Global cerebral ischemia in adult female rats interrupts estrous cyclicity and induces lasting changes in hypothalamic-pituitary-gonadal axis signaling peptides.

Persistent post-ischemic alterations to the hypothalamic-pituitary-adrenal (HPA) axis occur following global cerebral ischemia (GCI) in rodents. However, similar effects on hypothalamic-pituitary-gonadal (HPG) axis activation remain to be determined. Therefore, this study evaluated the effects of GCI in adult female rats (via four-vessel occlusion) on the regularity of the estrous cycle for 24-days post ischemia. A second objective aimed to assess persistent alterations of HPG axis activation through determination of the expression of estrogen receptor alpha (ERα), kisspeptin (Kiss1), and gonadotropin-inhibitory hormone (GnIH/RFamide-related peptide; RFRP3) in the medial preoptic area (POA), arcuate nucleus (ARC), dorsomedial nucleus (DMH) of the hypothalamus, and CA1 of the hippocampus 25 days post ischemia. Expression of glucocorticoid receptors (GR) in the paraventricular nucleus of the hypothalamus (PVN) and CA1 served as a proxy of altered HPA axis activation. Our findings demonstrated interruption of the estrous cycle in 87.5 % of ischemic rats, marked by persistent diestrus, lasting on average 11.86 days. Moreover, compared to sham-operated controls, ischemic female rats showed reduced Kiss1 expression in the hypothalamic ARC and POA, concomitant with elevated ERα in the ARC and increased GnIH in the DMH and CA1. Reduced GR expression in the CA1 was associated with increased GR-immunoreactivity in the PVN, indicative of lasting dysregulation of HPA axis activation. Together, these findings demonstrate GCI disruption of female rats' estrous cycle over multiple days, with a lasting impact on HPG axis regulators within the reproductive axis.

Understanding the Super-Theoretical Capacity Behavior of VO2 in Aqueous Zn Batteries.

VO2 material, as a promising intercalation host, is widely investigated not only in aqueous lithium-ion batteries, but also in aqueous zinc-ion batteries (AZIBs) owing to its stable tunnel-like framework and multivalence of vanadium. Different from lithium-ion storage, VO2 can provide higher capacity when storing zinc ions, even exceeding its theoretical capacity (323 mAh g-1 ), but the specific reason for this unconventional performance in AZIBs is still unclear. The present study proposes a catalytic oxygen evolution reaction (OER) coupled with an interface oxidation mechanism of VO2 during the initial charging to a high voltage. This coupling induces a phase transformation of VO2 into a high oxidation state of V5 O12 ∙6H2 O, enabling a nearly two-electron reaction and providing additional zinc storage sites to achieve super-theoretical capacity. Furthermore, it is demonstrated that these vanadium oxide cathodes (V2 O3 , VO2 , and V2 O5 ) will all undergo phase change after the first charge or short cycle. Notably, water molecules participate in the final formation of layered vanadium-based hydrate, highlighting their crucial role as "pillars" for stabilizing the structure. This work significantly enhances the understanding of vanadium-based oxide cathodes.

Pilates-mat training and detraining: Effects on body composition and physical fitness in pilates-trained women.

INTRODUCTION: Pilates-mat is an effective training method to enhance several physiological and fitness parameters, although the effects of pilates-mat detraining on body composition and physical fitness remains largely unknown. The purpose of the study was to investigate the effect of pilates-mat training and detraining on body composition and physical fitness in pilates-trained females. METHODS: Twenty females (age: 45.1 ± 8.7 years) followed an 8-week pilates-mat training program followed by a 3-week detraining period. Measurements performed at the beginning of the training intervention, at the end of the 8-week training program and at the end of the 3-week detraining period and included: anthropometric characteristics, body composition analysis, thigh, hip and waist circumferences, blood pressure, heart rate at rest (HRr), maximum handgrip strength, abdominal curls, lower body flexibility and aerobic capacity. RESULTS: Pilates-mat training significantly decreased body fat percentage (BF%), visceral fat and HRr (p < 0.05) but these variables returned to baseline after detraining. Trunk fat, thigh and waist circumferences decreased significantly after training and remained significantly low following detraining (p < 0.05). Abdominal curls, lower body flexibility and aerobic capacity increased significantly following pilates-mat training and remained unchanged after detraining (p < 0.05). CONCLUSIONS: These results suggest that 8 weeks of pilates-mat training enhanced body composition and physical fitness and these physiological and physical fitness benefits were remained unaltered during the 3-week of pilates-mat detraining period. However, BF% and visceral fat returned to baseline levels following the detraining period suggesting that for maintaining the reduction in BF% and visceral fat a long-period of pilates-mat detraining should be avoided.

