Immunological Response and Match Performance of Professional Tennis Players of Different Age Groups During a Competitive Season.

ABSTRACT: Kozlowska, M, Zurek, P, Rodziewicz, E, Góral, K, Zmijewski, P, Lipinska, P, Laskowski, R, Walentukiewicz, AK, Antosiewicz, J, and Ziemann, E. Immunological response and match performance of professional tennis players of different age groups during a competitive season. J Strength Cond Res 35(8): 2255-2262, 2021-We aimed to investigate the effect of physical workloads on immunological response, match performance, and iron metabolism in professional tennis players of different age groups throughout the tournament season and to determine the interdependence of vitamin D status and inflammation. Thirty-eight young, male tennis players with a top national ranking (1-25) participated in this study and were assigned to the following age groups: cadets (CG), juniors (JG), and seniors (SG). Blood samples were collected at the beginning, midpoint, and end of the tournament season to assess the proinflammatory cytokine (tumor necrosis factor-alpha [TNF-α]), anti-inflammatory myokines (interleukin [IL]-6 and IL-10), heat shock proteins (HSP70, HSP27), iron metabolism markers, and vitamin D concentrations. The total number of matches (won and lost) at the national and international events was recorded. The IL-6 and IL-10 concentrations significantly increased across all groups in the middle and end of the tournament season (effect large and very likely). The TNF-α concentration was elevated at the end of the season in CG and SG. The increase in TNF-α concentration corresponded with an increase in hepcidin concentration in these groups. The significant increase in HSP27 concentration was only noticed in SG with normal vitamin D concentrations. In JG and SG, a mild seasonal increase in vitamin D concentration was noted, but still it was insufficient. The immunological response was not affected by the number of tennis matches; however, the anti-inflammatory effect was regulated by higher concentrations of vitamin D. Unexpectedly, most tennis players had vitamin D deficiency. Iron status remained unchanged.

A transferable high-intensity intermittent exercise improves executive performance in association with dorsolateral prefrontal activation in young adults.

Although growing attention has been drawn to attainable, high-intensity intermittent exercise (HIE)-based intervention, which can improve cardiovascular and metabolic health, for sedentary individuals, there is limited information on the impact and potential benefit of an easily attainable HIE intervention for cognitive health. We aimed to reveal how acute HIE affects executive function focusing on underlying neural substrates. To address this issue, we examined the effects of acute HIE on executive function using the color-word matching Stroop task (CWST), which produces a cognitive conflict in the decision-making process, and its neural substrate using functional near infrared spectroscopy (fNIRS). Twenty-five sedentary young adults (mean age: 21.0 ± 1.6 years; 9 females) participated in two counter-balanced sessions: HIE and resting control. The HIE session consisted of two minutes of warm-up exercise (50 W load at 60 rpm) and eight sets of 30 s of cycling exercise at 60% of maximal aerobic power (mean: 127 W ± 29.5 load at 100 rpm) followed by 30 s of rest on a recumbent-ergometer. Participants performed a CWST before and after the 10-minute exercise session, during both of which cortical hemodynamic changes in the prefrontal cortex were monitored using fNIRS. Acute HIE led to improved Stroop performance reflected by a shortening of the response time related to Stroop interference. It also evoked cortical activation related to Stroop interference on the left-dorsal-lateral prefrontal cortex (DLPFC), which corresponded significantly with improved executive performance. These results provide the first empirical evidence using a neuroimaging method, to our knowledge, that acute HIE improves executive function, probably mediated by increased activation of the task-related area of the prefrontal cortex including the left-DLPFC.

The whole body cryostimulation modifies irisin concentration and reduces inflammation in middle aged, obese men.

