This study aimed to determine whether fat metabolism differs between males and females when exposed to extreme exercise-heat stress. Physically active males (n = 11, 23 ± 4 years, 81.7 ± 11.8 kg, body fat 16.4 ± 6.6%) and females (n = 13, 25 ± 4 years, 60.4 ± 7.1 kg, 24.4 ± 6.7%) completed a 2-h exercise-heat tolerance test (40 ° $\boldsymbol{{}^{\circ}}$ C, 40% relative humidity). Differences (pre-, post-, change, and mean difference (MD)) within and between groups were analyzed. The subcutaneous abdominal adipose tissue (SCAAT) interstitial glycerol concentration and adipose tissue blood flow (ethanol Output:Input (O:I)) pre-exercise, every 30 min (min) of exercise, and during recovery was measured with microdialysis. Non-esterified fatty acids, insulin, insulin-like growth factor, epinephrine and norepinephrine, and cortisol were measured in blood. Resting energy expenditure (REE) was measured pre- and post-exercise and exercising metabolic heat production (MHP) was collected during 30 and 90 min of the HTT. Despite no sex differences in systemic blood biomarkers, fat oxidation (g × min-1) was higher in males (M) (vs. Females (F)) at 30 min of HTT (3.92 ± 0.25 (M), 3.58 ± 0.38 (F), p = 0.021). SCAAT interstitial glycerol was similar across all time points between sexes (baseline glycerol ranges (mmol × L-1): 104.6-1260.0 (F), 165.0-775.6 (M)); however, females had a greater O:I ratio at 90 min of exercise (vs. M) (0.69 ± 0.33 (F); 0.44 ± 0.20 (M); p = 0.033). Pre- and post-exercise REE were 23% (MD: 447.5 kcal × day-1, p < 0.001) and 25% (MD: 485 kcal × day-1, p < 0.001) lower in females compared to males. Post-exercise RER (0.67 ± 0.06 (F); 0.72 ± 0.08 (M); p = 0.045) and mean MHP was higher in males (MD: 94W). Fat oxidation was higher in males compared to females at 30 min with no changes in SCAAT lipolysis or blood biomarkers before or after an acute bout of exercise-heat stress.

Background This study aims to determine low energy availability prevalence (LEA) in adolescent female artistic gymnasts and to compare the dietary habits and sleep between those with LEA and those without.Methods Height, weight, and body composition (BodPod) were measured following an overnight fast. Participants were then fitted with hip- and wrist-worn accelerometers to assess exercise energy expenditure (EEE) and sleep, respectively, for three consecutive days. Daily energy intake (EI) was assessed using a digital food log and evaluated against the International Society of Sports Nutrition (ISSN) dietary recommendations for athletic populations. As this was a free-living study, participants were asked to maintain their normal behaviors.Results Twelve female artistic gymnasts (15 ± 1 yrs, 160.6 ± 5.5 cm, 55.8 ± 4.6 kg, 14.9 ± 6.4% body fat, 47.4 ± 4.3 kg fat-free mass (FFM)) participated in the study. Mean EA was 28.9 ± 13.5 kcals/kg−1FFM with six gymnasts (50%) presenting in a LEA state. Gymnasts with LEA consumed significantly fewer calories than those without (1451 ± 447 vs 2388 ± 458 kcals; p = 0.008). Those in a LEA state also had significantly lower protein (0.8 ± 0.2 vs 1.5 ± 0.4 g/kg; p = 0.007) and carbohydrate (3.1 ± 0.8 vs 4.8 ± 0.8 g/kg; p = 0.004) intake compared to gymnasts without LEA. Based on ISSN recommendations, 33.3% of gymnasts met PRO (1.4–2.0 g/kg−1), 8.3% met CHO (5–7 g/kg−1), while 100% met recommendations for fat (20–35% of total EI). EEE was 550 ± 131 kcal−1, with no differences by EA status. Those with LEA spent less time in bed (390 ± 56 vs 498 ± 35 min; p = 0.002) and had a lower total sleep time (346 ± 57 vs 439 ± 33 min; p = 0.006), yet fewer number of awakenings (17 ± 6 vs 24 ± 4; p = 0.035) compared to gymnasts without LEA. No differences in body composition or other sleep parameters were observed.Conclusions In the present study, 50% of gymnasts presented in a LEA state. Regardless of EA status, most gymnasts did not meet the dietary recommendations for protein or carbohydrates. Additionally, those in a LEA state presented with sleep impairments, which could potentially impair recovery and performance. These findings underscore the need for future research to address the dietary and sleep habits in adolescent gymnasts to optimize health and athletic performance.

