J Int Soc Sports Nutr [JOURNAL]
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200 papers
Similar effects between animal-based and plant-based protein blend as complementary dietary protein on muscle adaptations to resistance training: findings from a randomized clinical trial.
Santini MH, Erwig Leitão A, Mazzolani BC … +5 more , Smaira FI, de Souza MSC, Santamaria A, Gualano B, Roschel H
J Int Soc Sports Nutr · 2025 Dec · PMID 41059835 · Full text
BACKGROUND: Recent evidence suggests that both animal and plant proteins support strength and hypertrophy gains when paired with resistance training and adequate protein intake. The purpose of this study was to investiga...
BACKGROUND: Recent evidence suggests that both animal and plant proteins support strength and hypertrophy gains when paired with resistance training and adequate protein intake. The purpose of this study was to investigate the effects of supplementary protein source (blend of plant-based [PLNT] vs. animal based [ANML]) to habitual diet on changes in muscle mass and strength in healthy young men undertaking resistance training. METHODS: Forty-four young untrained males were recruited for this study. Subjects were randomly allocated into two groups, and consumed three 15-g daily doses (45 g. d- total) of either a mixed plant- (i.e.; soy and pea) or animal-based (i.e.; whey) protein in drink form as a supplementary source of protein in their main meals of the day (i.e.; breakfast, lunch, and dinner) for 12 weeks combined with a 3 times/week linear periodized and supervised resistance training program. Prior to the start of the trial, three (2 nonconsecutive weekdays and 1 weekend day) 24-h dietary recalls were collected to determine baseline habitual protein intake and were repeated during the protocol at weeks 4, 8, and 12. Muscle cross-sectional area (CSA, via ultrasonography imaging) determination, body composition (via dual emission x-ray absorptiometry, DXA), and lower-body maximum dynamic strength (1RM, via leg press) were assessed at baseline (PRE) and after 12 weeks of intervention (POST). RESULTS: Both groups showed significant (all < 0.0001) PRE-to-POST increases in whole-body lean mass (PLNT: 2.4 kg ±1.6, ANML: 2.5 kg ±3.9), appendicular lean mass (PLNT: 1.2 kg ±0.2; ANML: 1.8 kg ±0.2) and leg lean mass (PLNT: 0.9 kg ±0.2; ANML: 1.3 kg ±0.2), vastus lateralis mCSA (PLNT: 0.9 cm ±0.2; ANML: 1.3 cm ±0.2) and leg-press 1RM (PLNT: 64 kg ±7.8; ANML: 63 kg ±7.5), with no between-group differences for any of the variables (all > 0.05). CONCLUSION: Complementing dietary protein intake with either a blend of plant- or an animal-based protein similarly supported resistance training-induced muscle adaptations. TRIAL REGISTRATION: Distinct Sources of Supplementary Protein in the Resistance Exercise Training-induced Adaptations, NCT05710614, 08/01/2023.
A randomized, placebo-controlled, crossover clinical trial to evaluate the effect of a turmeric formulation on muscle soreness and function recovery in moderately active adults.
Schönenberger KA, Laval J, Woods T … +4 more , Truillet R, Naranjo-Modad S, Mettler S, Fança-Berthon P
J Int Soc Sports Nutr · 2025 Dec · PMID 41040018 · Full text
BACKGROUND: Turmeric may alleviate exercise-induced muscle soreness (delayed onset muscle soreness) and muscular function loss due to the strong anti-inflammatory and antioxidant activities of its active compounds, the c...
BACKGROUND: Turmeric may alleviate exercise-induced muscle soreness (delayed onset muscle soreness) and muscular function loss due to the strong anti-inflammatory and antioxidant activities of its active compounds, the curcuminoids. The primary objective of this trial was to evaluate the effect of a highly bioavailable turmeric formulation on delayed onset muscle soreness in male adults. METHODS: In a randomized, double-blind, placebo-controlled, crossover trial (ClinicalTrials.gov NCT04946981), 44 moderately active adults (34 males, 10 females, mean [SD] age = 33.7 [6.4] years) ingested a turmeric formulation (300 mg/day, thereof 90 mg of active curcuminoids) or placebo for five days. On the second day, muscle damage was induced with exercise (30 min downhill run at 70% VO₂ max). Immediately before and 0, 24, 48, and 72 hours post-exercise, muscle soreness during squat on quadriceps (visual analog scale), muscular function (knee extension dynamometer), muscle power (vertical jump test), muscle damage (serum creatine kinase), range of motion (knee flexion), and perceived wellness and wellbeing (questionnaire) were assessed. During exercise, exhaustion was assessed using the Borg Rating of Perceived Exertion. The primary trial population consisted of the male participants, outcomes in females were considered exploratory. Adjusted least squares means with standard errors (SE) were obtained from mixed models for repeated measures. RESULTS: There were no significant differences between the turmeric formulation and placebo in muscle soreness area under the curve from pre-exercise to 72 hours post-exercise and at all timepoints, except for a trend observed in males 72 hours after exercise (adjusted mean [SE] for difference from placebo = -4.8 [2.7] mm, = 0.0776). Muscle soreness recovery (difference between soreness at 72 hours and maximal post-exercise soreness) was significantly greater with the turmeric formulation compared to placebo (adjusted mean [SE] for difference from placebo = -10.7% [4.3%], = 0.0184 for the male participants, and -7.9% [3.6%], = 0.0346 for the total sample). Furthermore, in males, the decrease from pre-exercise to 24 hours after exercise in isokinetic peak torque was significantly lower with the turmeric formulation (adjusted mean [SE] for difference from placebo = 11.0 [4.9] Nm, = 0.0275), as was the decrease in isokinetic max rep work (adjusted mean [SE] for difference from placebo = 11.6 [4.9] J, = 0.0195), while vertical jump peak power at 24 hours after exercise was higher (median [interquartile range] with the turmeric formulation vs. placebo = 931.1 [825.9; 1001.1] W vs. 916.5 [824.8; 989.5] W, = 0.0445). CONCLUSIONS: Supplementation with the turmeric formulation can accelerate exercise-induced muscle soreness recovery and could attenuate muscular function loss and improve performance after unaccustomed exercise in young, moderately active, male adults.
Caffeine and taurine: a systematic review and network meta-analysis of their individual and combined effects on physical capacity, cognitive function, and physiological markers.
Deng H, Wang L, Liu P … +2 more , Bin Naharudin MN, Fan X
J Int Soc Sports Nutr · 2025 Dec · PMID 41032459 · Full text
BACKGROUND: Caffeine (CAF) and taurine (TAU) have each demonstrated ergogenic effects across physical and cognitive domains. Often co-formulated in commercial energy drinks, they are widely regarded as the two principal...