The anti-inflammatory effect induced by exposure to low temperature might trigger the endocrine function of muscle and fat tissue. Thus, the aim of this study was to investigate the influence of the whole body cryostimulation (CRY) on irisin, a myokine which activates oxygen consumption in fat cells as well as thermogenesis. In addition, the relationship between hepcidin (Hpc) - hormone regulating iron metabolism, and inflammation was studied. A group of middle aged men (n = 12, 38 ± 9 years old, BMI > 30 kg m(-2)) participated in the study. Subjects were exposed to a series of 10 sessions in a cryogenic chamber (once a day at 9:30 am, for 3 min, at temperature -110 °C). Blood samples were collected before the first cryostimulation and after completing the last one. Prior to treatment body composition and fitness level were determined. The applied protocol of cryostimulation lead to rise the blood irisin in obese non-active men (338.8 ± 42.2 vs 407.6 ± 118.5 ng mL(-1)), whereas has no effect in obese active men (371.5 ± 30.0 vs 343.3 ± 47.6 ng mL(-1)). Values recorded 24 h after the last cryo-session correlated significantly with the fat tissue, yet inversely with the skeletal muscle mass. Therefore, we concluded the subcutaneous fat tissue to be the main source of irisin in response to cold exposures. The applied cold treatment reduced the high sensitivity C-reactive protein (hsCRP) and Hpc concentration confirming its anti-inflammatory effect.

Repeated "all out" interval exercise causes an increase in serum hepcidin concentration in both trained and untrained men.

This investigation assessed effects of high-intensity interval exercise (HIE; triple Wingate anaerobic test) on inflammatory markers, iron metabolism and hepcidin concentrations. Group of highly trained judo athletes (TR) and non-trained control males (CG) completed a triple Wingate test separated by 4.5min rest. Venous blood samples were collected before, immediately after, 1h, 24h, and 5days following exercise and analysed for serum of IL-6, IL-10, iron, and ferritin. Physiological response to exercise was also determined. Concentration of IL-6 and hepcidin increased 1h after exercise in both groups (p<0.05). Hepcidin returned post testing 24h in TR, whereas in CG it remained elevated during 5days following exercise. Changes in hepcidin did not correlate with shifts in serum IL-6, iron and ferritin concentrations. Gathered data suggest that following HIE, hepcidin increased independently of IL-6 and neither blood nor storage iron affected this phenomena.

Do high blood hepcidin concentrations contribute to low ferritin levels in young tennis players at the end of tournament season?

The purpose of the present study was to verify whether impaired iron metabolism in young athletes is a consequence of an excessive workload during the tournament season. Low levels of ferritin (under 25 µg·L(-1)) have been frequently observed in young tennis players. We considered this finding to be related to the high-intensity workload or to insufficient rest, which both trigger a strong immune response. Groups of male, well-trained young tennis players (16 ± 0.9 years old, average of 10-year training experience) and a control peer group participated in this study. The research consisted of two examination sessions (March and September 2010). Blood samples were collected to determine haematological and immunological parameters. Additionally, body composition and physical capacity were assessed. In both periods of the study, the trained groups were characterised by low levels of ferritin, but also elevated levels of pro- inflammatory cytokine IL-1ß. Moreover, an inverse correlation between IL-1ß and blood ferritin was observed. Additionally, an increased concentration of the iron homeostasis regulator hepcidin was found in blood samples (mean 71 ng·ml(-1); range from 48 to 100 ng·ml(-1)). We concluded that the pro- inflammatory cytokine IL-1ß, most likely induced by an extensive workload during the tournament season, was responsible for the low level of ferritin in young, professional athletes. Key PointsThe first research demonstrating low grade inflammation-induced iron deficiency to be associated with elevated blood hepcidin levels in young tennis athletes.Evaluation of immunological response after the complete tournament season in young male tennis players.Conclusion to introduce the assessment of hepcidin to monitor trainings as well as symptoms of overreaching more effectively.Research providing practical information for coaches that changes in diet and modifications in workloads applied in physical training could be more effective than iron supplementation in iron deficient athletes.

Exercise training-induced changes in inflammatory mediators and heat shock proteins in young tennis players.