Background CrossFitⓇ sessions and competitions are characterized by high-intensity challenges that combine aerobic and anaerobic activities with short recovery periods. As a result, effective nutritional practices play a crucial role in optimizing performance and enhancing recovery. Therefore, nutritional practices are central to optimizing performance and accelerating recovery. This review aims to summarize current evidence on nutritional and ergogenic aid responses to CrossFitⓇ practice.Methods The search was conducted in four electronic databases (PubMed, Web of Science, Scopus and SportDiscus). Gray literature was also extracted for studies exploring the nutritional habits of CrossFitⓇ participants as well as the ingestion of ergogenic aids. In addition, a meta-analysis was conducted to examine the impacts of dietary habits and ergogenic aids on performance.Results Forty-nine studies met the eligibility criteria and were included in the current review. Carbohydrate intake was below the recommendations for athletes, although protein ingestion remains adequate. High-carbohydrate diets had a positive effect on CrossFitⓇ performance. The evidence concerning the effects of a ketogenic diet on performance is limited. When used prior to or during the workout, the impact of carbohydrates on CrossFitⓇ performance was negligible, whereas the effect of caffeine was significant. Ergogenic aids, particularly creatine and protein, are commonly used by CrossFitⓇ participants.Conclusion The standard diets recommended to CrossFitⓇ participants need to be revised because they are characterized by lower values of carbohydrates. Caffeine should be used prior to or during the CrossFitⓇ sessions. Regarding the impact of ergogenic aids on recovery, future studies are needed.

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

Background Postmenopausal females have an elevated cardiovascular disease (CVD) risk, induced partly by reduced skeletal muscle microvascular blood flow (SMBF), elevated reactive oxygen (ROS), and impaired meal metabolism (glycerol, glucose, lactate). Evidence suggests that creatine monohydrate (CrM), holds promise for reducing CVD risk via improvements in blood flow and ROS reductions; however, data are limited. The current pilot study investigated the impact of CrM on SMBF, ROS concentrations, and markers of meal metabolism at rest and following the consumption of a high carbohydrate (HC) meal (a potent stimulator of ROS), in postmenopausal females. Methods Six postmenopausal females (66 +/- 7 yrs, 30.9 +/- 3.59 kg/m(2)) were enrolled in this randomized, double-blind, crossover study. Participants completed two randomized study arms: CrM (20g/day) and placebo (PL, maltodextrin, 20g/day), each for five days, separated by a four-week washout period. At PRE- and POST-supplementation visits, a microdialysis probe was inserted into the gastrocnemius muscle to measure SMBF (ethanol outflow/inflow ratio (o:i)), [H2O2] (an index of ROS), and dialysate contents. Following a 45min equilibrium period, participants rested for one hour and then consumed a HC meal (35% of daily energy requirements; similar to 80% carbohydrates). Dialysate samples were collected every 20 minutes and data is combined (1hr basal + 4hr post-prandial). ClinicalTrials.gov ID #NCT06018480. Results Five days of CrM increased SMBF (mean +/- SD; PRE CrM:0.71 +/- 0.11o:i, POST CrM: 0.61 +/- 0.10o:i; Visit*Treatment p<0.0001) compared to five days of PL (PRE PL: 0.65 +/- 0.19o:i, POST PL: 0.63 +/- 0.14o:i; Visit*Treatment p=0.44). CrM had no effect on [H2O2] (PRE CrM:1.24 +/- 0.73 mu M, POST CrM: 1.21 +/- 0.19 mu M; Visit*Treatment p=0.99). CrM increased dialysate glycerol (0.67 +/- 0.32 mu mol/L, 0.75 +/- 0.25 mu mol/L; Visit*Treatment p=0.04), with no change in dialysate glucose (Visit*Treatment p=0.49), and a non-significant decrease in dialysate lactate (Visit*Treatment p=0.06). Conclusions Five days of CrM increased SMBF and dialysate glycerol, suggesting enhanced blood flow and lipid mobilization that may support a reduction in CVD risk in postmenopausal females.