BACKGROUND: Caffeine (CAF) and taurine (TAU) have each demonstrated ergogenic effects across physical and cognitive domains. Often co-formulated in commercial energy drinks, they are widely regarded as the two principal bioactive compounds. However, findings regarding their combined efficacy remain inconclusive. This systematic review and Bayesian network meta-analysis aimed to quantify the individual and combined effects of CAF and TAU on physical capacity, cognitive function, and physiological responses, with a focus on identifying potential synergistic or antagonistic interactions. METHODS: Cochrane Library, PubMed, SciELO, SportsDiscus-EBSCO and Web of Science were searched through 25 July 2025. The pooled effect of each outcome was summarized using SMD (Hedge's g) by Bayesian arm-based multilevel network meta-analysis, and SUCRA ranking was applied to estimate the relative treatment effect. RESULTS: Twelve studies were included (8 on physical capacity, 7 on blood lactate (B[la]), and 6 each on cognitive function, heart rate (HR), and rating of perceived exertion (RPE)). Posterior estimates indicated that CAF+TAU was associated with a credible positive effect on anaerobic capacity (g = 0.46, 95% CrI [0.19, 0.71]) and reaction time (g = 0.75, 95% CrI [0.29, 1.18]) compared to CAF or TAU alone. CAF showed the greatest posterior reduction in RPE (g = -0.64, 95% CrI [-1.20, -0.10]), while its posterior mean estimate suggested a potential increase in B[la] (g = 0.24, 95% CrI [-0.48, 0.96]). In contrast, TAU showed a possible tendency toward reducing B[la] (g = -0.30, 95% CrI [-1.01, 0.42]). No credible differences in HR were observed across conditions. Effects on aerobic performance and physiological measures were variable and appeared to be context-dependent. SUCRA rankings consistently favored CAF+TAU across most outcome domains. CONCLUSIONS: CAF+TAU co-supplementation provides a balanced ergogenic effect, combining the central stimulation of CAF with the neuromodulatory and metabolic support of TAU, particularly beneficial for high-intensity, reaction-based tasks. Its effects on endurance and physiological indices vary by condition, highlighting the need for personalized application.
Comparison of cheese with and without subsp. LMGT 2951 on off-season muscle strength and VO max development in Nordic skiers: a randomized clinical trial.
Lundberg HE, Larsen S, Mathisen TF … +1 more , Sundgot-Borgen J
J Int Soc Sports Nutr · 2025 Dec · PMID 41025612 · Full text
BACKGROUND AND OBJECTIVE: Nordic skiers represent a low-impact, weight-sensitive sport and may be inclined to engage in weight-controlling behavior, hence increasing their risk for low energy availability and impairment...
BACKGROUND AND OBJECTIVE: Nordic skiers represent a low-impact, weight-sensitive sport and may be inclined to engage in weight-controlling behavior, hence increasing their risk for low energy availability and impairment in health and performance. Jarlsberg cheese (J) is rich in vitamin K₂ from fermentation by Propionibacterium freudenreichii subsp. shermanii LMGT 2951 (Pf) and lactic acid bacteria and increases the osteocalcin (OC) level. Vitamin K is essential for activating OC, which is described to be associated positively with muscle strength, whereas propionic acid bacteria are found to enhance endurance. Except for Pf and its by-products, J and Norvegia (N) cheeses have almost identical nutrient content. The objective of this study was to compare the effects of Jarlsberg and N as potential supplements to training on muscle strength (MS), lean body mass (LBM) and VO max. METHODS: Thirty female and 30 male Nordic skiers were block randomized 1:1 to either J or N and studied during a 24-week offseason training schedule. The Norvegia group served as a control group. Females and males were treated with 75 and 90 grams/day, respectively. MS by seated pulldown and half-squat, LBM by DXA, and VO max were measured at baseline and after the 24 weeks off-season period. Dietary intake and training hours were registered and monitored at baseline and every eight weeks during the study. RESULTS: MS significantly increased in both groups after 24 weeks ( < 0.01). The mean increase difference in MS-upper body favored Jarlsberg by 0.95 kg (95% CI: -0.02-1.46), approaching significance ( = 0.06). No significant difference was found between groups in MS-lower body. LBM and VO2-max both increased significantly in each group ( ≤ 0.05), with no notable differences between groups. Correlation analysis identified LBM as the dominant outcome variable at both baseline and 24 weeks. Endurance training was the dominant input variable and correlated significantly positively both multiply and partially to LBM, ( = 0.04, = 0.02), respectively. At baseline and 24-weeks sex, endurance training along with OC-level explained 65% and 68% of the LBM variations, respectively. CONCLUSION: Both Jarlsberg cheese, characterized by its unique Propionibacterium freudenreichii content, and Norvegia cheese, when combined with off-season training, led to increases in LBM, VO₂ max, and MS, with no significant differences observed between groups. However, there was a trend toward greater improvements in MS in the Jarlsberg group. Overall, increases in LBM through structured training appear to be a key driver of gains in both muscle strength and aerobic capacity. PROTOCOL NUMBER: XCS-Jarlsberg/IIA. CLINICALTRIAL.GOV: NCT06688032.
Hey athlete, you need to cut weight: weight loss guidance practices and perceptions of Chinese combat sports coaches.
Zhong Y, Weldon A, Luo Y … +14 more , Kirk C, Li P, Zhang Z, Chen C, Xu K, Yin M, Tao M, Ren Z, Wu Y, Liu S, I Gee T, Lakicevic N, Langan-Evans C, Li Y
J Int Soc Sports Nutr · 2025 Dec · PMID 41020766 · Full text
BACKGROUND: Weight loss (WL) before competition is a widespread practice in combat sports (CS). Among the various factors influencing athletes' WL practice, coaches are consistently identified as the most influential in...
