Ambient temperature and wet bulb globe temperature outperform heat index in predicting hydration status and heat perception in a semi-arid environment

BACKGROUND

Climate change is increasing temperatures, frequency of heatwaves, and erratic rainfall, which threatens human biology and health, particularly in already extreme environments. Therefore, it is important to understand how environmental heat stress measures are tied to human water needs and thermoregulation under increasingly hot conditions.

AIM

To test how ambient temperature, heat index, and wet bulb globe temperature (WBGT) relate to hydration status and thermal heat perception in a hot, semi-arid environment.

SUBJECTS AND METHODS

Urine samples, perceived heat stress, and anthropometrics were collected among Daasanach semi-nomadic pastoralists (n = 187 children, n = 231 adults) in northern Kenya. Environmental heat stress measures were recorded at sample collection; samples' urine specific gravity (USG) was measured.

RESULTS

Multiple linear and logistic regressions indicate that all environmental heat stress measures were associated with USG, odds of dehydration, and heat perception. Ambient temperature performed marginally better than WBGT, and both performed better than heat index. These associations were stronger among children than adults.

CONCLUSION

In a hot, semi-arid climate, ambient temperature and WBGT accurately predict human water needs and heat stress, with children more vulnerable to dehydration. To mitigate consequences of extreme heat, local bioculturally-appropriate hydration (e.g. tea) and cooling (e.g. shade) strategies should be encouraged.

The impact of intradialytic elastic band exercise on physical and cognitive abilities in patients on maintenance hemodialysis: a randomized controlled trial

Exercise benefits patients on maintenance hemodialysis (MHD) by addressing complications and dysfunctions. Elastic band exercise is cost-effective, but its safety, efficacy, and feasibility during dialysis are not well-established. The aim of this study is to investigate the physical and mental effects of intradialytic elastic band exercise in patients on MHD. Sixty patients on MHD were randomly assigned to the exercise or control group (30 patients/group). The control group received routine hemodialysis care, whereas those in the exercise group performed intradialytic elastic band exercises for 0.5-2 h during hemodialysis three times a week for 12 weeks. Physical function (Short Physical Performance Battery [SPPB]), cognitive function (Montreal Cognitive Assessment [MoCA]), fatigue (14-item Fatigue Scale [FS-14]), sleep quality (Pittsburgh Sleep Quality Index [PSQI]), and anxiety and depression (Hamilton Anxiety Rating Scale [HAMA]/Hamilton Depression Rating Scale [HAMD]) were assessed. The exercise group showed significant improvements in SPPB (p = 0.008) and MoCA (p < 0.001) scores compared to pre-intervention and control groups. FS-14 scores decreased significantly (p = 0.005). PSQI (p < 0.001) and HAMA (p < 0.001) scores improved post-intervention but not versus control. HAMD scores reduced significantly (p < 0.001). Satisfaction and recommendation scores were 9.57 and 9.71. In conclusions, intradialytic elastic band exercise improved physical and cognitive function and alleviated fatigue, sleep issues, depression, and anxiety in patients on MHD. With high compliance, no significant adverse events, and high patient satisfaction, it is recommended as a routine intervention during dialysis.

Caffeine's influence on vertical jump height: a real-life collegiate student-athlete approach

BACKGROUND

Caffeine's ergogenic potential in vertical jumping remains contested, particularly at dosages compliant with collegiate athletic regulations. The NCAA enforces a caffeine urinary threshold equivalent to ~5 mg/kg body mass, yet evidence supporting its efficacy in enhancing explosive performance among trained athletes is inconsistent. This study examined whether acute caffeine ingestion at this threshold improves squat jump (SJ) and countermovement jump (CMJ) performance in NCAA Division II student-athletes, while exploring sex-specific responses and trial-to-trial variability.

METHODS

Forty NCAA Division II athletes (18 females, 22 males; 21.3 ± 2.4 years) participated in a single-blind, randomized, crossover trial. Participants ingested 5 mg/kg caffeine or placebo, followed by SJ and CMJ testing on a force platform 60 minutes post-consumption. Three trials per jump type were retained to preserve intra-individual variance. Linear mixed-effects models (LMMs) assessed fixed effects of condition, sex, and trials, with random intercepts and slopes accounting for individual variability. A priori power analyses guided sample size determination, targeting sensitivity to detect small-to-medium effects (Cohen's f ≥ 0.2).

RESULTS

Caffeine elicited trivial, non-significant differences in SJ (β =  -0.24 cm, p = 0.646) and CMJ (β =  -0.71 cm, p = 0.183) heights compared to placebo. Males outperformed females in both SJ (Δ = 9.50 cm, p < 0.001) and CMJ (Δ = 11.30 cm, p < 0.001), though no condition-by-sex interactions emerged. Trial effects were observed, with SJ improving 2.31 cm (p < 0.001) and CMJ 1.05 cm (p = 0.014) from first to second attempts, suggesting warm-up or neuromuscular potentiation. High intraclass correlation coefficients (ICC = 0.76-0.85) underscored substantial interindividual variability. Models demonstrated robust fit (conditional R2 = 0.86-0.92), with sufficient power to detect medium-to-large effects (f ≥ 0.25).

CONCLUSIONS

A 5 mg/kg caffeine dose, compliant with NCAA thresholds, did not enhance vertical jump performance in habituated collegiate athletes, challenging prior assertions of its universal ergogenicity for ballistic tasks. While sex differences in baseline performance persisted, caffeine did not modulate these disparities, implicating neuromuscular and anthropometric factors as primary determinants. The absence of ergogenic effects aligns with NCAA safety-focused policies but highlights the need for personalized dosing strategies and research into higher doses, genetic variability, and hormonal influences. Future studies should integrate biomechanical metrics and controlled hormonal assessments to elucidate caffeine's nuanced role in anaerobic power sports.

Acute effects of isolated and combined dietary nitrate and caffeine ingestion on ergometer-based 1000 m time trial performance in highly trained kayakers

BACKGROUND

Dietary nitrate (BR) and caffeine (CAF) ingestion have been shown to increase sports performance. However, the isolated and combined effects of BR and CAF ingestion on time trial (TT) performance as well as the accompanying physiological and perceptual responses have never been investigated in highly trained kayak athletes. Therefore, the present study examined the impact of an isolated and combined supplementation with BR (140 ml beetroot concentrate, ~12.5 mmol nitrate) and CAF (3 mg/kg bodyweight) on 1000 m ergometer TT performance as well as the accompanying physiological (i.e. cardiorespiratory function, muscle oxygenation, muscle activity) and perceptual responses (i.e. fatigue, effort, and exercise-induced pain perception) in male highly trained kayakers. It was hypothesized that the isolated ingestion of BR and CAF would both improve ergometer-based 1000 m TT performance and induce supplement-specific physiological and perceptual responses. Considering the primary effects of BR on muscle function and of CAF on the central nervous system, it was further assumed that the combined ingestion will result in an additional performance increase and supplement-specific physiological and perceptual responses.

METHODS

Using a prospective, randomized, controlled, double-blind crossover design, 12 male highly trained kayak athletes from local clubs were investigated. They completed four measurement sessions resulting in four randomized conditions: (i) BR+CAF; (ii) BR+CAF placebo (BR+PLA); (iii) CAF+BR placebo (CAF+PLA); and (iv) BR placebo + CAF placebo (PLA+PLA). An air-braked instrumented kayak-ergometer was used to record 1000 m TT performance, power output, and stroke frequency. Heart rate (HR), oxygen uptake (VO2), maximum VO2 (VO2max), respiratory equivalent of O2 (VE/VO2), and carbon dioxide (VE/VCO2) were measured continuously. Furthermore, oxygenation of the deltoid muscle was measured with near-infrared spectroscopy (mNIRS) and muscle activity of nine unilateral muscles with surface electromyography (i.e. deltoideus, serratus anterior, triceps brachii caput lateralis, trapezius, infraspinatus, latissimus dorsi, obliquus externus, flexor carpi radialis, and vastus lateralis muscle) during the 1000 m TT. After the TT, fatigue, effort, and exercise-induced pain perception were queried. One- and two-way analysis of variance with repeated measures were conducted to determine differences between conditions for the entire 1000 m TT and predefined sections (0-50 m, 50-100 m, 100-150 m, 150-250 m, 250-500 m, 500-750 m, 750-1000 m), respectively (p ≤ 0.05).

RESULTS

The supplements did not have an ergogenic effect on TT performance compared to the PLA+PLA condition, either in isolation or in combination. The same applied to the majority of physiological parameters and the perceptual responses. Nevertheless, VE/VO2 was lower during the sections 150-250 m (-5.00%; p = 0.02) and 250-500 m (-3.49%; p = 0.03) in the BR+PLA condition, whereby VE/VCO2 was higher during the section 150-250 m (4.19%; p = 0.04) in the CAF+PLA compared to the PLA+PLA condition, respectively.

CONCLUSIONS

Data indicate that the isolated and combined ingestion of BR and CAF had no effect on 1000 m TT performance, the majority of physiological responses, and perceptual responses in highly trained kayakers. These findings might be related to the dosage and/or a ceiling effect due to the already efficient vascular, metabolic, and muscle function, including high amounts of endogenous produced nitric oxide, in athletes.

Individual responses to encapsulated caffeine and caffeine chewing gum on strength and power in strength-trained males

BACKGROUND

Liquid-dissolved and encapsulated powder are two popular ways to consume caffeine for performance-enhancing effects. Caffeine in other delivery methods, such as chewing gums, orally dissolvable strips, gels, mouthwashes, energy drinks, and nasal sprays, is believed to be absorbed more quickly into the bloodstream. Inter-individual responses to caffeine's enhancing effects are recognized. The present study examined the inter-individual responses to the acute effects of encapsulated caffeine and caffeinated chewing gum on the lower-body isokinetic and isometric strength and power in strength-trained males.

METHOD

A randomized, cross-over, placebo-controlled study was conducted with 15 strength-trained males (age: 25  ±  4 years, height: 176  ±  7 cm, weight: 75  ±  11 kg, habitual caffeine intake: 66  ±  15 mg·day-1). Participants were randomly assigned to three conditions: i) caffeinated chewing gum (CG), ii) caffeine capsule (CC), and iii) starch capsule as a placebo (PLA). Participants consumed approximately 3 to 4.5 mg·kg-1 of caffeine 60 minutes before testing. The washout period between conditions was one week. Participants performed the Sargent jump test, followed by a 5-minute active recovery (walking). Subsequently, isokinetic strength and power (60°/s and 180°/s) and isometric strength (45° and 60°) parameters were measured for knee extensor and flexor muscles. Data were analyzed using one-way repeated measures ANOVA and Bonferroni post hoc tests, with significance set at p ≤ 0.05. Responders to the caffeine conditions were identified using the smallest worthwhile change (SWC) analysis.

RESULTS

In knee extensors, 1) average peak torque and power at 60°/s were higher in CC (p = 0.045; + 11.2% and p = 0.038; + 14.1%) and CG (p = 0.044; + 7.3% and p = 0.015; + 11.4%) compared to PLA with a co-response rate of 60% and 66%, 2) maximum voluntary isometric contraction at 45° (MVIC-45°) was higher in CC compared to PLA (p = 0.031; + 10.1%), and 3) MVIC-60° was higher in CG compared to PLA (p = 0.037; + 10.1%) with a co-response rate of 60%. In knee flexors, 1) time to peak torque at 60°/s was higher in CG compared to PLA (p = 0.011; + 18.2%) with a co-response rate of 46%, 2) average rate of force development at 60°/s was higher in CC (p = 0.007; + 24.1%) and CG (p = 0.050; + 20.6%) compared to PLA with a co-response rate of 53%, and 3) average power at 180°/s was higher in CC compared to PLA (p = 0.033; + 18%) with a co-response rate of 46%. However, there were no differences between other strength indicators in the knee extensors and flexors between the different conditions. Vertical jump height (VJH) was higher in CC (p = 0.001; + 5.5%) and CG (p = 0.001; + 6.) compared to PLA, with a co-response rate of 53%.