Heat shock proteins (Hsp) represent proteins' groups, whose protective function, may be induced by heat, reactive oxygen species, cytokines etc. We evaluated blood levels of Hsp27 and Hsp70, and their relation to skeletal muscle damage and inflammation in young tennis players before and after the conditioning camp. Blood samples were collected directly after tournament season, 3-day rest and 14-day conditioning camp that followed. Hydrogen peroxide (H2O2) demonstrated the highest concentration directly after tournament season, which significantly decreased at camp's end. The pro-inflammatory cytokines IL-1ß and TNFα decreased, whereas anti-inflammatory cytokines IL-6 and IL-10 increased after 3d rest and 14d camp. Hsp27 increased after 3d rest and remained so after 14d camp, while Hsp70 decreased from baseline to camp's completion. Hsp27 and Hsp70 correlated significantly with H2O2, IL-1ß and TNFα. Muscle damage, observed as creatine kinase (CK) activity changes, increased after 14d camp similarly to Hsp27 and anti-inflammatory cytokines IL-6 and IL-10. Obtained data allows to conclude that decrease of Hsp27 and increase in pro-inflammatory cytokines could be a good indicator of overreaching. Reverse tendencies in these proteins may verify accuracy of conditioning camp. Finally, this training program caused an increase in the anti-inflammatory cytokines concentrations, improving individual status of recovery. Key PointsThe study demonstrating low grade inflammation-induced by the tournament season in young tennis player.Three days of active rest stimulated the anti-inflammatory response via rise of Hsp27 and anti-inflammatory cytokine IL-10.Observed decrease of blood Hsp70 may support mental recovery.Thirteen-day appropriate training program led to maintaining an immunological response balance.

Examining the effects of pre-competition rapid weight loss on hydration status and competition performance in elite judo athletes.

The prevalence of rapid weight loss (RWL) among martial arts athletes including judo is very high. Many applied RWL strategies could be dangerous to health and even lead to death. Therefore, the International Judo Federation (IJF) introduced changes in the weigh-in rules, changing the official weigh-in for the day before the competition. Thus, the purpose of this study was to examine the impact of the new IJF rules on hydration status and weight loss strategies among professional judo athletes. Seventeen elite judo athletes participated in the study. Body mass and hydration status, were analyzed before the competition. Moreover, competition result and practice of RWL survey were collected. All subjects reached their weight category limits for the competition. RWL resulted in body mass changes (p < 0.001, ηp2 = 0.79) and dehydration among participants (urine osmolality > 700 [mOsmol*kg]-1 and urine specific gravity > 1.020 [g*cm3]-1). However, urine osmolality (p > 0.05, ηp2 = 0.18), as well as urine specific gravity (p > 0.05, ηp2 = 0.16), at subsequent time points of measurement revealed no statistical differences. The prevalence of RWL was 100%, and only 17.6% of the athletes declared that they would compete in a different weight category if the competition would be conducted on the same day of the weigh-in. All judo athletes applied RWL procedures using traditional methods to achieve the required body mass (i.e., increased exercise, reduced fluid, and food intake). Dehydration state was not associated with competitive performance (p > 0.05).

Exercise-Induced Elevated BDNF Concentration Seems to Prevent Cognitive Impairment after Acute Exposure to Moderate Normobaric Hypoxia among Young Men.

Memory impairment, reduced learning ability, decreased concentration, and psychomotor performance can be all signs of deleterious impact of hypoxia on cognitive functioning. In turn, physical exercise can improve performance and enhance cognitive functions. The purpose of this study was to investigate whether the potential positive effects of exercise performed under normobaric hypoxia can counteract the negative effects of hypoxia on cognitive function, and whether these changes correlate with brain-derived neurotrophic factor (BDNF) concentrations. Seventeen healthy subjects participated in a crossover study where they performed two sessions of single breathing bouts combined with moderate intensity exercise under two conditions: normoxia (NOR EX) and normobaric hypoxia (NH EX). To assess cognitive function, Stroop test was applied. There were no significant differences in any part of the Stroop interference test regardless of the conditions (NOR, NH), despite a statistical decrease in SpO2 (p < 0.0001) under normobaric hypoxic conditions. In addition, a statistical increase (p < 0.0001) in BDNF concentration was observed after both conditions. Acute exercise under normobaric hypoxia did not impair cognitive function despite a significant decrease in SpO2. Exercise in such conditions may offset the negative effects of hypoxia alone on cognitive function. This may be related to the significant increase in BDNF concentration and, as a consequence, positively affect the executive functions.

Stress is not so bad-cortisol level and psychological functioning after 8-week HIIT program during pregnancy: a randomized controlled trial.