Effects of Photobiomodulation Therapy on Performance in Successive Time-to-Exhaustion Cycling Tests: A Randomized Double-Blinded Placebo-Controlled Trial.

The goal of this study was to investigate the effects of photobiomodulation therapy (PBMT) on performance, oxygen uptake (VO2) kinetics, and lower limb muscle oxygenation during three successive time-to-exhaustions (TTEs) in cyclists. This was a double-blind, randomized, crossover, placebo-controlled trial study. Sixteen cyclists (~23 years) with a cycling training volume of ~460 km/week volunteered for this study. In the first session, cyclists performed a maximal incremental test to determine maximal oxygen uptake and maximal power output (POMAX). In the following sessions, cyclists performed three consecutive TTEs at POMAX. Before each test, PBMT (135 J/thigh) or a placebo (PLA) was applied to both thighs. VO2 amplitude, O2 deficit, time delay, oxyhemoglobin (O2Hb), deoxyhemoglobin (HHb), and total hemoglobin (tHb) were measured during tests on the right vastus lateralis. The PBMT applied before three successive TTE increased performance of the first and second TTE (~10-12%) tests, speed of VO2 and HHb kinetics during the first test, and increased peripheral muscle oxygenation (increase in HHb and tHb) in the first and second exhaustion tests. However, the PBMT effects were attenuated in the third TTE, as performance and all the other outcomes were similar to the ones from the PLA intervention. In summary, PBMT application increased the first and second successive TTEs, speed of VO2, and muscle oxygenation.

Yoga as Adjunct Therapy for Chronic Heart Failure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Background Chronic heart failure (CHF) is a prevalent cardiovascular condition that can significantly impact the quality of life and increase mortality risk. Yoga is a mind-body therapy that has been studied as a potential complementary treatment for CHF. However, the effectiveness of yoga in improving outcomes in patients with CHF remains uncertain. Methods We conducted a systematic review of randomized controlled trials (RCTs) evaluating the effects of yoga on outcomes in patients with CHF. We searched the PubMed, Embase, Scopus, Cochrane Library, and IndMED databases from inception to March 2023. The outcomes of interest were left ventricular ejection fraction (LVEF), cardiac biomarkers, exercise capacity, quality of life, and cardiac function. Results We identified 11 RCTs that met our inclusion criteria, involving a total of 552 participants. The meta-analysis showed that yoga was associated with significant improvements in peak VO 2 (mean difference [MD]= 3.29; 95% Confidence Interval [CI]: 1.64 to 4.94; I 2 = 0%), exercise capacity (MD=101.54; 95% CI: 6.24 to 196.83; I 2 = 96%), quality of life (MD = -19.99; 95% CI: -25.76 to -14.22; I 2 = 43%), NT-proBNP (MD = -288.78; 95% CI: -492.20 to -85.37; I 2 = 94%), and 6-minute walk test (MD = 101.54; 95% CI: 6.24-196.83; I 2 = 96%), but not in the left ventricular ejection fraction (MD = 4.28; 95% CI: -1.14 to 9.70; I 2 = 93%). Subgroup analysis suggested that the effect of yoga on the quality of life is more pronounced in patients with the "New York Heart Association" (NYHA) class I and II CHF patients and in those who practiced yoga for longer durations. No serious adverse events related to yoga were reported. Most of the included studies were of "low" quality. Conclusion Current evidence suggests that yoga may be an effective complementary and integrative therapy for improving peak VO 2 exercise capacity, NT-proBNP, and quality of life in patients with CHF. However, the low-quality evidence does not render us to conclude anything beyond doubt or draw any firm clinical recommendation. Future high-quality studies are needed to explore the optimal duration and frequency of yoga practice and its effects on long-term outcomes in this population.

Effects of aerobic, resistance, and combined training on thyroid function and quality of life in hypothyroidism. A randomized controlled trial.