CONCLUSION

Caffeine supplementation in CC and CG forms significantly enhanced lower-body strength, power, and vertical jump height in strength-trained males, with over  ~50% of participants exceeding the SWC thresholds across key performance metrics. CC showed slightly higher responder rates for strength parameters, while CG excelled in time-dependent measures, supporting their use as effective and flexible ergogenic aids.

Impact of carbohydrate timing on glucose metabolism and substrate oxidation following high-intensity evening aerobic exercise in athletes: a randomized controlled study

OBJECTIVE

The study aimed to investigate the impact of nutrient timing in relation to evening exercise. Specifically, it examined the effects of pre- or post-exercise carbohydrate (CHO) ingestion on glucose metabolism, glucose regulation, and overall substrate oxidation in well-trained athletes during and after physical exercise (PE), spanning the nocturnal period and the subsequent morning.

METHODS

Ten male endurance cyclists participated in the study. The initial assessments included body composition measurements and an incremental cycle test to determine maximal oxygen uptake (V ˙ O2 max) and maximum power output (Wmax). Following this, participants underwent a control (rest previous day) oral glucose tolerance test (OGTT) and a familiarization exercise trial that had two objectives: (1) to establish the appropriate amount of CHO to use in the pre- or post-exercise drink during the experimental trials, and (2) to familiarize participants with the equipment and study protocol. In the three days prior to both the control and experimental trials, participants followed a standardized, individualized diet designed to meet their energy needs. During the experimental trials, participants completed two separate evening exercise sessions (50 min@70%Wmax +  ~24 min time-trial (TT)) with either pre- or post-exercise CHO ingestion (253 ± 52 g), matching the CHO oxidized during exercise. The CHO drink and a volume-matched placebo (PLA) drink (containing no energy) were randomly assigned to be consumed two hours before and directly after the experimental exercise sessions. Post-exercise nocturnal interstitial glucose levels (24:00-06:00) were continuously monitored, and a 120-min OGTT was conducted the following morning to assess substrate oxidation rates and glucose control.

RESULTS

Pre-exercise CHO intake significantly lowered capillary glucose levels during steady-state exercise (mean difference 0.41 ± 0.27 mmol/L, p = 0.001) without affecting perceived exertion and TT-performance. No difference was observed in nocturnal glucose regulation (00:00-06:00) regardless of whether CHO was consumed before or after exercise. Post-exercise CHO ingestion reduced glucose tolerance during the OGTT compared to the iso-caloric pre-exercise CHO intake (mean difference 0.76 ± 0.21 mmol/L, p = 0.017). However, a post-exercise CHO intake improved respiratory exchange ratio/metabolic flexibility (MetF) significantly. Enhanced MetF during the first OGTT hour after post-exercise CHO ingestion resulted in 70% and 91% higher CHO oxidation compared to pre-exercise CHO and control, respectively (p ≤ 0.029). Average 120-min OGTT fat oxidation rates were higher with both pre- and post-exercise CHO ingestion compared to control (p ≤ 0.008), with no difference between pre- and post-exercise CHO intake.

CONCLUSION

Morning glucose tolerance was markedly reduced in healthy athletes when CHO was ingested after evening exercise. However, the observed improvements in MetF during the OGTT compared to placebo post-exercise suggest a potential for enhanced athletic performance in subsequent exercise sessions. This opens exciting possibilities for future research to explore whether enhanced MetF induced by CHO-timing can translate to improved athletic performance, offering new avenues for optimizing training and performance.

Impact of the menstrual cycle phases and time of day on markers of stress: salivary α-amylase and secretory immunoglobulin A

Previous reports suggest that the menstrual cycle (MC) phases can impact cortisol concentrations. However, research is needed on whether the MC impacts other markers of stress and immune function. It has also been shown that some biomarkers are impacted by time of day, although differences between morning (AM) and afternoon (PM) biomarkers have not been studied over the course of the MC. This study assessed the effect of MC phases and time of day on salivary stress biomarkers [salivary α-amylase (sAA), secretory immunoglobulin A (SIgA)], progesterone, resting blood pressure and resting heart rate (RHR). A single-group repeated measure design was employed in which seventeen participants (n = 17) monitored their MC for two months while attending eight experimental sessions which included both AM and PM sessions during each predicted 1) menses, 2) follicular, 3) ovulatory and 4) luteal phases. Resting blood pressures, heart rates, body composition parameters (assessed via bioelectrical impedance analysis), sAA and SIgA concentrations were assessed. No time of day x MC phase interactions (p > 0.05) were noted for sAA or SIgA, resting blood pressure, heart rate, or body composition parameters. However, sAA and RHR were significantly higher in the PM, while SIgA was significantly higher in the AM. These data suggest that the MC phases do not impact sAA or SIgA, resting blood pressure, heart rates, or body composition parameters. However, time-of-day impacts RHR and concentrations of sAA and SIgA. These findings provide implications for female participants in research dealing with these biomarkers.

International Society of Sports Nutrition Position Stand: Long-Chain Omega-3 Polyunsaturated Fatty Acids

Position Statement: The International Society of Sports Nutrition (ISSN) presents this position based on a critical examination of the literature surrounding the effects of long-chain omega-3 polyunsaturated fatty acid (ω-3 PUFA) supplementation on exercise performance, recovery, and brain health. This position stand is intended to provide a scientific foundation for athletes, dietitians, trainers, and other practitioners regarding the effects of supplemental ω-3 PUFA in healthy and athletic populations. The following conclusions represent the official position of the ISSN: Athletes may be at a higher risk for ω-3 PUFA insufficiency.Diets rich in ω-3 PUFA, including supplements, are effective strategies for increasing ω-3 PUFA levels.ω-3 PUFA supplementation, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has been shown to enhance endurance capacity and cardiovascular function during aerobic-type exercise.ω-3 PUFA supplementation may not confer a muscle hypertrophic benefit in young adults.ω-3 PUFA supplementation in combination with resistance training may improve strength in a dose- and duration-dependent manner.ω-3 PUFA supplementation may decrease subjective measures of muscle soreness following intense exercise.ω-3 PUFA supplementation can positively affect various immune cell responses in athletic populations.Prophylactic ω-3 PUFA supplementation may offer neuroprotective benefits in athletes exposed to repeated head impacts.ω-3 PUFA supplementation is associated with improved sleep quality.ω-3 PUFA are classified as prebiotics; however, studies on the gut microbiome and gut health in athletes are currently lacking.

The effect of acute beetroot juice consumption prior to climbing on lower-body isokinetic and isometric strength, aerobic power, and muscle soreness among mountain climbers

BACKGROUND

Beetroot juice (BRJ) contains various bioactive compounds which can enhance athletes" performance. However, there is a limited number of studies assessing the effects of BRJ on climbers" performance and indicators of muscle soreness (MS). Thus, the present study aimed to investigate the effect of consuming beetroot juice acutely before climbing on lower-body isokinetic and isometric strength, aerobic power, and muscle soreness in mountain climbers.

METHODS

In a randomized, placebo-controlled, double-blinded study, 27 climbers (14 males and 13 females) were divided into three groups: Control (CON), Placebo (PLA), and Beetroot Juice (BRJ), with 9 participants in each group. The study evaluated swelling around the thigh (Sw-T), pressure pain threshold (PPT), isokinetic and isometric strength, horizontal jump (HJ), wall-sit, handgrip strength (HGS), flexibility, and the Queen's College Step test. Testing occurred in three sessions: baseline, climbing, and posttest. At baseline, all participants completed the full battery of tests at Shiraz University. One week later, during the climbing session, they consumed 70 mL of BRJ (400 mg nitrate), PLA, or water 2.5 hours before ascending to 3720 meters. Functional tests (HJ, wall-sit, and estimated VO₂max) were performed at the altitude. After completing these tests, participants immediately descended the mountain. DOMS was assessed using a visual analog scale (VAS) for the quadriceps, hamstrings, and gastrocnemius muscles at the following time points: 2 hours before climbing, and 0 (immediately), 12, 24, 48, and 72 hours after descending. The posttest session, held 72 hours after descending, repeated all baseline assessments.

RESULTS

The results revealed a statistically significant decrease in DOMS in the gastrocnemius muscles 24 hours post-descending in the BRJ group compared to the control group (p = 0.003, pEta2 = 0.204). However, no changes in DOMS were observed for the quadriceps (p = 0.090, pEta2 = 0.090) and hamstring (p = 0.254, pEta2 = 0.056) muscles. Moreover, notable improvements were observed in PPT (p = 0.001, pEta2 = 0.374), Estimated VO2max (p = 0.016, pEta2 = 0.291), HGS (p = 0.004, pEta2 = 0.270), flexibility (p = 0.003, pEta2 = 0.407), HJ (p = 0.008, pEta2 = 0.155), and isokinetic (peak torque, average power and rate of force development) and isometric (Maximum voluntary isometric contraction) strength indicators in the BRJ groups compare to the other groups (p˂0.05). However, no significant differences were observed in Sw-T between groups (p = 0.305).

CONCLUSIONS

The study suggested that acute consumption of BRJ before climbing improves climbers' lower-body isokinetic and isometric strength, power, and endurance performance, and it is associated with a reduced perception of muscle soreness.

Development of a preliminary multivariable model predicting hamstring strain injuries during preseason screening in soccer players: a multidisciplinary approach

OBJECTIVE

Reducing the incidence of hamstring strain injuries (HSIs) is a priority for soccer clubs. However, robust multifactorial predictive models are lacking and potential predictors such as sprint kinematics, performance fatigability, and psychological variables have been overlooked. Thus, the aim of this study was to develop a preliminary parsimonious multifactorial model to predict players at risk of HSI through preseason screening.

MATERIALS AND METHOD

Psychological, physiological, kinematic, performance fatigability and health-related variables were collected for 120 regional and national soccer players during the 2022 preseason. HSIs were prospectively recorded over the entire soccer season. After variable selection, logistic regressions with the Wald backward stepwise method were used to refine the model. The predictive abilities of the model and of the individual variables were determined using the area under the receiver operating characteristic curve (AUC).

RESULTS

Twenty-nine players sustained an HSI during the follow-up period. The final model included eight variables: age, sex, HSI history, knee flexor performance fatigability, sprint performance (best sprint time and maximal theoretical velocity V0), perceived vulnerability to injury, and subjective norms in soccer. While its model was preliminary, it showed good fit indices and strong predictive performance (true positive rate: 79%, AUC = .82). None of the variables evaluated independently demonstrated satisfactory performance in predicting HSI (AUC≤.65).

CONCLUSION

Using a multidisciplinary approach and measurements of only a few variables during preseason screening, the current model tends to demonstrate high accuracy in identifying soccer players at risk of HSI.

Caregivers nutrition knowledge and perspectives on the enablers and barriers to nutrition provision for male academy football players

BACKGROUND

The assessment of nutrition knowledge, alongside the enablers and barriers to optimal dietary intake, in youth football players has previously been documented. However, there is comparatively little research on either of these within parents or host families, which is of value to understand given the vital role that these stakeholders play as the primary food provider to young football players. Thus, the purpose of this study was to assess the nutrition knowledge of these caregivers and explore their perceptions of the barriers and enablers to nutrition provision for male academy football players.

