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J Int Soc Sports Nutr [JOURNAL]

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Acute effect of a multi-ingredient pre-workout supplement on pacing and kinetic expression during shorter and longer bouts of high intensity functional training.

Mangine GT, Staples C, Henley JW … +7 more , Hines A, McGeehan KC, Chaves W, King W, Esmat TA, McLester JR, Grazer JL

J Int Soc Sports Nutr · 2025 Dec · PMID 40627430 · Full text

BACKGROUND: High-intensity functional training (HIFT) varies daily workout programming, and trainees are often tasked with completing "as many repetitions as possible" (AMRAP) within a set time. Successful performance de... BACKGROUND: High-intensity functional training (HIFT) varies daily workout programming, and trainees are often tasked with completing "as many repetitions as possible" (AMRAP) within a set time. Successful performance depends on fatigue management skills and maintaining a consistent expression of force and velocity when performing and transitioning between exercises over the duration of the workout. Multi-ingredient pre-workout (MIPS) supplement formulations often contain ingredients shown to facilitate energy availability and mitigate fatigue, and therefore, might positively affect HIFT performance. This study aimed to assess a multi-ingredient pre-workout supplement's acute effect on pacing and the expression of kinetics throughout a 5- and 15-minute HIFT-style AMRAP. METHODS: Twelve men and 10 women (29.3 ± 7.1 years, 171 ± 7 cm, 80.5 ± 15.6 kg) with HIFT experience ( > 2 years) completed four weekly visits, consuming either the supplement (S) or placebo (P) before a 5- or 15-minute AMRAP of rowing (9 or 7 Calories for men and women), six barbell thrusters (43.1 kg and 29.5 kg), and three jumps onto a box (0.61 m and 0.51 m). Video recordings of each workout were analyzed to quantify repetitions completed, volume load (kg), and pace (i.e. time spent on each workout component, repetition completion rate). The expression of kinetics and related factors were quantified during rowing via the ergometer microcomputer (Calories per stroke, power [W], and strokes per minute), during barbell thrusters by a 3D motion tracking system (barbell velocity [m · sec] and power [W]), and by in-ground force plates during box jumps (peak and mean force [N], time-to-peak force [ms], rate of force development [RFD; N·sec], and impulse [N·sec]). The averages, standard deviation, and slope across rounds were calculated for all pacing and kinetic variables for separate 3-way (sex × workout durations × supplement conditions) repeated measures analysis of variance comparisons. RESULTS: Men and women completed a greater total volume load (~4.4%,  = 0.009) and repetitions at a faster rate (~2.2%,  = 0.043) during S compared to P and regardless of workout duration. These were best explained by participants completing a greater rowing volume load (~8.1%,  = 0.009) by averaging more powerful strokes (~7.0%,  = 0.005), more consistent transitions to rowing (~11.0%,  = 0.020), and a trend for faster barbell thruster repetition completion rate (~2.3%,  = 0.077). Interestingly, participants varied more across rounds during S (~16.8-29.4%,  < 0.05) in box jump force expression (peak force, mean force, time-to-peak force, and RFD). No other differences were seen between supplement conditions, only expected differences were seen between men and women and between workout durations. CONCLUSIONS: Although it did not affect repetitions completed, the multi-ingredient pre-workout supplement led to a greater volume load and faster overall repetition completion rate. These were primarily due to improvements surrounding rowing performance and evidence of an effect on thruster pacing and box jump force expression. The effects were similar in both sexes and workout durations. Athletes might consider this MIPS formulation to improve HIFT performance, particularly when a workout contains a component that requires sustained, continuous effort.

Combined exercise training and dietary interventions versus independent effect of exercise on ectopic fat in individuals with overweight and obesity: a systematic review, meta-analysis, and meta-regression.

Kazeminasab F, Mohebinejad M, Mahboobi MH … +4 more , Nojoumi M, Belyani S, Bagheri R, Dutheil F

J Int Soc Sports Nutr · 2025 Dec · PMID 40619882 · Full text

AIM: While it is well established that reducing ectopic fat can help prevent insulin resistance in individuals with overweight or obesity, it remains unclear whether diet alone, exercise alone, or their combination is mo... AIM: While it is well established that reducing ectopic fat can help prevent insulin resistance in individuals with overweight or obesity, it remains unclear whether diet alone, exercise alone, or their combination is most effective in reducing specific ectopic fat depots. Therefore, the objective of this study was to investigate the effects of diet-only, and combined diet-plus-exercise interventions versus exercise only on ectopic fat reduction, and weight loss in adults with overweight or obesity. METHODS: Web of Science, PubMed, and Scopus were searched for original articles, published until 1 March 2024 (no limitation on publication dates) that included diet only/or exercise and diet versus exercise alone on body weight, and ectopic fat in adults with overweight or obesity. Weighted mean differences (WMD) for body weight, liver fat, standardized mean differences (SMD) for visceral fat area (VFA), and intramuscular triglyceride (IMTG), and 95% confidence intervals (95% CI) were determined using random-effects models. Studies using noninvasive imaging techniques such as Computerized Tomography (CT), Magnetic Resonance Imaging (MRI), and hydrogen-based Magnetic Resonance Spectroscopy (H-MRs) for ectopic fat were included in this meta-analysis. RESULTS: A total of 17 studies, including 732 participants aged 24.27 to 70.5 years (309 participants with metabolic diseases, and 423 without metabolic diseases) and 38 intervention groups, met the inclusion criteria. The combined intervention of exercise and diet significantly reduced body weight compared to exercise alone [WMD = -2.85 kg,  = 0.001], with significant reductions observed in both adults with and without metabolic disease, and for interventions lasting more than 12 weeks. However, the combined intervention did not significantly reduce liver fat, VFA, or IMTG compared to exercise alone. Diet-only interventions significantly reduced body weight compared to exercise alone [WMD = -2.57 kg,  = 0.010], but did not significantly affect liver fat, VFA, or IMTG. Meta-regression indicated that weight loss was a significant moderator of the effect of combined interventions on VFA (coefficient: -0.15;  = 0.030), but not for other outcomes. Also, based on subgroup analysis by intervention duration, both exercise and calorie restriction interventions in long-term (more than 12 weeks) have been successful in decreasing VFA in adults with overweight/or obesity. CONCLUSION: Combined exercise and dietary interventions are more effective than exercise alone in reducing body weight. While VFA was reduced following long-term interventions of exercise in combination with caloric restriction, our analyses showed no change in liver fat, or IMTG. Additional investigation is required to delve into the processes behind these findings and to pinpoint treatments that efficiently focus on reducing ectopic fat.

