PURPOSE:This study aimed to investigate the incidence and risk factors of running-related injuries (RRIs) among Chinese marathon runners. METHODS:A nationwide cross-sectional survey was conducted in China from January to December 2024, with 5668 marathon runners participating in full or half marathons. Data on demographics, training characteristics, and RRIs in the past six months were collected through validated questionnaires. Logistic regression was used to identify predictors of RRIs. RESULTS:The overall incidence of RRIs was 46.5%, with a higher prevalence in males compared to females (p < 0.01). The most frequently affected areas were the knee (29.6%), the toe (22.9%), and the ankle (19.4%).Multivariable analysis showed that increasing age (OR = 0.98), longer running experience (≥7 years: OR = 0.71), and lower training levels (Public L1: OR = 0.74, Public L2: OR = 0.66, Unclassified: OR = 0.53) were protective factors. Higher body mass index (BMI) (24 ≤ BMI < 28: OR = 1.49; ≥28: OR = 1.67) and elite-level training were associated with increased injury risk. CONCLUSION:This study highlights a high burden of RRIs among Chinese marathon runners, with key modifiable risk factors including BMI and training intensity, while age and running experience offer protective effects.

Background: Recreational exercise has become increasingly common among Chinese adults. However, population-specific data on sweat rate and electrolyte composition during typical daily physical activities remain limited. Therefore, this study aimed to comprehensively characterize the hydration status, sweat rate, and sweat electrolyte composition among Chinese adults engaging in common daily exercises under controlled environmental conditions, and to examine sex-related differences. Methods: In this cross-sectional study, 285 healthy adults (143 men, 142 women) were assigned to one of three separate activity groups: brisk walking (n = 100), running (n = 90), or cycling (n = 95). Activity protocols were standardized using fixed activity-specific speeds corresponding to 5.2, 8.2, and 4.4 METs for brisk walking, running, and cycling, respectively, based on the Chinese Compilation of Physical Activities. Each participant completed one 60-min exercise session under controlled environmental conditions. Sweat samples were collected from the chest using sweat patches and analyzed for Na+, K+, Ca2+, Mg2+, Fe, Zn2+, and Cu2+ using ICP-MS/OES. Whole-body sweat sodium and potassium concentrations were estimated using validated regression equations. Body mass loss (BML) and sweat rate were calculated from pre- and post-exercise nude body mass. Results: Across all participants and activity types, the overall mean sweat rate was 0.71 ± 0.28 L/h, and the mean percentage of body mass loss (BML%) was 0.78 ± 0.45%. Among the three physical activities, running elicited higher sweat rates (0.92 ± 0.29 L/h) and BML% (1.16 ± 0.36%) than brisk walking or cycling (p < 0.05). The estimated whole-body Na+ and K+ concentrations across all participants were 34.10 ± 10.31 mmol/L and 3.35 (3.02-3.93) mmol/L, respectively, with 59.3% of participants classified as having moderate Na+ levels (30-60 mmol/L). Men exhibited higher sweat rates and Na+ concentrations, whereas women showed higher K+, Zn2+, and Cu2+ levels (p < 0.05). Conclusions: Chinese adults engaging in common daily physical activities under temperate environmental conditions demonstrated low-to-moderate sweat rates and sodium concentrations. These findings provide baseline reference data for population-specific hydration education and may inform future validation and application of wearable sweat-sensing technologies in public health monitoring.

ABSTRACT:Qiao, Z, Guo, B, Gao, Y, Wang, Y, Jiang, M, Yu, J, Yi, L, Yan, B, Qiu, J, and Girard, O. Energy expenditure analysis and prediction in Smith machine squats integrating mechanical loads and sex. J Strength Cond Res 40(5): 519-527, 2026-Calculating energy expenditure (EE) and metabolic equivalents (METs) from oxygen uptake (V̇o2) alone often underestimates resistance training intensity because of its intermittent, brief, and high-intensity nature. This study aims to refine EE and METs estimation during Smith machine squats by integrating mechanical work, glycolytic contribution, and postexercise EE, with particular emphasis on weight-dependent and sex-specific metabolic responses. Fifty-one subjects (31 men) performed weight-bearing squats (4 kg-80% 1 repetition maximum) for 5 repetitions across 3 sets with 4-minute rest intervals. Aerobic, glycolytic, and postexercise EE were estimated from V̇o2, blood lactate, and excess postexercise oxygen consumption, respectively. Mechanical work was measured using a linear-position transducer system. Training load (p < 0.05) and sex (p < 0.01) significantly influenced total EE. Mechanical efficiency was significantly influenced by training load (p < 0.001). Energy expenditure-based METs increased with training weight (p < 0.05) and were higher than V̇o2-based METs (p < 0.001). Training weight and mechanical work strongly correlated with total EE (r ≥ 0.80, p < 0.001). The optimal model, including body weight, training load, peak heart rate, and movement distance, demonstrated high accuracy (R2 = 0.885, cross-validated R2 = 0.803, MAE = 10.067). A simplified model using only body weight and training weight achieved comparable accuracy (R2 = 0.847, cross-validated R2 = 0.750, MAE = 10.883). Total EE increased with training weights, but low-to-moderate-weight squats showed superior mechanical efficiency. Women tended to expend less energy than men during squats, but no difference in mechanical efficiency was observed. V̇o2-based METs underestimated squat intensity. Both the simplified and optimal models accurately estimated squat EE, with the optimal model being more accurate.