BACKGROUND: Weight loss (WL) before competition is a widespread practice in combat sports (CS). Among the various factors influencing athletes' WL practice, coaches are consistently identified as the most influential in terms of guiding athletes' WL practices. However, little is known about coaches' guidance practices and perceptions of WL. Therefore, the aim of this study is to examine the WL guidance practices and perceptions of Chinese CS coaches. METHODS: The study employed an observational cross-sectional approach and adopted convenience sampling. The questionnaire consisted of 22 questions and featured four sections: (i) general information, (ii) personal experience, (iii) WL guidance practice, and (iv) perception about WL. It employed different response formats, including (i) 6 short-answer (fill-in-the-blank) questions, (ii) 15 single-choice questions consisting of 4 dichotomous items, 7 multiple-category items, and 4 Likert-type scale items, and (iii) 1 multiple-choice question. In total, 135 coaches completed the questionnaire and responses from 122 coaches (115 males, 7 females, 33.2 ± 7.1 years old) representing 10 CS modalities were included in the analysis. RESULTS: A high proportion of coaches reported being aware of their athletes' body mass (95%), as well as having previously required their athletes to undergo WL before competitions (96%), and having personally guided them through the WL process (94%). The primary basis for coaches' guidance on WL was their own experience as former athletes (81%). The most recommended WL method by coaches was increasing exercise (57%). The frequency of consultation with nutritionists/doctors did not differ significantly across coaching certification level ( = 0.286), perception of the impact of WL on health ( = 0.676), and perception of the impact of WL on performance ( = 0.751). Coaches considered 18.1 ± 3.5 years as the appropriate age for athletes to initiate WL, and 6.0% ± 2.7% of body mass as the appropriate highest WL magnitude. Typically, they advised athletes to begin WL 41.4 ± 17.5 days before competition. Most coaches perceived themselves as having "some influence" (50%) over their athletes' WL practices. The primary reason coaches ( = 117) encouraged WL was to "compete against lighter opponents to enhance winning potential" (69%). Most coaches believed that WL negatively impacts health (41%) and optimizes performance (49%). Regarding fairness in competition, most coaches believed that WL does not create an unfair competition (72%). The age at which coaches recommended athletes to begin WL differed significantly only in relation to sports discipline ( < 0.001), main competition level participated by the athlete they coached ( < 0.001), and perception of the impact of WL on health ( < 0.001), while no significant differences were observed across the remaining 24 independent variables (all p-values > 0.05). CONCLUSIONS: Coaches are the primary drivers of pre-competition WL practices in CS, actively requiring athletes to reduce weight to compete in lower categories. While many coaches recognize potential health risks, a substantial proportion perceive WL as neutral or beneficial, and their recommendations are often based on personal experience rather than scientific evidence. Coaches' perceptions influence the risk level of methods they recommend.
Dosing strategies for β-alanine supplementation in strength and power performance: a systematic review.
Ong SW, Chen WL, Chien KY … +1 more , Hsu CW
J Int Soc Sports Nutr · 2025 Dec · PMID 40995761 · Full text
BACKGROUND: β-alanine is a well-established ergogenic aid that enhances muscle carnosine levels and buffering capacity during high-intensity efforts. However, its role in improving strength and power performance remains...
BACKGROUND: β-alanine is a well-established ergogenic aid that enhances muscle carnosine levels and buffering capacity during high-intensity efforts. However, its role in improving strength and power performance remains inconsistent across the literature. This systematic review investigates whether dosing strategy, rather than duration alone, is the critical determinant of efficacy in resistance-trained populations. METHODS: A systematic search was conducted across PubMed, SPORTDiscus, Scopus, Web of Science, and Google Scholar up to 28 May 2025, following PRISMA guidelines. Studies were included based on the PICO framework, targeting trained individuals receiving β-alanine supplementation with defined dosing protocols and strength- or power-based outcomes. Methodological quality was assessed using the Joanna Briggs Institute tools. RESULTS: Nine studies comprising 197 participants were reviewed. Daily β-alanine doses between 4 g and 6.4 g, especially when divided into multiple smaller servings such as 0.8 g taken several times a day, were more likely to enhance maximal strength and power-related outcomes. In contrast, studies that used high total doses but relied on sustained-release formats, single large servings, or training protocols with limited metabolic stress such as low volume or long rest intervals often failed to show improvements in performance. These findings suggest that cumulative dose and delivery method may play a more critical role than duration alone in promoting strength and power adaptations. CONCLUSION: To optimize strength and power outcomes, β-alanine supplementation should emphasize fragmented dosing protocols of 4-6.4 g/day sustained over 5-8 weeks, particularly when implemented during training phases characterized by high metabolic stress - such as repeated submaximal efforts, short rest intervals, or high-volume hypertrophy sessions that elevate intramuscular acidity. These findings offer refined guidelines for coaches, athletes, and sport nutrition practitioners, and highlight the need for more individualized and mechanistically informed supplementation strategies.
High-dose beta-alanine supplementation for two weeks did not enhance intermittent endurance or sprint performance in trained futsal players.
Miraftabi H, Berjisian E, Nouri Dizicheh M … +5 more , Naderi A, Bodaghi M, Koozehchian MS, Shabkhiz F, Lopez-Samanes A
J Int Soc Sports Nutr · 2025 Dec · PMID 40981477 · Full text
BACKGROUND: This study aimed to investigate the effects of a high-dose beta-alanine (BA) supplementation on physical performance, blood lactate concentration, and ratings of perceived exertion (RPE) in trained futsal pla...
BACKGROUND: This study aimed to investigate the effects of a high-dose beta-alanine (BA) supplementation on physical performance, blood lactate concentration, and ratings of perceived exertion (RPE) in trained futsal players. METHODS: Sixteen trained futsal players participated in a randomized, parallel, double-blind experiment, completing a two-week supplementation period with either 12 g/day of BA ( = 8; age: 19 ± 2 years; height: 1.78 ± 0.03 m; body mass: 68.5 ± 5.4 kg) or a placebo (PLA) ( = 8; age: 18 ± 1 years; height: 1.74 ± 0.08 m; body mass: 65.6 ± 6.4 kg). Athletes completed the futsal intermittent endurance test (FIET) and a 30-m speed test before and after supplementation. Plasma lactate levels were measured before, immediately after, and three minutes post-FIET, while RPE was assessed during each FIET stage. RESULTS: There was a significant main effect of time for distance covered in the FIET (Pre-BA: 1618.13 ± 268.14 m; Post-BA: 1857.50 ± 277.81 m; Pre-PLA: 1519.13 ± 243.19 m; Post-PLA: 1621.88 ± 323.65 m; = 0.003; ηp = 0.73), while no significant interaction effect was revealed for FIET ( = 0.147; ηp = 0.27). Furthermore, no significant interaction effects were found in the 30-m sprint test ( = 0.149; ηp = 0.27, Pre-BA: 4.33 ± 0.25 s; Post-BA: 4.22 ± 0.124 s; Pre-PLA: 4.33 ± 0.26 s; Post-PLA: 4.37 ± 0.22 s). Neither plasma lactate levels nor RPE showed significant main effects of treatment or timepoint (all > 0.5). Conclusion: Two weeks of high-dose BA supplementation did not have an ergogenic impact on the distance covered during the intermittent endurance test, sprint performance, blood lactate, or RPE in trained futsal players.