Background/Objectives : Approximately 70% of transcatheter aortic valve replacement (TAVR) patients prior to TAVR have low muscle mass, increased mortality risk, and reduced quality of life (QoL) with little improvement in muscle mass and QoL after TAVR. Resistance training (RT) with protein supplementation is effective for maintaining and increasing muscle mass but has not been studied in TAVR patients. This study evaluated the effects of a 12-week telehealth program of RT combined with protein supplementation (RT + PRO; n = 11) versus PRO alone ( n = 11) on body composition, inflammation, strength, physical function, and QoL in TAVR patients (75.7 ± 6.5 years; body mass index: 31.3 ± 6.4 kg/m 2 ). Methods : RT + PRO completed a RT program of 12 exercises, 2×/week, 8–15 repetitions, for 1–3 sets and consumed 75 g (37.5 g 2×/day) of whey protein. PRO consumed the same protein but did not exercise. Results : There were no reported injuries. Adherence to the exercise and protein supplementation was greater than 90%. RT + PRO had greater improvements in strength (30-s chair stands: RT + PRO pre: 11 ± 3 vs. post: 13 ± 3; PRO pre: 12 ± 2 vs. post: 12 ± 3 repetitions; p = .003; time to complete five sit-to-stands: RT + PRO pre: 12.3 ± 3.8 vs. post: 9.6 ± 2.7; PRO pre: 11.2 ± 2.4 vs. post: 10.9 ± 2.9 s; p = .011) and QoL (Sarcopenia QoL Questionnaire: RT + PRO pre: 63.7 ± 12.9 vs. post: 74.0 ± 14.6; PRO pre: 69.7 ± 13.6 vs. post: 69.2 ± 16.1 points; p = .002). Conclusions/Implications : The telehealth exercise program was safe and well attended. The RT + PRO protocol significantly improved some measures of muscular strength and QoL in TAVR patients. A telehealth exercise program may serve as an alternative to traditional in person cardiac rehabilitation programs.

This article provides a recap of the 10 Questions/10 Experts session at the 2025 American College of Sports Medicine Annual Meeting. Each of the speakers considered the validity of common "myths" while providing evidence-based opinions to support or bust myths addressing the following questions: (a) Do people get enough dietary creatine from everyday foods? (b) Are nonsugar sweeteners an effective way to reduce energy intake in athletes? (c) Do beef jerky or chocolate milk provide enough leucine, making branched-chain amino acid supplementation unnecessary? (d) Can honey, applesauce, or other foods effectively replace carbohydrate gels for fueling exercise? (e) Is a homemade sports drink made from juice and a bit of salt just as effective as a commercially available sports drink? (f) Do vegetarians need to supplement carnosine and carnitine? (g) Is teff grain a rich source of iron? (h) Is coconut water a sufficient replacement for electrolyte drinks? (i) Can B vitamins influence the accuracy of urine color scoring to determine a low versus high urine concentration as a marker of hydration status? and (j) What is the impact of preexercise food-sourced calcium intake on acute bone metabolism in response to exercise? This article describes the content of each of the presentations including the most important outcomes and conclusions drawn by the presenters.