Background: Amid extensive pregnancy exercise research, the impact of High Intensity Interval Training (HIIT) on pregnant women's mental health is underexplored. Despite exercise benefits, it can trigger stress responses like elevated cortisol. This study fills the gap by investigating correlations between hair cortisol levels, mental health, and HIIT effects in pregnant women. Methods: We conducted a randomized control trial among 38 Caucasian women in uncomplicated, singleton pregnancy (age 31.11 ± 4.03 years, 21.82 ± 4.30 week of gestation; mean ± SD). The experimental group comprised 22 women engaged in an 8-week high-intensity interval training program (HIIT). The comparative group consisted of 16 pregnant women undergoing an 8-week educational program (EDU). Before and after the interventions, all women were evaluated using the following tools: Hair cortisol level measurements, Beck Depression Inventory - II for depressive symptoms assessment, Childbirth Attitudes Questionnaire for childbirth fear measurement, 12-item Short Form Health Survey to gage health-related quality of life, International Physical Activity Questionnaire for physical activity level estimation, and a Progressive maximal exercise test to evaluate maternal exercise capacity. Results: The key finding of our study reveals that women engaged in the HIIT intervention exhibited a distinct cortisol production pattern in contrast to the EDU group practicing standard moderate intensity physical activity. In the HIIT group, there was an increase in hair cortisol levels, while the EDU group showed a notable decrease. Remarkably, HIIT stimulated cortisol production without adversely impacting fear of childbirth and psychophysical condition during pregnancy. In fact, only the HIIT group showed a significant enhancement in mental health. Conclusion: No links were discovered between hair cortisol levels and the severity of depressive symptoms, psychophysical well-being, or fear of childbirth. Hence, based on our research, employing cortisol levels during pregnancy as an indicator of negative stress or depression risk appears unwarranted.

Effects of Strength Training on BDNF in Healthy Young Adults.

The physical improvements from strength and resistance training have been known for decades, but the cognitive benefits of this type of activity are not as well-known. The aim of this review article is to provide a summary of studies presenting the effects of strength and resistance training on BDNF in healthy young adults. A systematic search of various electronic databases (PubMed, Web of Science, Science Direct and Google Scholar) was conducted in September 2022. Studies that examined associations between strength training and BDNF in healthy young adults aged 18-30 years were included. The final sample included 10 studies published between 2009 and 2020. The results of this literature review are inconclusive. Based on the results of the 10 studies, there is no clear answer as to whether strength training has positive effects on BDNF in healthy young adults.

Improved Oxygen Uptake Efficiency Parameters Are Not Correlated with VO2peak or Running Economy and Are Not Affected by Omega-3 Fatty Acid Supplementation in Endurance Runners.

Peak oxygen uptake (VO2peak) is one of the most reliable parameters of exercise capacity; however, maximum effort is required to achieve this. Therefore, alternative, and repeatable submaximal parameters, such as running economy (RE), are needed. Thus, we evaluated the suitability of oxygen uptake efficiency (OUE), oxygen uptake efficiency plateau (OUEP) and oxygen uptake efficiency at the ventilatory anaerobic threshold (OUE@VAT) as alternatives for VO2peak and RE. Moreover, we evaluated how these parameters are affected by endurance training and supplementation with omega-3 fatty acids. A total of 26 amateur male runners completed a 12-week endurance program combined with omega-3 fatty acid supplementation or medium-chain triglycerides as a placebo. Before and after the intervention, the participants were subjected to a treadmill test to determine VO2peak, RE, OUE, OUEP and OUE@VAT. Blood was collected at the same timepoints to determine eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocytes. OUE correlated moderately or weakly with VO2peak (R2 = 0.338, p = 0.002) and (R2 = 0.226, p = 0.014) before and after the intervention, respectively. There was a weak or no correlation between OUEP, OUE@VAT, VO2peak and RE despite steeper OUE, increased OUEP and OUE@VAT values in all participants. OUE parameters cannot be treated as alternative parameters for VO2peak or RE and did not show changes following supplementation with omega-3 fatty acids in male amateur endurance runners.

Judo training program improves brain and muscle function and elevates the peripheral BDNF concentration among the elderly.

