due to the wide inter-individual variation in optimal recovery time of PAPE response, the baseline and best post-conditioning activity performance were also analyzed. RESULTS: The Friedman test revealed a significant difference in jump height within CTRL (p = 0.002) and CAF (p = 0.001) conditions, but no significant difference was found within the PAP condition. The post hoc showed a significant decrease in jump height in 8th min in CTRL condition (p = 0.022, effect size [ES] = -0.31), a significant increase in jump height in 2nd min in CAF condition (p = 0.013, ES = 0.3), without differences in PLAC condition in comparison to baseline values. Moreover, a significant jump height increases from baseline to best performance post conditioning activity value for CAF (p = 0.001, ES = 0.39) and PLAC (p = 0.001, ES = 0.3) condition, but no significant difference was found for the CTRL condition. CONCLUSIONS: The single set of heavy-loaded back squats with controlled velocity used as a conditioning activity in the current study enhanced subsequent CMJ performance in female volleyball players with no additional effect of caffeine.

Effect of CrossFit Training on Physical Fitness of Kickboxers.

Background: Kickboxing is a combat sport that is complex in technique, tactics, and movement structure, and requires an adequate level of motor skills as a foundation for activities during competitions. General physical fitness, defined as the effect of the externalization of motor skills, is the basis for athletic training regardless of the sport. The aim of this study was to determine the effect of modified training based on the principles of CrossFit on the development of general physical fitness in a group of kickboxers compared to a control group. Methods: The study was experimental in nature and was conducted in a group of 60 kickboxers, divided into experimental and control groups. Participants were selected by purposive sampling, and the criteria were training experience, sports skill level (minimum class 1 athletes), and consent to participate in the experiment. The intervention in the study group involved the introduction of CrossFit-based training into a conventional kickboxing training program. General and special physical fitness of the athletes were diagnosed. Results: Statistically significant differences were found in general fitness in terms of abdominal strength (p < 0.001), pull-ups (p < 0.001), dynamometric measurement of handgrip force (p < 0.001) (kg), clap push-ups (p < 0.001), standing long jump (p < 0.001), shuttle run (p < 0.001), sit-and-reach (p < 0.001), and tapping (p < 0.001). Furthermore, changes in special fitness were also demonstrated for the special kickboxing fitness test (SKFT) (p < 0.02), the total number of punches (p < 0.001), punching speed (p < 0.001), and hip turning speed (p < 0.001). There was also a correlation between characteristics of general fitness and special fitness (p < 0.001). Conclusions: The experimental training program based on the principles of CrossFit training had a positive effect on the general and special kickboxing physical fitness.

The Effect of Caffeinated Chewing Gum on Volleyball-Specific Skills and Physical Performance in Volleyball Players.

No previous study analyzed the effect of caffeinated chewing gum on volleyball-specific skills and physical performance in volleyball players. Twelve volleyball players participated ina randomized, crossover, and double-blind experiment after ingestion of (a) ~3.2 ± 0.4 mg/kg of body mass (BM) of caffeine via chewing gum or (b) non-caffeinated chewing gum (placebo) and performed: (a) a countermovement jump, (b) a squat jump, (c), an attack jump, (d) a block jump, (e) 5 and 10 m sprints, (f) a modified agility t-test, (g) an attack and service speed test, and (h) a spike and serve accuracy test. Compared to the placebo, the caffeine chewing gum supplementation significantly improved the accuracy of the attack (15 ± 4 vs. 18 ± 3 points, p = 0.02). However, the ingestion of caffeinated chewing gum had no effect on the remaining other performance tests (p from 0.12 to 1.00). A caffeine-containing chewing gum with a dose of ~3 mg/kg BM effectively improved the attack's accuracy in volleyball players. However, this effect was not observed in better results in jumping, running, and other skill-based volleyball tests.

Evaluation of the Level of Technical and Tactical Skills and Its Relationships with Aerobic Capacity and Special Fitness in Elite Ju-Jitsu Athletes.