PURPOSE: This study aimed to compare the effects of aerobic, resistance, and combined exercises on thyroid function, lipid profile, exercise capacity, and quality of life (QoL) in hypothyroid women. METHODS: Sixty women aged 35 to 45 with clinical hypothyroidism were randomized to four equal groups: aerobic training (AT), resistance training (RT), combined AT/RT, and control groups. All exercises were performed at low to moderate intensity, three days per week, and for 12 weeks. Patients in all groups were on levothyroxine therapy. Outcome measures were free thyroxin (T4), thyroid stimulating hormone (TSH), lipid profile, estimated maximal oxygen consumption (VO2 max) and QoL assessed by the 12-item Short Form (SF-12) Health Survey. RESULTS: All exercise groups showed significant improvements in all outcome measures compared to the baseline and the controls (p < 0.05). The combined AT/RT group showed more significant improvements in TSH and the mental component summary score of the SF-12 compared to the AT and RT groups (p < 0.05). The AT group showed the most significant improvement in estimated VO2 max, followed by the combined AT/RT and then the RT group. Non-significant differences were found between exercise groups in T4, blood lipids, and the physical component summary score of the SF-12 (p > 0.05). CONCLUSION: In women with hypothyroidism on levothyroxine treatment, all AT, RT, and combined AT/RT could equally improve T4 levels, lipid profile, and physical health-related QoL. However, the combined AT/RT could induce the greatest improvements in TSH and mental health-related QoL, while the AT could have the greatest impact on exercise capacity in these patients. TRIAL REGISTRATION: Pan African Clinical Trial Registry (PACTR), retrospective, PACTR202305810673587.

Quantitative Evidence of the effect of Baduanjin exercise on quality of life and cardiac function in adults with chronic heart failure.

BACKGROUND: This study aimed to assess the effects of Baduanjin exercise on the quality of life (QoL), cardiac function, and maximal oxygen consumption (VO2max) in patients with chronic heart failure (CHF). METHODS: A systematic search of relevant literature published from inception until February 2023 was performed in the Scopus, PubMed, MEDLINE, CINAHL, Cochrane Library, SPORTDiscus, and China National Knowledge Infrastructure databases. We included randomized controlled trials (RCTs) that examined the effects of Baduanjin exercise on QoL (Minnesota Living with Heart Failure Questionnaire [MLHFQ]), cardiac function (N-terminal B-type natriuretic peptide [NT-Pro BNP] and left ventricular ejection fraction [LVEF]), and VO2max in patients with CHF. RESULTS: Fifteen studies (1180 participants) were included in this analysis. The synthesized results suggested that Baduanjin exercise contributed to significant improvements in the MLHFQ scores (standard mean difference [SMD] = 1.10, 95% confidence interval [CI]: 0.81 to 1.39, p < 0.001), NT-Pro BNP levels (SMD = 0.62, 95% CI: 0.31 to 0.93, p < 0.01), LVEF (SMD = 0.53, 95% CI: 0.18 to 0.88, p < 0.01), and VO2max (SMD = 0.92, 95% CI: 0.24 to 1.60, p < 0.001) compared with the results of the control groups. Subgroup analyses revealed that engaging in Baduanjin exercise 5-7 times per week was more effective in improving the MLHFQ score compared with 3-4 times per week (p = 0.04). CONCLUSION: Evidence from the meta-analysis support the beneficial effects of Baduanjin exercise on the QoL, cardiac function, and VO2max in patients with CHFin China. For optimal QoL improvements, it is recommended to engage in Baduanjin exercise 5-7 times per week for 30-60 min, over a duration of at least 8 weeks. In terms of NT-Pro BNP, Baduanjin exercise sessions of 30-60 min, 2-7 times per week, for a minimum of 8 weeks are recommended.

Effects of high-intensity interval training on aerobic capacity and sports-specific skills in basketball players.

