J Int Soc Sports Nutr [JOURNAL]
Sun
200 papers
Blood metabolic profiling associated with a short-term intensive training period in elite male water polo athletes: an exploratory metabolomics study.
Sun Z, Wang L
J Int Soc Sports Nutr · 2026 Dec · PMID 41851918 · Full text
OBJECTIVE: This exploratory metabolomics pilot study employed non-targeted liquid chromatography-tandem mass spectrometry (LC‒MS/MS) to characterize serum metabolic profiles in elite male water polo athletes, thereby ass...
OBJECTIVE: This exploratory metabolomics pilot study employed non-targeted liquid chromatography-tandem mass spectrometry (LC‒MS/MS) to characterize serum metabolic profiles in elite male water polo athletes, thereby assessing physiological adaptation to high-intensity training. We aimed to provide a scientific basis for evaluating physical fitness and optimizing performance capacity in elite athletes. METHODS: Sixteen male water polo athletes of the Chinese national team were recruited. All athletes underwent a one-week complete break following the end of the previous competitive season to mitigate accumulated fatigue and establish a true resting metabolic baseline. Fasting venous blood samples (5 mL) were collected at 7:00 AM on two time points: the first sample (E1) was collected before commencement of the official training week, and the second sample (E2) was collected immediately after the completion of that week of training. The data were analyzed via XCMS, MetaboAnalyst 6.0, SPSS 21.0, and GraphPad Prism. RESULTS: (1) Metabolomic analysis identified 363 metabolites in total, 33 of which were differentially expressed between pre- and post-training time points. After one week of routine training, 11 metabolites were significantly up-regulated ( 0.01), and 22 were significantly down-regulated ( 0.01). (2) KEGG pathway analysis identified the top eight metabolic pathways, with MetPA further highlighting lysine degradation ( 0.01) and vitamin B6 metabolism ( 0.05) as key altered pathways. (3) Three metabolites were identified as potential markers associated with the training week changes in water polo athletes on the basis of significant alterations post-training. N6, N6, N6-trimethyl-L-lysine ( 0.01) and 2-aminoadipic acid ( 0.01) were significantly decreased, whereas 4-pyridoxic acid ( 0.01) was significantly increased. CONCLUSIONS: Non-targeted LC‒MS/MS provides a valuable tool for monitoring metabolic adaptations at the molecular level in aquatic athletes. In this exploratory study, we observed associated changes in the serum metabolome following intensive training, pointing to adjustments in amino acid and lipid metabolism. These findings offer preliminary insights for guiding fitness and performance optimization.
Effects of the micronutrient Sanopal® (5-hydroxymethyl-2-furfural and α-ketoglutaric acid) on oxygen affinity of hemoglobin, oxygen saturation and exercise responses at altitude.
Woyke S, Troppmair T, Mair N … +4 more , Oberacher H, Haller T, Faulhaber M, Gatterer H
J Int Soc Sports Nutr · 2026 Dec · PMID 41841293 · Full text
BACKGROUND: With increasing altitude, the partial pressure of oxygen and oxygen saturation (SpO) decrease, reducing physical performance. This study investigates whether the nutritional supplement Sanopal® (5-hydroxymeth...
BACKGROUND: With increasing altitude, the partial pressure of oxygen and oxygen saturation (SpO) decrease, reducing physical performance. This study investigates whether the nutritional supplement Sanopal® (5-hydroxymethyl-2-furfural and -ketoglutaric acid) increases hemoglobin-oxygen affinity and SpO₂ during exercise at moderate altitude. METHODS: Nineteen healthy young sports students (12 females, 7 males) participated in a single-blinded, placebo-controlled crossover study investigating the effects of Sanopal® at low (590 m) and moderate altitude (2900 m). Participants received Sanopal® or placebo in a randomized order, with measurements of SpO₂, heart rate, and blood parameters taken before and after ingestion, as well as before and after exercise at altitude. RESULTS: Under resting and acute hypoxia conditions, Sanopal® did not increase hemoglobin-oxygen affinity or SpO₂. At altitude and post-exercise, Hb-O₂ affinity decreased by approximately 5% in the PL trial but increased by approximately 2% in the SA session (interaction effect: = 0.030). There were no significant differences in SpO₂ or heart rate between the Sanopal® and placebo groups. CONCLUSIONS: Sanopal® did not alter hemoglobin-oxygen affinity or SpO₂ under resting conditions in normoxia or acute hypoxia. After exercise at altitude, it slightly increased Hb-O₂ affinity without significantly affecting SpO₂ or other measured blood parameters. The modest increase in Hb-O affinity following exercise may have limited the exercise-induced decrease in Hb-O affinity. However, this increase was likely too small to significantly raise SpO₂ in this cohort at a relatively low altitude.
Revisiting the evidence on caffeine mouth rinse: effects on exercise and cognitive performance: a meta-analytic review.
Deng H, Fan X, Song T … +3 more , Bin Mohd Nasiruddin NJ, Ahmad Fuaad AA, Bin Naharudin MN
J Int Soc Sports Nutr · 2026 Dec · PMID 41774525 · Full text
BACKGROUND: Caffeine mouth rinsing (Caff-MR) may activate oropharyngeal receptors and rapidly engage central networks for motivation, attention, and pacing without systemic absorption. The only prior meta-analysis found...