METHODS

A validated 35-item online questionnaire (A-NSKQ) was completed by 30 parents and 31 host family providers of youth academy football players from 16 different professional football clubs in England. The questionnaire consisted of 35 questions (total), 11 of which focussed on the assessment of general nutrition knowledge (GNK) and the remaining 24 assessed sports nutrition knowledge (SNK). Scores are presented as a percentage for total and each sub-section (GNK & SNK) and classified by the following rating: "poor" (0-49%); "average" (50-65%); "good" (66-75%); and "excellent" knowledge (76-100%). Differences in Total, GNK and SNK were compared between parents and host families using Independent-samples t-tests, with the alpha value set at p < 0.05 for all tests. A series of focus groups was also conducted with six parents and twelve host family representatives from four clubs to explore their perspectives of the enablers and barriers to providing nutrition support to youth football players. Thematic analysis was used to interpret the data.

RESULTS

Host family providers demonstrated significantly better total nutrition knowledge than Parents (49.95   ±   11.64% vs. p = 42.67   ±   14.43%; p = 0.035), although the knowledge of both groups is classed as "poor." For the sub-sections of GNK & SNK, GNK was considered "average" and significantly better than SNK, which was classed as "poor" (GNK = 58.12   ±   16.87% vs. SNK = 40.98   ±   14.91%; p < 0.001). Host family providers reported significantly better SNK than parents (44.89   ±   13.21% vs. 36.94   ±   15.69%; p = 0.037) whilst no significant differences were observed in GNK between groups (61.00   ±   15.07% vs. 55.15   ±   18.33%; p = 0.180). Three key themes were generated relating to the caregivers' perceptions of the barriers and enablers to their food provision: 1) Club Support and Communication; 2) Time and Financial Resources; 3) Player-specific Characteristics.

CONCLUSIONS

These findings suggest a clear need for football clubs to educate caregivers in the fundamental principles of healthy nutrition and football-specific nutrition requirements and encourage clubs to develop initiatives to better support caregivers in helping to young players to meet their dietary requirements.

Unveiling the impact of competition weight loss on gut microbiota: alterations in diversity, composition, and predicted metabolic functions

BACKGROUND

Competitive sports and sports nutrition, popular among amateur athletes aiming for a lean physique, have limited research on gut microbiota.

METHODS

We conducted a 46-week study to analyze the consequences of fat loss and diet restrictions in 23 fitness athletes who prepared for a physique competition. Body composition, dietary intakes, serum cytokines and chemokines, and fecal samples were analyzed.

RESULTS

Fat loss through caloric restriction and aerobic exercise led to an increased phylogenetic diversity of gut microbiota and changes in the composition of gut microbiota, with Faecalibacterium, Lachnospiraceae, Bacteroides, and Intestinimonas showing altered abundances. Fat loss also changed the predicted microbial functions responsible for the metabolism of carbohydrates and amino acids. Consumption of energy, carbohydrates, fiber, vitamins and minerals, and various fatty acids decreased during the preparation for the competition, which was partly associated with changes in gut microbiota. Several cytokine levels decreased (IL1a, IL1b, IL10, and TFNα), and certain chemokine levels increased (GROa and RANTES). During the 23-week regain period after the competition, gut microbiota showed signs of recovery, with increased diversity compared to pre- and post-competition measurements. Most taxonomic changes returned to their baseline levels after the regain period.

CONCLUSIONS

The study highlights the dynamic nature of gut microbiota and its response to fat loss and regain in non-obese fitness/physique competitors and provides novel insights into how competitive sports and sports nutrition can influence the gut ecosystem.

The impact of low energy availability risk on pre-competition physiological function in Chinese female combat athletes

BACKGROUND

Low energy availability (LEA) can negatively impact athletes' physiological function and performance. This study aims to examine the prevalence of LEA in Chinese female combat athletes and monitor changes in physiological function and performance during the pre-competition period.

METHOD

We assessed the incidence of low energy availability (LEA) and eating disorder (ED) risks in 84 female combat athletes (judo, freestyle wrestling, and sanda) from Beijing using the Low Energy Availability in Females Questionnaire (LEAF-Q) and the Eating Disorder Examination Questionnaire (EDE-Q). From this group, 11 judo athletes who were preparing for competition were selected and divided into a low energy availability (LEA) group and a non-LEA group based on their energy availability levels. Dietary intake, training energy expenditure, body composition, resting metabolic rate, blood markers, and special judo fitness tests were monitored at 4 weeks, 2 weeks, and 0 weeks before the competition.

RESULTS

Among the 84 athletes, 45.2% of athletes (n = 38) were at increased risk of LEA, and 21.4% of athletes (n = 18) were classified as high in eating disorder risk. There were no significant differences in LEA and ED risk between elite and recreational athletes. Among the 11 athletes preparing for competition, 6 athletes (45.5%) were in a state of LEA at the initial stage (4 weeks before the competition), and by the competition week, all 11 athletes exhibited LEA. Additionally, athletes in the LEA group experienced significant reductions in VO2 and resting metabolic rate at 0 week of the competition compared to 4 weeks prior (p < 0.05). Thyroid function indicators and IGF-1 levels of LEA group also significantly decreased (p < 0.05). After completing the four-week pre-competition weight loss, heart rate recovery during the special judo fitness test improved significantly in both the LEA and non-LEA groups (p < 0.05).

CONCLUSION

The current study identified a risk of LEA among Chinese female combat sport athletes, with no significant difference in the prevalence of LEA between elite and recreational athletes. It is essential for Chinese coaches and sports medicine staff to implement LEA-related nutritional education across all performance levels. Moreover, preventive measures during training are recommended to mitigate the impact of LEA on physiological function during the pre-competition weight loss phase.

Sport supplementation in competitive swimmers: a systematic review with meta-analysis

BACKGROUND

Competitive swimmers have a high prevalence of sports supplement (SS) consumption. However, only a few SS are scientifically proven to be safe, effective, and legal. Therefore, before incorporating supplements to enhance performance and health in competitive swimming, it is crucial to conduct an analysis and review to assess their effects. The objective of this study was to analyze the demonstrated effects of SS, as reported in published studies, on the swimming performance of competitive swimmers.

METHODS

Following PRISMA guidelines, a systematic search was conducted across six databases for the selection of studies included in this review. Studies that analyzed the effects of sports supplementation compared to placebo were included and subjected to meta-analysis.

RESULTS

This revision included 23 studies, 16 of them (69.6%) qualified as excellent and 7 (30.4%) as good at the methodological level based on the punctuation in the PEDro scale. The systematic review included 422 swimmers (61.8% male, 38.2% female), with distances assessed ranging from 50 m to 800 m, including studies employing interval procedures. Creatine showed a significant effect (ES = -0.46; 95% CIs = -0.75 to -0.17, p = 0.002; I2 = 11%) on swimming performance, while the rest of the analyzed supplements did not show significant effects (all p > 0.05).

CONCLUSIONS

Creatine supplementation demonstrated ergogenic benefits for competitive swimmers, although the evidence supporting the use of this supplement is still limited. Sodium bicarbonate and β-alanine may enhance performance in distances with higher glycolytic demands, while caffeine is effective at dosages of 3-6 mg/kg administered 60 min before exercise. Further research is needed to confirm the potential ergogenic effects of other supplements, such as beetroot juice.

Macronutrient requirements and intake by professional male rugby players

BACKGROUND

Rugby union is a high-contact team sport where professional rugby players are exposed to considerable training and game loads in pre-season and in-season. Some studies have shown that rugby players' dietary intake remains inadequate for the three macronutrients (carbohydrates [CHO], proteins and fats) required for optimal performance. This study aimed to describe the macronutrient intake of professional male rugby players at Zebre Rugby Club in Parma, Italy, during in-season, and to compare players' macronutrient intake to international recommendations.

METHODS

Thirty-four professional male rugby players participated in the cross-sectional study. A self-developed questionnaire, a food frequency questionnaire and food records (on training and competition days and off day) were used to investigate players' macronutrient intake. Anthropometric measurements were obtained using the International Society for the Advancement of Kinanthropometry (ISAK) standardized techniques. Descriptive statistics were calculated, and associations were investigated using chi-square, Fisher's exact and Wilcoxon rank tests as applicable.

RESULTS

The players' median age was 25.8 years (range 20.6-33.0 years) and 47.5% were Italian. Most players (64.7%) held forward positions and had a median of 5 years (range 2-14 years) of professional experience. More than 75.0% of players lived with a spouse or partner and 30.3% earned between 4 000-4 999 euros per month. The median body weight and height of players were 106.9 kg and 186.3 cm, respectively. The forwards weighed heavier (p < 0.0001) than the backs, which was expected due to positional demands, with no significant difference in height distribution. The median body mass index (p < 0.0001), waist circumference (p < 0.001) and waist-to-height ratio (p < 0.03) of forwards were higher than the backs. Additionally, the median body fat percentage of all players exceeded the international recommendation of 8-17% for rugby union players. The American College of Sports Medicine (ACSM), International Olympic Committee (IOC) and International Society of Sports Nutrition (ISSN) recommend an intake of 5.0-8.0 g/kg body weight (BW)/day CHO, 1.5-2.0 g/kg BW/day proteins and 20-35% total energy (TE) from fats for rugby players. The overall median intake of the three-day food records for all the players was 2.7 g/kg BW CHO, 1.7 g/kg BW protein and 35.1% TE from fat. On each of the three reported days, 90.0% of players' CHO intake fell below the recommended range, with almost all players (>90.0%) consuming less than the recommended amount of carbohydrates and almost 30.0% of players consuming below the recommended amount of protein on competition day. At least 50.0% of players' protein and fat intake was within the recommended range on each of the three reported days.

CONCLUSION

The study's findings can assist various stakeholders at Zebre Rugby Club to align rugby players' dietary requirements to their workload, and encourage players' adherence to dietary guidelines and recommendations. It is advised that attention be focused on accurate dietary education, intake and monitoring to promote individualization and optimal performance and recovery. Future research is needed to adapt standardized macronutrient recommendations for rugby-specific requirements and address obstacles that may impede the optimal intake of macronutrients.

Effectiveness of abdominal bracing core exercises as rehabilitation therapy for reducing abdominal symptoms in patients with autosomal dominant polycystic kidney disease and significant polycystic liver disease

In patients with autosomal dominant polycystic kidney disease (ADPKD) who also have polycystic liver disease (PLD), organomegaly often leads to abdominal symptoms. Abdominal bracing core (ABC) exercises have been validated as effective for alleviating chronic back pain. The purpose of this study was to assess the effectiveness of ABC rehabilitation exercises in reducing pain in ADPKD patients with significant PLD. Significant PLD was defined as a height-adjusted total liver volume (htTLV) exceeding 1,600 mL/m. Both the control groups (n = 11) and intervention (n = 12) and received an outpatient consultation on nutrition and exercise; however, only the intervention group participated in ABC exercises. After a 3-month biweekly intervention, changes in pain assessed by the Korean Oswestry Disability Index, abdominal symptoms, quality of life (QoL) by the second version of the short-form 36-item Health Survey, and bioelectrical impedance analysis (BIA) were analyzed. The participants comprised 23 individuals (male: 4, female: 19). Their mean age was 54, and the mean ± SD of htTLV was 2,706 ± 1,335 mL/m. The mean ± SD of eGFR was 53.9 ± 29.0 mL/min/1.73 m2. After the intervention, pain and pressure-related symptoms significantly decreased in some cases; however, gastrointestinal symptoms did not improve. Pain (control vs. intervention: -1.9 vs. 1.0) and QoL (1.20 vs. 0.93) and showed significant improvements. The results of BIA indicated a noticeable change in the soft lean mass of the proximal body (0.4 vs. -0.2). Our study demonstrates that ABC exercise is effective in alleviating pain and increasing soft lean mass in ADPKD patients who have significant PLD.

Efficacy of time restricted eating and resistance training on body composition and mood profiles among young adults with overweight/obesity: a randomized controlled trial

BACKGROUND/OBJECTIVE

Dietary restriction or exercise regimens can promote weight loss or physical fitness among patients with obesity. However, intervention-associated adverse effects may impede patients' motivation to participate in dietary/exercise interventions. We examined the effects of time restricted eating (TRE) with or without resistance training (RT) on body composition, mood profile, and sleep quality in young college adults with overweight or obesity.