Ergogenic effects of supplement combinations on endurance performance: a systematic review and meta-analysis of randomized controlled trials.

Zart S, Fröhlich M

J Int Soc Sports Nutr · 2025 Dec · PMID 40619880 · Full text

BACKGROUND: Supplements such as caffeine and sodium bicarbonate have been found to exert ergogenic effects on endurance performance. However, little is known about the effects of supplementary combinations on performance... BACKGROUND: Supplements such as caffeine and sodium bicarbonate have been found to exert ergogenic effects on endurance performance. However, little is known about the effects of supplementary combinations on performance parameters. This review and meta-analysis aimed to summarize and analyze studies that investigated the effects of performance-enhancing supplements in combination and isolation on endurance (>35 s). METHODS: A structured search was conducted in accordance with the PRISMA® statement and PICOS guidelines in the PubMed, Scopus and Dimensions databases in January 2024 without restriction to specific years. Sixteen studies that compared isolated and combined supplementation with placebo in an identical situation and tested their effects on endurance performance (time, distance, power) were included. The studies were all blinded, randomized controlled crossover studies that showed some concerns about risk of bias. Meta-analyses could be calculated for the supplement combinations caffeine (CAF) with sodium bicarbonate (SB) and CAF with beetroot juice (BJ), as sufficient studies were available for these two combinations. For the comparisons of the trials (e.g. placebo (PLA) vs. CAF; PLA vs. BJ; PLA vs. CAF-BJ; CAF-BJ vs. CAF; CAF-BJ vs. BJ), five studies each were included in the meta-analyses. A random-effects model and pooled standardized mean differences (SMD) according to Hedges' g were used for the ergogenic effect. RESULTS: The results showed no significant differences for either the isolated (CAF/PLA [CAF+SB studies]: SMD = 0.30, 95% CI [-0.12, 0.73],  = 0.16; SB/PLA: SMD = 0.31, 95% CI [-0.18, 0.80],  = 0.22; CAF/PLA [CAF+BJ studies]: SMD = 0.28, 95% CI [-0.08, 0.63],  = 0.13; BJ/PLA: SMD = 0.02, 95% CI [-0.33, 0.38],  = 0.90) or the combined supplement intake (CAF-SB/PLA: SMD = 0.43, 95% CI [-0.05, 0.91],  = 0.08; CAF-BJ/PLA: SMD = 0.33, 95% CI [-0.03, 0.69],  = 0.07) compared with the PLA trial. The subgroup analysis "test protocols" showed a borderline significance for cycling tests for the comparison of CAF-BJ with PLA (SMD = 0.39, 95% CI [-0.00, 0.78],  = 0.05). In addition, no significant differences were found between the isolated supplements and the co-ingestion (CAF-SB/CAF: SMD = 0.12, 95% CI [-0.30, 0.54],  = 0.57; CAF-SB/SB: SMD = 0.12, 95% CI [-0.29, 0.54],  = 0.56; CAF-BJ/CAF: SMD = 0.06, 95% CI [-0.30, 0.41],  = 0.76; CAF-BJ/BJ: SMD = 0.28, 95% CI [-0.08, 0.64],  = 0.13). According to the I statistics (0-22%), there was no or a low heterogeneity in the studies. CONCLUSIONS: In summary, it can be stated that the current state of research with few small studies and different methodological approaches (e.g. different types of sport, test protocols) only allows a limited reliable statement to be made about the combined effect of supplements. Although not statistically significant, trends observed in the forest plots suggest a potential advantage of combined supplement intake. Athletes should therefore test a possible benefit under their competition conditions. Further studies with a homogeneous design are required in the future in order to obtain more clarity about the tendencies of a combined ergogenic effect.

Measuring bioelectric impedance outputs following coffee consumption in healthy adults using an 8-electrode segmental BIA device.

Chamberlin C, Lena A, Radia D … +6 more , Rees D, Lodge J, Rutherford J, da Silva Dos Santos BC, Patel B, McLaren S