INTRODUCTION: High intensity interval training (HIIT) are widely used to improve the cardiac performance in Basketball players. The current study aims to evaluate the effectiveness of High-Intensity Interval Training on the Aerobic Capacity and sports-specific skills in basketball players. METHODS: 40 male basketball players in the age group 18-25 years were recruited after necessary ethical clearance. Athletes were categorized into two groups of 20 people each: Group 1 control group (age: 21.9 ± 2.4 years, height: 184.6 ± 12.1 cm BMI: 23 ± 3 kg/m2) and Group 2 study group with HIIT (age: 21.4 ± 2.6 years, height: 177.4 ± 6.0 cm BMI: 22.1 ± 2.3 kg/m2). The study group players underwent 5 weeks (10 sessions) of HIIT training. Pre and post intervention evaluation of the Aerobic Capacity (VO2 max) and sports-specific skills were quantified for both the groups. Statistical analysis was performed using one tailed t-test with p < 0.05 for significance. Cohen's D method was used to calculate the effect size and minimum important difference. RESULT: There was a significant increase (p < 0.05) in VO2 max (pre:52.8 ± 2.3 ml/min/kg to post: 54.5 ± 2.4 ml/min/kg) in Group 2 whereas in Group 1 the change was not significant (pre:51.1 ± 2.6 ml/min/kg to post: 51.4 ± 2.9 ml/min/kg). Similarly, there was an increase in agility for Group 2 (pre:11.0 ± 1.0 s to post: 10.1 ± 1.0 s) compared to Group 1. In sports specific skills: Control Dribble, passing skills, Lower body power and shooting skills there was a significant increase in post HIIT training for Group 2, whereas in Group 1 there was no significant difference. DISCUSSION: The HIIT training improved the aerobic capacity (VO2 max) and sports-specific skills in basketball players. CONCLUSION: A 5-week HIIT training improved the aerobic capacity and sports specific skills and may be included as a part of training regime to improve the athletic performance in basketball players.

Key ingredients in Verbena officinalis and determination of their anti-atherosclerotic effect using a computer-aided drug design approach.

Lipid metabolism disorders may considerably contribute to the formation and development of atherosclerosis (AS). Traditional Chinese medicine has received considerable attention in recent years owing to its ability to treat lipid metabolism disorders using multiple components and targets. Verbena officinalis (VO), a Chinese herbal medicine, exhibits anti-inflammatory, analgesic, immunomodulatory, and neuroprotective effects. Evidence suggests that VO regulates lipid metabolism; however, its role in AS remains unclear. In the present study, an integrated network pharmacology approach, molecular docking, and molecular dynamics simulation (MDS) were applied to examine the mechanism of VO against AS. Analysis revealed 209 potential targets for the 11 main ingredients in VO. Further, 2698 mechanistic targets for AS were identified, including 147 intersection targets between VO and AS. Quercetin, luteolin, and kaempferol were considered key ingredients for the treatment of AS based on a potential ingredient target-AS target network. GO analysis revealed that biological processes were primarily associated with responses to xenobiotic stimuli, cellular responses to lipids, and responses to hormones. Cell components were predominantly focused on the membrane microdomain, membrane raft, and caveola nucleus. Molecular functions were mainly focused on DNA-binding transcription factor binding, RNA polymerase II-specific DNA-binding transcription factor binding, and transcription factor binding. KEGG pathway enrichment analysis identified pathways in cancer, fluid shear stress, and atherosclerosis, with lipid and atherosclerosis being the most significantly enriched pathways. Molecular docking revealed that three key ingredients in VO (i.e., quercetin, luteolin, and kaempferol) strongly interacted with three potential targets (i.e., AKT1, IL-6, and TNF-α). Further, MDS revealed that quercetin had a stronger binding affinity for AKT1. These findings suggest that VO has beneficial effects on AS via these potential targets that are closely related to the lipid and atherosclerosis pathways. Our study utilized a new computer-aided drug design to identify key ingredients, potential targets, various biological processes, and multiple pathways associated with the clinical roles of VO in AS, which provides a comprehensive and systemic pharmacological explanation for the anti-atherosclerotic activity of VO.

Creatine supplementation and VO2max: a systematic review and meta-analysis.

Although creatine supplementation is well-known to increase exercise performance in acute high-intensity exercises, its role in aerobic performance based on VO2max is more controversial. Thus, we performed a systematic review and meta-analysis on the effects of creatine supplementation on VO2max. PubMed, Cochrane, Embase, and ScienceDirect were searched for randomized controlled trials (RCTs) reporting VO2max in creatine supplementation and placebo groups before and after supplementation. We computed a random-effects meta-analysis on VO2max at baseline, within groups following supplementation, on changes on VO2max between groups, and after supplementation between groups. Sensitivity analyses and meta-regression were conducted. We included 19 RCTs for a total of 424 individuals (mean age 30 years old, 82% men). VO2max did not differ at baseline between groups (creatine and placebo). Participants in both groups were engaged in exercise interventions in most studies (80%). Using changes in VO2max, VO2max increased in both groups but increased less after creatine supplementation than placebo (effect size [ES] = -0.32, 95%CI = -0.51 to -0.12, p = 0.002). Comparisons after creatine supplementation confirmed a lower VO2max in the creatine group compared to the placebo group (ES= -0.20, 95%CI = -0.39 to -0.001, p = 0.049). Meta-analysis after exclusion from meta-funnel resulted in similar outcomes in a subgroup of young and healthy participants. Meta-regressions on characteristics of supplementation, physical training, or sociodemographic were not statistically significant. Creatine supplementation has a negative effect on VO2max, regardless of the characteristics of training, supplementation, or population characteristics.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.2008864 .