METHODS

Fifty-four young college students with overweight/obesity were randomized into control (CON), TRE, RT, and TRE plus RT (TRE+RT) trials. The TRE trials restricted to an eating window of 10-hour/day for 8-week. The RT trials performed supervised resistance exercise, while the control trial maintained a regular lifestyle. Changes in body composition variables, blood pressure, mood status, and sleep quality were measured before and after the intervention.

RESULTS

TRE intervention alone or in combination with RT significantly (p < 0.01) decreased body weight (>2 kg) and BMI (~1 kg/m2) in adults with overweight/obesity. Both RT alone and combined with TRE substantially decreased fat mass by 1.1 ± 0.5 and 3.2 ± 0.4 kg, respectively. The decreased fat mass was greater in the combination trial than in the RT trial, whereas TRE alone had no effect. In contrast, fat-free mass was significantly (p < 0.01) decreased with TRE (-2.3 ± 06 kg), increased with RT (1.6 ± 0.3 kg), and was stably maintained with combination interventions. The reduced waist and hip circumferences in the TRE (p < 0.01) were similar to those in the TRE+RT trials, however, RT alone had no effect. Time and group interaction showed a large effect size (partial eta squared) for all body composition variables. In addition, RT with or without TRE notably decreased diastolic blood pressure (RT: -5.5 ± 1.9 mmHg, TRE+RT: -4.1 ± 1.5 mmHg, p < 0.05). Mild anxiety levels at baseline in RT (4.8 ± 2.6) and TRE+RT (4.1 ± 3) trials were found to be normal at postintervention in TRE+RT (3.6 ± 1.7) but not in RT (5.6 ± 3.5). No depression or stress was recorded among the participants during the intervention. The reported poor sleep quality among participants at baseline was significantly improved with RT (4.8 ± 2.9; p < 0.05), and tended to improve with TRE+RT interventions (4.5 ± 1.9).

CONCLUSIONS

10-hour TRE is beneficial for weight/fat loss without affecting mood status. However, TRE combined with RT might be more effective for weight/fat loss, maintaining muscle mass, and good quality of sleep among young adults with overweight or obesity.

Physiological effects of spirulina supplementation during lactate threshold exercise at simulated altitude (2,500 m): a randomized controlled trial

BACKGROUND

Existing literature indicates that spirulina supplementation can improve a variety of blood morphological parameters (such as hemoglobin) in healthy and clinical populations. Given the importance of hemoglobin for endurance exercise, particularly at altitude, this study aimed to investigate whether spirulina supplementation can improve blood morphological parameters in healthy cyclists and positively influence physiological variables when completing a lactate threshold test at simulated moderate altitude (2,500 m).

METHODS

Twenty (18 male; 2 female) healthy participants (Mean  ±  SD; Age 37   ±   9 years, Stature 181   ±   6 cm, Mass 81   ±   9 kg, V ˙ O2max 51.8   ±   7.8 ml·kg-1·min-1) ingested 6 g/day of spirulina or placebo for 3-weeks in a double-blinded randomized counter-balanced cross-over design, then completed a lactate threshold test at simulated moderate altitude, with a 14-day washout period between trials.

RESULTS

Following spirulina supplementation, heart rate at the lactate threshold was significantly lower in comparison to placebo supplementation (spirulina = 152   ±   11 b.min -1 vs. placebo = 155   ±   12 b.min -1, p < 0.05). No other physiological variables (Watts, RER, RPE, VO2) were significantly different (p > 0.05) at the calculated threshold, or during the first four lower stages. Red Cell Distribution Width significantly increased following spirulina supplementation in comparison to placebo (spirulina = 13.3   ±   0.9 % vs. placebo = 12.5   ±   0.7 %, p < 0.05). Plateletcrit significantly decreased following spirulina supplementation (spirulina = 0.288   ±   0.032 vs. placebo = 0.293   ±   0.050, p < 0.05). No other blood morphological parameters changed (p > 0.05).

CONCLUSION

In conclusion, three weeks of spirulina supplementation at 6 g/day reduced heart rate during a lactate threshold test at a simulated moderate altitude (2,500 m), but did not produce additional physiological or hematological benefits.

Elite collegiate swimmers do not meet sport nutrition recommendations during heavy training: effects of sex and within-day nutrient timing

BACKGROUND

Compared to the general population, athletes experience high energy expenditures requiring increased energy and macronutrient intakes to sustain training and optimize performance. While the International Olympic Committee (IOC) and International Society for Sports Nutrition (ISSN) have established recommendations for nutrient intakes, many athletes do not meet the recommended daily allowance (RDA) for the general population, and sport and sex-specific differences are not well documented. Exploration of within-day energy balance (WDEB) shows athletes may achieve energy balance by the end of the day but may present with poor WDEB. Data support that female athletes are at greater risk of nutrient deficiencies than their male counterparts, and it is unclear whether swimmers meet sport-specific nutrient intake and timing recommendations. Following our previous WDEB analysis, the purpose of this investigation was to assess dietary macronutrient intake as related to RDAs (USDA and IOC/ISSN), within-day macronutrient timing, and associated sex differences in swimmers.

METHODS

In elite male and female swimmers (n = 25; 18-22 yr), we assessed energy intake (EI), total daily energy expenditure (TDEE), macronutrient intake (fat (FAT), protein (PRO), carbohydrate (CHO)) and timing during heavy training. Frequency analysis was utilized to determine the number of athletes meeting general and athlete-specific RDAs. Repeated-measures ANOVA was used to assess nutrient timing across sex groups.

RESULTS

When compared to IOC/ISSN daily recommendations, only 6/25 swimmers met FAT intake, 7/25 met CHO intake, and 24/25 met PRO intake IOC/ISSN daily recommendations.Males had greater EI and TDEE compared to females (p < 0.05). PRO consumption (% of EI) was a larger percentage of total intake in male vs females (28 ± 5% vs 23 ± 3%; F = 2.996; p = 0.014). No swimmers met CHO recommendations (g⋅kg-1) pre- or during exercise for the first daily training session. 13/25 met pre-exercise CHO recommendations, while 6/25 and 11/25 met during and post-exercise CHO recommendations for the second training session. Repeated measures ANOVA revealed effects of sex and time on intake (g⋅kg LBM-1⋅hr-1) for FAT (Sex; F = 5.659, p = 0.26; time; F = 12.068, p = 0.006) and PRO (Sex; F = 6.719, p = 0.016; time; F = 13.177, p = 0.011). There was a significant sex*time interaction for CHO consumption (F = 6.520, p = 0.017).

CONCLUSION

The results from this study demonstrate significant sex-differences, indicating that most swimmers meet athlete-specific recommendations for PRO, but not CHO or FAT intake. CHO timing for pre-, during, and post-exercise was met by only 52% swimmers. Results suggest that swimmers should prioritize CHO intake, emphasized around and during training bouts.

International society of sports nutrition position stand: nutrition and weight cut strategies for mixed martial arts and other combat sports

Following an extensive literature review, the International Society of Sports Nutrition (ISSN) has developed an official position on nutritional and weight cut strategies for combat sports. The type of combat sport, length of the fight camp, and time between weigh-in and competition are factors influencing nutritional and weight cut strategies. The following 16 points constitute the Position Statement of the Society; the Research Committee has approved them. 1. Combat sports have differing weight categories, official weigh-in times, and competition frequencies, influencing the nutritional and weight cut strategies for training and competition. 2. As the duration of a combat match increases, >4 min, contribution of the aerobic system can rise to >70%, yet anaerobic alactic pathways and anaerobic glycolytic pathways support high-output bursts. 3. During the off camp/general preparation phase, athletes should maintain a weight ranging 12% to 15% above the weight division requirement. 4. Supplements including creatine, beta-alanine, beta-hydroxy-beta-methylbutyrate, and caffeine have been shown to enhance performance and/or recovery during preparation phases, competition, and post-competition. 5. During fight camp, strategic decreases in calorie intake are necessary for an efficient longitudinal weight descent. Individual caloric needs can be determined using indirect calorimetry or validated equations such as Mifflin St. Jeor or Cunningham. 6. Protein should be prioritized during longitudinal weight descents to preserve lean body mass, and the timely delivery of carbohydrates supports training demands. Macronutrients should not drop below the following: carbohydrates 3.0-4.0 g/kg, protein 1.2-2.0 g/kg, and fat 0.5 to 1.0 g/kg/day. 7. Suitable losses in body mass range from 6.7% at 72 h, 5.7% at 48 h, and 4.4% at 24 h, prior to weigh-in. 8. Sodium restriction and water loading are effective for inducing polyuria and acute water loss. 9. During fight week, water-bound glycogen stores can be depleted through exercise and carbohydrate restriction, facilitating a 1% to 2% loss in body mass, with equivalent losses from a low-fiber intake of <10 g/day for 4 days. 10. During fight week, acute water loss strategies, including sauna, hot water immersion, and mummy wraps, can be used effectively with appropriate supervision (optimally ~2-4% of body mass within 24 h of weigh-in). 11. Post-weigh-in, rapid weight gain strategies are utilized to recover lost body fluid/mass before competition with the intent of gaining a competitive advantage. 12. Oral rehydration solutions (1 to 1.5 liters/h) combined with a sodium range of 50-90 mmol/dL should take precedence immediately post-weigh-in. 13. Fast-acting carbohydrates at a tolerable rate of ≤ 60 g/h should follow oral rehydration solutions. Post weigh-in intake of fiber should be limited to avoid gastrointestinal distress. 14. Post-weigh-in carbohydrate intake at 8-12 g/kg may be appropriate for combat athletes that undertook significant glycogen depletion strategies during fight week. About 4-7 g/kg may be suitable for modest carbohydrate restriction. 15. Post weigh-in, rehydration/refueling protocols should aim to regain ≥10% of body mass to mitigate declines in performance and the negative effects of rapid weight loss. 16. The long-term effects of frequent weight cuts on health and performance are unknown, necessitating further research.

Cardiorespiratory fitness in Chinese children and adolescents: a systematic review and meta-analysis

BACKGROUND

Cardiorespiratory fitness (CRF) has become a significant focus in the field of public health. CRF is considered a strong predictor of health outcomes. However, cardiorespiratory fitness levels of children and adolescents are declining.

AIMS

(1) To analyse the cardiorespiratory fitness levels of children and adolescents in China, focusing on maximum oxygen uptake (VO2max), maximum heart rate (HRmax), peak oxygen uptake (Peak VO2) and 20-metre shuttle run test (20 m-SRT). (2) To provide baseline data, with the goal of supporting the development of sports programs, intervention strategies, and public health decision-making.

SUBJECTS AND METHODS

A meta-analysis was conducted using 30 studies selected from five databases.

RESULTS

The average performance on 20 m-SRT for Chinese children and adolescents was 34.67 laps, with a VO2max of 46.47 ml/kg/min, HRmax of 195.02 bpm, and Peak VO2 of 48.58 ml/kg/min. Boys outperformed girls in VO2max, 20 m-SRT, and HRmax, although the differences in HRmax and Peak VO2 were not statistically significant. Tibetan children showed better performance than Han children in three indicators with no significant differences found.

CONCLUSION

Cardiorespiratory fitness in Chinese children and adolescents is within a healthy range but not optimal. Boys generally perform better than girls, and Tibetan children outperform Han children.