J Int Soc Sports Nutr · 2025 Dec · PMID 40611594 · Full text

INTRODUCTION: Bioelectric impedance analysis (BIA) is increasingly used to measure body composition in athletic, clinical and research settings. The reliability of BIA measurements relies on following procedures carefull... INTRODUCTION: Bioelectric impedance analysis (BIA) is increasingly used to measure body composition in athletic, clinical and research settings. The reliability of BIA measurements relies on following procedures carefully. However, some practices for ensuring reliable measures may be unnecessarily restrictive. Previous research using BIA outputs as study outcome measures, has required participants to avoid coffee and caffeine-containing foods and beverages prior to measurements. The aim of this study was to determine whether BIA outputs are affected by coffee consumption at different caffeine concentrations. METHODS: This study used a blinded, randomized, cross-over trial design. Participants ( = 13) received one of three treatments per visit: 200 mL hot water (80°C) mixed with 5 g instant coffee, 2.5 g instant coffee with 2.5 g decaffeinated coffee, or 5 g decaffeinated instant coffee. Body composition and fluid parameters were measured over 50 minutes using a Seca mBCA 515 device. RESULTS: The treatment predictor ( > 0.05) and sex-time-treatment interaction for all outcomes was found to be non-significant ( > 0.05). The time predictor was statistically significant ( < 0.05) for impedance, resistance and reactance but not for phase angle ϕ50 ( = 0.731), ϕ5 ( = 0.059) or urine osmolality ( = 0.066). The sex predictor was statistically significant for Z ( = 0.001), Z ( = 0.002), R ( = 0.001), R ( = 0.002), ϕ ( = 0.01), ϕ ( = 0.049), fat mass (%) ( = 0.016) and fat free mass (%) ( = 0.016). The effect size for this predictor was η < 0.336. A significant sex-time interaction was found for Z ( = 0.025) with a small effect size (η < 0.01). Effect sizes for the treatment predictor and time-treatment interaction were found to be small (η < 0.01). Effect size for the time predictor was small (η > 0.01). CONCLUSION: Changes in impedance, resistance and reactance were detected over the course of the experiment, and these changes were greater than could be explained by the technical error of measurement. However, the amount of caffeine in coffee did not affect BIA outputs. Effect sizes were small, suggesting little practical significance of drinking coffee before taking BIA measurements. Therefore, coaches, athletes, researchers and clinicians may be able to obtain reliable BIA measurements even when coffee has been consumed up to 50 minutes prior to measurements, however, fluid consumption and being adequately hydrated should still be considered.

Sex differences in energy intake, sweat rate, and electrolyte loss among world-class archers during competition.

Esen O, Goodall S

J Int Soc Sports Nutr · 2025 Dec · PMID 40611367 · Full text

BACKGROUND: Limited evidence reports energy and macronutrient intake during competitive archery and whether any sex differences exist. Understanding these factors will provide insights into physiological demands and coul... BACKGROUND: Limited evidence reports energy and macronutrient intake during competitive archery and whether any sex differences exist. Understanding these factors will provide insights into physiological demands and could inform more effective strategies to optimize performance for all archers in this precision-demanding sport. This study aimed to evaluate sweat rate (SR), sweat electrolyte loss, and energy intake (EI) in world-class archers throughout competition. METHOD: Eight (4 females) elite-standard archers (age: 21 ± 2 and 19 ± 1 years; body mass: 65.1 ± 2.8 and 60.1 ± 4.1 kg; stature: 179.3 ± 5.1 and 162.3 ± 0.8 cm, for males and females, respectively) from the Turkish National Archery Team participated. Data were collected over four days; assessments of hydration, SR, sweat composition ([Na] and [K]), and nutritional intake were completed at the same time each day. RESULTS: Male archers consumed more total energy (2,889 vs. 2,353 kcal,  = 0.007) and carbohydrates (5.3 vs. 3.9 g/kg,  = 0.046) compared to females, with intake fluctuating based on competition demands (i.e. match duration, and the total distance walked). SR and sweat [K] loss, were greater in males compared to females ( ≤0.006). In contrast, no sex differences were observed in other hydration parameters (sweat [Na] loss, urine-specific gravity). Moreover, all archers maintained adequate hydration status throughout the competition, with no differences in pre- and post-competition hydration levels ( > 0.05). CONCLUSION: This study expands on previous research by incorporating sex-specific analyses, demonstrating that while energy and carbohydrate intake varies between male and female archers, hydration-related variables remain consistent.

Low-dose caffeine enhances cognitive processing but not physical performance in fatigued taekwondo athletes: a randomized crossover trial.

Nana A, Ramyarangsi P, Jamwai L … +3 more , Hiranphan P, Siripornpanich V, Ajjimaporn A

J Int Soc Sports Nutr · 2025 Dec · PMID 40581775 · Full text

BACKGROUND: Caffeine is commonly used to combat fatigue and enhance both cognitive and physical performance. However, its effects on neurophysiological responses and sport-specific performance following fatigue induction... BACKGROUND: Caffeine is commonly used to combat fatigue and enhance both cognitive and physical performance. However, its effects on neurophysiological responses and sport-specific performance following fatigue induction remain unclear, particularly in combat sports such as Taekwondo. This study investigated the effects of a 200 mg caffeine dose on physiological markers, electroencephalographic (EEG) brainwave activity, auditory P300 event-related potentials (ERPs), and Taekwondo-specific performance following combined mental and physical fatigue. METHODS: Thirteen male Taekwondo athletes participated in a randomized, double-blind, crossover study with caffeine (CAF) and placebo (PLA) conditions. Measurements were taken at baseline (pre-supplementation), 30 minutes post-supplementation (post-Sup), and after fatigue induction (post-I). Physiological parameters (heart rate, blood glucose, blood lactate, and ratings of perceived exertion), EEG brainwave activity during resting eyes-open conditions, auditory P300 ERPs, and Taekwondo-specific agility (TSAT) were assessed at all time points. RESULTS: Caffeine significantly reduced delta wave power at frontal and parieto-occipital sites at post-Sup ( < 0.05), indicating decreased cortical drowsiness; however, this effect was not sustained at post-I ( > 0.05). P300 amplitude significantly increased in the CAF condition compared to PLA from post-Sup to post-I at the central and parietal electrode sites ( < 0.05), while P300 latency remained unchanged ( > 0.05). No significant differences were observed in reaction time, accuracy, or error rate in the auditory oddball task or TSAT performance across conditions ( > 0.05). Similarly, physiological parameters remained unchanged between groups ( > 0.05). CONCLUSION: A single 200 mg dose of caffeine reduced central fatigue and enhanced cognitive processing, as reflected by suppressed delta wave activity at post-Sup and increased P300 amplitude at post-I. However, caffeine did not influence physiological responses or Taekwondo-specific performance. These findings suggest that low-dose caffeine primarily benefits cognitive function rather than physical performance in combat sports. Future studies should explore dose-response relationships and individual variability in caffeine metabolism to optimize its application in competitive settings.