BACKGROUND: Caffeine mouth rinsing (Caff-MR) may activate oropharyngeal receptors and rapidly engage central networks for motivation, attention, and pacing without systemic absorption. The only prior meta-analysis found no stable ergogenic effect, yet the evidence base has continued to expand and remains heterogeneous. METHODS: Six electronic databases were searched up to 2 October 2025 for Caff-MR studies on exercise and cognitive outcomes. Study quality was assessed using modified PEDro and RoB-2. Three-level meta-analyses synthesized both outcomes. Prespecified moderators were sex, training status, habitual caffeine use, feeding state, exercise or cognitive type, rinse duration, and total oral exposure. Sensitivity analyses addressed assumed within-subject correlations, outliers, and influential cases. RESULTS: Thirty-one studies (k = 167 effects) met inclusion. Caff-MR was associated with trivial-to-small improvements in exercise performance (k = 114; g = 0.12, = 0.01). Benefits were most consistent for aerobic endurance and in the fed state; ~5-s rinses outperformed longer durations. Primary dose-response suggested a U-shape (32-133 mg window), but this pattern was not robust to outlier removal; under 5-s conditions, higher total exposure related negatively to performance. Cognitive effects were inconsistent overall (k = 53; g = 0.23, = 0.07), yet after outlier removal the overall and speed-based effects reached significance, whereas accuracy remained variable. Risk of bias was predominantly "some concerns"; GRADE certainty was moderate (exercise) and very low/low (cognition). CONCLUSIONS: Caff-MR is a practical, ingestion-free strategy yielding small, context-dependent benefits, optimized by brief (~5 s) rinses and moderate exposure, particularly for aerobic endurance. Standardized, well-powered trials are needed to refine dosing, timing, and cognitive applications.
Exogenous carbohydrate form during low-muscle glycogen conditions has minimal impact on cycling performance.
Matthews IR, Rosales AM, Walker JK … +4 more , Wilfong NB, Perez RE, Ruby BC, Slivka DR
J Int Soc Sports Nutr · 2026 Dec · PMID 41746762 · Full text
BACKGROUND: Skeletal muscle recovery is improved with immediate postexercise carbohydrate feeding. Little is known regarding muscle recovery and performance when feeding is delayed. The purpose of this study was to exami...
BACKGROUND: Skeletal muscle recovery is improved with immediate postexercise carbohydrate feeding. Little is known regarding muscle recovery and performance when feeding is delayed. The purpose of this study was to examine the effects of varying exogenous carbohydrates on cycling performance with delayed feedings and low skeletal muscle glycogen content. METHODS: Following 60 min of cycling and an overnight fast (12.1 ± 0.4 h), the participants consumed 2.10 ± 0.13 g·kg bodyweight carbohydrate of one of the following: whole potatoes (POT), cooked pasta (PAS), energy gel (GEL) or remained unfed (control, CON), then rested for 120 min. The participants then cycled for 60 min at 65% W and completed a 19.4 km time trial. Muscle and blood samples were collected prefeeding, 120 min postfeeding, and after cycling for glycogen, glucose, and insulin analyses. RESULTS: The time trial mean power output was higher in the PAS (213 ± 56W, = 0.006) and GEL (209 ± 71W, = 0.011) compared to CON (179 ± 68W), but POT (196 ± 51W, = 0.199) was not different from CON. Power was similar between POT, PAS, and GEL ( > 0.05). Time trial finish time trended towards significance ( = 0.088) with carbohydrate trials averaging 3 min faster than CON. Muscle glycogen was similar between trials ( = 0.446) and did not change due to feeding (prefeeding: 44 ± 21 mmol·kg, postfeeding: 47 ± 23 mmol·kg, = 0.120). Glycogen declined after cycling for 60 min (26 ± 16 mmol·kg, < 0.001) compared to pre-feeding and post-feeding samples. Glucose and insulin were elevated in carbohydrate trials over CON 0-30 min post-feeding (< 0.05). CONCLUSIONS: Varied pre-exercise exogenous carbohydrate sources effectively improve cycling time trial performance in a glycogen compromised state.
Beetroot juice supplementation enhances the effects of blood flow restriction training on lower limb strength and vertical jump performance under fatigue in male university students: a randomized, double-blind, placebo-controlled study.
Yang X, Lu Y, Lee SK … +4 more , Xu H, Chang H, Liu Q, Quan H
J Int Soc Sports Nutr · 2026 Dec · PMID 41733365 · Full text
BACKGROUND: Beetroot juice (BRJ) supplementation has the potential to enhance the effects of blood flow restriction (BFR) training in improving muscle strength and fatigue resistance; however, evidence supporting their c...