Objectives:This cross-sectional study aimed to assess fluid replenishment behaviors, knowledge, and attitudes among Chinese recreational marathon runners and to inform future health education strategies regarding optimal hydration. Design:The survey was conducted between January and December 2024. Based on previously validated questionnaires, the instrument was adapted and administered to assess hydration behaviors, knowledge, and attitudes among marathon participants in major road races across China. A total of 461 valid responses were collected, including 357 male participants (38.9 ± 9.3 years) and 104 female participants (39.5 ± 8.9 years), representing a range of athletic performance levels. The response rate was 94.9%. Data were analyzed using IBM SPSS 27.0 and Microsoft Excel. Result:Over 70% of runners (72.5%) failed to meet recommended daily fluid intake standards (p < 0.001). Over half (57.7%) consumed 150 mL of fluid before the race, mainly plain water before (68.1%) and sports drinks during (56.6%) and after (54.0%) the race. Participants primarily obtained hydration knowledge from friends/family (54.9%) and social media (45.6%). Most participants (93.7%) acknowledged water's health benefits and were willing (92.2%) to improve hydration habits to enhance athletic performance (p < 0.001 for all). Hydration knowledge varied by gender, age, and training level. Participants better understood pre- and mid-exercise hydration and the concept that thirst indicates existing dehydration. However, only 21.5% knew the recommended daily intake (1500-1700 ml), 39.9% understood the differences among mineral, spring, and purified water, and 46.8% recognized the need for post-exercise rehydration. Conclusion:These findings indicate that over half of recreational marathon runners are at risk of dehydration, highlighting that a lack of knowledge poses a dilemma for some runners who fall into a dehydrated state. This underscores the need for targeted education and awareness programs on scientific hydration knowledge and attitudes among recreational marathon runners to improve their health and athletic performance.

PurposeGastrointestinal (GI) symptoms are prevalent among endurance athletes, especially marathon runners, and can negatively affect performance and wellbeing. However, data on the prevalence and nutritional contributors to GI symptoms in Chinese recreational long distance runners remain limited. This study aimed to investigate the prevalence, severity, and dietary influences of GI symptoms in this population.MethodologyA total of 805 valid responses were collected through an online and offline questionnaire conducted in China between January and December 2024. Participants were recreational long distance runners recruited via running clubs, community organizations, sports associations, and online platforms. The questionnaire covered six areas: demographics, exercise habits, dietary strategies, GI symptom severity and frequency, influencing factors, and knowledge and attitudes. GI symptoms during races were assessed using the Gastrointestinal Symptom Rating Scale (GSRS), which includes 11 symptoms rated on a 7-point Likert scale.ResultsNotably, 26.1% of participants reported GI symptoms during races, with bloating (18.6%), urge to defecate (17.8%), and stomach pain (16.5%) being the most frequent. Symptoms peaked in prevalence and severity during the middle phase of the race. GI symptoms were more common in males (27.9%) than females (20.8%), and runners aged 34 years and younger had a higher symptom rates. Nutritional factors, particularly pre- and mid-race dietary strategies, significantly influenced symptom occurrence. Foods high in fat, protein, fiber, or fermentable carbohydrates were commonly associated with GI distress. Eating within 30 min before a race increased the risk of bloating and urge to defecate. The use of energy gels, sports drinks, and hydration strategies also correlated with higher GI symptom risk. Other contributing factors included a history of GI issues and high monthly running volume.DiscussionThe findings underscore the importance of individualized dietary planning to reduce GI symptoms among recreational long distance runners. Adjusting pre-race meal timing and avoiding certain food types may mitigate discomfort. In addition to nutrition, variables such as sex, age, training load, and medical history should be considered in preventive strategies. Future research should explore tailored nutrition and training approaches to improve athlete health and performance during endurance events.