Predictors of caffeine consumption patterns in high school athletes.

O'Connell EM, Hatfield DL, Stors A … +1 more , Cohen SA

J Int Soc Sports Nutr · 2025 Dec · PMID 40581773 · Full text

PURPOSE: The purpose of this study was to examine caffeine consumption and the factors that affect caffeine use in high school athletes. METHODS: Three hundred and ninety-four Rhode Island high school athletes (age: 16.8... PURPOSE: The purpose of this study was to examine caffeine consumption and the factors that affect caffeine use in high school athletes. METHODS: Three hundred and ninety-four Rhode Island high school athletes (age: 16.8 ± 1.27 years) completed a cross-sectional online survey to assess caffeine consumption. A multivariate logistic regression analysis and binary logistic regression were performed to characterize associations between use and nonuse and the independent variables of ethnicity, grade, sex, and sport played. 95% confidence intervals (CI) were calculated for all models. Statistical significance was set to  ≤ 0.05 for all analysis. RESULTS: Fifteen point five percent of the variance in caffeine use was related to ethnicity, grade, and sex(R = 0.155), with significant results for each variable. A majority of female athletes consumed caffeine (67.4%), compared to male athletes (37.8%) ( < 0.001). Athletes identifying as Caucasian reported significantly more caffeine use (55.9%), compared to athletes from underrepresented backgrounds (32.6%) ( < 0.001). Caffeine use was significantly different across grades, where 30.6% of 9th graders, 49.2% of 10th graders, 55.2% of 11th graders, and 49.2% of 12th graders reported caffeine use ( = 0.049). Coffee (51%) and energy drinks (43%) were the primary sources of caffeine consumption. Dance, cheerleading, and gymnastics participants were more than ten times as likely to consume caffeine compared to other sports (95% CI [2.28, 48.94], Exp (β) = 10.57). CONCLUSION: Caffeine use in young athletes is related to factors including sex and ethnicity. Given the prevalence of use, young athletes, coaches, and parents/guardians should be educated on the risks and benefits of caffeine use. Future research should focus on the potential benefits of caffeine use to athletic performance verses possible side effects in this population. SUPPORTED BY: The Clean Competition Grant from the Rhode Island Foundation.

Evolution of research trends and emerging hotspots in bioelectrical impedance analysis over the last two decades: a bibliometric analysis.

Niu C, Zhang P, Zhang C … +9 more , Dong J, Liang H, Xiao D, Liu B, Wei L, Lai H, Ye J, Ma L, Zhang L

J Int Soc Sports Nutr · 2025 Dec · PMID 40569570 · Full text

BACKGROUND AND OBJECTIVE: Over the last two decades, bioelectrical impedance analysis (BIA) has gained popularity as a method for assessing body compartments in nutrition studies, sports medicine, and evaluating hydratio... BACKGROUND AND OBJECTIVE: Over the last two decades, bioelectrical impedance analysis (BIA) has gained popularity as a method for assessing body compartments in nutrition studies, sports medicine, and evaluating hydration levels, fat mass, and fat-free mass variations in both healthy and diseased individuals. This study aims to offer researchers an overview of the research trends in BIA. METHODS: The data was obtained from the Web of Science Core Collection database. Bibliometric analysis was conducted using a package of R software (Bibliometrix 4.0). RESULTS: A total of 9471 articles have been published over the past 20 years, with an average annual growth rate of 10.1%. The research field primarily focuses on nutrition and dietetics, followed urology and nephrology, endocrinology and metabolism, general and internal medicine, engineering, geriatrics and gerontology, sport sciences, cardiovascular system and cardiology, physiology and science and technology-other topics. The research hotspots of BIA over the past 20 years have transitioned from "water" to "fat," and subsequently to "sarcopenia." "Sarcopenia" and "phase angle" (PhA) have emerged as recent research hotspots in the field of BIA. CONCLUSION: A total of 9471 articles have been published over the past 20 years, with an average annual growth rate of 10.1%. Nutrition and dietetics have consistently been the primary research areas in the field of BIA. "Sarcopenia" and "PhA" have emerged as recent research hotspots in the field of BIA. The application of BIA in clinical practice still holds significant untapped potential.

Neither pre-sleep nor post-exercise protein consumption influences resistance exercise training adaptations in older adults.