BACKGROUND: Ju-jitsu training has to be comprehensive in terms of training intensity, developing a wide range of physical fitness and learning multiple technical skills. These requirements result from the specificity of the competition characteristic of the sport form of this martial art. The aim of this study was to evaluate the aerobic capacity and special physical fitness of ju-jitsu athletes at the highest sports performance level and to determine the relationships between special fitness and the indices of technical and tactical skills. METHODS: In order to determine the current level of special fitness of the athletes, a set of karate fitness tests were used, namely, the Special Judo Fitness Test and the Kickboxer Special Physical Fitness Test. Furthermore, maximal oxygen uptake (VO2peak) was measured using a graded exercise test in a group of 30 sport ju-jitsu athletes at the highest level of sports performance. To evaluate the level of technical and tactical skills, an analysis of recordings of tournament bouts was carried out, and, based on the observations, the indices of effectiveness, efficiency, and activeness of the attack were calculated. RESULTS: Individuals with higher fitness were more active and effective in the attack. The special efficiency indices showed significant correlations with the technical and tactical parameters. Better fighting performance was dependent on the speed of the punches, kicking range, and the results of the special fitness tests. CONCLUSIONS: To achieve greater efficiency and effectiveness of sport ju-jitsu, the training process should be based on comprehensive motor development and an optimal level of special fitness.

Body Balance and Physiotherapy in the Aquatic Environment and at a Gym.

The increase in the average age of our society represents a growing medical and social problem, which requires concentration on the issue concerning balance disorders. The aquatic environment has a number of complex properties that have miscellaneous effects on the human body. In the light of the above, water is becoming an ideal environment to learn correct neuromuscular communication, and a properly prepared training session in water helps to practice balance and movement coordination. The objective of the study was to assess the impact of rehabilitation in the aquatic environment on patients' balance and compare the results obtained with patients who received rehabilitation at a gym. The study was carried out among patients hospitalised in the "Krzeszowice" Rehabilitation Centre. It encompassed 137 patients, randomly assigned to either the study group (the aquatic environment) or the control group (the gym). The preliminary examination included general medical history and a test on the stabilometric platform. The patients attended training sessions for 4 weeks, 5 times a week for 30 minutes. It was a single-blinded study wherein the authors did not know which group a given patient had been assigned to. Upon completion of a monthly therapy, the stabilometric test was carried out again. The study revealed that the patients from both groups experienced a significant improvement in balance. However, the improvement was slightly greater in those exercising in the pool. Physiotherapy in the aquatic environment makes a greater contribution to the improvement of body balance compared to physical exercises performed at a gym.

Absolute and relative reliability of several measures of static postural stability calculated using a GYKO inertial sensor system.

PURPOSE: The aim of this study was to analyse absolute and relative reliability of a number of postural static stability measures obtained from a GYKO inertial sensor system in young adults. METHODS: The study examined 29 healthy non-athlete young adults. A test was performed for 30 s while standing on one foot, without moving, with eyes open and arms relaxed along the sides of the body. The examinations were performed twice, with a one-week interval. Relative reliability was measured using the intraclass correlation coefficient (ICC) and the 95% confidence interval (95% CI), whereas the absolute reliability was evaluated based on the standard error of measurement (SEM) and the minimal detectable change (MDC). RESULTS: The results of this study showed moderate to good relative reliability scores for all the postural stability measures, with ICC values ranging from 0.62 to 0.70. For most of the analysed variables, SEM% ranged from ca. 10 to 14%. Relatively high SEM% values were obtained only for two variables (Area, Convex Hull Area). CONCLUSIONS: The low costs of GYKO inertial sensor systems, the fast and easy installation, the mobility and high reliability of the measurement of postural stability show that it can be effective alternative to stabilographic platforms.

Distribution of feet pressure on ground and maintaining body balance among 8-10-year-old children with and without external load application.