Background Low energy availability (LEA) can negatively impact athletes’ physiological function and performance. This study aims to examine the prevalence of LEA in Chinese female combat athletes and monitor changes in physiological function and performance during the pre-competition period.Method We assessed the incidence of low energy availability (LEA) and eating disorder (ED) risks in 84 female combat athletes (judo, freestyle wrestling, and sanda) from Beijing using the Low Energy Availability in Females Questionnaire (LEAF-Q) and the Eating Disorder Examination Questionnaire (EDE-Q). From this group, 11 judo athletes who were preparing for competition were selected and divided into a low energy availability (LEA) group and a non-LEA group based on their energy availability levels. Dietary intake, training energy expenditure, body composition, resting metabolic rate, blood markers, and special judo fitness tests were monitored at 4 weeks, 2 weeks, and 0 weeks before the competition.Results Among the 84 athletes, 45.2% of athletes (n = 38) were at increased risk of LEA, and 21.4% of athletes (n = 18) were classified as high in eating disorder risk. There were no significant differences in LEA and ED risk between elite and recreational athletes. Among the 11 athletes preparing for competition, 6 athletes (45.5%) were in a state of LEA at the initial stage (4 weeks before the competition), and by the competition week, all 11 athletes exhibited LEA. Additionally, athletes in the LEA group experienced significant reductions in VO2 and resting metabolic rate at 0 week of the competition compared to 4 weeks prior (p < 0.05). Thyroid function indicators and IGF-1 levels of LEA group also significantly decreased (p < 0.05). After completing the four-week pre-competition weight loss, heart rate recovery during the special judo fitness test improved significantly in both the LEA and non-LEA groups (p < 0.05).Conclusion The current study identified a risk of LEA among Chinese female combat sport athletes, with no significant difference in the prevalence of LEA between elite and recreational athletes. It is essential for Chinese coaches and sports medicine staff to implement LEA-related nutritional education across all performance levels. Moreover, preventive measures during training are recommended to mitigate the impact of LEA on physiological function during the pre-competition weight loss phase.

This study investigated the weight loss (WL) practices, perceptions, and eating disorders (ED) symptoms of Chinese female adolescent combat sport (CS) athletes. An adapted Rapid WL Questionnaire (RWLQ) and Eating Disorder Examination-Questionnaire 8 (EDE-Q8) were completed during the off-season of female adolescent CS athletes to provide WL practices, perceptions, and global ED score. There were 130 and 78 respondents for the adapted RWLQ and EDE-Q8, respectively. Seventy-three percent of participants purposefully engaged in WL practices. The average habitual WL was 8.0% of body mass (BM), and the average highest WL was 9.1% of BM. Participants predominantly allocated 15 + days before the weigh-in for WL (65%). Coaches were most commonly reported as the primary guides for WL (64%). Athletes engage in WL mainly to compete against lighter opponents (65%). Most participants perceived that WL had no impact on health (51%), is beneficial to performance (52%), and does not lead to unfair competition (79%). Only six percent of participants were considered as having ED symptoms. No significant differences or association in global ED scores and ED symptoms were observed across any examined dependent variables. The prevalence and magnitude of WL are high amongst Chinese female adolescent CS athletes. Most athletes adopted long-term strategies to lose a substantial percentage of their BM. Athletes' WL practices did not differ according to their perceptions regarding the impact of WL on performance, health, or fairness. Off-season prevalence of ED symptoms and global ED score showed no significant differences or associations with athletes' habitual WL behaviors.

This study aimed to explore the role of macrophage polarization and TLR4/NF-κB pathway in promoting browning of white adipose tissue through different hypoxic exercises. (1) Fifty obese female rats were selected after 16 weeks of high-fat diet feeding and randomly divided into normoxic sedentary (NC), normoxic exercise (NE), hypoxic sedentary (HC), Living-High Training-High (HH), and Living-Low Training-High (LH) groups. Four weeks of hypoxic and exercise interventions were conducted to investigate changes in the expression of the TLR4/NF-κB pathway and inflammatory factors in obese rat adipose tissue and the expression of genes and proteins related to adipose tissue browning. (2) After the 4-week intervention, adipose tissue macrophages (ATM) were isolated from HH and LH groups, activated with NF-κB activator, and co-cultured with adipocyte-induced adipose-derived stem cells to explore the role of the TLR4/NF-κB pathway in promoting browning of white adipose tissue by inducing changes in macrophage polarization through different hypoxic exercise. (1) After 4 weeks of different hypoxic interventions, the proportion of M1 macrophages decreased (p < 0.01), and HH intervention increased the proportion of M2 macrophages (p < 0.05). The protein expression levels of TLR4, NF-κB, p-NF-κB, and MyD88 in ATM of the HH and LH groups were significantly lower than those of the NC group (p < 0.01). Four weeks of LH intervention significantly upregulated the protein expression levels of CIDEA, C/EBP-β, PPAR-γ, PGC-1α, PRDM-16, and UCP-1 in rat adipose tissue (p < 0.01). (2) NF-κB activator intervention for 24 h significantly upregulated the protein expression levels of TLR4, p-NF-κB, and MyD88 in adipose tissue of HH and LH group rats (p < 0.01). NF-κB activator intervention for 24 h downregulated the protein expression levels of CIDEA, C/EBP-β, PPAR-γ, PGC-1α, PRDM-16, and UCP-1 in co-cultured adipocytes for 48 h in ATM of the LH group rats (p < 0.05). Four weeks of HH and LH interventions could reduce M1 polarization of ATM, downregulate the expression levels of the TLR4-NF-κB pathway in ATM, and promote browning of white adipose tissue. The TLR4-NF-κB pathway plays a more critical role in promoting the browning of white adipose tissue by regulating macrophage polarization in LH intervention.