Experiences and perspectives on pregnancy and motherhood in elite athletes - a qualitative study

Elite athletes routinely undertake strenuous training routines, which often involve high-intensity sessions. However, there are knowledge gaps in how they experience training during pregnancy and subsequent return to sport. Combined with inadequate financial and contractual safety, female athletes may jeopardise their careers when starting families. This study aimed to describe female athletes' experiences and perspectives related to pregnancy and motherhood within the context of elite sports in Norway. We interviewed five world-class athletes between October 2022 and April 2023, using a descriptive qualitative approach. Full interview transcripts were analysed based on a reflexive thematic analysis model. Five overarching themes were identified: (1) uncertainty, (2) lack of supportive networks, (3) physical capacity, (4) the impact of postpartum return to sports on maternal health, and (5) combining motherhood and elite sports. Our findings emphasise the challenges that Norwegian pregnant and postpartum athletes face in balancing motherhood with successful careers, highlighting the importance of providing adequate support systems to ensure their health and the well-being of their child.

Investigation of the effect of nitrate and L-arginine intake on aerobic, anaerobic performance, balance, agility, and recovery in elite taekwondo athletes

BACKGROUND

Taekwondo is a complex martial art that requires speed, balance, agility, and endurance. This study aims to examine the effects of nitrate and L-arginine supplementation on acute aerobic and anaerobic performance, balance, agility, and recovery in elite taekwondo athletes.

METHOD

This study was conducted as a double-blind, randomized, crossover study with the participation of 15 experienced taekwondo athletes aged 19.06 ± 0.96 years and 8.93 ± 1.27 years of training experience. Participants visited the laboratory a total of nine times, including a practice session and anthropometric measurements. These visits consisted of eight experimental sessions conducted at 72-hour intervals. The experimental sessions were conducted with nitrate, L-arginine, and a combination of both supplements (NIT*L-ARG) and placebo. Nitrate supplementation was provided by homogenizing fresh spinach (837.40 mg/kg), while L-ARG was given as a single dose of 6 g in powder form three hours before exercise.

RESULTS

NIT*L-ARG supplementation significantly improved the anaerobic performance of athletes in Wingate peak power and peak power (w/kg) compared to placebo and in mean power compared to NIT, L-ARG, and PLA. In addition, NIT*L-ARG supplementation significantly improved blood lactate levels and agility performance immediately after Wingate and Shuttle run tests.

CONCLUSION

The combined intake of NIT*L-ARG was found to be effective in improving aerobic, anaerobic, and agility performances as well as fatigue levels of athletes. It was determined that taking NIT and L-ARG supplements alone contributed to the improvement of improving athletes' performance in Wingate mean power values and subsequent fatigue level compared to PLA.

Childhood predictors of high school sport participation and effects of participation on young adult activity and mental health

INTRODUCTION

In the United States, sport is a common form of youth physical activity (PA) with demonstrated health benefits. However, limited longitudinal dataexists on the psychosocial determinants and consequences of youth sport participation. This study examined grade 6 (11-12-year-old) predictors of high school organized sport participation and effects of high school sport participation on age 26 behavior, mental health and wellbeing.

METHODS

Structural equation models tested relationships using the National Institute for Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development (SECCYD). Half of the sample was male, and played organized sports at ages 15 and 18. Eighty percent of the sample was white.

RESULTS

Grade 6 predictors of playing high school sport were: child enjoys PA, parent enjoys PA, parent feels physical education (PE) is important, and vigorous PA minutes/week. Playing sports at ages 15 and 18 was associated with better wellbeing, lower depression, increased sport and fitness activity participation. Enjoyment of PA was directly associated with fitness activities at age 26, more than a decade later. High school sport participation at both age 15 and 18 further mediated relationships between enjoyment with wellbeing and depression at age 26.

DISCUSSION

Sport participation is a common accessible means of PA, and participating in sports in high school is associated with better mental health and PA outcomes at age 26. Fostering enjoyment of PA during childhood helps shape PA in early adulthood and adult mental health benefits derived from high school sport participation.

Creatine in women's health: bridging the gap from menstruation through pregnancy to menopause

BACKGROUND

Creatine supplementation in women has gained attention for its potential benefits beyond muscle growth, including reproductive health, cognitive health and aging. Women exhibit distinct physiological differences from men, influenced by hormonal fluctuations during pre-menopause, pregnancy, and menopause, and these factors should be considered for their influence on creatine metabolism.

OBJECTIVE

This review aims to provide a historical evaluation of creatine supplementation in women, its potential applications across female-specific life stages, recent research highlights, and targets for future research. The review also considers the impact of hormonal changes on creatine metabolism and effectiveness as a dietary supplementation.

METHODS

This is a narrative overview of historical and recent research evaluating the effects of creatine in women.

RESULTS

Early studies demonstrated the benefits of creatine on exercise performance in women, though they often overlooked menstrual cycle variability. Recent research has begun to account for these hormonal fluctuations, enhancing the understanding of creatine's applications. Creatine supplementation has shown positive effects on muscle strength, exercise performance, and body composition, particularly when combined with resistance training. Additionally, creatine may improve mood and cognitive function, potentially alleviating symptoms of depression. Emerging evidence suggests creatine's benefits during pregnancy and post-menopause, though data on perimenopausal women remains limited.

CONCLUSION

Creatine supplementation presents a promising strategy for enhancing various aspects of women's health across the lifespan. Future research should focus on optimizing dosing strategies, understanding long-term health implications, and exploring creatine's effects during pregnancy and perimenopause.

Toward promoting performance nutrition behaviors among tactical athletes: a mixed methods study

BACKGROUND

Appropriate and adequate nutrition is essential for the health and performance of tactical athletes, including army recruits and trainees. However, previous research shows they commonly experience suboptimal intakes of energy and carbohydrate. To date, little research has been conducted to understand the causes of their poor dietary intakes. The objectives of this study were to (1) assess infantry trainees' dietary intakes and (2) explore their beliefs, barriers, and self-efficacy toward performance nutrition using the Health Belief Model (HBM).

METHODS

Participants undergoing their 17-week Australian Army Infantry Initial Employment Training (Infantry IET) were recruited. During weeks 1 and 17, self-reported dietary intakes were assessed, and four focus groups were conducted.

RESULTS

Mean daily energy, carbohydrate, and protein intakes were 7864 ± 1135 kJ, 1.8 ± 0.6 g/kg, and 1.5 ± 0.3 g/kg, respectively, in week 1, and 9084 ± 2535 kJ/day, 2.2 ± 1.1 g/kg and 1.5 ± 0.2 g/kg, respectively, in week 17. Three themes and seven subthemes were developed from the focus group data, falling under the following HBM domains: Cues to Action, Perceived Barriers, and Self-Efficacy.

CONCLUSIONS

Infantry trainees' ability to eat well for their health and performance was hindered by their limited time during their intensive training schedule, their limited access to a sufficient variety of healthy foods, and their limited self-efficacy regarding performance nutrition. They require further performance nutrition knowledge, especially in regard to adopting practical fueling and refueling strategies surrounding physical training, as well as access to a greater quantity and variety of healthy foods outside of their main mealtimes.

Optimized Individualized Nursing Improves Recovery and Reduces Complications in ICU Patients with Severe Pneumonia

OBJECTIVE

This study evaluates the effectiveness of optimized individualized nursing interventions on clinical outcomes in intensive care unit (ICU) patients with severe pneumonia.

METHODS

In this randomized controlled trial, 76 patients with severe pneumonia were randomized into a control group and an experimental group. Both groups received routine nursing care. On this basis, the experimental group received optimized individualized nursing. After the nursing intervention, clinical outcomes, respiratory function, coagulation function, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and St. George's Respiratory Problems Questionnaire (SGRQ) score were assessed, and the complication and mortality rates were counted.

RESULTS

After the intervention, compared with the control group, the experimental group exhibited shorter times of fever reduction, white blood cell count recovery, and off-boarding and ICU stay, higher oxygenation index, lower rapid shallow breathing index, respiratory rate, activated partial thromboplastin time, prothrombin time, fibrinogen, and D-Dimer levels, lower APACHE II scores and SGRQ scores (p < 0.05). Additionally, the experimental group possessed a lower complication rate and mortality rate than the control group (p < 0.05).

CONCLUSION

Implementing optimized individualized nursing can significantly enhance recovery and reduce complications in ICU patients with severe pneumonia.

Saddle pressures distribution at different pedaling intensities in young off-road cyclists: focus on sex

BACKGROUND

The pressures on the saddle depend on several factors and can compress specific neurovascular tissues, leading to acute and chronic genital pathologies. Based on the pelvic differences between males and females, the aim of this study was to explore any differences on saddle pressures distribution according to sex.

METHODS

Twenty young off-road cyclists (10 m, 10 f) were recruited. Each participant was evaluated on own bike installed on a specific bike roller with a magnetic resistance. Firstly, each participant was asked to warm-up for 10 min at a self-selected cadence and intensity. Then, saddle pressures distribution was measured at three different pedaling intensities (100, 140, 180 W) with a pedaling cadence of 90 rpm, using a device equipped with sensors capable of acquiring pressures.

RESULTS

A significant difference in the ischial distance was found between males and females (p = 0.007). As pedaling intensity increased, results showed a significant higher pressure in the pubic region (p = 0.004) in males and a significant higher pressure in the posterior region in females (p = 0.034). Post hoc multiple comparisons test revealed a significant increase from 100 to 180 W (p = 0.003) in the pubic region pressure in males, while no significant differences were detected in the posterior region pressure in females.

CONCLUSIONS

In male off-road cyclists, the pressure in the pubic region is higher with increasing pedaling intensity. Hence, to prevent acute and chronic genital pathologies, it would be advisable to fix the saddle in the best possible way during the bike fitting.

Part II. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?

Creatine monohydrate supplementation (CrM) is a safe and effective intervention for improving certain aspects of sport, exercise performance, and health across the lifespan. Despite its evidence-based pedigree, several questions and misconceptions about CrM remain. To initially address some of these concerns, our group published a narrative review in 2021 discussing the scientific evidence as to whether CrM leads to water retention and fat accumulation, is a steroid, causes hair loss, dehydration or muscle cramping, adversely affects renal and liver function, and if CrM is safe and/or effective for children, adolescents, biological females, and older adults. As a follow-up, the purpose of this paper is to evaluate additional questions and misconceptions about CrM. These include but are not limited to: 1. Can CrM provide muscle benefits without exercise? 2. Does the timing of CrM really matter? 3. Does the addition of other compounds with CrM enhance its effectiveness? 4. Does CrM and caffeine oppose each other? 5. Does CrM increase the rates of muscle protein synthesis or breakdown? 6. Is CrM an anti-inflammatory intervention? 7. Can CrM increase recovery following injury, surgery, and/or immobilization? 8. Does CrM cause cancer? 9. Will CrM increase urine production? 10. Does CrM influence blood pressure? 11. Is CrM safe to consume during pregnancy? 12. Does CrM enhance performance in adolescents? 13. Does CrM adversely affect male fertility? 14. Does the brain require a higher dose of CrM than skeletal muscle? 15. Can CrM attenuate symptoms of sleep deprivation? 16. Will CrM reduce the severity of and/or improve recovery from traumatic brain injury? Similar to our 2021 paper, an international team of creatine research experts was formed to perform a narrative review of the literature regarding CrM to formulate evidence-based responses to the aforementioned misconceptions involving CrM.

Assessing the risk of low energy availability, bone mineral density and psychological strain in endurance athletes

BACKGROUND

Adequate energy intake is crucial for athletic performance and recovery. However, many endurance athletes experience Low Energy Availability (LEA), which, if prolonged, can detrimentally impact both health and performance.

METHODS

A total of 55 endurance athletes (23 females; 45  ±  13 years, 1.64  ±  0.06 m, 64.4  ±  11.4 kg and 32 males; 44  ±  13 years, 1.76  ±  0.18 m, 78.8  ±  9.2 kg) underwent physical assessments and completed questionnaires on dietary habits, training loads, and psychological stress. Dual-Energy X-ray Absorptiometry (DEXA) scans measured bone mineral density (BMD) in the lumbar L1-L4 spine, and body composition. Risk of LEA burnout, and psychological strain were assessed using sport-specific questionnaires.