PURPOSE: The aim of this study was to analyse the impact of applying an external load on the distribution of pressure on the plantar side of the foot and maintaining body balance, using the podobarographic platform. METHODS: The study was conducted on 130 school children aged 8-10: girls (n = 68, body mass = 22.8 ± 6.0 kg, body height = 129.3 ± 7.5 cm) and boys (n = 62, body mass = 31.1 ± 6.5 kg, body height 134.4 ± 7.3 cm). The study involved 2 trials. At first, children stood on the platform assuming a natural position. Then, they put on a 5-kg backpack and stood on the platform once more. RESULTS: The results indicate that after backpack loading, for the total research group of girls and boys, statistically significant differences were found in the distribution of foot force on the ground in the left forefoot ( p = 0.008), metatarsus ( p = 0.000) and heel areas ( p = 0.002). While in the right foot, these differences were noted for the forefoot ( p = 0.024) and metatarsus ( p = 0.000). The results of balance testing were also statistically significant. They concerned measurements of the body barycentre area (cop-bars p = 0.003), the barycentre area of the left foot (l-bars p = 0.034) and the parameter comparing distance to surface ratio (cop-lsf p = 0.000). CONCLUSIONS: It may be concluded that prolonged overloading with backpacks affects movement patterns, which may further lead to the acquisition and consolidation of postural defects.

Off-Ice Agility Provide Motor Transfer to On-Ice Skating Performance and Agility in Adolescent Ice Hockey Players.

Agility plays a crucial role in ice hockey training, and it can be developed directly on the ice or by additional off-ice training. Since the effectiveness of on-ice and off-ice training on players' agility have not been previously described, the purpose of this research is to compare the effects of on-ice and off-ice agility training on skating performance. Fourteen ice hockey players performed agility training on-ice for 4 weeks and off-ice for 4 weeks in a crossover design; they were tested before the agility program, after the first month and after finishing both training programs. The players were randomly assigned into one of two groups (n = 7 in each group), either performing the on-ice training protocol first (Ice1) followed by the off-ice agility training or performing the off-ice protocol first and the on-ice training second (Ice2). The test battery included straight sprints to 6.1 m and 35 m and the S corner test, test with break, weave agility with puck test and reactive agility test. The magnitude based decision showed the effect of agility training in both groups in the weave agility (Ice1, 2.9±2.8% likely improvement; Ice2, 3.1±2.5% possible improvement) and reactive agility tests (Ice1, 3.1 ±2.5% likely improvement; Ice2, 1.7±2.1% possible improvement), where the Ice1 protocol resulted in a likely positive change and Ice2 resulted in a possible positive change. The comparison of the training effect resulted in a possibly harmful change of performance in Ice2 protocol (-0.5 ± 8.9%) compared to Ice1 protocol (-1.0 ± 5.1%). On-ice training is more effective in the development of specific types of agility in adolescent U16 players. However, there is evidence that off-ice agility have motor transfer to on-ice agility. Therefore, we recommend developing on-ice agility with additional off-ice agility training during the ice hockey season.

Polygenic Study of Endurance-Associated Genetic Markers NOS3 (Glu298Asp), BDKRB2 (-9/+9), UCP2 (Ala55Val), AMPD1 (Gln45Ter) and ACE (I/D) in Polish Male Half Marathoners.