BACKGROUND: Beetroot juice (BRJ) supplementation has the potential to enhance the effects of blood flow restriction (BFR) training in improving muscle strength and fatigue resistance; however, evidence supporting their combined effects remains limited. This study investigated whether BRJ supplementation enhances the effects of BFR training on muscle strength and fatigue resistance. METHODS: This randomized, double-blind, placebo-controlled trial included 20 male university students from the School of Sports, who were randomly assigned to a BFR group ( = 10, age: 21.9 ± 1.7 years) or a BFR + BRJ group ( = 10, age: 21.8 ± 1.5 years; nitrate: 8 mmol/day). Participants completed a one-week BRJ pre-supplementation phase followed by a four-week bilateral knee extensor/flexor BFR training program (40% limb occlusion pressure, 30% of peak torque load), performed three times per week. Knee extensor and flexor strength (at 60°/s, 180°/s, and MVIC) and countermovement jump (CMJ) performance were assessed using an isokinetic dynamometer and a force plate pre- and post-intervention. RESULTS: Both the four-week BFR and BFR+BRJ interventions significantly increased the relative peak torque of the knee extensors/flexors at 60°/s (Left: = 0.23, d = -0.89, ηp² = 0.775; Right: = 0.017, d = -0.63, ηp² = 0.744), 180°/s (Left: = 0.028, d = -1.32, ηp² = 0.319; Right: = 0.007, d = -1.48, ηp² = 0.822), and MVIC (Left: = 0.007, d = -0.11, ηp² = 0.825; Right: = 0.009, d = -1.31, ηp² = 0.842). They also improved the torque of the knee extensors in both the left and right legs during the 100-repetition maximal voluntary contraction test at 90°/s, with both initial (first 20 reps) and final (last 20 reps) values significantly increased (Left: = 0.029, d = -0.96, ηp² = 0.612; Right: = 0.007, d = -1.21, ηp² = 0.725). The CMJ test showed significant improvements in fatigued bilateral CMJ height ( = 0.048, d = -0.534, ηp² = 0.556), peak force ( = 0.047, d = -0.913, ηp² = 0.444), and rate of force development (RFD; = 0.044, d = -0.902, ηp² = 0.656) following both BFR and BFR + BRJ interventions. Notably, single-leg countermovement jump performance showed no significant improvements for either the left or right leg. Notably, post-intervention, only the BFR+BRJ group showed significant improvements in fatigued bilateral CMJ height ( = 0.012, d = -1.307, ηp² = 0.846). CONCLUSIONS: The results indicate that four weeks of BFR training, with or without BRJ supplementation, can improve knee flexor and extensor strength and bilateral CMJ performance. However, the effects of BRJ were selective rather than broadly superior, as BRJ mainly enhanced BFR training by reducing fatigue-related declines in vertical jump performance.
Seasonal changes in energy intake and emerging indicators of energy availability in young elite Nordic skiers.
Lundberg HE, Larsen S, Sundgot-Borgen J … +1 more , Mathisen TF
J Int Soc Sports Nutr · 2026 Dec · PMID 41723749 · Full text
BACKGROUND: Nordic skiing, an energy-demanding endurance sport, may be particularly susceptible to low energy availability (LEA) and relative energy deficiency in sport (REDs). The objective was to examine the nutritiona...
BACKGROUND: Nordic skiing, an energy-demanding endurance sport, may be particularly susceptible to low energy availability (LEA) and relative energy deficiency in sport (REDs). The objective was to examine the nutritional practices and physical symptoms associated with (REDs among young elite Norwegian Nordic skiers during the off-season, with particular emphasis on energy and CHO intake, in the transition from the competitive season to preparation for the subsequent season. METHODS: Thirty female and thirty male Nordic skiers participated in a 24-week controlled clinical trial. The daily dietary intake variables were carbohydrates (CHO), protein, and calcium (Ca) intake and weekly training hours. The blood variables were vitamin D, total osteocalcin (tOC), procollagen type 1 N-terminal propeptide/cross-linked C-telopeptide type 1-collagen (PINP1/CTX1) ratio, heart rate (HR), resting metabolic rate (RMR), bone mineral density (BMD), lean body mass (LM), visceral adipose tissue (VAT), and body fat percentage (BF%). RESULTS: Energy intake increased by 25%, and CHO increased by 14.5% for both sexes during the study, and training volume increased by 41% for female athletes and 83% for male athletes, respectively. There were positive correlations between higher BMD, bone markers, RMR, and LM and negative correlations between VAT and REDs symptoms. VAT was correlated with RMR and bone markers. LM emerged as a key predictor for health variables, explaining variability across multiple REDs markers. CONCLUSIONS: Nordic skiers seem unable to increase energy intake sufficiently during the preparation period, leading up to the competitive season, as demonstrated by a large discrepancy between changes in energy intake, especially CHO, and exercise volume. The correlations between energy intake and BMD, RMR, VAT, and HR underscore the clinical consequences of insufficient energy intake, which may arise if individuals focus on low body mass and body fat percentage without sufficient knowledge. VAT, tOC, and the P1NP/CTX-ratio are promising indicators for monitoring dietary interventions in individuals with REDs and should be considered in future research on REDs treatment strategies.
Anti-inflammatory effects of nicotinamide mononucleotide (NMN) in human skeletal muscle after BFR-exercise.
Yang DL, Chao KC, Yang HT … +8 more , Chen KH, Dewi L, Condello G, Ye M, Nicholls A, Liao YC, Huang CY, Kuo CH
J Int Soc Sports Nutr · 2026 Dec · PMID 41705654 · Full text
BACKGROUND: β-Nicotinamide mononucleotide (NMN) inhibits acute inflammation in injured animal tissues. AIM: We examined whether NMN supplementation attenuates inflammation induced by blood flow restriction-resistance exe...
BACKGROUND: β-Nicotinamide mononucleotide (NMN) inhibits acute inflammation in injured animal tissues. AIM: We examined whether NMN supplementation attenuates inflammation induced by blood flow restriction-resistance exercise (BFR-exercise) in human skeletal muscle. METHODS: Eleven untrained men (22.8 ± 1.5 y) completed a randomized, placebo-controlled, counterbalanced crossover trial, receiving either Placebo or NMN (1200 mg/d) for 7 d, with a 3-week washout between conditions. Multiple muscle biopsies were obtained before and after BFR-exercise. RESULTS: BFR-exercise-induced significant muscle necrosis at 0 h, which resolved within 24 h in both conditions. NMN supplementation suppressed exercise-induced increases in TNF-α and IL-10 mRNA but delayed the rise in p21 mRNA, suggesting attenuated inflammatory signaling and delayed myogenic differentiation. The resolution of infiltrating cells from necrotic regions was moderately delayed by NMN. BFR-exercise increased the mitochondrial content in exercised muscle by 171% after 24 h of recovery. However, this adaptation was abolished with NMN. Immunofluorescence staining with TOM20 and myeloperoxidase (MPO) revealed that infiltrating phagocytes carried substantially more mitochondria than myofiber cytoplasm, forming a diffusion gradient toward damaged regions of myofibers. This concentration difference between phagocytes and myofibers was further confirmed using COX4 immunostaining in biopsied muscle from an additional participant. CONCLUSIONS: NMN supplementation, while inhibiting inflammatory signaling in exercised human skeletal muscle, may also suppress mitochondrial replenishment from phagocytes to repairing myofibers.