RESULTS

Seventy-seven percent of female athletes were identified as at risk of LEA by the LEAF-Q. These females had higher body weight and fat percentage than those at low risk of LEA. Male athletes had a higher prevalence of low lumbar BMD (31%) compared to females, associated with older age, and longer training histories. Although only 9% of female athletes had low-BMD, those affected had a history of amenorrhea and were identified as at risk of LEA by the LEAF-Q.

CONCLUSION

A high proportion of endurance athletes had low-BMD and were at risk of LEA. This underscores the need for targeted nutritional strategies to mitigate the risks associated with LEA and promote overall athlete well-being.

Effects of different dietary supplements on athletic performance in soccer players: a systematic review and network meta-analysis

BACKGROUND

As dietary supplements play a crucial role in meeting the unique nutritional needs of soccer players, a growing body of studies are exploring the effects of dietary supplements on athletic performance in soccer players. The effectiveness of certain supplements, such as caffeine and creatine, remains debated due to inconsistent results across studies. Therefore, this systematic review and Bayesian network meta-analysis was conducted to tentatively identify the most effective dietary supplements for soccer players.

METHODS

We searched PubMed, Web of Science, Cochrane, Embase, and SPORTDiscus from database establishment to 5 February 2024 to identify randomized controlled trials (RCTs) evaluating the effects of different dietary supplements on athletic performance in soccer players. The risk of bias was assessed using the revised Cochrane risk-of-bias tool for randomized trials. A Bayesian network meta-analysis was performed using the R software and Stata 18.0. A subgroup analysis was conducted based on the competitive level of the athletes.

RESULTS

Eighty RCTs were included, with 1,425 soccer players randomly receiving 31 different dietary supplements or placebo. The network meta-analysis showed that compared with placebo, carbohydrate + protein (SMD: 2.2, very large), carbohydrate + electrolyte (SMD: 1.3, large), bovine colostrum (SMD: moderate) and caffeine (SMD: 0.29, small) were associated with a significant effect on increasing the distance covered. Kaempferia parviflora (SMD: 0.46, small) was associated with a significant effect on enhancing muscular strength. Beta-alanine (SMD: 0.83, moderate), melatonin (SMD: 0.75, moderate), caffeine (SMD: 0.37, small), and creatine (SMD: 0.33, small) were associated with a significant effect on enhancing jump height. Magnesium creatine chelate (SMD: -3.0, very large), melatonin (SMD: -1.9, large), creatine + sodium bicarbonate (SMD: -1.4, large), and arginine (SMD: -1.2, moderate) were associated with a significant effect on decreasing sprint time. Creatine + sodium bicarbonate (SMD: -2.3, very large) and caffeine (SMD: -0.38, small) were associated with a significant effect on improving agility. Sodium pyruvate (SMD: 0.50, small) was associated with a significant effect on increasing peak power. Magnesium creatine chelate (SMD: 1.3, large) and sodium pyruvate (SMD: 0.56, small) were associated with a significant effect on increasing mean power. Carbohydrate + electrolyte (SMD: -0.56, small) was associated with a significant effect on improving the rating of perceived exertion.

CONCLUSIONS

This study suggests that a range of dietary supplements, including caffeine, creatine, creatine + sodium bicarbonate, magnesium creatine chelate, carbohydrate + electrolyte, carbohydrate + protein, arginine, beta-alanine, bovine colostrum, Kaempferia parviflora, melatonin, and sodium pyruvate, can improve athletic performance in soccer players. This review provides evidence-based guidance for soccer coaches and nutritionists on using dietary supplements to enhance specific performance measures.

Comparison of concurrent, resistance, or aerobic training on body fat loss: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis compared the differential effects of resistance training (RT), aerobic training (AT), and concurrent training (CT) on body mass and body fat loss in metabolically healthy individuals.

METHODS

A systematic search of PubMed, SportDiscus, and Web of Science databases for randomized controlled trials published between January 1980 and January 2023, comparing RT, AT, and CT in healthy adults was conducted. Primary outcomes of interest included changes in fat mass and body fat percentage; secondary outcomes were body mass and fat-free mass (FFM). Sub-analyses on intervention duration (< or ≥ 10 weeks), CT timing (aerobic and resistance exercises done on the same day versus different days within a week), and workload matching (equating workloads between AT, RT, and CT), were conducted. Study protocols followed PRISMA 2020 guidelines and were pre-registered on PROSPERO (CRD42023396530).

RESULTS

In total, 36 studies with 1564 participants were included in the systematic review, with only 31 studies included in the meta-analysis due to missing data. For studies lasting at least 10 weeks, AT outperformed RT in reducing body mass (mean difference (MD) = -1.82 kg [95% CI = -2.72 to -0.93]; p < 0.001) and fat mass (MD = -1.06 kg [95% CI = -1.88 to -0.24]; p = 0.01) but led to less FFM retention (MD = - 0.88 kg [95% CI = -1.73 to -0.03], p = 0.04). CT reduced significantly more fat mass compared to RT (MD: -1.09 kg [95% CI = -0.27 to -1.91]; p = 0.009). No significant differences were found between CT, AT, and RT in altering body fat percentage (p > 0.05). For studies shorter than 10 weeks, no significant differences were noted across exercise modalities (p > 0.05). Under conditions where AT, RT, and CT workloads were matched, similar fat mass, body mass, body fat percentage, and FFM changes were observed between exercise modalities (p > 0.05). Similar body mass and body fat percentage loss was observed between same-day and different-day CT (p > 0.05); body fat mass loss only differed in a single study (n = 1) when comparing RT to different-day CT (aerobic and resistance exercises done on different days within a week).

CONCLUSIONS

While there are no differences in percent body fat loss between exercise modes, AT and CT are more effective than RT alone in reducing absolute fat mass; however, RT neither improved nor impeded fat mass loss when incorporated into CT. Combining aerobic and resistance exercises on the same-day or different-day does not appear to influence the effectiveness of CT. When exercise interventions are short in duration (<10 weeks), there does not appear to be a difference in fat loss between exercise modalities. These results support the concurrent use of aerobic and resistance exercises for fat mass reduction, as well as an emphasis on workload and duration when programming exercise for fat loss.

The TSST triggers self-reported stress and biological stress and frustrates basic psychological needs: general and specific buffering effects of physical activity and social support

Situations characterized by uncontrollability and critical social evaluation frustrate basic psychological needs, as outlined in Self-Determination Theory (SDT). Uncontrollability and social evaluation are central elements of the Trier Social Stress Test (TSST), leading to the hypothesis that the TSST, in addition to increasing self-reported stress and cortisol responses, also frustrates the needs for autonomy, competence, and social relatedness. Participants (N = 195) reported elevated stress and reduced need satisfaction, and increased cortisol responses during the TSST. The roles of assessed physical activity and experimentally-induced social support were also examined. Indeed, in time-sensitive and specific manner, the TSST frustrated basic psychological needs. Social support however mitigated frustration of social relatedness. Physical activity buffered against self-reported stress, the frustration of competence and the cortisol response. Further research is recommended to explore more differentiated interventions that can counteract the negative effects of psychosocial stressors.

Dietary supplement use and knowledge among athletes: prevalence, compliance with AIS classification, and awareness of certification programs

BACKGROUND

The use of dietary supplements is widespread among athletes, with intake influenced by factors such as sport-discipline, competitive level, and gender. The Australian Institute of Sport (AIS) has categorized supplements based on scientific evidence regarding their efficacy and safety. Despite extensive global research on dietary supplement use among athletes, data on Polish athletes remain limited. Therefore, this study aimed to evaluate supplement use among Polish athletes, considering their competitive level and gender. Additionally, it assessed whether athletes select supplements in accordance with the AIS classification and examined their awareness of supplement certification programs.

METHODS

This cross-sectional study included 659 Polish athletes (309 women, 350 men) from various sports, representing both professional (57.7%) and nonprofessional (42.3%) levels. An online questionnaire was used to assess dietary supplement consumption, sources of information regarding supplementation, and knowledge of anti-doping and supplement certification programs. Supplement use was categorized according to the AIS classification (Groups A - D). Statistical analyses, including chi-square tests and Mann - Whitney U tests, were conducted to evaluate differences between professional and nonprofessional athletes, as well as between male and female participants.

RESULTS

A high prevalence of dietary supplement use (91.1%) was observed among Polish athletes, with no significant differences between professional (95.8%) and nonprofessional (94.3%) athletes or between men (92.0%) and women (90.0%). The most frequently consumed supplements were sports drinks (63.9%), electrolyte supplements (51.6%), and isolated protein supplements (54.6%), vitamin D (71.6%), vitamin C (59.8%), with significantly higher intake among professional athletes. Male athletes were more likely than females to consume caffeine (p < 0.001), creatine (p < 0.001), and β-alanine (p < 0.001). Melatonin use was significantly higher among professionals (p < 0.05). Awareness of WADA regulations was moderate (72.7%), but knowledge of supplement certification programs was low, with only 18.2% of professional athletes familiar with Informed Sport, and 10.7% with the Cologne List. Social media was the most common source of supplement information (41.9%), while only 17.6% of athletes consulted qualified specialists in sports nutrition and supplementation area.

CONCLUSIONS

This study highlights the widespread use of dietary supplements among Polish athletes, irrespective of competitive level or gender. While many athletes select supplements from AIS Group A, their knowledge of AIS classification and supplement certification programs remains limited. The high reliance on social media for supplement information, combined with the lack of professional guidance, underscores the need for improved education on safe and effective supplementation practices. Given the risks associated with supplement contamination, targeted initiatives should enhance athletes' awareness of anti-doping regulations and certified supplement options.

Hypercaloric 16:8 time-restricted eating during 8 weeks of resistance exercise in well-trained men and women

BACKGROUND

The effectiveness and practicality of time-restricted eating (TRE) when trying to maximize muscle mass and strength is unclear. Thus, we examined the effects of a hypercaloric 16:8 TRE approach during supervised progressive resistance exercise.

METHODS

Seventeen healthy and well-trained men (n = 10) and women (n = 7) were randomly assigned to TRE or control (FED). Both groups consumed a 10% hypercaloric high-protein (2.2 g/kg/d) diet and performed supervised resistance exercise 4× per wk for 8 wk. TRE consumed all calories within an 8 h window starting at least 1 h post-exercise, while FED consumed the same number of calories throughout the day.

RESULTS

Eating windows were significantly different (TRE: 7.9 ± 0.1 h vs. FED: 13.2 ± 0.6 h). Calorie, carbohydrate, fat, and protein intake did not differ statistically between groups. Total exercise volume was significantly lower in TRE than FED (6,960 ± 287 vs. 7,334 ± 289 repetitions), as were subjective daily energy ratings (week 4 = -1.41; p = 0.04, week 8 = -1.04; p = 0.06). Both groups increased maximal upper and lower body strength (1RM) and muscular endurance (ME); however, gains in squat 1RM were 4.0 ± 1.9 kg lower in TRE (p = 0.05). Both groups increased fat-free mass similarly (TRE: 2.67 kg; FED: 1.82 kg, p = 0.04), but FED added 1.4 ± 0.6 kg more fat mass (p = 0.04). Subjective mood and sleep ratings did not change in either group.

CONCLUSIONS

16:8 TRE is viable during periods of muscle size, strength, and endurance development in well-trained young men and women when engaging in progressive resistance exercise and eating in a caloric surplus with adequate protein. However, the differences in total training volume, squat 1RM, fat mass accumulation, and energy are notable and practically relevant. These findings should be considered within the broader context of an individual's goals, lifestyle, preferences, and exercise demands.

General and sport-specific nutrition knowledge and behaviors of adolescent athletes

INTRODUCTION

Most youth do not meet national nutrition recommendations and overconsume high-calorie, low nutrient-dense foods. Adequate nutritional intake is crucial for growth and development. Nutrition practices play a key role in sports performance and recovery. Nutritional knowledge can affect eating patterns. However, there is limited research on general and sport-specific nutrition knowledge and behaviors of adolescent athletes.