Klemp AO, Ormsbee MJ, Yeh M … +4 more , Sokolowski CM, Kim DH, Panton LB, Kim JS

J Int Soc Sports Nutr · 2025 Dec · PMID 40539259 · Full text

PURPOSE: Limited data exists that compare pre-sleep versus post-exercise protein intake during resistance exercise training (RET) in older adults. This study examined whether 40 g of protein consumed post-exercise (PRP)... PURPOSE: Limited data exists that compare pre-sleep versus post-exercise protein intake during resistance exercise training (RET) in older adults. This study examined whether 40 g of protein consumed post-exercise (PRP) or pre-sleep (PSP) enhances muscle thickness (MT) and strength compared to RET alone (RETO) in older men. METHODS: Thirty untrained older men (65.7 ± 4.0 yrs) completed 12 weeks of supervised RET (2×/week) and were randomized to PRP ( = 9), PSP ( = 11), or RETO ( = 10). MT of the vastus lateralis (VL), rectus femoris (RF), and vastus intermedius (VI) and 1-repetition maximum (1-RM) for leg and chest press were assessed at weeks 0, 6, and 12. RESULTS: VL (0 to 12 weeks: + 0.16 cm, 95% C.I. [0.06, 0.25]), RF (0 to 12 weeks: + 0.13 cm, 95% C.I. [0.03, 0.23]), and VI MT (0 to 12 weeks: + 0.18 cm, 95% C.I. [0.05, 0.31]) and chest press (0 to 12 weeks: + 10.9 kg, 95% C.I. [5.50, 16.3]) and leg press (0 to 12 weeks: + 28.3 kg, 95% C.I. [19.63, 37.1]) 1-RM increased ( < 0.050) with no group differences. CONCLUSION: Consuming 40 g of protein post-exercise or pre-sleep did not enhance RET-induced improvements in muscle thickness or strength in older adults with adequate baseline protein intake (≥1.0 g/kg/day). RET alone elicited significant gains, emphasizing that adherence to training and meeting daily protein requirements are more critical than timing strategies for untrained older adults. ClinicalTrials.gov identifier: NCT05922475, 06/23/2023, retrospectively registered.

Beta-alanine supplementation improves time to exhaustion, but not aerobic capacity, in competitive middle- and long-distance runners.

Marko D, Snarr RL, Bahenský P … +3 more , Bunc V, Krajcigr M, Malý T

J Int Soc Sports Nutr · 2025 Dec · PMID 40528157 · Full text

BACKGROUND: Beta-alanine (βA) is a non-essential amino acid purportedly used to enhance aerobic exercise performance. While previous research indicates the benefits of βA on time to exhaustion (TTE) and aerobic capacity... BACKGROUND: Beta-alanine (βA) is a non-essential amino acid purportedly used to enhance aerobic exercise performance. While previous research indicates the benefits of βA on time to exhaustion (TTE) and aerobic capacity (VO) in adults, evidence is lacking in adolescent athletes. Thus, the purpose of this study was to determine the effects of 4 weeks of βA supplementation on aerobic performance in adolescent runners. METHODS: Twenty-seven middle- and long-distance runners (aged 17.36 ± 2.17 years) were randomly divided into a βA or placebo (PL) group (maltodextrin). Subjects performed maximal graded exercise tests (GXT) and submaximal trials (SMT; 80% of VO for 1500 m) on a treadmill before and after 14 and 28 days of supplementation or PL. Respiratory (V) metabolic (VO, RER, lactate [La]), and cardiovascular (HR) variables were measured during the GXT and SMT, along with the first (VT1) and second ventilatory threshold (VT2) and TTE monitored during the GXT only. Within- and between-group differences were assessed using a repeated-measures mixed-model analysis of variance. RESULTS: Findings indicated that despite a trivial increase in VO over 4 weeks, the βA group increased TTE by 6.5% compared to 1.4% in the PL group ( = 0.46). Additionally, small effects in HR, V, [La], and TTE were observed between groups favoring βA. Regarding the SMT, both average HR and RER decreased by 4% in the βA group, with no changes for the PL. CONCLUSIONS: Despite no evidence to suggest increases in VO, practitioners should note that improvements in TTE may be observed after 28 days of βA supplementation in adolescent runners.

Improvement of sports nutrition knowledge by a dual method education program in track and field athletes: a randomized controlled trial.

Jayawardena R, Weerasinghe K, Nanayakkara I … +3 more , Madhujith T, Hills AP, Kalupahana NS

J Int Soc Sports Nutr · 2025 Dec · PMID 40525378 · Full text

BACKGROUND: Athletes with strong sports nutrition knowledge are believed to have sound nutritional practices and better performance. This study aimed to evaluate the effectiveness of a dual-method personalized nutrition... BACKGROUND: Athletes with strong sports nutrition knowledge are believed to have sound nutritional practices and better performance. This study aimed to evaluate the effectiveness of a dual-method personalized nutrition education program in improving sports nutrition knowledge (SNK) among Sri Lankan track and field athletes. METHODS: This parallel-group, randomized controlled trial recruited national-level track and field athletes aged 18 and above. The intervention group (IG) received personalized sports nutrition consultations at 0, 4, and 8 weeks, along with online educational materials via WhatsApp from weeks 10 to 16, while the control group (CG) did not receive any intervention. A per-protocol analysis was followed, and t-tests were used to compare the means. RESULTS: Of the 30 participants enrolled, 13 from IG and 14 from CG completed the study. Following the 16-week intervention, the IG demonstrated significant improvements in total nutrition knowledge (TNK) relative to the CG (IG: 34.41 ± 4.15 vs. CG: 20.96 ± 4.38;  = 0.01), with significant increases in general nutrition knowledge (GNK) (IG:24.54 ± 3.66 vs. CG:15.64 ± 2.33;  = 0.004) and SNK (9.87 ± 3.87 vs. 5.32 ± 4.07;  = 0.006). Changes in TNK were also significantly greater in the IG compared to the CG; (IG:9.45 ± 0.10 vs. CG: -2.63 ± 0.37;  < 0.0001), GNK (IG:4.47 ± 0.08 vs. CG: -1.28 ± 0.09;  < 0.0001), and SNK (IG:4.99 ± 0.72 vs. CG: -1.25 ± 0.74;  < 0.0001). CONCLUSIONS: The 16-week dual-method nutrition education intervention was effective in improving TNK, GNK, and SNK among track and field athletes in Sri Lanka. TRIAL REGISTRATION: This trial is registered at the Sri Lanka Clinical Trials Registry (SLCTR/2024/013), Universal Trial Number (UTN): U1111-1304-8890 on 10 April 2024.