Effectiveness of a soccer injury prevention program based on creatine supplementation and internal load monitoring: a randomized controlled pilot study.
Soler Hurtado M, Treguier M, González-de-la-Flor Á … +4 more , Domínguez-Balmaseda D, García-Arrabé M, Miñambres Martin D, García-Pérez-de-Sevilla G
J Int Soc Sports Nutr · 2025 Sep · PMID 41704196 · Full text
BACKGROUND: Musculoskeletal injuries are frequent in soccer, occurring more often in matches than in training sessions, and mainly affecting the lower limbs. While creatine supplementation is commonly used to enhance per...
BACKGROUND: Musculoskeletal injuries are frequent in soccer, occurring more often in matches than in training sessions, and mainly affecting the lower limbs. While creatine supplementation is commonly used to enhance performance, evidence regarding its role in injury prevention among soccer players remains limited. This pilot study investigated whether creatine supplementation could reduce the incidence of musculoskeletal injuries in amateur soccer players. METHODS: A 14-week randomized controlled pilot trial was conducted with 23 amateur soccer players randomly assigned to the creatine group ( = 12; 3 g/day) or the placebo group ( = 11; maltodextrin). Primary outcomes were injury incidence and training availability. Secondary outcomes included isometric strength, countermovement jump (CMJ) performance, perceived pain, well-being, and internal load. Assessments were performed at baseline (January 2025) and post-intervention (April 2025). RESULTS: Twenty-four players were randomized (12 creatine, 11placebo). Injury incidence was lower with creatine (8.3%) than placebo (36.4%) (RR = 0.23, 95% CI 0.03-1.75; = 0.155). Missed training sessions were fewer with creatine (0.25 ± 0.87 vs 0.82 ± 1.40; = 0.135). Significant time × group effects favored creatine for knee extension, knee flexion, hip extension, right hip flexion, and CMJ height (all < 0.01). CONCLUSION: Creatine supplementation improved strength and jump performance and showed a trend toward lower injury incidence, supporting its potential as an adjunct in soccer injury-prevention programs.
International Society of Sports Nutrition position stand: effects of dietary antioxidants on exercise and sports performance.
Gonzalez DE, Dickerson BL, Roberts BM … +15 more , Kurtz JA, S Waldman H, Gonzalez AM, McAllister MJ, Heileson JL, Bloomer RJ, Arent SM, Candow DG, Stout JR, Hecht KA, Campbell B, Kerksick CM, Kalman D, Antonio J, Kreider RB
J Int Soc Sports Nutr · 2026 Dec · PMID 41701327 · Full text
Following a comprehensive review, the International Society of Sports Nutrition (ISSN) has developed an official position on the role of dietary antioxidants in exercise and sport. Antioxidants play a complex, context-de...
Following a comprehensive review, the International Society of Sports Nutrition (ISSN) has developed an official position on the role of dietary antioxidants in exercise and sport. Antioxidants play a complex, context-dependent role in vivo; they can facilitate recovery from exercise but may also hinder training adaptations when consumed at supraphysiological doses. While endogenous antioxidant systems can effectively maintain redox balance, dietary sources, particularly whole foods, can help mitigate excessive oxidative stress following intense/heavy training or inadequate recovery. The influence of dietary antioxidants depend on timing, dosage, type, and individual factors. The ISSN's official position encompasses the following: (1) Redox balance exists on a spectrum, with mild oxidative eustress driving beneficial physiological adaptations and excessive oxidative distress impairing health, recovery, and performance; (2) Moderate levels of exercise-induced reactive oxygen and nitrogen species (ROS/RNS) can support training adaptations but excessive levels can result in muscle damage, inflammation, and reduced physical performance and immune function; (3) Endogenous and exogenous antioxidants protect cells by neutralizing free radicals and reducing oxidative damage to biomolecules; (4) FDA labeling for "antioxidant" claims applies to nutrients with established RDIs and demonstrated antioxidant activity; this typically includes vitamins C and E, β-carotene (a source of vitamin A), selenium, zinc, copper, and manganese; (5) While dietary antioxidants show potential for both direct and indirect effects, the evidence varies, and their use should be tailored to individual performance or recovery goals; (6) Long-term exercise augments endogenous antioxidant defense and should be the primary strategy for enhancing redox capacity before considering supplementation; (7) Whole foods and beverages rich in flavonoids, polyphenols, carotenoids, vitamins, and minerals are preferred antioxidant sources; (8) Dietary supplementation is best reserved for nutrient insufficiencies or deficiencies, inadequate dietary intake, or periods of high training distress; (9) Responses to supplementation vary by individual factors, such as training status, baseline antioxidant capacity, demographics, diet, and injury risk, with some antioxidant compounds offering cognitive, behavioral, or physical-related benefits; and (10) Creatine monohydrate (i.e. 0.1 g/kg/day), omega-3 fatty acids (1000-6000 mg/day EPA+DHA for 6-12 weeks), tart cherry (480 mg powder or 60-90 mL juice/day for 7-14 days), and astaxanthin (4-12 mg/day for 4-12 weeks) rank among the top nutrients for their antioxidant effects, with moderate- to high-quality evidence supporting their use in recovery or performance without interfering with training adaptations. Most others show weak or low efficacy. This position promotes an individualized, evidence-based approach, recognizing that small to moderate exercise-induced oxidative stress aids adaptation, while excess oxidative stress causes harm; it also emphasizes food-forward and dietary supplementation strategies.