Performance-enhancing effects of caffeine and L-Theanine among Iranian elite wrestlers: a focus on cognitive and specific physical performance.
Razazan R, Hemmatinafar M, Imanian B … +3 more , Jahaniboushehri N, Rezaei R, Nazemzadegan G
J Int Soc Sports Nutr · 2025 Dec · PMID 40977612 · Full text
BACKGROUND: Caffeine is a well-known ergogenic aid that can enhance physical and cognitive performance. However, it often induces side effects, such as anxiety and overstimulation, which can be problematic in high-pressu...
BACKGROUND: Caffeine is a well-known ergogenic aid that can enhance physical and cognitive performance. However, it often induces side effects, such as anxiety and overstimulation, which can be problematic in high-pressure sports like wrestling. L-theanine, a non-stimulant amino acid found in tea, may help mitigate these effects by promoting a calm yet focused mental state. This study aimed to investigate the acute effects of caffeine, L-theanine, and their combination on physical performance, cognitive function, and anxiety in elite male wrestlers. METHODS: In a double-blind, placebo-controlled, crossover design, 12 elite male wrestlers (21.8 ± 2.1 years) completed four test sessions under randomized conditions: placebo (PLA), caffeine (CAF; 3 mg/kg), L-theanine (THE; 3 mg/kg), and caffeine + L-theanine (CAF+THE; 3 mg/kg each). After 60 minutes, athletes performed the wall-squat test, vertical jump height (VJH), medicine ball throw (MBT), handgrip strength, and the Specific Wrestling Fitness Test (SWFT). Cognitive function was assessed pre- and post-SWFT using a computerized Stroop test. Anxiety was assessed using the State-Trait Anxiety Inventory (STAI), and side effects were recorded. RESULTS: CAF+THE outperformed PLA in wall-squat time ( = 0.001), MBT ( = 0.005), VJH ( = 0.011), and grip strength ( = 0.004). SWFT throw count was highest in CAF+THE versus all other conditions ( < 0.001). Post-SWFT Stroop reaction time was faster in CAF+THE than PLA ( = 0.004) and THE ( = 0.036), and accuracy was also higher ( = 0.009 vs PLA). CAF alone increased state anxiety compared to PLA ( = 0.021), while CAF+THE reduced anxiety to below placebo levels (8% incidence vs 33%). Trait anxiety was lower in CAF+THE compared to CAF ( = 0.018). The prevalence of caffeine-induced tachycardia (92%) was notably reduced under CAF+THE (17%). CONCLUSION: CAF+THE (3 mg/kg each) enhances elite wrestlers' strength, endurance, cognitive speed, and accuracy while reducing anxiety and physiological side effects commonly associated with caffeine alone. This combination represents a safe, practical supplement strategy for combat sports athletes who must maintain explosive performance and mental control under stress. Coaches are encouraged to trial CAF+THE protocols during training to personalize timing and dosage.
Associations between dietary patterns and sarcopenia: insights from cross-sectional and Mendelian randomization analyses.
Tan J, Chen X, Peng Z … +4 more , Bai H, Shi L, Sun Y, Chen J
J Int Soc Sports Nutr · 2025 Dec · PMID 40977601 · Full text
BACKGROUND: Sarcopenia is defined as a progressive and generalized skeletal muscle disorder characterized by the accelerated loss of muscle mass and function. Current studies have revealed the significant impact of some...
BACKGROUND: Sarcopenia is defined as a progressive and generalized skeletal muscle disorder characterized by the accelerated loss of muscle mass and function. Current studies have revealed the significant impact of some dietary factors on the development and progression of sarcopenia. However, these studies often focused on single nutrients but little had examined complete dietary strategies. Thus, comprehensive evaluations of diverse dietary factors in larger populations are crucial for effectively adjusting diets to delay sarcopenia progression, enhancing quality of life and independence in the elderly. METHODS: We conducted a cross-sectional analysis to assess the potential correlation between various dietary factors and sarcopenia based on the population data from the UK Biobank. This analysis employed multivariate logistic regression models adjusted for different covariates (demographic data including age, sex, ethnics, etc., and potential confounders including smoking status, activity group, body mass index, etc.). Furthermore, to evaluate the robustness of our findings, we performed sub-analyses and calculated the Variance Inflation Factor. To investigate the causal influence of dietary factors on sarcopenia-related phenotypes, including low hand grip strength and appendicular lean mass (ALM), we conducted a Mendelian Randomization (MR) analysis. The analytic methods of MR were selected based on the outcomes of sensitivity analyses. RESULTS: In the cross-sectional analysis, a total of 211,027 participants were included in the final analysis, with a mean age of 56 years, comprising 104,271 females and 106,756 males. We identified significant correlations between the frequency and type of food intake and sarcopenia. For probable sarcopenia diagnosed by grip strength, a higher intake frequency of oily fish is negatively correlated with sarcopenia risk, whereas processed meat shows a positive correlation. Preference for FloraPro-Active/Benecol in spreads also relates to a reduced risk. Preliminary findings indicate correlations between tea (OR = 1.02, < 0.01), coffee (OR = 1.02, < 0.01), fresh fruit intake (OR = 1.01, < 0.01), and probable sarcopenia. For confirmed sarcopenia diagnosed by grip strength and ALM, a higher intake frequency of processed meat could increase sarcopenia risk and preference for Bran cereal in cereal type and wholemeal or wholegrain in bread type also related to a reduced risk. The MR analysis revealed that coffee (ground coffee (OR = 3.44, < 0.0035), instant coffee (OR = 2.69, < 0.015), decaffeinated coffee (OR = 3.94, < 0.0004)) intake significantly increased the risk of low grip strength, while water (OR = 1.06, < 0.000398) and fruit (OR = 1.10, < 0.0065) intake enhance ALM. Conversely, psychoactive drinks (OR = 0.91, < 0.00001), alcohol (OR = 0.906, < 0.0012), and decaffeinated coffee (OR = 0.65, < 0.0047) decreased ALM. These results have undergone sensitivity analysis validation. CONCLUSIONS: Our analysis using UK Biobank data explored associations between dietary factors and sarcopenia. We found strong links between probable sarcopenia and the intake of oily fish, processed meat, lamb, and coffee, whereas processed meat remained significantly related with confirmed sarcopenia. Preference for specific foods, such as FloraPro-Active/Benecol spreads, Bran cereal and wholemeal or wholegrain bread were associated with reduced risk. MR confirmed the causal effects of coffee intake on low hand grip strength and ALM. Our study provides insights for dietary strategies in sarcopenia patients, though further research is needed to validate and explore these mechanisms.