Programmed exercise interventions modulating both physical fitness and cognitive functions have become a promising tool to support healthy aging. The aim of this experiment was to determine the effect of a 12-week judo training (JEX) on cognitive processing and muscle function among the elderly. Forty participants were divided into two groups: the JEX group and the control group (CTL). Before and after 12-week of JEX, participants performed a battery of physiological and psychological tests. The peripheral level of brain-derived neurotrophic factor (BDNF) was analyzed. A 12-week JEX intervention led to improved Stroop performance reflected by a shortening of the response time related to Stroop "naming" interference. In addition, the peripheral concentration of BDNF was significantly increased following the JEX compared with the CTL group. In response to JEX, balance and lower limb strength significantly increased. The current results suggest that JEX could have beneficial effects on cognitive functions, denoted by elevated peripheral BDNF, as well as on balance and strength abilities. A combination of positive effects with respect to movement and cognition makes JEX an ideal preventive lifestyle modification for the aging population.

Acute Normobaric Hypoxia Lowers Executive Functions among Young Men despite Increase of BDNF Concentration.

BACKGROUND: Decreased SpO2 during hypoxia can cause cognitive function impairment, and the effects of acute hypoxia on high-order brain functions such as executive processing remain unclear. This study's goal was to examine the impact of an acute normobaric hypoxia breathing session on executive function and biological markers. METHODS: Thirty-two healthy subjects participated in a blind study performing two sessions of single 30 min breathing bouts under two conditions (normoxia (NOR) and normobaric hypoxia (NH), FIO2 = 0.135). The Stroop test was applied to assess cognitive function. RESULTS: No significant difference was observed in the Stroop interference in the "reading" part of the test in either condition; however, there was a significant increase in the "naming" part under NH conditions (p = 0.003), which corresponded to a significant decrease in SpO2 (p < 0.001). There was a significant increase (p < 0.013) in the brain-derived neurotrophic factor (BDNF) level after NH conditions compared to the baseline, which was not seen in NOR. In addition, a significant drop (p < 0.001) in cortisol levels in the NOR group and a slight elevation in the NH group was noticed. CONCLUSIONS: According to these findings, acute hypoxia delayed cognitive processing for motor execution and reduced the neural activity in motor executive and inhibitory processing. We also noted that this negative effect was associated with decreased SpO2 irrespective of a rise in BDNF.

Aerobic and anaerobic changes with high-intensity interval training in active college-aged men.

We investigated the aerobic and anaerobic benefits of high-intensity interval training performed at a work-to-rest ratio of 1:2 because little performance enhancement data exist based on this ratio. Recreationally active male volunteers (21 years, 184 cm, 81.5 kg) were randomly assigned to a training (interval training [IT] n = 10) or control group (n = 11). Baseline assessments were repeated after the last training session. Each participant underwent basic anthropometric assessment and performed a VO2max test on an electronically braked cycle ergometer and a 30-second Wingate test. Venous samples were acquired at the antecubital vein and subsequently processed for lactate (LA); samples were obtained at rest, and 5 and 15-minute post-Wingate test. The interval training used a cycling power output equivalent to 80% of VO2max (80% p VO2max) applied for 6 90-second bouts (each followed by 180-second rest) per session, 3 sessions per week, for 6 weeks. The control group maintained their normal routine for the 6-week period. Group × time repeated-measures analyses of variance revealed that IT improved VO2max (5.5 ml · kg(-1) · min), anaerobic threshold (3.8 ml · kg(-1) · min), work output (12.5 J · kg(-1)), glycolytic work (11.5 J · kg(-1)), mean power (0.3 W · kg), peak power (0.4 W · kg(-1)), and max power (0.4 W · kg(-1)); p < 0.05. Posttesting LA was lower on average for IT at the 5-minute mark but significantly so at the 15-minute mark. Twenty-seven minutes of cycling at 80% p VO2max applied with a work-to-rest ratio of 1:2 and spread over 3 sessions per week for 6 weeks provided sufficient stimulus to significantly improve markers of anaerobic and aerobic performance in recreationally active college-aged men. Inclusion of such a protocol into a training program may rapidly restore or improve a client's or athlete's maximal functional capacity.

Prolonged Sojourn at Very High Altitude Decreases Sea-Level Anaerobic Performance, Anaerobic Threshold, and Fat Mass.