Correction.
J Int Soc Sports Nutr · 2026 Dec · PMID 41697283 · Full text
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A comprehensive review of the physiology and evidence base to guide the use of ergogenic and medical supplements for enhanced cycling performance.
Rowland A, Edwards S, Prieto-Bellver G … +6 more , Menz B, Rowland A, Cornelisse E, Karapetis CS, Wallen MP, Hopkins AM
J Int Soc Sports Nutr · 2026 Dec · PMID 41685663 · Full text
BACKGROUND: A growing body of evidence supports the use of supplements to enhance cycling performance through both direct and indirect mechanisms. METHODS: This review was informed by a structured literature search condu...
BACKGROUND: A growing body of evidence supports the use of supplements to enhance cycling performance through both direct and indirect mechanisms. METHODS: This review was informed by a structured literature search conducted in PubMed, Scopus and Web of Science for peer-reviewed studies published up to May 2025. Studies were included if they involved human participants, were published in English and evaluated outcomes related to endurance performance, recovery or physiological function. RESULTS: Direct enhancement with ergogenic supplements is primarily achieved via modulation of skeletal muscle energy metabolism. During exercise, adenosine triphosphate (ATP) resynthesis is driven by the phosphagen system, glycolysis, oxidative phosphorylation and beta-oxidation, with each system contributing according to the intensity and duration of the effort. Supplements such as beta-alanine, caffeine, carbohydrates, carnitine, creatine monohydrate, dietary nitrates, electrolytes, exogenous ketones, N-acetylcysteine and sodium bicarbonate support these energy systems by improving substrate utilization, buffering capacity, energy availability or resistance to fatigue. In addition to ergogenic supplements that directly enhance performance, medical supplements play an important indirect role by supporting bone health, connective tissue integrity, inflammation management, micronutrient status, muscle repair and gut function. Evidence-based options for cyclists include calcium, cherry juice, collagen, curcumin, iron, multivitamins, omega-3 fatty acids, pickle juice, probiotics, protein, vitamin C, vitamin D and zinc. Each contribute to either improved recovery, immune support or long-term physiological adaptation. Evidence quality varied substantially across supplements, with strongest support for Australian Institute of Sport (AIS) Group A compounds. The integration of physiological testing including assessments of maximal oxygen consumption (VOmax), lactate threshold, metabolic substrate utilization and blood biomarkers may inform the development of individualized supplementation strategies tailored to training demands and competitive goals. CONCLUSIONS: This evidence-informed approach underscores the synergistic relationship between nutrition, training and performance optimization in cycling. Future research should explore personalized nutrition frameworks, interactions between multi-supplement protocols and the molecular mechanisms underpinning adaptation to endurance training and nutritional interventions.
Intra-individual reliability of blood bicarbonate responses and gastrointestinal symptoms following sodium citrate supplementation.
McManus CJ, Liew BXW, Waterworth SPW … +1 more , Chung HC
J Int Soc Sports Nutr · 2026 Dec · PMID 41661559 · Full text
BACKGROUND: Sodium citrate (SC) can elevate extracellular buffering capacity, yet the intra-individual reliability of its blood bicarbonate ([HCO₃]) kinetics and gastrointestinal (GI) responses is unclear, limiting indiv...
BACKGROUND: Sodium citrate (SC) can elevate extracellular buffering capacity, yet the intra-individual reliability of its blood bicarbonate ([HCO₃]) kinetics and gastrointestinal (GI) responses is unclear, limiting individualized dosing strategies. METHODS: Twelve healthy males (21 ± 1 yr) ingested a solution containing 0.5 g·kg SC on two visits 3-7 days apart. Capillary [HCO₃] was sampled at baseline and every 30 min to 240 min to derive baseline and peak [HCO₃], time to peak (TTP), time to exceed +5 and +6 mmol·L above baseline, and area under the curve (AUC). Reliability was quantified with ICC, typical error (TE), and CV; a Monte Carlo simulation estimated the probability of exceeding +5 and +6 mmol·L at each time point. GI symptoms (12-item questionnaire) were recorded concurrently. RESULTS: [HCO₃] rose significantly over time from 30 min in both visits ( < 0.001). Reliability was moderate for baseline [HCO₃] (ICC = 0.72 [0.25, 0.91]; CV = 3.5%) and AUC (ICC = 0.56; CV = 3.5%), but poor for peak [HCO₃] (ICC = 0.23 [-0.29, 0.68]; CV = 5.4%) and all time-based metrics, including TTP (ICC = 0.07; TE = 49.1 min; CV = 32.5%) and time to +5 and +6 mmol·L. Simulation showed an ≥ 80% probability of exceeding +5 mmol·L from 120-240 min (83.9-85.8%), whereas +6 mmol·L peaked at 69.7% (150 min). GI symptoms were common, unchanged across visits, and moderately reliable for overall burden (ICC = 0.61; TE = 2.63; CV = 46.6%). CONCLUSION: SC elicits a consistent group-level alkalosis, yet individual timing metrics are unreliable. Concentration-based indices are more stable for monitoring. Practically, a 2-3 h ingestion window maximizes the probability of achieving ≥+5 mmol·L, but individual profiling is recommended where precise timing is critical.