Pre-workout multi-ingredients or carbohydrate alone promote similar resistance training outcomes in middle-aged adults: a double-blind, randomized controlled trial.

Puente-Fernández J, Larumbe-Zabala E, Roberts J … +1 more , Naclerio F

J Int Soc Sports Nutr · 2025 Dec · PMID 40512050 · Full text

BACKGROUND: Pre-workout multi-ingredients are designed to enhance energy levels and acutely increase exercise performance. This study compared the effectiveness of ingesting an admixture providing caffeinated ingredients... BACKGROUND: Pre-workout multi-ingredients are designed to enhance energy levels and acutely increase exercise performance. This study compared the effectiveness of ingesting an admixture providing caffeinated ingredients and plant-based protein enriched with amino acids versus carbohydrates alone on body composition, hypertrophy and physical performance. METHODS: Forty-three middle-aged physically active individuals (26 peri- and post-menopausal females and 17 males) completed the study after being randomly assigned to one of the following intervention groups: pre-workout (PREW  = 24, 54 ± 4 years, body mass 77.6 ± 16.0 kg) or a carbohydrate-only comparator (COMP  = 19, 52 ± 4 years, body mass 80.6 ± 16.0 kg). Measurement of fat and fat-free mass (via plethysmography), waist and hip circumferences, muscle thickness (via ultrasound), strength, power output and muscle endurance performance were collected before and after a 6-week resistance training programme performed 3 times per week. Treatment consisted of ingesting 30g of the assigned supplement, mixed with 400mL of plain water, 15min before each workout session. RESULTS: Both groups significantly ( < 0.05) reduced fat mass (mean ± SD) (PREW -1.4 ± 1.6 kg; COMP -1.0 ± 1.5 kg), increased fat-free mass (PREW +0.9 ± 1.1 kg; COMP + 0.8 ± 0.9 kg); vastus lateralis (PREW +0.2 ± 0.2 cm; COMP + 0.1 ± 0.6 cm), and elbow flexors (PREW +0.5 ± 0.3 cm; COMP + 0.4 ± 0.2 cm) muscle thickness. Only the PREW group showed a significant reduction in the waist circumference (-1.8 ± 1.8 cm,  < 0.01). However, no significant differences between groups (PREW vs. COMP) were identified at post-intervention. Isometric force, countermovement jump, medicine ball throw, and upper and lower body muscle endurance performance improved ( < 0.05) for both treatments, with no difference between groups. CONCLUSION: Except for waist circumference reduction, ingesting a pre-workout vegan protein-based caffeinated supplement promotes no further resistance training benefits in middle-aged individuals.

Creatine and post-viral fatigue syndrome: an update.

Ostojic SM, Candow DG, Tarnopolsky MA

J Int Soc Sports Nutr · 2025 Sep · PMID 40481620 · Full text

Post-viral fatigue syndrome, classified as a neurological condition by the WHO (ICD-11 code: 8E49), manifests as persistent fatigue, cognitive difficulties, and post-exertional malaise following viral infections. It shar... Post-viral fatigue syndrome, classified as a neurological condition by the WHO (ICD-11 code: 8E49), manifests as persistent fatigue, cognitive difficulties, and post-exertional malaise following viral infections. It shares commonalities with chronic fatigue syndrome and myalgic encephalomyelitis but is distinct due to its association with preceding viral events. Emerging research identifies bioenergetic disruptions, particularly mitochondrial dysfunction and impaired creatine metabolism, as key contributors. Recent studies suggest creatine supplementation may alleviate symptoms and improve energy metabolism. This narrative review summarizes recent advancements in utilizing creatine as a diagnostic and therapeutic target for post-viral fatigue syndrome and explores future directions for its application in managing this perplexing condition.

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

Martinho DV, Rebelo A, Clemente FM … +8 more , Costa R, Gouveia ÉR, Field A, Casonatto J, van den Hoek D, Durkalec-Michalsk K, Ormsbee MJ, Sarmento H

J Int Soc Sports Nutr · 2025 Dec · PMID 40471841 · Full text

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... 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 resistance training performance, rating of perceived exertion, and blood biomarkers after six weeks of supplementation with L-citrulline vs. L-citrulline DL-malate in resistance-trained men: a double-blind placebo-controlled trial.

Bayat D, Azizi M, Behpour N … +1 more , Tinsley GM

J Int Soc Sports Nutr · 2025 Dec · PMID 40470618 · Full text

PURPOSE: This study aimed to investigate and compare the effects of chronic supplementation with L-Citrulline (LC) vs. L-Citrulline DL-malate (CM) on resistance training (RT) performance. METHODS: Thirty-three resistance... PURPOSE: This study aimed to investigate and compare the effects of chronic supplementation with L-Citrulline (LC) vs. L-Citrulline DL-malate (CM) on resistance training (RT) performance. METHODS: Thirty-three resistance-trained men were randomly assigned to ingest LC (8 g), CM (12 g), or Placebo (PL) daily, along with participation in a 6-week RT protocol. Muscular strength (1-repetition maximum [1RM] for hack squat [HS] and bench press [BP]), muscular endurance (repetitions to failure [RTF] for HS, leg extension [LE], BP, and incline press [IP]), rating of perceived exertion (RPE), and blood biomarkers (lactate, urea, and nitric oxide metabolites [NO]) were assessed before and after the intervention. This study was registered on irct.ir (IRCTID: IRCT20221128056642N1). RESULTS: Comparing mean ∆ scores revealed a significant difference between LC and PL ( < 0.001) and between CM and PL ( = 0.026) for total upper body (the sum of BP and IP) RTF, but only a trend for difference between LC and PL ( = 0.070) for total lower body (the sum of HS and LE) RTF. A significant time effect for NO was detected only for LC ( = 0.014) and CM ( = 0.003). In addition, a significant difference between CM and PL ( = 0.009) and a marginally significant difference between LC and PL ( = 0.057) was detected regarding post-exercise NO values at post-intervention. There were no other between-group differences for any outcome measure. CONCLUSION: Chronic citrulline supplementation seems to enhance upper body muscular endurance and post-exercise NO response to RT, but there is no apparent difference between LC and CM in these aspects.