PURPOSE

To examine general and sport-specific nutrition knowledge and behaviors of adolescent athletes.

METHODS

Adolescent athletes were assessed on nutrition knowledge and general and sport-specific nutrition behaviors, including food group consumption, hydration practices, and sport supplement use. Gender differences in general and sport-specific nutrition behaviors were compared using a Mann-Whitney U test. Odds ratios and logistic regression, controlling for age, ethnicity, and years in sport participation were used to determine differences in correct responses between genders. Significance was set at the p < 0.05 level.

RESULTS

One hundred and ninety-four athletes (n = 63 male, n = 132 female, mean age = 14.9 ± 1.63 years) were assessed. Differences in nutrition behaviors were found in fruit, dairy, and sugary beverage consumption between genders. Male athletes were more likely to monitor hydration and use sports supplements. Both males and females scored less than 50% on both general and sport-specific knowledge questions.

CONCLUSION

Adolescent athletes report lower than recommended food group consumption and lack knowledge of general and sport-specific nutrition information. Improvements in these areas can play a significant role in the health and performance of adolescent athletes.

Nutrition in CrossFit® - scientific evidence and practical perspectives: a systematic scoping review

BACKGROUND

CrossFitⓇ sessions and competitions are characterized by high-intensity challenges that combine aerobic and anaerobic activities with short recovery periods. As a result, effective nutritional practices play a crucial role in optimizing performance and enhancing recovery. Therefore, nutritional practices are central to optimizing performance and accelerating recovery. This review aims to summarize current evidence on nutritional and ergogenic aid responses to CrossFitⓇ practice.

METHODS

The search was conducted in four electronic databases (PubMed, Web of Science, Scopus and SportDiscus). Gray literature was also extracted for studies exploring the nutritional habits of CrossFitⓇ participants as well as the ingestion of ergogenic aids. In addition, a meta-analysis was conducted to examine the impacts of dietary habits and ergogenic aids on performance.

RESULTS

Forty-nine studies met the eligibility criteria and were included in the current review. Carbohydrate intake was below the recommendations for athletes, although protein ingestion remains adequate. High-carbohydrate diets had a positive effect on CrossFitⓇ performance. The evidence concerning the effects of a ketogenic diet on performance is limited. When used prior to or during the workout, the impact of carbohydrates on CrossFitⓇ performance was negligible, whereas the effect of caffeine was significant. Ergogenic aids, particularly creatine and protein, are commonly used by CrossFitⓇ participants.

CONCLUSION

The standard diets recommended to CrossFitⓇ participants need to be revised because they are characterized by lower values of carbohydrates. Caffeine should be used prior to or during the CrossFitⓇ sessions. Regarding the impact of ergogenic aids on recovery, future studies are needed.

Changes in aerobic capacity to prepubertal children in sports 12-month training period

INTRODUCTION

This study was long-term and lasted for one year. The study aims to determine whether there is a change in aerobic capacity indicators for prepubertal children when playing football.

METHODS

There were two groups of subjects: children of prepubertal age who trained in football and those who did not attend football. There were 16 participants in the FG (football-trained group) and 15 in the CG (control group) who attended no football lessons. An incremental treadmill test was performed three times with a half-year break to determine the following peak variables: oxygen uptake, stroke volume, cardiac output, and minute ventilation.

RESULTS

After one year of training, the VO2 peak at FG increased from 51.81 ± 6.55 ml/kg/min. to 53.11 ± 5.27 ml/kg/min. (p = 0.0412), stroke volume at FG increased from 41.3 ml/min to 46.4 ml/min. (p = 0.0012), cardiac output (Q) also increased from 8.15 l/min to 9.44 l/min. At stage II and 10.2 l/min at stage III (p = 0.0143) at FG.

CONCLUSIONS

After one year of football training at FG-related VO2, RR (-respiratory rate), and Q also shifted, SV (-stroke volume) also increased significantly, while at UG, results were the opposite- only a few parameters, such as HR, increased significantly, while the others did not.

Caffeine supplementation improved movement patterns and reactive agility in rugby sevens matches in male collegiate players

PURPOSE

Rugby sevens is a high-intensity contact sport often played in two-day tournaments. Caffeine is widely used by rugby players for its performance-enhancing effects. This study aimed to investigate the impact of caffeine supplementation on various performance metrics, including distance covered at different speeds, acceleration, deceleration, collisions, and repeated high-intensity efforts across four matches over two consecutive days in collegiate male rugby sevens players. Reactive agility, a key performance attribute in rugby sevens, was also assessed before each match.

METHODS

A position-matched, double-blind, randomized crossover design was employed, with six male collegiate rugby players (mean height: 1.78 ± 0.09 m, mean weight: 81.3 ± 9.2 kg, mean age: 21.5 ± 0.8 years) participating in two trials. Each trial consisted of a two-day tournament, with two matches per day. Performance was monitored using global positioning system units to track distance covered in various speed zones, as well as total distance, frequency of acceleration, deceleration, collisions, and repeated high-intensity efforts.

RESULTS

The results indicated that in the placebo trial, participants covered significantly more distance at a walking pace (0-6 km/h) in match 4 compared to match 3 (match 3: 480.3 ± 32.7 m; match 4: 629.4 ± 21.3 m, p < 0.001, d = 0.117). In the caffeine trial, players covered significantly more distance at a jogging pace (6-12 km/h) in match 4 compared to the placebo trial (caffeine: 405.9 ± 9.8 m; placebo: 303.6 ± 20.2 m, p = 0.015, d = 1.693). Reactive agility was significantly better in the caffeine trial before match 3 (caffeine trial: 1.80 ± 0.17 s; placebo trial: 2.07 ± 0.18 s, p = 0.038, d = 0.858).

CONCLUSIONS

Caffeine supplementation at 3 mg/kg may increase jogging and reduce walking and standing in the final match of a two-day rugby sevens tournament, while also improving reactive agility on the second day. This suggests that by mitigating fatigue in the later stages of the tournament, caffeine allowed players to shift from low-intensity activities to higher-intensity efforts. These adjustments may improve both offensive and defensive performance during rugby sevens matches. Therefore, rugby sevens players could benefit from taking caffeine supplements in the later stages of 2-day tournaments to optimize their performance.

Pre-sleep casein ingestion with probiotic strains improves anaerobic power and lower-body-specific strength and power performance in soccer players

BACKGROUND

Probiotics comprise various strains that offer numerous health benefits. Researchers have recently focused on the relationship between probiotic consumption and improved gut microbiota function, enhanced digestion, increased nutrient absorption, and enhanced sports performance. Therefore, the present study investigated the effects of pre-sleep casein intake, coupled with probiotic strains, on soccer players' anaerobic power, lower-body-specific strength, and power performance.

METHODS

A randomized, double-blinded, and placebo-controlled study was conducted with forty-four male soccer players (Age: 22.81 ± 2.76 years, Height: 177.90 ± 6.75 cm, Weight: 67.42 ± 8.44 kg). The participants underwent the isokinetic strength, Wall-squat, and running-based anaerobic sprint (RAST) tests initially; then, they were randomly divided into four groups: probiotics (PRO), casein (CAS), probiotics with casein (PRO+CAS), and placebo (PLA). The PRO groups were given one probiotic capsule (containing eight bacterial strains: Lactiplantibacillus plantarum BP06, Lacticaseibacillus casei BP07, Lactobacillus acidophilus BA05, Lactobacillus bulgaricus BD08, Bifidobacterium infantis BI04, Bifidobacterium longum BL03, Bifidobacterium breve BB02, and Streptococcus thermophilus BT01, with a total dose of 4.5 × 1011 CFU) during dinner, while the CAS groups consumed 20 grams of casein powder 45 minutes before bed. The PRO+CAS group was given one probiotic capsule during dinner and 20 grams of casein powder 45 minutes before bed. The participants in the PLA group were given one red capsule (containing 5 grams of starch) during dinner. All participants were instructed to take the supplements only on training days, three times a week for four weeks. Additionally, isokinetic strength parameters, including absolute peak torque (APT) and average rate of force development (AvRFD), were measured for the knee extensors (ext) and flexors (flx) muscles (concentric phase at angular velocities of 60°/s and 180°/s, using the dominant leg). One-way analysis of covariance (ANCOVA) or Quade tests with a significance level of p < 0.05 was used to analyze the collected data.

RESULT

The current study's findings indicated that APT-180°/s (ext) significantly increased in CAS (p = 0.008) and PRO+CAS (p = 0.003) compared to PLA. Additionally, the AvRFD-180°/s (ext) increased significantly in the PRO compared to the PLA (p = 0.007). Also, the AvRFD-60°/s (flx) increased significantly in the PRO+CAS group compared to the PLA (p = 0.014), CAS (p = 0.001), and PRO (p = 0.007). Furthermore, the AvRFD-180°/s (flx) increased significantly in the PRO+CAS compared to the CAS (p = 0.010). Moreover, the RAST average power increased dramatically in PRO+CAS compared to PLA (p = 0.003) and CAS (p = 0.02). Additionally, the Wall-squat test demonstrated a significant increase in PRO+CAS compared to PLA (p = 0.001) and PRO (p = 0.001). However, there were no significant differences in the APT-60°/s (ext&flx), APT-180°/s (flx), and AvRFD-60°/s (ext) between groups (p > 0.05).

CONCLUSION

The simultaneous consumption of casein and probiotics significantly improved anaerobic power, isokinetic strength, and lower-body muscular endurance in male soccer players. These enhancements were more pronounced than those observed with casein or probiotics alone, as supported by statistical significance and effect sizes. The findings suggest a synergistic benefit of combined supplementation for athletic performance.

Microbial diversity and fitness in the gut-brain axis: influences on developmental risk for Alzheimer's disease

The gut-brain axis (GBA) denotes the dynamic and bidirectional communication system that connects the gastrointestinal tract and the central nervous system (CNS). This review explored this axis, focusing on the role of microbial diversity and fitness in maintaining gastrointestinal health and preventing neurodegeneration, particularly in Alzheimer's disease (AD). Gut dysbiosis, characterized by the imbalance in populations of beneficial and harmful bacteria, has been associated with increased systemic inflammation, neuroinflammation, and the progression of AD through pathogenic mechanisms involving amyloid deposition, tauopathy, and increased blood-brain barrier (BBB) permeability. Emerging evidence highlighted the therapeutic potential of probiotics, dietary interventions, and intermittent fasting in restoring microbial balance, reducing inflammation, and minimizing neurodegenerative risks. Probiotics and synbiotics are promising in helping improve cognitive function and metabolic health, while dietary patterns like the Mediterranean diet were linked to decreased neuroinflammation and enhanced gut-brain communication. Despite significant advancement, further research is needed to elucidate the specific microbial strains, metabolites, and mechanisms influencing brain health. Future studies employing longitudinal designs and advanced omics technologies are essential to developing targeted microbiome-based therapies for managing AD-related disorders.

Safety of creatine supplementation: analysis of the prevalence of reported side effects in clinical trials and adverse event reports

BACKGROUND

Individual studies have indicated that creatine supplementation is generally well tolerated and not associated with clinically significant side effects. Nevertheless, anecdotal reports about side effects persist primarily from popular and social media and on the Internet.

METHODS

This study evaluated side effects reported from 685 human clinical trials on creatine supplementation, worldwide adverse event report (AER) databases, and performed a social media sentiment analysis. The presence of side effects (No, Yes) in studies was evaluated using chi-squared analysis. The frequency of side effects among study participants was evaluated using a multivariate analysis of variance.