Development of an individualized prediction model for dynamic adaptations in performance and immune function associated with dietary patterns in endurance athletes using machine learning.
Hou Y, Chen M, Qin G … +1 more , Wang Z
J Int Soc Sports Nutr · 2026 Dec · PMID 41618909 · Full text
BACKGROUND: Psychological resilience significantly influences immune function and health outcomes in high-stress populations, yet mechanisms underlying nutrition-psychology-immunity interactions remain poorly understood....
BACKGROUND: Psychological resilience significantly influences immune function and health outcomes in high-stress populations, yet mechanisms underlying nutrition-psychology-immunity interactions remain poorly understood. This study developed an individualized prediction model integrating dietary patterns with psychological and immune adaptations to inform personalized therapeutic approaches. METHODS: A retrospective cohort analysis examined 200 endurance athletes over 12 months using integrated datasets from NHANES athletic subcohort, UK Biobank, and training monitoring databases. Athletes were categorized into three dietary pattern groups (high-carbohydrate, high-protein, balanced micronutrient) based on their naturalistic dietary intake. This observational design examined associations between dietary patterns and health outcomes without manipulating participant diets. A hybrid LSTM-XGBoost machine learning architecture with SHAP analysis predicted individual responses based on psychological variables, immune markers (IL-6, TNF-, CRP, IgA), and performance metrics. Statistical analyses controlled for multiple comparisons using Bonferroni correction. Non-normally distributed variables were log-transformed or analyzed using non-parametric methods. Mediation analyses examined psychological pathways linking dietary patterns to immune outcomes. RESULTS: Psychological resilience emerged as the primary predictor of dietary pattern response (SHAP importance = 0.342), with psychological improvements consistently preceding immune function recovery by 1-2 months. Three distinct resilience-based subgroups demonstrated different response trajectories: high resilience athletes achieved superior improvement rates (0.43 vs. 0.10 points/month) and reached plateau phases earlier (6.8 vs. 11.2 months) compared to low resilience individuals. The predictive model achieved exceptional performance metrics (91.2% sensitivity, 87.6% specificity) for identifying non-responders to dietary patterns. Mediation analysis revealed that 42.4% of the associations between dietary patterns and immune function operated through psychological pathways, with cortisol reduction serving as a critical mechanism. CONCLUSIONS: Psychological resilience predicts responsiveness to dietary patterns through psychoneuroimmunological pathways. Baseline psychological assessment should guide personalized nutrition strategies in clinical populations experiencing chronic stress and immune dysfunction.
Short-term creatine supplementation enhances strength, reduces fatigue, and accelerates recovery in resistance-trained athletes: a double-blind, randomized, crossover trial.
Salem A, Ammar A, Kerkeni M … +12 more , Boujelbane MA, Merve Uyar A, Moritz Köbel L, Selvaraj S, Zare R, Heinrich KM, Jahrami H, Tounsi S, Grosso G, I Schöllhorn W, Trabelsi K, Chtourou H
J Int Soc Sports Nutr · 2025 Sep · PMID 41579075 · Full text
BACKGROUND: While the long-term ergogenic benefits of creatine monohydrate (CrM) supplementation are well-documented, the potential advantages of acute ingestion followed by short-term consumption remain relatively under...
BACKGROUND: While the long-term ergogenic benefits of creatine monohydrate (CrM) supplementation are well-documented, the potential advantages of acute ingestion followed by short-term consumption remain relatively underexplored. This double-blind, randomized crossover study investigated the acute and short-term effects of CrM supplementation on strength performance, heart rate variability (HRV) responses, and recovery of lower limbs strength and muscle soreness in resistance-trained males. METHODS: A total of eleven physically active participants were recruited; however, due to incomplete data, one participant was excluded, and ten participants (age: 21.3 ± 1.9 years) were analyzed. Participants ingested either creatine monohydrate (CrM: 0.3 g·kg·d) or a placebo (PLA) for three days, with the first day's dose consumed 2 h pre-test and subsequent doses divided into three daily doses. Participants completed two test sessions in a randomized order, separated by a seven-day washout period. Each session included bench press (BP) and back squat (BS) tests performed at 60%, 70%, and 80% of one-repetition maximum (1RM) under either CrM or PLA conditions. Strength performances (repetitions, velocity, power), HRV and peak heart rate (HR), jump tests (Countermovement Jump (CMJ) and Squat Jump (SJ)), and delayed-onset muscle soreness (DOMS) were assessed. RESULTS: Compared to PLA, CrM supplementation significantly increased repetitions completed at 60-80% 1RM in BP and BS ( ≤ 0.041, = 0.72-1.6) during both test sessions. CrM reported higher velocity compared to PLA at all intensities (60-80% 1RM) for both exercises and sessions ( ≤ 0.035, = 0.78-4.09). CrM reduced cardiovascular strain compared to PLA at 60% 1RM during back squat ( = 0.017, = 1.05). Peak HR increased with intensity for both conditions ( = 1.1-4.28), with CrM showing lower HR at 60% ( = 0.017, = 1.05) and higher HR at 80% ( = 0.047, = 0.82) compared to PLA. CrM enhanced post-exercise parasympathetic reactivation in the 1 session demonstrating higher favorable response in RMSSD ( = 0.015, = 2.99) and HF power ( = 0.022, = 2.76) compared to PLA. CMJ performance was higher in CrM compared to PLA at 24 h post-1 session and immediately before and after the 2 session ( ≤ 0.019, = 1.10-1.93), also DOMS was reduced in upper and lower limbs ( ≤ 0.012, = 1.15-1.04) immediately before the 2 session. CONCLUSION: These findings demonstrate that even three days of CrM supplementation have the potential to enhance strength performance, reduce physiological stress, and accelerate recovery, suggesting it as an effective ergogenic strategy for athletes seeking immediate performance gains and reduced post-exercise soreness.