The combined effects of Tabata training and cinnamon supplementation on metabolic changes and body composition in soldiers with overweight or obesity.
Sabzevari Rad R, Omidi H, Alipour M
J Int Soc Sports Nutr · 2025 Dec · PMID 40970779 · Full text
AIM: This study investigated the effect of the combining Tabata training and cinnamon supplementation on metabolic changes and body composition in overweight and obese soldiers. MATERIALS AND METHODS: 40 overweight and o...
AIM: This study investigated the effect of the combining Tabata training and cinnamon supplementation on metabolic changes and body composition in overweight and obese soldiers. MATERIALS AND METHODS: 40 overweight and obese soldiers were divided into Tabata (T), Tabata training+supplement (T+S), supplement (S) and control (C) groups. The intervention completed during eight weeks with three sessions per week. Pre- and post-intervention assessments included body composition (body mass index [BMI], body fat percentage [BFP], performance parameters) push-up, squat, plank and vertical jump), metabolic markers (fasting blood sugar [FBS], insulin and [HOMA], liver enzymes (Serum Glutamic-Oxaloacetic Transaminase [SGOT], Serum Glutamic-Pyruvic Transaminase [SGPT], and Gamma-Glutamyl Transferase [GGT] (and inflammatory markers (C-Reactive Protein [CRP], Tumor Necrosis Factor-alpha [TNF-α], Adiponectin and Irisin). Cinnamon supplement was taken in 500 mg capsules three times a day. RESULTS: Body mass, BMI, and body fat percentage significantly decreased in all intervention groups ( < 0.001), with the greatest fat loss in T + S (-7.86%, < 0.001), significantly more than T ( = 0.013). Performance (push-up, squat, plank, jump) improved in T and T + S (all < 0.001), with no difference between them ( > 0.05). Fasting blood sugar, insulin, HOMA-IR, and liver enzymes (SGOT, SGPT, GGT) decreased across all interventions ( < 0.05), with the greatest reductions in T + S. Inflammatory markers (CRP, TNF-α) declined, while adiponectin and irisin increased in all interventions ( < 0.001), with superior changes in T + S versus all groups ( < 0.05). The control group showed no significant changes ( > 0.05). CONCLUSION: Tabata training resulted in synergistically effect on performance, body composition, metabolic-inflammation markers, and liver enzyme function in overweight and obese individuals. Moreover, the cinnamon supplementation as an ergogenic potentiated the observed beneficial effects.
Effects of carbohydrate, caffeine, and combined mouth rinses on physiological and perceptual responses during high-intensity interval exercise following a pre-exercise meal: a double-blinded, placebo-controlled, randomized crossover trial.
Suen MW, Sun F, Ali A … +1 more , Poon ET
J Int Soc Sports Nutr · 2025 Dec · PMID 40966095 · Full text
BACKGROUND: Mouth rinsing with carbohydrate (CHO), caffeine (CAF), and their combined (CHO+CAF) solutions has been shown to enhance exercise performance. However, most previous studies were conducted under fasted conditi...
BACKGROUND: Mouth rinsing with carbohydrate (CHO), caffeine (CAF), and their combined (CHO+CAF) solutions has been shown to enhance exercise performance. However, most previous studies were conducted under fasted conditions, which may not accurately reflect the typical practices of athletes who generally consume food before intense exercise or competition. This study examined the effects of CHO, CAF, and CHO+CAF mouth rinses on physiological and perceptual responses during high-intensity interval exercise (HIIE) following a pre-exercise meal. METHODS: Twelve recreationally active males (age: 23.4 ± 3.2 years) completed four HIIE trials involving 8 bouts of 1-min cycling at 85% of peak power output (PPO), separated by 1-min active recovery at 20% of PPO. Using a double-blinded randomized crossover design, participants rinsed with either 10% maltodextrin (CHO), 1.2% caffeine (CAF), 10% maltodextrin + 1.2% caffeine (CHO+CAF), or water (PLA) twice in each trial (after warm-up and interval 4). All solutions were taste-matched using the artificial sweetener sucralose. A standardized CHO-rich (1 g·kg body weight) breakfast was provided an hour before testing. RESULTS: Ratings of perceived exertion were significantly different between conditions after interval 4 (CHO: 12.3 ± 1.6; CAF: 13.5 ± 2.2; CHO+CAF: 12.7 ± 1.7; PLA: 13.7 ± 2.4; = 0.049, = 0.21), but no significant effects of the mouth rinse conditions were observed on heart rate, blood glucose, blood lactate, affective valence, perceived activation, or affective responses (pleasure, arousal, and dominance) (all > 0.05). CONCLUSION: These findings suggest a limited ergogenic benefit of CHO and/or CAF mouth rinse through physiological and perceptual responses following sufficient food intake.
Single high-dose vitamin D supplementation impacts ultramarathon-induced changes in serum levels of bone turnover markers: a double-blind randomized controlled trial.
Stankiewicz B, Kochanowicz A, Brzezińska P … +8 more , Niespodziński B, Reczkowicz J, Waldziński T, Kowalik T, Piskorska E, Wędrowska E, Antosiewicz J, Mieszkowski J
J Int Soc Sports Nutr · 2025 Dec · PMID 40963202 · Full text
BACKGROUND: Recent studies indicate a protective role of vitamin D supplementation against sports performance-induced dysregulation of body homeostasis. However, the effects of a single high dose of vitamin D on changes...
BACKGROUND: Recent studies indicate a protective role of vitamin D supplementation against sports performance-induced dysregulation of body homeostasis. However, the effects of a single high dose of vitamin D on changes in bone formation and resorption markers due to ultramarathon running have yet to be explored. This study aimed to analyze the effect of a single high-dose vitamin D supplementation on serum levels of bone turnover markers after a mountain ultramarathon run. METHODS: In this clinical trial (reg. number NCT03417700), 35 semiprofessional male ultramarathon runners were assigned into two groups: supplemented group, administered a single high dose of vitamin D (cholecalciferol, 150,000 IU) in vegetable oil 24 h before the start of the run ( = 16), and placebo group ( = 19), administered placebo solution 24 h before the start of the run. Blood samples were collected for analysis at three timepoints: 24 h before, immediately after, and 24 h after the run. RESULTS: Serum 25(OH)D level significantly increased ( ≤ 0.05.) after the ultramarathon in both groups. The increase was more pronounced in the supplemented population, especially 24 h after the run (147.01% vs 84.71%). According to post-hoc and other analyses, the levels of N-terminal propeptides of type I collagen, a PINP marker, were increased immediately after the run. The increase was significantly higher in the supplemented group than in the control group. CTX, PTH, sclerostin, and procalcitonin levels were significantly higher 24 h after the run in the control group. CONCLUSIONS: The observed attenuation of post-exercise bone resorption and enhancement of bone formation suggest that vitamin D supplementation may modulate bone metabolism in response to extreme physical exertion, potentially through effects on calcium - PTH homeostasis.