The purpose of this study was to investigate individually and in combination the association between the ACE (I/D), NOS3 (Glu298Asp), BDKRB2 (-9/+9), UCP2 (Ala55Val) and AMPD1 (Gln45Ter) variants with endurance performance in a large, performance-homogenous cohort of elite Polish half marathoners. The study group consisted of 180 elite half marathoners: 76 with time < 100 minutes and 104 with time > 100 minutes. DNA of the subjects was extracted from buccal cells donated by the runners and genotyping was carried out using an allelic discrimination assay with a C1000 Touch Thermal Cycler (Bio-Rad, Germany) instrument with TaqMan® probes (NOS3, UCP2, and AMPD1) and a T100™ Thermal Cycler (Bio-Rad, Germany) instrument (ACE and BDKRB2). We found that the UCP2 Ala55Val polymorphism was associated with running performance, with the subjects carrying the Val allele being overrepresented in the group of most successful runners (<100 min) compared to the >100 min group (84.2 vs. 55.8%; OR = 4.23, p < 0.0001). Next, to assess the combined impact of 4 gene polymorphisms, all athletes were classified according to the number of 'endurance' alleles (ACE I, NOS3 Glu, BDKRB2 -9, UCP2 Val) they possessed. The proportion of subjects with a high (4-7) number of 'endurance' alleles was greater in the better half marathoners group compared with the >100 min group (73.7 vs. 51.9%; OR = 2.6, p = 0.0034). These data suggest that the likelihood of becoming an elite half marathoner partly depends on the carriage of a high number of endurance-related alleles.

Modification of Strength Training Programs in Handball Players and its Influence on Power During the Competitive Period.

A high level of muscle power is necessary for the effective use of technique during handball competitions. The presented research concentrated on comparing the effectiveness of two training modes directed towards the development of muscle power - plyometric and traditional strength training. Furthermore, we evaluated whether resistance training performed twice a week was sufficient to guarantee an increase in muscle power of handball players. We also investigated whether strength training designed according to the "waving" model (one training session per week oriented towards the development of maximal strength and one towards the development of power) was sufficient to increase muscle power in handball players. The study included 28 professional handball players who were divided into 3 groups: Group 1 subjected to additional strength training (8 individuals), Group 2 subjected to traditional plyometric training (8 individuals) and Group 3 following standard training (12 individuals). Research was conducted at the beginning and at the end of the 1st round of competitions and consisted of the following measurements: CMJ (countermovement jump) and SJ (squat jump), a 10-s trial on a cycle-ergometer and ball-throwing velocity. Analysis of the results showed that both the plyometric and strength training programs induced a statistically significant increase in jumping height and generated power during the CMJ. The group subjected to additional strength training achieved greater increases in CMJ power than the group carrying out plyometric training, which in case of the CMJ peak power turned out to be statistically significant (p < 0.05). Different results were obtained when studying changes in the flight speed of the thrown ball; the group undergoing plyometric training registered minor increases (significant in the standing throw ), and there were decreases in the flight speed of the thrown ball (significant in the leaning back throw) in the group following the traditional strength training program.

Post-Effort Changes in Activity of Traditional Diagnostic Enzymatic Markers in Football Players' Blood.

BACKGROUND: Long-term and intensive physical effort causes metabolic and biochemical adaptations for both athletic and non-athletic objectives. Knowing the importance of aerobic training in football players, the aim of this study was to evaluate changes in the activity of: creatinine kinase (CK), creatine kinase MB (CKMB), lactate dehydrogenase (LDH), α-hydroxybutyrate dehydrogenase (HBDH), cholinesterase (ChE) and alkaline phosphatase (ALP) in response to a semi-long distance outdoor run under aerobic conditions among both female and male football players. METHODS: Sixteen participants aged 21.9±2 years (women) and 18.4±0.5 years (men), all of them voluntarily recruited football players, took part in an outdoor run, the women covering a distance of 7.4±0.3 km while men covered a distance of 10.7±1.0 km. Plasma activities of the studied enzymes were determined using an appropriate diagnostic assay kit. RESULTS: Our results indicate that total LDH activity could be a useful tool in evaluating physical fitness among athletes. We simultaneously established that ChE could not be a marker useful in assessing metabolic response to physical effort in athletes. Moreover, our results suggest that post-effort changes in ALP activity might be used to estimate early symptoms of certain vitamin deficiencies in an athlete's diet. CONCLUSIONS: We confirmed that the assessment of activity of selected traditional diagnostic enzymatic markers provides information about muscle state after physical effort.