Objective: Dance, as a globally practiced physical activity, presents challenges in accurately assessing energy expenditure due to its diverse styles and tempos. Traditional methods, relying on empirical formulas within ActiGraph accelerometers, often result in significant biases. While multiple wearable sensors have been introduced to mitigate these biases, they increase model complexity. Methods: This study proposes the Triple-E principle—Effectiveness, Efficiency, and Extension—as a framework for developing state-of-the-art (SOTA) machine learning models aimed at accurately estimating energy expenditure, while minimizing model complexity and optimizing sensor placement. To validate the proposed approach, we recruited a cohort of 250 participants (mean age: 63.0 ± 6.0 years), each performing ballroom, aerobic, or square dance routines. Participants were fitted with ActiGraph wGT3X-BT accelerometers at five anatomical locations, along with the CORTEX MetaMax 3B gas analyzer for metabolic data collection. We analyzed 311 physiological signal sequences and 1,555 acceleration count sequences. Results: Empirical formulas were proved inaccurate for dance energy expenditure, with Mean Absolute Percentage Error (MAPE) exceeding 50% and Root Mean Squared Error (RMSE) surpassing 3.23. A bidirectional stepwise regression model incorporating heart rate or triaxial motion sequences from accelerometers achieved an average goodness-of-fit of 0.73, identifying optimal accelerometer sites based on Efficiency principle. A random forest regression model minimized errors to 5% (MAPE) and 0.33 (RMSE) with data from all sites. Notably, wrist accelerometers and heart rate alone provided sufficient accuracy (RMSE: 0.35-0.36), highlighting a trade-off between Effectiveness and Efficiency. A deep-learning network pipeline based on the Extension principle automatically extracted features, achieving an average RMSE to 0.15. Conclusion: This study introduces a pioneering quantitative and unified model assessment system. Thoroughly analyzed and validated in the context of dance, the research offers detailed explanations of the most effective, efficient, and extensive models.

Aims The elevated branched-chain amino acids (BCAAs) have been strongly associated with the development of metabolic diseases in recent years. It remains unclear whether the altered BCAA metabolism plays a functional role in mediating the beneficial effects of exercise against metabolic dysfunctions.Methods Diet-induced obese (DIO) mice underwent an aerobic exercise regimen with or without BCAA supplementation. Fibroblast growth factor 21 (FGF21) was either knocked down or overexpressed specifically in the liver using an adeno-associated virus. Various metabolic phenotypes were assessed. HepG2 cells were cultured and treated with varying concentrations of BCAAs.Results Aerobic exercise significantly reduced circulating BCAA levels in obese mice (leucine: -15.21%; isoleucine: -18.13%; valine: -20.83%), concomitant with decreased body weight (-8.89%), better glycaemic control and improved hepatic steatosis. Notably, BCAA supplementation restored plasma BCAA levels and counteracted the metabolic benefits of aerobic exercise. Exercise upregulated hepatic FGF21 expression (+66.67%), which was abolished by BCAA supplementation (-63.67%). Deletion of hepatic FGF21 eliminated the metabolic benefits of exercise, while over-expression of hepatic FGF21 mitigated the metabolic dysfunctions induced by BCAA supplementation in exercised mice. BCAAs suppressed hepatic FGF21 expression likely through the general control nonderepressible (GCN2)-activating transcription factor 4 (ATF4) pathway.Conclusions Long-term aerobic exercise mitigates obesity and associated metabolic disorders by reducing BCAA abundances and subsequently FGF21 induction. The causal relationship between dietary BCAA intake and the anti-obesity effects of exercise provides novel insight into the metabolic interplay between exercise and BCAAs, underscoring the potential of integrating exercise with precise nutrient modulation as an effective strategy to improve metabolic health.