Whey protein intakes up to 0.4g/kg body mass are well tolerated before a 10km run at 85% of race pace: a clinical trial.
Shaw K, Lindstrom B, Moss A … +1 more , Parnell JA
J Int Soc Sports Nutr · 2026 Dec · PMID 41556283 · Full text
BACKGROUND: Exercise induced gastrointestinal (GI) symptoms affect a significant portion of endurance runners, resulting in discomfort and suboptimal performance. Protein intakes pre-exercise may have benefits; however,...
BACKGROUND: Exercise induced gastrointestinal (GI) symptoms affect a significant portion of endurance runners, resulting in discomfort and suboptimal performance. Protein intakes pre-exercise may have benefits; however, research investigating dietary intake prior to exercise suggests that many runners avoid foods high in protein before running to manage their GI symptoms. Unfortunately, clinical trials evaluating the effectiveness of this strategy are lacking. This study aimed to quantify exercise-induced GI symptoms, gut fullness, blood glucose response, and ratings of perceived exertion in response to low-protein (LP) and moderate-protein (MP) pre-exercise shake. METHODS: This single-blind crossover study involved 13 recreational runners (eight females, five males) who completed a 10 km treadmill run at 85% of their 10 km race pace after consuming a shake with carbohydrate and whey protein at either a low-protein (0.15 g/kg body mass) or moderate-protein (0.4 g/kg body mass) dose 60 minutes prior to exercise. Due to increased whey protein and standardized carbohydrate, the shakes had differing energy contents. GI symptoms were assessed pre-shake, 60 minutes post-shake, and post-run using a questionnaire and gut fullness was assessed pre-shake, 15-, 30-, and 60 minutes post-shake, and post-run using a visual analog scale. Blood glucose was measured pre-shake, 30- and 60 minutes post-shake, and post-run using a capillary blood sample and rating of perceived exertion was assessed following the 10 km run. RESULTS: Total symptoms experienced increased over time ( < 0.01) and were greater during the run than at fasting ( < 0.01) or post-shake ( = 0.01) but were not affected by protein content ( = 0.85). A significant increase in bloating severity was observed following the moderate-protein shake as compared to the low-protein shake during the run (0.54 vs 1.23; = 0.03), but no other symptoms assessed were significantly impacted by the shake composition. Blood glucose was significantly higher at 30 minutes post-shake than at any other time; however, there was no difference between the shakes ( = 0.20). Gut fullness increased post-shake ( < 0.01) but did not differ significantly between the two conditions at any time point; however, remained above fasting at all time points only in the MP group. Rating of perceived exertion was not significantly different between the two conditions (low-protein = 14.9 ± 1.0; moderate-protein = 14.9 ± 0.7; = 1.00). CONCLUSIONS: Easily digestible protein sources up to 0.4 g/kg body mass consumed one hour before exercise are advised and generally well tolerated, though 0.4 g/kg body mass of protein was associated with increased bloating. However, protein intakes before exercise should be trialed prior to competition due to variations in individual tolerance.
Acute phenylcapsaicin supplementation improves CrossFit® performance: a randomized, triple-blind, placebo-controlled crossover trial.
Triviño AR, Díaz-Romero C, Martin-Olmedo JJ … +6 more , Jimenez-Martinez P, Alix-Fages C, Cwiklinska M, Pérez D, Funes Pol D, Jurado-Fasoli L
J Int Soc Sports Nutr · 2026 Dec · PMID 41536004 · Full text
BACKGROUND: Phenylcapsaicin (PC) may enhance high-intensity exercise performance by reducing perceived exertion, increasing mechanical output, and limiting muscle damage, making it potentially beneficial for CrossFit (CF...
BACKGROUND: Phenylcapsaicin (PC) may enhance high-intensity exercise performance by reducing perceived exertion, increasing mechanical output, and limiting muscle damage, making it potentially beneficial for CrossFit (CF) athletes. OBJECTIVE: To examine the acute effects of PC supplementation on performance, recovery, and metabolic responses during a CF session. METHODS: This study had a randomized, triple-blind, placebo-controlled crossover design. Fifty CF-trained athletes (50% women) ingested either 2.5 mg of PC or a placebo (PLA) 45 minutes before a standardized CF session, including a warm-up, weightlifting block, and WOD. Delayed-onset muscle soreness (DOMS) was assessed 24- and 48-hours post-session. Countermovement jump (CMJ) was evaluated pre- and post-session, while a deep squat at 70% 1RM was performed post-session. Throughout the session, heart rate, capillary lactate, rating of perceived exertion (RPE), and perceived recovery status (PRS) were monitored. RESULTS: Compared to PLA, PC improved squat performance at 70% 1RM in both load and repetitions ( ≤ 0.035), attenuated the decline in CMJ ( < 0.001), and maintained weightlifting performance over time ( interaction = 0.011), with significantly higher load in round 9 ( = 0.030). No differences were observed during the WOD ( interaction ≥ 0.826). DOMS was significantly lower in the PC group at both 24 h and 48 h ( = 0.030), while no group differences were found for lactate, RPE, PRS, or heart rate ( interaction ≥ 0.340). Analysis stratified by sex showed that PC reduced CMJ loss in men ( = 0.043) and increased squat load in women ( = 0.021). CONCLUSION: In conclusion, acute PC supplementation enhances performance and recovery in CF athletes.