Background Nutrient timing strategies are commonly employed by athletes to support recovery, sleep quality, muscle protein synthesis, and overnight metabolic regulation. However, limited research has explored the glycemic impact of different macronutrients consumed prior to sleep, particularly in elite female athletes. α-lactalbumin (ALA), a whey-derived protein rich in tryptophan, has been proposed to support stable overnight glucose levels and sleep quality. In contrast, carbohydrate (CHO) ingestion before bed is known to acutely elevate blood glucose, yet its influence on nocturnal glycemia during sleep remains less understood in high-performing athletes. This This study compared the effects of pre-sleep ingestion of ALA, casein (CAS), CHO, and a non-caloric placebo (PLA) on nocturnal continuous glucose monitoring (nCGM) metrics over a 4-week, randomized, double-blind, crossover study in elite female athletes.Methods Each participant consumed one of four pre-sleep treatments—40 g of ALA, CAS, CHO, or a non-caloric PLA – for three consecutive nights per condition. Supplement was taken 2 hours after the final meal and 30 minutes before bedtime. Blood glucose was tracked every 15 minutes using continuous glucose monitoring (CGM) devices that were worn on the back of the arm for the duration of the study. Glycemic responses were collected for 24 hours each day of the study; starting from the two hours before the participants reported their bedtime, while they were sleeping, and continued up to the hour after the participant reported waking up was analyzed. Participants reported their bed and wake times in daily surveys, and CGM data was matched accordingly. Repeated measures ANOVA was used to evaluate the effects of time, condition, and time × condition interaction on glucose concentrations.Results Six NCAA Division I female athletes (n = 6; Age: 22.5 ± 0.96 yrs, Height: 1.68 ± 0.06 m, Weight: 60.77 ± 7.02 kg) completed the study. A significant main effect of time on nocturnal glucose was observed (p = 0.008), reflecting expected glycemic variation during sleep. However, no significant differences were found between macronutrient conditions (p = 0.187), and there was no time × condition interaction (p = 0.550), suggesting the type of macronutrient ingested before bed did not significantly influence overnight glucose dynamics. Wake-time blood glucose values also did not differ significantly across conditions (p = 0.58).Conclusion Pre-sleep ingestion of protein (ALA or CAS), carbohydrate, or placebo does not significantly impact nocturnal or next-morning glycemic control in elite female athletes. These findings suggest that pre-sleep macronutrient intake can be flexibly applied without negatively affecting overnight glucose regulation in elite female athletes.

ABSTRACT:Griest, TD, McCarthy, CM, Rentería, LI, Paterson, KGP, Eurich, DF, Laskin, GR, and Ormsbee, MJ. Supramaximal walkouts protect against performance decrements experienced in repeated sets of back squats. J Strength Cond Res 39(6): 617-624, 2025-The purpose of this study was to determine whether performing supramaximal walkouts (SMW) enhances subsequent repeated back squat performance. Thirteen resistance-trained men (age: 23.2 ± 3.0 years, 1 repetition maximum [1RM] back squat: 2.1 ± 0.4 kg·bodymass -1 ) completed 2 trials in a randomized, counterbalanced, crossover design. Each trial began with 1 back squat at 92.5% 1RM (PRE). Five minutes post-PRE, subjects un-racked either 110% 1RM (SMW) or 30% 1RM (CON) for a 10-second hold. After 5 minutes rest, 3 sets of 1 back squat at 92.5% 1RM were completed with 5 minutes between each. Performance and muscle activation indicators were measured during each repetition. All data were analyzed through Friedman's 2-way ANOVA by ranks. Significance was set at p < 0.05. Average power and velocity decreased from PRE in all 3 sets ( p < 0.05) following CON. Following SMW, these variables decreased during POST2 and POST3 ( p < 0.05) but not POST1 ( p > 0.219). In addition, rating of perceived exertion was elevated at POST2 following CON ( p = 0.044), while there were no differences with SMW ( p = 0.716). Peak power, peak velocity, and electromyography amplitude of the vastus lateralis and gluteus maximus were unaltered ( p > 0.077). Performing an SMW at 110% 1RM before back squats may attenuate performance decrements resulting from repeated repetitions for 1 set and, therefore, could be used to maintain performance for 1 additional set during training.