With the rapid growth of wearable technology, smartwatches have become widely used for tracking health metrics, including energy expenditure (EE). This study involved 20 athletes performing aerobic dance under three protocols—High-Intensity Interval Training (HIIT), Moderate-Intensity Continuous Training (MICT), and TABATA—while wearing four popular smartwatches alongside ActiGraph accelerometers. Indirect calorimetry and Scott’s method served as reference standards. Anaerobic energy accounted for 8 error (MAPE): 14.51

Heart rate (HR) monitoring using earbuds presents a promising avenue for precise measurement, yet its validity remains under investigation during stationary cycling. In this study, we assessed the validity of the Hera Leto consumer earbuds by enrolling twenty-eight athletes as participants. Each participant wore a chest-strap Polar H10, considered the gold-standard reference, while simultaneously testing three HR monitors: the Hera Leto (worn on the ears), the Polar Verity Sense (worn on the upper arm), and the Polar Vantage V (worn on the wrist). The exercise protocol included four steady-state exercise sessions, six sessions of severe intensity exhaustive exercise, and three high-intensity interval training (HIIT) sessions. Our findings revealed a robust correlation ([Formula: see text]=0.970, [Formula: see text]<0.001) between the HR measurements obtained from Hera Leto and Polar H10 across all exercise intensities, with a minimal systematic bias of - 0.67 bpm. with a minimal systematic bias of -0.67 bpm. Notably, Hera Leto demonstrated superior performance, with a mean absolute error (MAE) of 2 bpm and concordance correlation coefficient (CCC) of 0.97, compared to the Polar Verity Sense (MAE = 4 bpm, CCC = 0.88) and Polar Vantage V (MAE = 4 bpm, CCC = 0.93). Although the precision of HR measurement decreased with increasing exercise intensity, Hera Leto exhibited a slower onset of this decline compared to the other devices. Overall, our study underscores the potential of Hera Leto earbuds as a valid tool for HR monitoring, particularly in scenarios involving steady-state exercise.

Obesity is a global health challenge and increases the risk of chronic diseases. Mobile health technologies (mHealth) have emerged as a personalized and multimodal intervention for weight management. This meta-analysis evaluated the effectiveness of mHealth-based lifestyle interventions on weight loss and BMI reduction in overweight and obese adults. A total of 42 randomized controlled trials were identified and included from five major databases. Analyses were conducted using RevMan 5.4. Primary and secondary outcomes were changes in body weight and BMI, respectively. The meta-analysis showed that mHealth-based lifestyle interventions significantly reduced body weight (MD = − 1.79 kg, p < 0.00001) and BMI (MD = − 0.65 kg/m2, p < 0.00001). Subgroup analyses revealed that mobile applications interventions significantly declined both body weight (MD = − 1.97 kg, p < 0.00001) and BMI (MD = − 1.20 kg/m2, p = 0.002). Wearable-based technologies interventions also significantly reduced body weight (MD = − 1.08 kg, p = 0.0006) and BMI (MD = − 0.44 kg/m2, p < 0.00001). Web-based technologies interventions significantly decreased body weight loss (MD = − 1.99 kg, p < 0.00001), but no BMI (MD = − 0.44 kg/m2, p = 0.09). Health education based on mHealth interventions significantly lowered body weight (MD = − 0.78 kg, p = 0.01) and BMI (MD = − 0.44 kg/m2, p = 0.0003). Furthermore, intelligent management based on mHealth interventions significantly dropped body weight (MD = − 0.70 kg, p < 0.0001) and BMI (MD = − 0.38 kg/m2, p < 0.00001). No significant difference was found between mHealth-based online interventions and face-to-face interventions for body weight (MD = − 1.73 kg, p = 0.11) or BMI (MD = − 0.88 kg/m2, p = 0.10). mHealth-based lifestyle interventions are effective in reducing body weight and BMI in overweight and obese adults. Further optimization is needed to enhance long-term effectiveness and user adherence.