Long-term iron supplementation combined with vitamin B6 enhances maximal oxygen uptake and promotes skeletal muscle-specific mitochondrial biogenesis in rats.

Introduction: Iron is an essential micronutrient that plays a crucial role in various biological processes. Previous studies have shown that iron supplementation is related to exercise performance and endurance capacity improvements. However, the underlying mechanisms responsible for these effects are not well understood. Recent studies have suggested the beneficial impact of iron supplementation on mitochondrial function and its ability to rescue mitochondrial function under adverse stress in vitro and rodents. Based on current knowledge, our study aimed to investigate whether the changes in exercise performance resulting from iron supplementation are associated with its effect on mitochondrial function. Methods: In this study, we orally administered an iron-based supplement to rats for 30 consecutive days at a dosage of 0.66 mg iron/kg body weight and vitamin B6 at a dosage of 0.46 mg/kg. Results: Our findings reveal that long-term iron supplementation, in combination with vitamin B6, led to less body weight gained and increased VO2 max in rats. Besides, the treatment substantially increased Complex I- and Complex II-driven ATP production in intact mitochondria isolated from gastrocnemius and cerebellum. However, the treatment did not change basal and succinate-induced ROS production in mitochondria from the cerebellum and skeletal muscle. Furthermore, the iron intervention significantly upregulated several skeletal muscle mitochondrial biogenesis and metabolism-related biomarkers, including PGC-1α, SIRT1, NRF-2, SDHA, HSL, MTOR, and LON-P. However, it did not affect the muscular protein expression of SIRT3, FNDC5, LDH, FIS1, MFN1, eNOS, and nNOS. Interestingly, the iron intervention did not exert similar effects on the hippocampus of rats. Discussion: In conclusion, our study demonstrates that long-term iron supplementation, in combination with vitamin B6, increases VO2 max, possibly through its positive role in regulating skeletal muscle-specific mitochondrial biogenesis and energy production in rats.

Inspiratory Muscle Training Improves Aerobic Fitness in Active Children.

Research on the effect of inspiratory muscle training (IMT) on exercise performance is inconsistent. IMT has not been applied to fit child athletes, who are more likely to develop inspiratory muscle fatigue, and, consequently, to benefit from IMT. Methods: Thirty children (mean age: 10.7 ± 1.2 years) were recruited and randomly assigned to a high-intensity (HG), a low-intensity (LG), or a control group (CG). For both training groups, a double-blind procedure was applied. In the HG, 80% of maximal inspiratory pressure (MIP) was used as the level of training intensity. The LG used 30% MIP. Training groups were trained at 6 breaths a set, 4 sets a day, totaling 24 breaths a day for 6 weeks. Exercise capacity outcomes include maximal and submaximal aerobic capacity, as measured as VO2max and distance from six-minute walk test (6MWD). Results show improvement in MIP, VO2max, and 6MWD only in the HG. MIP in the HG significantly increases from 108.7 (100.8-143.3) to 144.4 (130.0-175.6) cmH2O. VO2max in the HG increases from 43.0 (40.5-45) to 53.0 (46-63) mL·kg-1·min-1. The 6MWD increases from 792.0 (737.5-818.0) to 862.0 (798.5-953.5) m. Data are presented as median (interquartile range). No difference is found in the LG or CG. Conclusion: high-intensity IMT increases MIP, maximal, and submaximal exercise capacity in the HG, but no difference is found in the LG or CG. Therefore, high-intensity type of IMT improves aerobic fitness in fit children by appropriately applying inspiratory muscle strength training.

No Effect of Calanus Oil on Maximal Oxygen Uptake in Healthy Participants: A Randomized Controlled Study.