RESULTS

A total of 13,452 participants in 652 studies ingested placebos (PLA), while 12,839 participants in 685 studies consumed creatine (Cr). Nearly all studies (95%) provided CrM at an average dose of 0.166 [0.159, 0.173] g/kg/d (about 12.5 g/d) for 64.7 [52.0, 77.3] days in studies lasting up to 14 yrs. Side effects were reported in 13.2% of studies in the PLA groups and 13.7% of studies in the Cr-supplemented groups, with no significant differences observed between the groups (p = 0.776). There was a slightly higher percentage of studies reporting gastrointestinal (GI) issues (PLA 4.3%, Cr 4.9%, p < 0.001) and muscle cramping/pain (PLA 0.9%, Cr 2.9%, p = 0.008) with Cr supplementation, but not when the total number of participants in these studies was evaluated (muscle cramping/pain: PLA 0.07%, Cr 0.52%, p = 0.085; GI issues: PLA 4.05%, Cr 5.51%, p = 0.820). Additionally, there was no significant multivariate difference among the 49 side effects evaluated (p = 0.340), no significant difference in the total frequency of side effects reported among participants (PLA 4.21%, Cr 4.60%, p = 0.828), and no significant differences in any of the other side effect evaluated that included markers of renal function and health. The percentage prevalence of side effects was small, with differences between groups generally within ± 0.5%. Analysis of 28.4 million AERs revealed that the mention of Cr was rare (0.00072%), 46.3% of CAERS had no Cr in the products listed, and 63% of AERs with Cr in the product involved the use of other types of Cr or ingestion with other supplements or drugs. The overall sentiment analysis was neutral about perceptions of Cr, although those with strong perceptions about Cr were slightly more negative.

CONCLUSION

Results demonstrate that Cr supplementation does not increase the prevalence or frequency of side effects when compared to participants ingesting PLA. Therefore, claims that Cr supplementation increases the risk of side effects are unfounded.

Skeletal response to Yoda1 and whole-body vibration in mice varied with animal age, bone compartment, treatment duration, and radiation exposure

In this study, we investigated the skeletal effects of Yoda1, an agonist of the mechanosensitive Piezo1 channels, and whole-body vibration (WBV), alone and combined, in young mice (8-week-old) and in mature (31- to 36-week-old) mice after radiation exposure. Our goal was to determine whether the two mechanobiology-based interventions, known to induce anabolic response individually in young subjects, could promote bone health of older subjects undergoing cancer treatments such as radiotherapy. Our hypothesis was that the combination of Yoda1 and WBV could improve young skeletons and protect mature skeletons after radiotherapy better than Yoda1 or WBV alone. Our in vivo experiments demonstrated (1) that Yoda1 (5 mg/kg body weight) alone or combined with WBV (0.3 g, 13 Hz, 30 min/day, 5 days/week, 4 weeks) enhanced bone growth similarly (∼2 folds relative to nontreated controls) in young mice; (2) that mature mice were unresponsive to individual interventions but exhibited less polar moment of inertia loss (-56 %) in the tibiae receiving the combination of Yoda1 and WBV (15 min/day) but no radiation exposure; and (3) that the contralateral tibiae receiving fractionated radiation (2 × 8 Gy over three days) did not show different treatment responses in Week 4, while they responded to the combination therapy (increased cortical bone formation) in Week 2. Interestingly, pair comparisons of the irradiated and non-irradiated tibiae of the same animals revealed that radiation exposure resulted in decreased trabecular bone loss regardless of the treatments and increased the percentage of tibiae maintaining better cortical polar moment of inertia and cortical area in the groups receiving Yoda1 or the combination therapy. The complex skeletal responses to Yoda1 and/or WBV were compartment specific (cortical or trabecular bone) and dependent on animal age, radiation exposure, and treatment duration. This study partially supported our original hypothesis, while suggesting the need of finetuning the Yoda1 and WBV regimens and elucidating the underlying mechanisms in order to effectively treat age and radiation induced bone loss.

Effects of high-intensity interval training vs. moderate-intensity continuous training on arterial stiffness in adults: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Arterial stiffness (AS) is regarded as an independent predictor of cardiovascular events and all-cause mortality, and it is significantly associated with global mortality rates. Physical activity (PA) plays a positive role in reducing AS and improving cardiovascular health. The aim of this study is to compare the differences between high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) in their effects on reducing AS.

METHODS

We conducted a comprehensive search of the PubMed, Cochrane, Embase, Web of Science, and EBSCO electronic databases, covering the period from their inception to January 10, 2025. We used a fixed-effect model to compare the changes in pulse wave velocity (PWV) before and after intervention between the HIIT group and the MICT group. Data were reported using the weighted mean difference (WMD) and 95 % confidence interval (95 % CI).

RESULTS

This study included 619 participants from 22 studies. Compared to MICT, HIIT demonstrated a more significant reduction in PWV (-0.10 m/s [95 % CI:0.16 to -0.03], P = 0.005). Additionally, we found that HIIT was superior in reducing CF-PWV (-0.10 m/s [95 % CI:0.17 to -0.02], P = 0.01).

CONCLUSION

HIIT is more effective than MICT in improving PWV and promoting arterial health in adults.

Impact of infrapatellar fat pad injury severity on subsequent patellofemoral cartilage degeneration following acute ACL tear

Objective

The infrapatellar fat pad (IFP) is important in the homeostasis of the knee joint due to its structural and immune-modulating properties. This study investigates the relationship between IFP injury severity during acute Anterior Cruciate Ligament (ACL) tears, and the future development of Patellofemoral Compartment (PFC) chondrosis.

Methods

Adult participants aged 18-45 years old who were known to have first-time ACL tears between 01/01/2009 and 10/1/2022 were included. Patients with concomitant knee pathologies at the time of injury were excluded from the study. All participants received ACL reconstruction surgery and had follow-up MRIs conducted within two years postoperatively. Preoperative IFP edema levels were assessed alongside both pre-and postoperative PFC. We analyzed the relationship between the initial IFP edema and future PFC progression on subsequent MRI scans.

Results

A total of 69 participants were included in this study. No significant correlation was found between the severity of initial IFP injury and the initial presence of PFC chondrosis (r = -0.04, P = 0.61). However, a significant positive correlation was observed between the severity of initial IFP injury and the future progression of PFC chondrosis (r = 0.44, P < 0.001). Additionally, a significant difference in the progression of PFC chondrosis was noted when comparing grade 1 to grade 2 IFP injuries (P = 0.001). No significant difference in PFC chondrosis development was identified when comparing grade 2 to grade 3 IFP injuries (P = 0.72).

Conclusion

Our study underscores the potential role of the IFP in preserving cartilage homeostasis by establishing a link between the severity of IFP injury and the subsequent development of PFC following ACL injury.

Ecological momentary assessment of between- and within-person sleep quality as a predictor of disordered eating behaviors among young women with disordered eating

Although disordered eating and sleep problems often co-occur, there has been limited research on mechanisms underlying their association. Previous studies using ecological momentary assessment (EMA) to evaluate links between sleep quality and disordered eating behaviors (e.g., loss-of-control eating, restricting, purging, excessive exercise) have largely not found statistically significant temporal associations; however, studies with larger samples are warranted. We used EMA to evaluate sleep quality and next-day engagement in disordered eating behaviors. Participants were 137 women aged 18-25 (M = 20.22, SD = 1.78) with current disordered eating behaviors (DEBs). Participants completed seven days of EMA, in which they reported the past night's sleep quality and answered six surveys daily about engagement in DEBs. DEBs were aggregated at the day level and dichotomized as present or absent (n = 438 days). We conducted four multilevel logistic regressions, nesting days within subjects. We predicted loss-of-control eating, purging, restricting, and excessive exercise using past night's sleep quality and survey day as fixed effects with random intercepts by subjects. Results indicated that neither between- nor within-person sleep quality predicted engagement in any DEBs (all ps > .10). Findings replicated past studies that found no or few prospective associations between sleep quality and engagement in DEBs. It is possible that other sleep metrics (e.g., variability in sleep and wake timing) may predict DEBs or associations may vary by gender. Future studies should examine subjective and objective sleep indices across genders to better understand potential links between sleep and DEBs.

Hyperbaric oxygen therapy as an adjunt treatment for glioma and brain metastasis: a literature review

The incidence and mortality rates of malignant tumors are increasing annually, with gliomas and brain metastases linked to a poor prognosis. Hyperbaric oxygen therapy is a promising treatment modality for both gliomas and brain metastases. It can alleviate tumor hypoxia and enhance radiosensitivity. When combined with other treatments for gliomas, this therapy has the potential to enhance survival rates. This review addresses the progress in research on the use of hyperbaric oxygen therapy combined with radiotherapy. For brain metastases, the combination of hyperbaric oxygen therapy and stereotactic radiosurgery is both feasible and advantagenous. This combination not only offers protection against radiation-induced brain injury but also supports the recovery of neurological and motor functions. The incidence of adverse reactions to hyperbaric oxygen therapy is relatively low, and it is safe and manageable. Future efforts should be made to investigate the mechanisms by which hyperbaric oxygen therapy combined with radiotherapy treats gliomas and brain metastases, optimize protection of the combined treatment against brain injury, minimizing adverse reactions, conducting multidisciplinary research and clinical trials, and training healthcare providers to facilitate broader clinical application.

Strategies for preventing anterior cruciate ligament injuries in athletes: Insights from a scoping review

Background and aims

Anterior cruciate ligament (ACL) injuries significantly impact young athletes, leading to long-term physical, psychological, and socioeconomic consequences. There is an urgent need to develop effective preventive strategies. This scoping review aims to evaluate modifiable and non-modifiable risk factors for ACL injuries and assess existing preventive strategies.

Methods

A comprehensive literature search was performed on November 20, 2024, across databases including Embase, PubMed, Web of Science, Google Scholar, and Cochrane Library. Articles published between 2000 and 2024 focusing on ACL injury prevention were included, while editorial content, non-clinical studies, and non-English publications were excluded.

Results

The search yielded 322 articles, narrowing down to 94 after deduplication. After title screening, 46 studies progressed to full review, ultimately leading to the inclusion of 14 relevant manuscripts. Key findings indicate that ACL injuries result from various factors, with female athletes being 2.2 times more susceptible. Genetic predispositions linked to collagen-related SNPs and biomechanical patterns, such as landing techniques and knee positioning, were identified as significant contributors. Effective preventive programs integrated strength training, neuromuscular training, and advanced technology, including wearable devices and video analysis.

Conclusion

The study reinforces the importance of a personalized, multifaceted approach to ACL injury prevention, focusing on risk stratification and optimizing training strategies alongside technological advancements. Implementing these strategies can significantly mitigate the risk of ACL injuries in high-risk populations.

Molecular hydrogen inhalation modulates resting metabolism in healthy females: findings from a randomized, double-blind, placebo-controlled crossover study

Initially, molecular hydrogen was considered a physiologically inert and non-functional gas. However, experimental and clinical studies have shown that molecular hydrogen has anti-inflammatory, anti-apoptotic, and strong selective antioxidant effects. This study aimed to evaluate the effects of 60 minutes of molecular hydrogen inhalation on respiratory gas analysis parameters using a randomized, double-blind, placebo-controlled, crossover design. The study was conducted at Faculty of Physical Culture, Palacký University Olomouc from September 2022 to March 2023. Twenty, physically active female participants aged 22.1 ± 1.6 years who inhaled either molecular hydrogen or ambient air through a nasal cannula (300 mL/min) for 60 minutes while resting were included in this study. Metabolic response was measured using indirect calorimetry. Breath-by-breath data were averaged over four 15-minute intervals. Compared with placebo (ambient air), molecular hydrogen inhalation significantly decreased respiratory exchange ratio and ventilation across all intervals. Furthermore, the change in respiratory exchange ratio was negatively correlated with body fat percentage from 30 minutes onwards. In conclusion, 60 minutes of resting molecular hydrogen inhalation significantly increased resting fat oxidation, as evidenced by decreased respiratory exchange ratio, particularly in individuals with higher body fat percentages.