Effect of different sports drink compositions on endurance performance and substrate oxidation: a randomized, double-blind, placebo-controlled crossover study in trained athletes.

Ketelhut S, Moehle M, Hottenrott L

J Int Soc Sports Nutr · 2025 Dec · PMID 40468684 · Full text

BACKGROUND: The consumption of sports drinks before, during, and after endurance exercise is a common practice among athletes. These drinks typically contain a variety of components, each of which has been shown to offer... BACKGROUND: The consumption of sports drinks before, during, and after endurance exercise is a common practice among athletes. These drinks typically contain a variety of components, each of which has been shown to offer individual benefits. However, the combined effects of these components, as formulated in many sports drinks, have not been thoroughly investigated. This study aims to evaluate the impact of typical sports drink components on endurance performance, perceived exertion, and carbohydrate and fat metabolism, using a sequential additive design. METHODS: Twelve healthy, trained endurance athletes aged 20 to 35 years participated in a randomized, double-blind, placebo-controlled study. The study involved a baseline assessment and four exercise protocols, each separated by a 7-day washout period. During each exercise protocol, participants cycled for 40 minutes at 80% of their previously determined peak oxygen uptake , followed by an incremental protocol performed to voluntary exhaustion. Participants were randomly assigned to ingest one of four 300 ml solutions 60 and 30 minutes before each exercise protocol: solution A (placebo mineral water), solution B (dextrose and sodium), solution C (solution B + beetroot extract), or solution D (solution C + arginine and L-citrulline). Ventilation and heart rate were continuously monitored before and throughout the exercise. Lactate and glucose levels were measured at specific time points before and during the exercise, while ratings of perceived exertion were recorded every 10 minutes. Power output was continuously tracked throughout the exercise protocol. Body weight was assessed both before and after each exercise session. RESULTS: There were no significant differences between the four solutions in terms of time to exhaustion ( = .703), power output ( = .822), peak oxygen uptake ( = 990), maximum lactate concentration ( = .720), and maximum heart rate ( = .884). During the exercise, no significant differences were observed in lactate and glucose concentrations, heart rate, or ventilatory parameters (ps > .050). However, significant differences ( < .001) in blood glucose concentrations were noted at rest and during the warm-up phase. CONCLUSIONS: The effect of the tested sports drink compositions on performance during the selected exercise protocol to voluntary exhaustion appears minimal. This study found no significant differences between the solutions and the placebo. Thus, it can be concluded that consuming a dextrose-based solution before exercise did not offer any performance advantage over water. The additional substances included in solutions B, C, and D did not influence performance, carbohydrate metabolism, or fat metabolism during the exercise.

Impact of 16/8 time-restricted eating on body composition and lipolytic hormone regulation in female DanceSport dancers.

Li X, Guo X, Zhou Y … +3 more , Cao G, Chen M, Mu J

J Int Soc Sports Nutr · 2025 Dec · PMID 40462558 · Full text

OBJECTIVE: The aim of this study was to investigate the effect of a 16/8 time-restricted eating (TRE) program over 6 weeks on body composition and lipolytic hormone levels in female DanceSport dancers. Importantly, parti... OBJECTIVE: The aim of this study was to investigate the effect of a 16/8 time-restricted eating (TRE) program over 6 weeks on body composition and lipolytic hormone levels in female DanceSport dancers. Importantly, participants were not subject to any calorie restrictions during the study period. METHODS: A total of 20 female DanceSport dancers were recruited to participate in the randomized controlled trial. The participants were randomly assigned to either a time-restricted eating group (TRE,  = 10) or a control group ( = 10). The TRE group adhered to a 16/8 time-restricted eating protocol for a period of six weeks, consuming food within an eight-hour window (11:00-19:00) and fasting for 16 hours. The control group was instructed to maintain their usual dietary habits without any intervention. Body composition parameters, including body fat percentage (BF%), fat mass (FM), and fat-free mass (FFM), were measured before and after the intervention. Additionally, serum levels of epinephrine (E), norepinephrine (NE), adiponectin (ADPN), leptin (LEP), growth hormone (GH), insulin-like growth factor 1 (IGF-1), and blood lipid profiles (including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG)) were assessed. RESULTS: After 6 weeks, the TRE group showed significant reductions in FM and BF% compared to baseline ( < 0.01). No significant changes were observed in body weight or FFM ( > 0.05). Regarding blood lipid profiles, HDL-C levels significantly increased in the TRE group ( < 0.05) following the 6-week intervention. In contrast, no significant changes were observed in TC, TG and LDL-C (p>0.05). Hormonal analysis revealed significant changes in the TRE group. Serum levels of epinephrine (E) and norepinephrine (NE) increased significantly following the intervention ( < 0.05), with E showing a particularly marked increase ( < 0.01). Additionally, serum adiponectin (ADPN) levels were significantly elevated ( < 0.05), while GH, IGF-1 and LEP levels did not show significant changes ( > 0.05). Group-by-time interactions were observed for FM ( < 0.05), BF% ( < 0.05), and E ( < 0.05). Comparisons of baseline and post-intervention dietary data indicated no significant changes in total calorie or macronutrient intake within either the TRE or control groups ( > 0.05). CONCLUSION: Time-restricted eating without caloric restriction may offer a promising approach to regulating body composition and promoting lipid metabolism, especially for female DanceSport dancers where maintaining a lean body mass is critical. However, the long - term effects of this approach still warrant continued observation.