We aimed to investigate the long-term effect of daily Calanus oil supplementation on maximal oxygen uptake (VO2max) in healthy 30- to 50-year-old participants. The study was motivated by preclinical studies reporting increased VO2max and metabolic health with omega-3 rich Calanus oil. In a double-blinded study, 71 participants were randomized to receive 2 g/day of Calanus or placebo supplementation for a total of 6 months. The participants underwent exercise testing and clinical investigations at baseline, 3 months, and 6 months. Main study endpoint was change in VO2max from baseline to 6 months. Fifty-eight participants completed the 6-month test and were included in the final data analysis (age: Calanus, 39.7 [38.0, 41.4] and placebo, 38.8 [36.8, 40.9] years; body mass index: Calanus, 24.8 [24.0, 25.6] and placebo, 24.8 [23.7, 25.8] kg/m2; and VO2max: Calanus, 50.4 [47.1, 53.8] and placebo, 50.2 [47.2, 53.1] ml·kg-1·min-1). There were no between-group differences at baseline, nor were there any between-group differences in absolute (Calanus, 3.74 [3.44, 4.04] and placebo, 3.79 [3.44, 4.14] L/min) or relative VO2max (Calanus, 49.7 [46.2, 53.2] and placebo, 49.5 [46.0, 53.1] ml·kg-1·min-1) at 6 months (mean [95% confidence interval]). There were no between-groups change in clinical measures from baseline to 3 and 6 months. In conclusion, VO2max was unaffected by 6 months of daily Calanus oil supplementation in healthy, physically fit, normal to overweight men and women between 30 and 50 years old.

Green tea catechin EGCG could prevent obesity-related precocious puberty through NKB/NK3R signaling pathway.

This study aimed to explore the potential regulatory pathways of (-)-epigallocatechin-3-gallate (EGCG) in preventing obesity-related precocious puberty. A retrospective analysis on the impact of EGCG on puberty onset in obese girls was conducted on plasma samples collected from a human randomized controlled trial. In the trial, participants consumed EGCG capsules for 12 weeks. In the animal experiment, rats were divided into four groups: normal diet control (NC) group, high-fat diet (HFD) group, NC+EGCG group, and HFD+EGCG group. Blood samples were collected on postnatal days 27, 33, and 36 to detect sexual development indicators. The hypothalamic expressions of kisspeptin/Kiss1R and neurokinin B (NKB)/NK3R signaling were measured by RT-qPCR and Western blot assay. The ovary NKB protein expression was assessed by immunohistochemical assays. Serum NKB level in the EGCG group was lower than the placebo group by 0.599 ng/mL [ß=-0.599, 95% CI: (-1.005, -0.193)], at the end of intervention and after adjusting for confounders (clinical study). In the animal experiment, EGCG intervention could significantly delay the vaginal opening (VO) time of rats fed with HFD. On day 33, EGCG intervention could significantly reduce serum NKB, luteinizing hormone (LH) levels, ovarian NKB protein expression, and endometrial thickness of HFD-fed rats, while EGCG intervention could remarkably increase mRNA and protein expression of NKB/NK3R. EGCG could prevent obesity-related precocious puberty through NKB/NK3R signaling pathway, which may provide a novel insight into the role of EGCG in preventing precocious puberty in obese girls.

Correlation between the Positive Effect of Vitamin D Supplementation and Physical Performance in Young Male Soccer Players.

The aim of this study was to determine whether supplementation with vitamin D during eight weeks of high-intensity training influences muscle power and aerobic performance in young soccer players. A total of 25 athletes were divided into two groups: the supplemented group (GS; n = 12; vitamin D 20,000 IU, twice a week) and the non-supplemented group (GN; n = 13). A set of measurements, including sprint tests, explosive power test, maximal oxygen uptake (VO2max), and serum 25(OH)D concentration, were obtained before (T1) and after (T2) the intervention. A significant group x time interaction was found in the 25(OH)D serum levels (p = 0.002; ES = 0.36, large). A significant improvement in VO2max was found in the TG (p = 0.0004) and the GS (p = 0.031). Moreover, a positive correlation between 25(OH)D and VO2max (R = 0.4192, p = 0.0024) was calculated. The explosive power tests revealed insignificant time interactions in the average 10-jump height and average 10-jump power (p = 0.07, ES = 0.13; p = 0.10, ES = 0.11, respectively). A statistically insignificant trend was observed only in the group-by-time interaction for the sprint of 10 m (p = 0.05; ES = 0.15, large). The present study provides evidence that vitamin D supplementation has a positive but trivial impact on the explosive power and locomotor skills of young soccer players, but could significantly affect their aerobic performance.