Comparative effects of continuous glucose monitoring-informed and traditional interval-based carbohydrate refueling protocols on endurance exercise responses: an exploratory study.
Poon ET, Lau KW, Tsang JH … +2 more , Zhang X, Wongpipit W
J Int Soc Sports Nutr · 2025 Dec · PMID 40957601 · Full text
BACKGROUND: Recent advancements in Continuous Glucose Monitoring (CGM) technology provide a novel solution for monitoring dynamic glucose fluctuations during endurance exercise, enabling personalized carbohydrate refueli...
BACKGROUND: Recent advancements in Continuous Glucose Monitoring (CGM) technology provide a novel solution for monitoring dynamic glucose fluctuations during endurance exercise, enabling personalized carbohydrate refueling strategies. However, direct evidence demonstrating its superiority over traditional refueling guidelines has been lacking. This exploratory study compared a CGM-informed protocol with a traditional interval-based (TRAD) carbohydrate refueling protocol on endurance exercise responses. METHODS: Twelve healthy, non-diabetic males (age = 32.3 ± 6.3 years) participated in two trials involving 75 minutes of continuous cycling at 50% peak power output, with the two carbohydrate refueling protocols implemented in a randomized, crossover order. In the TRAD protocol, participants received standard carbohydrate solutions at regular 15-min intervals, while replenishment timing in the CGM-informed protocol was guided by real-time glucose trends, particularly during declines. RESULTS: No significant differences were observed in heart rate, blood lactate, or perceived exertion between conditions (all p > 0.05). However, CGM-informed protocol displayed a lower coefficient of variation of glucose levels (8.82 ± 4.68%) than the TRAD protocol (11.95 ± 3.41%, Cohen's d = 0.76, p = 0.013), indicating a steadier blood glucose trend. The mean 75-minute interstitial glucose total area under the curve was significantly lower for the CGM-informed protocol (423.4 ± 39.1 mmol·min·L-1), compared to the TRAD protocol (448.6 ± 38.2 mmol·min·L-1, Cohen's d = 0.65, p = 0.008). CONCLUSION: While the CGM-informed protocol did not demonstrate beneficial effects on physiological responses over the TRAD protocol, it may aid in stabilizing glucose levels during prolonged endurance exercise. Further research is warranted to explore the applications of personalized carbohydrate refueling strategy based on CGM technology on athletic performance across various exercise protocols. .
Neuromuscular adaptations to caffeine supplementation in low-load resistance training with blood flow restriction.
Lin YT, Wu CL, Wu CC … +3 more , Hu CL, Chen YC, Hwang IS
J Int Soc Sports Nutr · 2025 Dec · PMID 40954555 · Full text
BACKGROUND: Although blood flow restriction (BFR) resistance training effectively enhances muscle strength, it increases fatigue susceptibility due to hypoxic stress. This study investigated whether combining caffeine -...
BACKGROUND: Although blood flow restriction (BFR) resistance training effectively enhances muscle strength, it increases fatigue susceptibility due to hypoxic stress. This study investigated whether combining caffeine - a common ergogenic aid - with BFR could provide additional training benefits. METHODS: Twenty-eight young adults completed a 4-week low-load resistance training program for wrist extensors, divided into two groups: BFR ( = 14) and BFR with caffeine (BFRC, = 14). Both groups performed the same occluded training at 20% of maximal voluntary contraction (MVC), with the BFRC group consuming 6 mg·kg caffeine one hour prior. Pre- and posttests assessed MVC and force control during a task involving gradual force increase and release. RESULTS: The results demonstrated comparable training-related increases in MVC and precision of control of force in both groups ( > .05). However, only the BFRC group exhibited a significant training-related decline in the size of force fluctuations ( = .002) with enhanced complexity during force release ( = .036). Consistent with the characteristic changes in force fluctuations, the BFRC group exhibited smaller variability ( = .002) and a higher mean frequency ( = .023) of pooled motor unit discharges during force release. CONCLUSIONS: While caffeine does not significantly enhance strength gains after four weeks of isometric BFR training in untrained individuals, it improves force release precision by globally reducing motor unit discharge variability.
Chronic low water intake is associated with altered exercise-induced oxidative stress and immune cell responses: a cross-sectional study.
Sim M, Song W, Choi EY … +2 more , Shin DM, Kim CS
J Int Soc Sports Nutr · 2025 Dec · PMID 40899572 · Full text
BACKGROUND: Hydration status plays a critical role in modulating oxidative stress during exercise, which can influence physical performance and recovery. While the acute effects of hydration on exercise-induced oxidative...
BACKGROUND: Hydration status plays a critical role in modulating oxidative stress during exercise, which can influence physical performance and recovery. While the acute effects of hydration on exercise-induced oxidative stress are well-documented, the long-term impact of chronic water intake remains poorly understood. Therefore, this study aimed to investigate the relationship between chronic low water intake and exercise-induced oxidative stress, as well as changes in the phenotypic composition of peripheral immune cells. METHODS: We assessed the usual plain water intake of the participants ( = 26; 19-29 years) using a questionnaire and classified them as habitually high-water drinkers (HIGH; = 16; mean plain water intake = 1.22 ± 0.19 L/d) or low-water drinkers (LOW; = 10; 0.41 ± 0.10 L/d). We conducted a maximal graded exercise test and investigated whether the extent of exercise-induced oxidative stress and immunological changes differed depending on the habitual water intake. Free radical production before and after the exercise test was assessed using serum concentrations of reactive oxygen metabolites (ROMs). The antioxidant capacity to eliminate free radicals was assessed using the serum biological antioxidant potential (BAP). We profiled peripheral blood mononuclear cells (PBMCs; CD4, CD8, CD20, CD14, CD11b, and Annexin V) using fluorescence-activated cell sorting. RESULTS: At baseline, the LOW group showed higher concentrations of serum ROMs than the HIGH group ( = 0.033). In a maximal graded exercise test, both groups showed comparable performance parameters including peak heart rate, VOmax, and exercise duration. However, the biochemical responses differed markedly: serum BAP significantly increased in the HIGH group but remained unchanged in the LOW group ( = 0.030). Furthermore, the LOW group showed a larger increase in PBMC apoptosis than the HIGH group, both in absolute cell number and percentage ( = 0.031 and = 0.034, respectively). The LOW group also showed differential PBMC subset frequencies, with greater CD11b cell recruitment ( = 0.015) and less pronounced CD14 cell reduction compared to the HIGH group ( = 0.050). CONCLUSION: Habitual low water intake was associated with elevated concentrations of free radical by-products in the resting state and impaired antioxidant capacity during acute exercise stress. In response to exercise stress, impaired redox balance in low-water drinkers resulted in accelerated cellular damage and increased myeloid cell recruitment. These findings highlight the importance of maintaining adequate habitual water intake to cope with exercise-induced oxidative stress and prevent excessive cellular stress responses. CLINICAL TRIAL REGISTRATION: Registered at the Clinical Research Information Service (CRIS) on 12 April 2019 (Registry No. KCT0003763).