Background: Insufficient physical activity and prolonged sedentary behavior have emerged as major global public health challenges. Short bouts (≤10 min) of accumulated exercise (SBAE) throughout the day may be a promising strategy to mitigate the adverse effects of prolonged sitting and promote physical activity, ultimately promoting overall health. However, previous ambiguity in defining this concept has resulted in a fragmented and inconsistent evidence base, impeding practical applications, the development of guidelines, and policymaking. The purpose of this study is to establish an operational definition of SBAE by synthesizing systematic reviews and research trials alongside an expert consensus. Additionally, it seeks to evaluate acute and long-term efficacy and feasibility, providing evidence-based recommendations for practice and future research directions. Methods: A literature search was performed across PubMed and Web of Science, followed by systematic screening and summarization of eligible studies based on predefined inclusion criteria. Inclusion criteria encompassed various modes/types of SBAE (bouts lasting ≤10 min, performed multiple times daily with ≥30 min intervals); both aerobic and resistance exercise were considered. Relevant systematic reviews and research trials were included. Methodological quality, risk of bias, and evidence certainty were assessed. Expert consensus was obtained through a survey to evaluate recommendations and agreement levels on findings. Results: After analyzing 27 systematic reviews, 135 research studies, and an expert consensus involving 48 researchers from 11 countries, SBAE is defined as any exercise mode of activity, regardless of intensity, that is accumulated in either continuous or intermittent bouts lasting ≤10 min per session (including multiple intermittent sets) that are performed multiple times (≥2 sessions/day) per day, with intervals of ≥30 min between bouts or otherwise sufficient time for recovery. When used to interrupt prolonged periods of sedentary time, SBAE mitigates the acute adverse effects of sedentary behavior on more than 10 clinical biomarkers of endocrine, cardiovascular, and brain health/function among adults of diverse ages and conditions. Moreover, SBAE was superior for improving acute glycemic control compared to a single continuous exercise session. As a long-term intervention (average of 11 weeks), SBAE can improve over 20 health outcomes, including peak oxygen uptake, resting blood pressure, and metabolic health. Additionally, SBAE might be more effective than continuous exercise for improving longer-term glycemic control and body composition. Long-term completion rates for SBAE interventions are generally high (95%), with low dropout rates (12%) and high adherence rates even without supervision (85%), and its safety has been preliminarily validated. Conclusion: An operational definition of SBAE is provided along with its classification and acute and long-term efficacy. Practical exercise prescription recommendations and evidence-based strategies for various populations and contexts are provided. Future research should focus on generating high-quality evidence for SBAE in 5 key areas: quantification and monitoring, population-specific responses, optimization of exercise prescriptions, intervention efficacy, and practical implementation. Additionally, addressing policy, environmental, and promotional barriers is crucial for transitioning from expert consensus to public consensus, and for facilitating the application of this strategy in real-world environments.

BACKGROUND:The increasing popularity of marathon running in China highlights the need to better understand the dietary habits and nutritional needs of marathon runners to optimize performance and health outcomes. The study aimed to assess the dietary behaviors, nutritional knowledge, and running-specific nutritional practices of Chinese marathon runners as part of the China Marathon Nutrition Survey (CMNS). METHODS:This nationwide cross-sectional survey was conducted between January and December 2024. Participants were recruited via official websites, social media, and onsite events. A structured and pre-tested questionnaire, referred to as the China Marathon Nutrition Survey questionnaire, was developed by the research team for the CMNS project. The CMNS questionnaire was used to collect data on demographic characteristics, running experience, and nutrition-related behaviors among Chinese marathon runners across different genders, ages, and performance levels. Descriptive statistics, chi-square tests, and logistic regression were employed to identify factors associated with nutritional practices. RESULTS:A total of 5668 valid questionnaires were included in the analysis, comprising 77.6% male (39.8 ± 10.9 yrs) and 22.4% female (41.0 ± 9.7 yrs) runners, representing a wide distribution across age groups and performance levels. Nearly half of the runners (49.1%) of runners reported no specific dietary habits, while among those with dietary practices, 26.4% adhered to a high-carbohydrate diet. In terms of running-related nutrition, 23.3% of Chinese runners regularly or frequently used dietary supplements, and 31.7% used them occasionally before important races. Carbohydrate-loading strategies were adopted by 57.2% of runners prior to races. However, only 36.7% of participants met the recommended fluid intake (1500-1700 mL/day) set by the Chinese Nutrition Society. Higher nutrition knowledge significantly predicted adherence to recommended hydration practices (p < 0.001), according to logistic regression analysis. Significant variability in the nutritional knowledge of Chinese marathon runners was observed, with 36.6% scoring 6 or higher on a 9-point scale. Male runners (OR = 1.39, 95% CI: 1.22-1.57, p < 0.001) and younger participants (≤34 years) (OR = 1.42, 95% CI: 1.22-1.66, p < 0.001) tended to score higher. CONCLUSION:This study provides insights into the nutritional knowledge, dietary behaviors, and race-specific nutrition practices of Chinese marathon runners, offering important baseline data for improving endurance nutrition. Common issues were identified in daily macronutrient intake, hydration, and race-day fueling. These findings underscore the gaps between knowledge and practice, emphasizing the need for tailored nutrition education, particularly for recreational runners through race organizers or public platforms.