Correction.
J Int Soc Sports Nutr · 2026 Dec · PMID 41456084 · Full text
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J Int Soc Sports Nutr · 2026 Dec · PMID 41452467 · Full text
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The effectiveness of protein supplements on athletic performance and post-exercise recovery - a Bayesian multilevel meta-analysis of randomized controlled trials.
Zhao S, Zhang X, Liang T … +3 more , Ng S, Liu Y, Ning Z
J Int Soc Sports Nutr · 2026 Dec · PMID 41433039 · Full text
BACKGROUND: Protein supplements are a popular category of dietary supplements among fitness enthusiasts and athletes. However, research providing definitive conclusions on the effects of protein on athletic performance a...
BACKGROUND: Protein supplements are a popular category of dietary supplements among fitness enthusiasts and athletes. However, research providing definitive conclusions on the effects of protein on athletic performance and post-exercise recovery remains limited. Key factors, such as protein source, timing, and optimal dosage, require further investigation to clarify their impact. METHOD: A systematic search across seven databases identified 6,129 studies, which were screened using the Covidence online tool. After independent selection, data extraction, and risk of bias assessment by two reviewers, 75 studies involving 1,206 athletes were included in the meta-analysis. A multilevel meta-analysis synthesized data from the included studies using a Bayesian hierarchical model with the brms package. Publication bias was assessed using a funnel plot generated with the PublicationBias package and by calculating the P value of Egger's test through the metafor package. Additionally, a moderation analysis with the brms package was conducted to examine the relationship between seven moderators and effect sizes. RESULTS: The results demonstrated that the effects of protein-carbohydrate supplements showed statistical significance in comparison to the placebo group [μ(SMD): 0.57, 95% CI: 0.2 to 0.93] in enhancing endurance performance. Pure protein supplements demonstrated statistically significant effects compared to the placebo group in both endurance performance [μ(SMD): 0.37, 95% CI: 0.02 to 0.71] and muscle strength [μ(SMD): 0.72, 95% CI: 0.18 to 1.27]. For post-exercise recovery, pure protein supplements also showed statistically significant effects compared to carbohydrate supplements for maintaining glycogen resynthesis [μ(SMD): 0.83, 95% CI: 0.21 to 1.46]. However, the results indicated that all significant effects were observed in randomized controlled trials where the energy intake between the intervention and control groups was not matched. CONCLUSION: The effects of protein supplementation on athletic performance and post-exercise recovery appear to be limited. Protein supplements showed beneficial effects compared to no supplementation. However, all statistically significant results were derived from studies in which energy intake was not matched between groups. This suggests that the observed benefits may not be attributable to protein per se. An additional intake of 1 g/kg/day of protein from supplements, resulting in a total daily protein intake of approximately 2 g/kg/day, appears to be most effective for enhancing athletic performance. REGISTRATION: Registered at the International Prospective Register of Systematic Reviews (PROSPERO) (identification code CRD42024608194).
Creatine supplementation and resistance training: a comparison between novice and experienced lifters - a systematic review and dose-response meta-analysis.
Ashtary-Larky D, Mohammadi S, Hajizadeh L … +4 more , Mousavi SAH, Forbes SC, Candow DG, Antonio J
J Int Soc Sports Nutr · 2025 Sep · PMID 41433021 · Full text
BACKGROUND: Creatine (Cr) supplementation is well established for enhancing fat-free mass (FFM) when combined with resistance training (RT). However, the influence of prior training experience on supplementation efficacy...
BACKGROUND: Creatine (Cr) supplementation is well established for enhancing fat-free mass (FFM) when combined with resistance training (RT). However, the influence of prior training experience on supplementation efficacy remains unknown. OBJECTIVE: This systematic review and dose-response meta-analysis of controlled trials evaluated the effects of Cr supplementation combined with RT on body composition, with particular emphasis on the differences between trained (experienced) and untrained (novice) individuals. METHODS: A systematic search of major databases was conducted to identify controlled trials published until March 2025. The effects of Cr supplementation on body mass, body mass index (BMI), FFM, fat mass (FM), and body fat percentage (BFP) were examined using random-effects meta-analysis. RESULTS: A pooled analysis of 61 trials revealed that Cr supplementation significantly increased FFM (weighted mean difference [WMD]: 1.39 kg; 95% confidence intereval (CI): 1.07,1.70; < 0.001) and body mass (WMD: 0.89 kg; 95% CI: 0.76,1.01; < 0.001) without significant effects on FM, BMI, and BFP. Trained individuals exhibited greater, though non-significant, gains in FFM (1.82 vs. 1.23 kg) compared with untrained participants, despite similar increases in total body mass. Dose-response analyses identified significant relationships between Cr dose and changes in body mass and BMI. Furthermore, supplementation duration was associated with changes in BFP and body mass. CONCLUSION: Both novice and experienced lifters gained FFM with Cr supplementation compared to placebo. The increase in FFM was approximately 0.6 kg (≈50%) greater in experienced participants; however, this between-group difference was not statistically significant.
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