A new estimation equation to assess body composition in an athletic population.

Magee MK, Fields JB, Miller A … +4 more , Jagim AR, Stroiney D, Lockard B, Jones MT

J Int Soc Sports Nutr · 2025 Dec · PMID 40434031 · Full text

BACKGROUND: Research has shown air displacement plethysmography (ADP) to be a valid and reliable alternative to dual-energy X-ray absorptiometry (DXA) in the general population; however, its validity and reliability indi... BACKGROUND: Research has shown air displacement plethysmography (ADP) to be a valid and reliable alternative to dual-energy X-ray absorptiometry (DXA) in the general population; however, its validity and reliability indicate conflicting evidence in an athletic population. The purpose of this study is to develop a novel estimation equation using body density obtained from ADP in an athletic population to assess body fat percent (BF%) more accurately. METHODS: One hundred and thirty (males,  = 69; females,  = 61) National Collegiate Athletic Association Division I athletes participated in this study. Thirty athletes were randomly withheld for the hold-out sample, and the remaining 100 athletes were used in the development of the equation. Body composition was evaluated using ADP and DXA. Linear regression was used to develop a new prediction equation (Equation 1) with body density (ADP) as the independent variable and BF% (DXA) as the dependent variable. Repeated measures analysis of variance was used to identify differences between ADP-Brozek, DXA, and Equation 1. Interclass correlation coefficients (ICCs) were assessed to evaluate the reliability of the equation. RESULTS: Significance was set to  < 0.05. Linear regression was conducted to create Equation 1, which explained 90.5% of the variance. ADP-Brozek reported lower BF% than Equation 1 ( < 0.001) in the development and hold-out samples; however, BF% from Equation 1 and DXA were not different from each other ( = 0.999). ICCs were strong in both samples (original sample: ICC = 0.975,  < 0.001; hold-out sample: ICC = 0.964,  < 0.001). CONCLUSION: The newly proposed equation may be used with ADP measurements to interpret BF% in an athletic population.

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

Lafontant K, Rukstela A, Hanson A … +13 more , Chan J, Alsayed Y, Ayers-Creech WA, Bale C, Ohigashi Y, Solis J, Shelton G, Alur I, Resler C, Heath A, Ericksen S, Forbes SC, Campbell BI

J Int Soc Sports Nutr · 2025 Dec · PMID 40405489 · Full text

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 heal... 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];  < 0.001) and fat mass (MD = -1.06 kg [95% CI = -1.88 to -0.24];  = 0.01) but led to less FFM retention (MD = - 0.88 kg [95% CI = -1.73 to -0.03],  = 0.04). CT reduced significantly more fat mass compared to RT (MD: -1.09 kg [95% CI = -0.27 to -1.91];  = 0.009). No significant differences were found between CT, AT, and RT in altering body fat percentage ( > 0.05). For studies shorter than 10 weeks, no significant differences were noted across exercise modalities ( > 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 ( > 0.05). Similar body mass and body fat percentage loss was observed between same-day and different-day CT ( > 0.05); body fat mass loss only differed in a single study ( = 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.

Training load influences gut microbiome of highly trained rowing athletes.

Charlesson B, Jones J, Abbiss C … +3 more , Peeling P, Watts S, Christophersen CT

J Int Soc Sports Nutr · 2025 Dec · PMID 40400144 · Full text

BACKGROUND: Despite the importance of the gut microbiome on physical performance and health, little is known on the impact of training on an athlete's gut health. OBJECTIVE: This study investigates the effect of training... BACKGROUND: Despite the importance of the gut microbiome on physical performance and health, little is known on the impact of training on an athlete's gut health. OBJECTIVE: This study investigates the effect of training load on markers of gut health. METHODS: Whole stool (24 h) samples were collected from 23 highly trained rowers (mean ± SD; age 19.2 ± 1.1 y; weight 80.1 ± 11.4 kg; height 1.83 ± 0.09 m) following periods of high (HT) and low training load (LT). The microbiome and short-chain fatty acid concentrations were characterized from the whole stool samples. Three-day weighted food records were used to determine diet quality (ADIcore), macronutrient, and fiber intakes during HT and LT. RESULTS: By design, training duration (147%) and intensity (130%) were greater during (HT), compared with (LT) ( < 0.001). Carbohydrate, fat, protein, and fiber intake remained stable, but ADIcore was higher in HT (55 ± 10) compared with LT (49 ± 9; t(15) = 2.78,  0.014; CI: 1.34 to 10.155). Stool frequency (1.11 ± 0.47 vs 0.67 ± 0.76;  0.007) was lower in HT compared with LT, and a greater number of participants were unable to produce a stool sample during LT (8% vs 47%). Short chain fatty acid (SCFA), propionic (120.64 ± 30.06 mm vs 91.35 ± 34.91 mm;  0.007), and butyric acid (104.76 ± 50.02 vs 64.23 ± 22.05 mm,  0.003) concentrations were lower in HT compared with LT. Alpha diversity, Shannon-Wiener diversity index (3.43 ± 0.37 vs 3.67 ± 0.34,  0.09) was lower in HT than LT. The abundance of the dominant was greater at HT compared to LT and ratio of firmicutes to ( = 16, 1.31 ± 1.19 vs 4.29 ± 3.88, t(15) = -3.44,  0.04, CI = -4.82 to -1.13) was lower in HT compared to LT. CONCLUSION: Results of this study indicate that gut microbiome, SCFA concentrations, stool frequency, and diet quality vary between periods of high and low training load in athletes. The relationship between these factors and impact of such changes in gut health is currently unclear and warrants further investigation.
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