Cardiorespiratory and metabolic demand of the 6-minute pegboard and ring test in healthy young adults.

OBJECTIVE: To determine the cardiorespiratory and metabolic demand of the Six-Minute Pegboard and Ring Test (6PBRT) in healthy young adults and its association with maximal arm cycle ergometer test (arm CET). METHODS: Volunteers were randomized to performed the 6PBRT test or arm CET. The second test was performed after 48 h. Oxygen consumption (VO2), heart rate (HR), dyspnea and upper limb fatigue were assessed during the tests. Demographic data, body composition, level of physical activity, arm strength and endurance were also evaluated. RESULTS: During 6PBRT, VO2 values increased from 5.8 to 11.1 mL kg-1.min-1 (p < 0.001). VO2peak, HR Mean and HRmax at 6PBRT were 47.2% and close to 65% respectively of those achieved during the arm CET. There was a positive correlation between the score on 6PBRT and VO2mean and VO2peak achieved at arm CET (r = 0.268; p = 0.003 and r = 0.247; p = 0.046 respectively). No correlation was found between the HRmean, HRpeak, level of physical activity or strength with 6PBRT (p > 0.05). Handgrip endurance had a positive correlation with score on 6PBRT (r = 0.237; p = 0.054). Body Mass Index, body fat and fat mass were negatively correlated with the score on 6PBRT (r = 0.301; p = 0.014, 0.329; p = 0.007 and r = 0.427; p = 0.001). CONCLUSIONS: The 6PBRT test showed a moderate cardiorespiratory and metabolic demand in healthy individuals in comparison of arm CET. BMI, body fat and fat mass correlated with the score on 6PBRT.

The Effects of L-Citrulline on Blood-Lactate Removal Kinetics Following Maximal-Effort Exercise.

The accumulation of lactate in muscle and blood during high-intensity exercise is negatively correlated with the duration exercise can be sustained. Removal of lactate is a key component of acute recovery between consecutive bouts of such exercise. Low-intensity exercise enhances recovery by accelerating lactate turnover in metabolically active tissues, largely mediated by blood flow to these tissues. Therefore, the purpose of this research was to clarify if L-citrulline, a nutritional supplement purported to promote vasodilation via enhanced nitric oxide availability, would augment the removal of blood lactate during active recovery (AR). L-citrulline ingestion will augment the rate of blood lactate concentration decrease during AR, reduce the oxygen-cost of submaximal exercise, and increase time-to-exhaustion and peak oxygen uptake (V̇O2peak) during a test of maximal aerobic power. Healthy university students (five males & five females) participated in this double-blind, randomized, placebo-controlled study. Participants exercised on a cycle ergometer at submaximal steady-state intensities followed by progressively increasing intensity to exhaustion, 10 min of AR, and then supramaximal intensity exercise to exhaustion. Oxygen uptake was measured throughout the trial and blood lactate was sampled repeatedly during AR. The protocol elicited very high peak blood lactate concentrations after exercise (11.3 + 1.3 mmol/L). L-citrulline supplementation did not significantly alter blood lactate kinetics during AR, the oxygen cost of exercise, V̇O2peak, or time-to-exhaustion. Despite a strong theoretical basis by which L-citrulline could augment lactate removal from the blood, L-citrulline supplementation showed no effect as an exercise-recovery supplement.

Effects of chronic betaine supplementation on performance in professional young soccer players during a competitive season: a double blind, randomized, placebo-controlled trial.