Oxygen uptake (V˙O2) is an essential metric for evaluating cardiopulmonary health and athletic performance, which can barely be directly measured. Heart rate (HR) is a prominent physiological indicator correlated with V˙O2 and is often used for indirect V˙O2 prediction. This study investigates the impact of HR placement on V˙O2 prediction accuracy by analyzing HR data combined with the respiratory rate (RESP) and minute ventilation (V˙E) from three anatomical locations: the chest; arm; and wrist. Twenty-eight healthy adults participated in incremental and constant workload cycling tests at various intensities. Data on V˙O2, RESP, V˙E, and HR were collected and used to develop a neural network model for V˙O2 prediction. The influence of HR position on prediction accuracy was assessed via Bland–Altman plots, and model performance was evaluated by mean absolute error (MAE), coefficient of determination (R2), and mean absolute percentage error (MAPE). Our findings indicate that HR combined with RESP and V˙E (V˙O2HR+RESP+V˙E) produces the most accurate V˙O2 predictions (MAE: 165 mL/min, R2: 0.87, MAPE: 15.91%). Notably, as exercise intensity increases, the accuracy of V˙O2 prediction decreases, particularly within high-intensity exercise. The substitution of HR with different anatomical sites significantly impacts V˙O2 prediction accuracy, with wrist placement showing a more profound effect compared to arm placement. In conclusion, this study underscores the importance of considering HR placement in V˙O2 prediction models, with RESP and V˙E serving as effective compensatory factors. These findings contribute to refining indirect V˙O2 estimation methods, enhancing their predictive capabilities across different exercise intensities and anatomical placements.

Objectives: The purpose of this study was to examine the acute effects of branched-chain amino acids (BCAAs)-containing electrolyte beverage (AE) on water–electrolyte balance, muscle damage, time to finish the final 5 km, and muscle strength compared to a standard commercially available carbohydrate–electrolyte sports beverage (CE), pure water (W), and no rehydration (N). Methods: Fourteen trained male participants (20 ± 2 years old) completed four randomized 21 km running trials. The participants were instructed to consume their drink (150 mL W, 150 mL CE, or 150 mL AE) or no rehydration (N) at 5 km, 10 km, and 15 km. Body mass and muscle strength were assessed, and blood samples were collected before and after exercise. Perceptual scales were administered during and after running. Blood electrolyte levels (sodium, potassium, and chloride) and creatine kinase (CK) concentration were analyzed. Results: The change in plasma volume with AE was significantly smaller than that with N (p < 0.05). Consuming AE maintained the best potassium balance (p < 0.05). Twenty-four hours after exercise, serum CK concentrations significantly elevated in N, W, and CE (p < 0.05), but did not reach statistical significance in the AE group (p > 0.05). Compared to N, consuming AE resulted in significantly less soreness 24 h after exercise (p < 0.05). There was no difference in time to finish the final 5 km (p > 0.05). Maximal voluntary isometric force output was significantly lower after exercise with N and W (p < 0.05) but not with CE or AE (p > 0.05). Conclusions: Consuming a BCAAs-containing sports beverage during a 21 km run can help reduce dehydration, maintain potassium balance, lower muscle damage, and prevent the decline in lower limb strength after 21 km running.

Background: The present study aimed to examine the effects of a 500 kcal reduction in daily energy intake alone and in combination with 90 min of moderate-to-vigorous aerobic exercise per week on body weight, body composition, and appetite sensations in young women with normal BMI and abnormal body fat percentage. Methods: sixty-six young women with normal BMI and abnormal body fat percentage (21.33 ± 1.20 kg/m2 and 34.32 ± 2.94%) were randomly assigned into three groups: (1) caloric restriction (CR; n = 22), (2) caloric restriction with exercise (CR–EX; n = 22), and (3) control (C; n = 22). Data on anthropometry, blood samples, and subjective appetite sensations pre- and post-intervention were collected. Results: After 4 weeks of intervention, CR and CR–EX groups both reduced body weight, fat percentage, and waist and hip circumferences compared to the C group (p < 0.05). Muscle mass of the CR group was significantly lower than that of the C group (−1.21 ± 0.86 kg vs. −0.27 ± 0.82 kg, p < 0.05), and no significant difference between CR–EX and C groups was observed. For appetite sensations, the subjects of the CR group showed significant increases in change of scores in desire to eat and prospective consumption than that of the C group (p < 0.05), while no significant difference between CR–EX and C groups was observed. Conclusion: A 500 kcal reduction in daily energy intake alone and in combination with 90 min of moderate-to-vigorous aerobic exercise per week could both reduce weight and improve body composition in young adult women with normal BMI and abnormal body fat percentage. More importantly, calorie restriction combined with exercise intervention was superior to calorie restriction alone in improving muscle mass loss and regulating appetite sensations.