Background: The influence of high altitude on an organism's physiology depends on the length and the level of hypoxic exposure it experiences. This study aimed to determine the effect of a prolonged sojourn at very high altitudes (above 3,500m) on subsequent sea-level physical performance, body weight, body composition, and hematological parameters. Materials and Methods: Ten alpinists, nine males and one female, with a mean age of 27±4years, participated in the study. All had been on mountaineering expeditions to 7,000m peaks, where they spent 30±1days above 3,500m with their average sojourn at 4,900±60m. Their aerobic and anaerobic performance, body weight, body composition, and hematological parameters were examined at an altitude of 100m within 7days before the expeditions and 7days after they descended below 3,500m. Results: We found a significant (p<0.01) decrease in maximal anaerobic power (MAPWAnT) from 9.9±1.3 to 9.2±1.3W·kg-1, total anaerobic work from 248.1±23.8 to 228.1±20.1J·kg-1, anaerobic threshold from 39.3±8.0 to 27.8±5.6 mlO2·kg-1·min-1, body fat mass from 14.0±3.1 to 11.5±3.3%, and a significant increase (p<0.05) in maximal tidal volume from 3.2 [3.0-3.2] to 3.5 [3.3-3.9] L after their sojourn at very high attitude. We found no significant changes in maximal aerobic power, maximal oxygen uptake, body weight, fat-free mass, total body water, hemoglobin, and hematocrit. Conclusion: A month-long exposure to very high altitude led to impaired sea-level anaerobic performance and anaerobic threshold, increased maximal tidal volume, and depleted body fat mass, but had no effect on maximal aerobic power, maximal oxygen uptake, or hemoglobin and hematocrit levels.

Effects of Composite Coatings Functionalized with Material Additives Applied on Textile Materials for Cut Resistant Protective Gloves.

The objective of the present work was to evaluate the effects of different types of particles added to a polymer paste applied onto a textile carrier on the cut resistance of the resulting material. Knitted aramid textile samples were coated in laboratory conditions using a polymer paste that was functionalized with 12 types of reinforcing particles of different chemical compositions and size fractions. Cut resistance was tested in accordance with the standard EN ISO 13997:1999 and the results were subjected to statistical analysis. The effects of additive particles on the microstructure of the polymeric layer were assessed by means of scanning electron microscopy. The type and size of the particles affected the cut resistance of the functionalized knitted fabric. They were also found to change the morphology of the porous structure. Composite coatings containing the smallest additive particles exhibited the best cut resistance properties.

Effect of Acute Normobaric Hypoxia Exposure on Executive Functions among Young Physically Active Males.

BACKGROUND: On the one hand, hypoxic exposure may result in progressive brain metabolism disturbance, causing subsequent cognitive impairments. On the other hand, it might also enhance neurogenesis and brain vascularization as well as accelerate cerebral blood flow, leading to cognitive function improvement. The aim of this study was to investigate whether progressive stages of normobaric hypoxia (NH) (FIO2 = 13%, FIO2 = 12%, and FIO2 = 11%) differentially affect post-exposure cognitive performance. METHODS: Fifteen physically active men (age = 23.1 ± 2.1) participated in the study. The Stroop test (ST) was applied to assess cognitive function. To generate NH conditions, a hypoxic normobaric air generator was used. RESULTS: We observed an executive function impairment ("naming" interference p < 0.05) after NH exposure (FIO2 = 13%). After exposure at FIO2 = 12% and FIO2 = 11%, no changes were observed in the Stroop test. Also, changes in SpO2 during subsequent NH exposure were observed. CONCLUSIONS: The current investigation shows that executive functions deteriorate after acute NH exposure and this post-exposure deterioration is not proportional to the normobaric hypoxia stages among young physically active males.

The Specific Judo Training Program Combined With the Whole Body Cryostimulation Induced an Increase of Serum Concentrations of Growth Factors and Changes in Amino Acid Profile in Professional Judokas.