OBJECTIVE: Various nutritional strategies are adopted for athletes to maintain and to improve performance during the competition season. Betaine may enhance performance during a competitive season by increasing the testosterone to cortisol ratio and reducing systemic inflammation. The aim of this study was to investigate the effect of betaine supplementation on the bio-motor abilities in young professional soccer players. METHODS: Twenty-nine young professional soccer players (age, 15.5±0.3 years) were matched by position and randomly assigned to one of two groups for 14 weeks: betaine (BG, 2 g/day; n=14) or placebo (PG n=15). Diet was standardized by a nutritionist, and measures of muscular power (countermovement jump: CMJ), change of direction: modified 5-0-5), acceleration (10 m sprint), sprint performance (30 m sprint time: SpT), muscular strength (leg press and bench press one repetition maximum: 1-RM), repeated sprint ability (running-based anaerobic sprint test: RAST), and aerobic capacity (30-15 intermittent fitness test) were assessed in the pre (P1), mid (P2) and post (P3) season over the course of 5 days. All subjects participated in one soccer match and five training sessions per week. RESULTS: Significant (p < 0.05) group x time interactions were found for maximal oxygen uptake (VO2max), anaerobic peak power, and muscular strength favoring BG at P2 and P3 compared to P1. There were meaningful (p < 0.05) group x time interactions for CMJ, SpT, and peak power during the RAST that favored the BG. CONCLUSIONS: 14-week of betaine supplementation increased predicted 1-RM, VO2max, and repeated sprint ability performance in youth professional soccer players. Betaine supplementation seems to be a useful nutritional strategy to improve and to maintain performance during a competitive soccer season.

The effect of food ration bar enriched with ß-alanine, L-arginine, and Nigella sativa on performance and inflammation following intense military training: A double-blind randomized clinical trial.

BACKGROUND: There are growing interests in using dietary supplements to improve athletic performance. This study aimed to evaluate the effect of the food ration bar enriched with ß-alanine, L-arginine, and Nigella sativa on athletic performance and inflammation following intense military training. METHODS: This double-blind, randomized, controlled clinical trial was conducted on 54 new cadets. Eligible participants were randomly assigned in a 1:1 ratio to receive food ration bars enriched with arginine (2 g/day), ß-alanine (2 g/day), and Nigella sativa (2 g/day) or nonenriched food ration bars during a 2-week military training. Aerobic and anaerobic performances were evaluated by the Cooper and RAST tests, respectively. RESULTS: A significant increase in anaerobic powers (min, mean, and max) and a significant reduction in fatigue index were observed in the intervention group as compared to the control group, even after the adjustment for confounding factors. Also, increased levels of hs-CRP and TNF-α following military training were significantly lower in the intervention group as compared to the control group (hs-CRP: 0.55 ± 0.1 versus 2.43 ± 0.1 mg/L; p-value: 0.01; TNF-α: 0.12 ± 0.04 versus 0.62 ± 0.04 pg/ml; p-value: 0.03). No significant changes were observed in VO2 max in both groups. CONCLUSIONS: Our results showed that the combination of ß-alanine, L-arginine, and Nigella sativa can improve anaerobic performance and reduce inflammation following intense physical activities. Further studies with long-term duration are needed to confirm the cumulative/synergic effects of these ingredients in trained and nontrained subjects.

Three weeks of passive and intervallic heat at high temperatures (100±2 °C) in a sauna improve acclimation to external heat (42±2 °C) in untrained males.

Currently, the effect of passive heat acclimation on aerobic performance is still controversial. Therefore, this study aimed to observe the effect of passive and intervallic exposure to high temperatures (100 ± 2 °C) in untrained males. Forty healthy untrained men participated in this investigation. They were randomised into a Control Group (CG; n = 18) and an Experimental Group (EG; n = 22). Both groups performed maximum incremental tests until exhaustion in normothermia (GXT1; 22 ± 2 °C), and 48h afterwards, in hyperthermia (GXT2; 42 ± 2 °C). The EG performed 9 sessions of intervallic exposure to heat (100 ± 2 °C) over 3 weeks. Subsequently, both groups performed two maximal incremental trials in normothermia (GXT3; 22 ± 2 °C) and 48h later, in hyperthermia (GXT4; 42 ± 2 °C). In each test, the maximal ergospirometric parameters and the aerobic (VT1), anaerobic (VT2) and recovery ventilatory thresholds were recorded. The Wilcoxon Test was used for intra-group comparisons and the Mann-Whitney U for inter-group comparisons. There were improvements in absolute VO2max (p = 0.049), W (p = 0.005) and O2pulse (p = 0.006) in hyperthermia. In VT1 there was an increase in W (p = 0.046), in VO2 in absolute (p = 0.025) and relative (p = 0.013) values, O2pulse (p = 0.006) and VE (p = 0.028) in hyperthermia. While W increased in hyperthermia (p = 0.022) at VT2. The results suggest that passive and intervallic acclimation at high temperatures improves performance in hyperthermia. This protocol could be implemented in athletes when they have to compete in hot environments.