IntroductionEmerging evidences suggests that the disrupted branched-chain amino acids (BCAAs) homeostasis and elevated BCAAs promote obesity-related insulin resistance (IR). Exercise improves insulin sensitivity. However, whether BCAAs plays a role in the exercise-attenuated IR remains to be fully investigated.MethodsIn this study, male C57BL/6J mice were induced to become diet-induced obese (DIO) and served as subjects. The initial investigation focused on the impact of exercise on IR and BCAAs. The DIO mice were randomly assigned to either a sedentary group (CON, n = 16) or an exercise group (EX, n = 16). The EX group underwent a 12-week aerobic exercise regimen on a treadmill. After 12-week, plasma BCAAs and branched-chain keto acids (BCKAs) were measured by liquid chromatography-mass spectrometry, glucose tolerance test (GTT) and insulin tolerance test (ITT) were performed, and the expression and phosphorylation of BCAAs catabolic proteins, as well as AKT T308 in gastrocnemius muscle and liver tissues, were evaluated using western blotting. Subsequently, the study explored the role of BCAAs in enhancing IR through exercise. Mice were randomly allocated into 4 groups: sedentary group (CON, n = 8), sedentary with BCAAs supplementation group (CON+BCAA, n = 8), exercise group (EX, n = 16), and exercise with BCAAs supplementation group (EX+BCAA, n = 16). The exercise protocol was as above. Mice in the BCAAs supplemented groups received drinking water containing 2% BCAAs. After 12-week, plasma BCAAs and BCKAs were measured, GTT and ITT tests were performed, and the phosphorylation of AKT T308, as well as p70S6K T389 in gastrocnemius muscle and liver, were compared between the EX group and the EX+BCAA group. Additionally, the phosphorylation of AMPKα T172 in both tissues was measured across all four groups.Results12-week aerobic exercise improved insulin sensitivity in DIO mice while inducing BCAAs catabolic protein expression in skeletal muscle and liver, and reducing the plasma BCAAs level. Importantly, BCAAs supplementation elevated the plasma level of BCAAs and counteracted the exercise-attenuated IR. In skeletal muscle and liver tissues, BCAAs supplementation impaired the exercise-improved insulin signaling without enhancing mammalian target of rapamycin activity. AMPK activity was enhanced by aerobic exercise, which was abolished by BCAAs supplementation.ConclusionAerobic exercise attenuated insulin resistance via restoring BCAAs homeostasis and AMPK activity. The impacts of BCAAs intake on the metabolic effects of exercise sheds light on the combined exercise and nutrition intervention strategy for diabetes management.

Objectives To test the hypothesis that ‘live high-base train high-interval train low’ (HiHiLo) altitude training, compared to ‘live low-train high’ (LoHi), yields greater benefits on performance and physiological adaptations. Methods Sixteen young male middle-distance runners (age, 17.0 ± 1.5 y; body mass, 58.8 ± 4.9 kg; body height, 176.3 ± 4.3 cm; training years, 3–5 y; training distance per week, 30–60 km.wk−1) with a peak oxygen uptake averaging ~65 ml.min−1.kg−1 trained in a normobaric hypoxia chamber (simulated altitude of ~2,500 m, monitored by heart rate ~170 bpm; thrice weekly) for 3 weeks. During this period, the HiHiLo group (n = 8) stayed in normobaric hypoxia (at ~2,800 m; 10 h.day−1), while the LoHi group (n = 8) resided near sea level. Before and immediately after the intervention, peak oxygen uptake and exercise-induced arterial hypoxemia responses (incremental cycle test) as well as running performance and time-domain heart rate variability (5-km time trial) were assessed. Hematological variables were monitored at baseline and on days 1, 7, 14 and 21 during the intervention. Results Peak oxygen uptake and running performance did not differ before and after the intervention in either group (all P > 0.05). Exercise-induced arterial hypoxemia responses, measured both at submaximal (240 W) and maximal loads during the incremental test, and log-transformed root mean square of successive R-R intervals during the 4-min post-run recovery period, did not change (all P > 0.05). Hematocrit, mean reticulocyte absolute count and reticulocyte percentage increased above baseline levels on day 21 of the intervention (all P < 0.001), irrespective of group. Conclusions Well-trained runners undertaking base training at moderate simulated altitude for 3 weeks, with or without hypoxic residence, showed no performance improvement, also with unchanged time-domain heart rate variability and exercise-induced arterial hypoxemia responses.