This study aimed to evaluate the effect of a specific training program, supported by 10 sessions of whole body cryostimulation, on growth factors concentrations, amino acids profile and motor abilities in professional judokas. Ultimately, twelve athletes took part in the study. They were randomly assigned to the cryostimulation group (CRY, n = 6) or the control group (CON, n = 6). During 2 weeks of the judo training program, the CRY group performed 10 cryo-sessions (3-min, at a temperature of -110°C) and the CON group rested passively. Anthropometric measurements, a strength test, the Special Judo Efficiency Test (SJET) were assessed 2 days before and after the judo training program. Blood samples were collected at rest, 1 h after the first and the second SJET and 1 h after the first and the last cryo-session to establish growth factors and amino acid concentrations. Lactate level was measured before, immediately after and 1 h after the first and the second SJET. The applied intervention resulted in a significant increase of resting concentrations of brain-derived neurotrophic factor (from 10.23 ± 1.61 to 15.13 ± 2.93 ng⋅ml-1; p = 0.01) and insulin-like growth factor 1 (IGF-1; from 174.29 ± 49.34 to 300.50 ± 43.80 pg⋅ml-1; p = 0.00) in the CRY group. A different response was registered 1 h directly post SJET in the CRY group (a significant increase of IGF-1, interleukin 15 and irisin: p = 0.01; p = 0.00; p = 0.03). Additionally, the significant drop of proline and leucine concentrations in the CRY group was obtained. Athletes' performance remained unchanged in both groups. However, subjects perceived positive changes induced by the intervention - not directly after cryostimulation but in response to the specific training workload. The increase of growth factors concentrations and the improvement of amino acid profile (proline and leucine) contributed to maintaining a high level of muscle function.

Significant Predictors of Sports Performance in Elite Men Judo Athletes Based on Multidimensional Regression Models.

BACKGROUND: This research aimed to identify the most significant predictors of sports level using regression modeling. METHODS: This study examined 16 judokas (aged 23 (±2.5)) from four weight categories, with four athletes in each category (66 kg, 73 kg, 81 kg and 90 kg). Each athlete was a member of the Polish National Team, an international master class (IM) or national master class (M). The tests were carried out twice (every two weeks) during the pre-competitive season in the morning, after a 10-min warm-up. The tests were performed according to the following protocol: Explosive Strength Lower Limbs (ExSLL) [W], Strength Endurance Lower Limbs (SELL) [%], Explosive Strength Upper Limbs (ExSUL) [W], Strength Endurance Upper Limbs (SEUL) [%]. The relationships between the dependent variable (ranking score) and the other analyzed variables (predictors) were estimated using the one-factor ridge regression analysis. RESULTS: There were significant intergroup and intragroup differences in the results of explosive strength and strength endurance of the lower and upper limbs. The best predictors were identified using regression modeling: ExSLL, SELL, and SEUL. CONCLUSIONS: Increasing the value of these predictors by a unit should significantly affect the scores in the ranking table. Correlation analysis showed that all variables that are strongly correlated with the Polish Judo Association (PJA) ranking table scores may have an effect on the sports performance.

The Effect of Vitamin D3 Supplementation on Physical Capacity among Active College-Aged Males.

Vitamin D3 supplementation can affect strength and power; however, the effect on both aerobic and anaerobic performance remains unclear. Here, we investigate the effects of eight weeks of a high dose of vitamin D3 supplementation and its impact on circulating 25-hydroxyvitamin D (25-OH-D3) concentrations and selected indicators of physical capacity. Subjects (n = 28, age 21.1 ± 1.6) were divided into two groups: supplemented (SUP), which was given 6000 IU of vitamin D3 daily for eight weeks; and placebo group (PLA). Serum 25-OH-D3 concentrations were determined in pre- and post-intervention. Aerobic (VO2max test) and anaerobic (Wingate Anaerobic Test) capacity were determined before and after the supplementation. The mean baseline concentration of 25-OH-D3 was recognized as deficient (20 ng/mL) and significantly increased over time in the supplemented group (p < 0.01, η2 = 0.86), whilst it remained unchanged in the placebo group. Moreover, the supplementation caused a significant improvement in maximal aerobic (p < 0.05, η2 = 0.27) and anaerobic power (p < 0.01, η2 = 0.51) whereas no changes were observed in PLA group. The VO2max differences were also significant in the supplemented group (p < 0.05). In summary, the changes in aerobic and anaerobic capacity observed in this study were associated with a serum concentration of 25-OH-D3. Our data imply that vitamin D3 supplementation with a dose of 6000 IU daily for eight weeks is sufficient to improve physical capacity and vitamin D3 status.