Transcranial direct current stimulation combined with caffeine promotes executive function in healthy females.
Yuan W, Nitsche MA, Yue T … +2 more , Yu Y, Qi F
J Int Soc Sports Nutr · 2025 Dec · PMID 40888092 · Full text
BACKGROUND: Studies have demonstrated that both transcranial direct current stimulation (tDCS) and caffeine improve cognitive abilities through similar mechanisms. This study investigated the acute effects of tDCS combin...
BACKGROUND: Studies have demonstrated that both transcranial direct current stimulation (tDCS) and caffeine improve cognitive abilities through similar mechanisms. This study investigated the acute effects of tDCS combined with caffeine on executive functions. METHODS: Eighty females were randomly assigned to four groups (tDCS + caffeine, tDCS + placebo, sham tDCS + caffeine, and sham tDCS + placebo). Each participant completed two experimental sessions. In the first session, participants performed the Stroop, 3-back, and More-Odd Shifting tasks (T0). For the second session, participants ingested a 200 mg caffeine capsule/placebo, waited 45 minutes, and then received 2 mA real or sham tDCS for 20 minutes. Next, they performed the same cognitive tasks as in the first session (T1), and rested for 30 minutes before completing the cognitive test again (T2). RESULTS: Accuracy in the 3-back task was significantly improved for the tDCS + caffeine group at T1 and T2, for the tDCS + placebo group at T1, and for the sham tDCS + caffeine group at T2 compared to the sham tDCS + placebo group. Accuracy on the Stroop task was significantly enhanced in the tDCS + caffeine group at T1 compared to the sham tDCS + caffeine and sham tDCS + placebo groups, and in the tDCS + placebo group at T1 compared to the sham tDCS + caffeine group. No significant differences were observed among groups for the More-Odd Shifting task. CONCLUSIONS: These findings suggest that both tDCS and caffeine interventions can improve cognitive task performance, and their combination results in more persistent improvements in executive functions compared to tDCS or caffeine alone.
Weight loss practices in Chinese national and international-level Sanda athletes.
Zhong Y, Tang W, Gee TI … +12 more , Li M, Jiang H, Yin M, Xu K, Lakicevic N, Drid P, Kirk C, Langan-Evans C, Artioli GG, Reale R, Weldon A, Li Y
J Int Soc Sports Nutr · 2025 Dec · PMID 40876444 · Full text
BACKGROUND: Sanda is an unarmed combat sport (CS) comprises punching, kicking, throwing, wrestling, and defensive techniques that has increased in popularity. To ensure athletes compete against opponents of similar body...
BACKGROUND: Sanda is an unarmed combat sport (CS) comprises punching, kicking, throwing, wrestling, and defensive techniques that has increased in popularity. To ensure athletes compete against opponents of similar body size and weight for fairness, Sanda competition is classified according to weight classes. Previous studies revealed that CS athletes tend to intentionally lose weight to gain a competitive advantage over their opponents. However, little is known about weight loss (WL) practices in Sanda athletes. Therefore, the aim of this study is to investigate the WL practices of Chinese Sanda athletes. METHODS: In total, 169 (96 males, 73 females) national and international-level Sanda athletes completed the Rapid WL Questionnaire. Participants were categorized by sex (male, female), age (junior, senior), competition weight categories, and competitive levels (national, international). RESULTS: Over half (56%) of athletes purposefully implemented WL practices pre-competition. Their mean habitual WL was 7.6 ± 3.7%, and mean highest WL was 10.8 ± 4.2%. Participants usually allocated 15+ days pre-competition for WL (64%). Their rapid WL score (RWLS) was 30.4 ± 6.4. There were no significant differences across Sanda athletes concerning habitual WL% ( = 0.386, = 0.542, = 0.207), highest WL% ( = 0.631, = 0.232, = 0.091), RWLS ( = 0.055, = 0.395, = 0.736) between junior and senior athletes, across weight categories, or between competitive levels. There were no significant differences in habitual WL% across WL time ( = 0.135). However, male athletes habitual WL% ( = 0.009), highest WL% ( = 0.002), number of WL in the last year between sexes ( = 0.048), and RWLS ( = 0.011) were significantly higher than female athletes. International athletes more frequently conducted WL per year than national athletes ( = 0.005). There were no significant differences in age groups ( = 0.447) and weight categories ( = 0.585). Participants usually allocated 15+ days before the competition for WL (64%), followed by 11-14 days (21%), 8-10 days (5%), 6-7 days (4%), 4-5 days (4%), and 1-3 days (1%). Training in plastic suits (87.4%), increasing exercise (85.2%), skipping meals (56.8%), limiting fluid intake (75.8%), gradually dieting (60.0%), and training in a heated room (54.7%) were the most frequently used WL practices for Sanda athletes. Sports coach (68.5%), strength and conditioning coaches/physical trainers (42.1%), other athletes (same sport) (39.0%), and parents (32.6%) were considered to have the highest impact on athletes' WL practices. CONCLUSIONS: This study found the prevalence of WL is relatively low among Chinese national and international Sanda athletes, but the magnitudes are very high compared to other combat sports. Given that coaches have the greatest influence, the wider athlete support team must work cohesively with coaches to ensure that appropriate, individualized, and safe WL practices are applied.
Making weight makes sense: relative performance gains after rapid weight loss in powerlifting: a randomized controlled trial.
Matras A, Czapla M, Struzik A
J Int Soc Sports Nutr · 2025 Dec · PMID 40864504 · Full text
BACKGROUND: Rapid weight loss (RWL) is a common strategy among competitive powerlifters aiming to qualify for lower weight categories and improve competitive advantage. However, the effects of RWL followed by short-term...
BACKGROUND: Rapid weight loss (RWL) is a common strategy among competitive powerlifters aiming to qualify for lower weight categories and improve competitive advantage. However, the effects of RWL followed by short-term recovery on maximal strength performance remain unclear. This study aimed to examine whether a ~ 5% RWL protocol followed by a 2-hour recovery period affects changes in maximal and relative strength performance in trained male powerlifters. METHODS: This randomized controlled trial (RCT) was registered in the Australian New Zealand Clinical Trials Registry (ACTRN12622000924752). In this RCT study, 26 male powerlifters (24.6 ± 4.5 y; 92.8 ± 13.6 kg) were assigned to a rapid weight loss (RWL; = 13) or control group (CON; = 13). RWL participants followed a 4-day protocol including caloric restriction (-10%), low carbohydrate intake ( <50 g/day), low sodium, and fluid manipulation, targeting a 5% body mass reduction. The CON group maintained habitual diet and hydration. Maximal strength was assessed via simulated powerlifting competition conducted before (C1) and after (C2) the intervention. Performance variables included squat (SQ), bench press (BP), deadlift (DL), and total load (TOTAL), along with IPF GL (International Powerlifting Federation GoodLift points) and IPF GL BP (International Powerlifting Federation GoodLift for Bench Press) scores. Body composition and rate of perceived exertion (RPE) were also evaluated. RESULTS: The RWL group achieved a mean body mass reduction of 4.81%, with significant decreases in fat mass (-15.7%), fat-free mass (-2.36%), and body water (-2.41%) compared to CON (all < 0.01). Despite these changes, no significant differences in maximal strength (SQ, BP, DL, TOTAL) were observed between C1 and C2 or between groups. However, the RWL group showed a significant post-intervention increase in IPF GL ( = 0.015) and IPF GL BP scores ( = 0.017). RPE values showed no consistent or practically relevant changes. CONCLUSION: In the group that underwent a rapid weight loss of approximately 5%, followed by a short-term recovery period, maximal strength performance was maintained. This indicates that it is possible to reduce body mass without compromising absolute strength levels in competitive powerlifters. At the same time, RWL group achieved higher IPF GL and IPF GL BP values.
Topical carnosine gel improves intermittent high-intensity exercise performance in world-class rugby sevens players.
Beaven CM, James C, McMaster DT … +1 more , Brockelbank N
J Int Soc Sports Nutr · 2025 Dec · PMID 40859880 · Full text
BACKGROUND: The topical application of a carnosine gel may increase intramuscular carnosine concentrations and thereby improve exercise performance. This study investigated the effect of a topical carnosine gel on interm...
BACKGROUND: The topical application of a carnosine gel may increase intramuscular carnosine concentrations and thereby improve exercise performance. This study investigated the effect of a topical carnosine gel on intermittent high-intensity exercise performance in rugby sevens players. METHODS: Seven world-class rugby sevens players (body mass: 97.5 ± 4.1 kg; 1,452 International caps) completed two performance tests in a counterbalanced, crossover, triple-blind design. Players applied either 10 mL of a topical carnosine gel (CAR) or an ultrasound placebo gel (PLA) 40 minutes before undertaking 12 intermittent sprints on a cycle ergometer, interrupted by a 2-minute break after Sprint 6. The activity profile was 24 s cycling at 3 W/kg, 6 s at maximal intensity sprint, followed by a 30s rest. Average power, peak power, and HR were recorded for every 6 s sprint. RPE was recorded at the end of Sprint 6 and Sprint 12. RESULTS: For peak power, two-way ANOVA revealed time ( = 5.49 × 10) and treatment effects ( = 1.44 × 10). Following CAR, peak power output was higher in Sprint 2 (1433 vs 1332 W; = 0.048; = 0.99; ), Sprint 4 (1347 vs 1244 W; = 0.043; = 0.74; ) and Sprint 7 (1426 vs 1270 W; = 0.025; = 0.98; ) compared to PLA. For mean power output, HR, and RPE there were time effects but no treatment effect ( = 0.211 to 0.847). CONCLUSIONS: Topical carnosine gel improved power production in world-class rugby sevens players. Future research should determine whether carno- sine gels increase intramuscular carnosine concentrations to support the observed improvements in anaerobic performance during high-intensity exercise.
Reevaluating the definition of rapid weight loss in sports: a call for change.
Zhong Y, Tang W, Weldon A … +9 more , Gough LA, Gee TI, Lakicevic N, Xu K, Yin M, de Liang Z, Ren Z, Franchini E, Li Y
J Int Soc Sports Nutr · 2025 Dec · PMID 40849677 · Full text
BACKGROUND: Pre-competition weight loss (WL) is a widely adopted strategy in weight-sensitive sports, particularly among combat sport. This strategy enables athletes to compete at a weight or weight classes below their h...
BACKGROUND: Pre-competition weight loss (WL) is a widely adopted strategy in weight-sensitive sports, particularly among combat sport. This strategy enables athletes to compete at a weight or weight classes below their habitual body mass (BM). Although research on WL for weight-sensitive sports has steadily grown, it mostly employs the term "RWL". However, there is no compelling or universally accepted definition of RWL. OBJECTIVE: In this current opinion, we discussed the deficiencies and misuse of the current definition of RWL and proposed a new theoretical framework to provide a basis for better defining RWL in the future. DISCUSSION: A most commonly used definition describes RWL as losing 5% of body mass within 7 days. However, this definition is somewhat arbitrary and lacks empirical justification. This definition is based on two parameters: magnitude (5% BM) and duration (7 days), yet its cut-off remains rigid and lacks empirical support. Several studies on combat athletes have found that a relatively faster rate of WL can lead to significant negative impacts on performance and health variables. We argue that using WL rate as the core criterion is more robust, as the term "rapid" emphasizes the speed of WL. However, at what rate does WL become classified as RWL? The limited research in this area underscores the need for studies to establish a solid foundation for defining RWL. In many studies, authors use the term "RWL," especially in quantitative research. However, using the current definition, some practices reported by participants (e.g., losing 2% BM over 30 days) do not qualify as RWL. Finally, we propose that WL (not RWL) practices be classified along two dimensions: WL rate and WL magnitude. Based on rate, practices can be categorized as slow, moderate, or rapid WL. Based on magnitude, they can be classified as low, moderate, or high WL.
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