Purpose: To examine the association between trajectories of physical activity (PA) over 12 years and epigenetic age acceleration (EAA) in 3600 middle-aged and older adults of the Health and Retirement Study. Methods: Latent variable mixture modeling identified subgroups with similar trajectories of vigorous, moderate, and light PA from 2004 to 2016. Six EAAs, including Horvath's age acceleration, Hannum's age acceleration, GrimAge acceleration, PhenoAge acceleration, DunedinPoAm acceleration, and ZhangAA were calculated by regressing epigenetic age on chronological age in 2016. Linear regression models tested associations of PA trajectories with EAAs, controlling for age, sex, race, education, smoking, alcohol consumption, and depression. Results: Five trajectories were identified for each PA type. Moderate and light PA trajectories were stable or slightly changed over time. In contrast, vigorous PA trajectories were either consistently low (27.2%), slightly increased at a low level (14.9%), decreased from moderate to low levels (25.9%), increased to a high level (11.9%), or consistently high (20.1%). Moderate PA trajectories were negatively associated with EAA across six epigenetic clocks (p < .01). Light PA trajectories were not associated with any EAA. Vigorous PA trajectories were associated with slower GrimAge acceleration (p = .004) and DunedinPoAm acceleration (p = .03). Participants that showed consistently high or increasing vigorous PA had slower EAA compared to those with consistently low vigorous PA. Conclusion: Moderate and vigorous, but not light, PA trajectories were associated with slower EAAs.

Purpose Sleep is essential for recovery in athletes and overall health. While pre-sleep feeding (PSF), defined as consuming calories 2 hours after the last meal and 30 minutes before bed, is theorized to influence sleep and recovery, there is both a paucity of and conflicting data on whether PSF improves or impairs sleep quality and recovery. α-Lactalbumin (a milk-derived protein), in particular, is hypothesized to be a potentially superior PSF option due to its high tryptophan content, yet little data exist regarding its efficacy compared to other strategies.Methods This randomized, double-blind, crossover study investigated the effects of four pre-sleep feeding treatments over a 4–8 week period in elite NCAA Division 1 female athletes (n = 25). Each participant consumed 40 g of: (1) α-Lactalbumin (ALA); (2) casein protein (CAS); (3) carbohydrate (CHO); or (4) non-caloric placebo (PLA) mixed with water, for three consecutive nights, two hours after last meal, 30 mins before bed. Diets were tracked using food logs. Objective sleep (total sleep time [TST]) and recovery metrics (heart rate variability [HRV] and resting heart rate [RHR]) were collected continuously using a wrist-worn device. Daily morning questionnaires assessed subjective sleep (subjective sleep quality [SSQ] and subjective sleep onset latency [SSOL]) and subjective recovery (SREC). Data were analyzed using repeated measures ANOVA.Results Twenty-one (n = 21) female athletes completed the study (body mass: 66.89 ± 11.85 kg; body fat% %: 27.28 ± 4.57%; height: 1.69 ± 0.07 m, BMI of 23.28 ± 2.96 kg/m2; FFMI of 16.85 ± 1.74 kg/m2). No significant differences were observed between the four treatments for any objective sleep metrics (TST: PLA 7.52 ± 1.11 h; CHO 7.62 ± 1.06 h; ALA 7.53 ± 0.89 h; CAS 7.47 ± 1.14 h; p = 0.91), subjective sleep metrics (SSQ: PLA 71.31 ± 20.60; CHO 74.88 ± 17.81; ALA 72.92 ± 15.39; CAS 69.12 ± 16.66; p = 0.35; SSOL: PLA 16.62 ± 14.08 min; CHO 16.45 ± 12.28 min; ALA 20.21 ± 16.83 min; CAS 18.09 ± 18.71 min; p = 0.20), or objective and subjective recovery metrics (RHR: PLA 53.71 ± 6.55 bpm; CHO 54.05 ± 6.66 bpm; ALA 53.54 ± 6.19 bpm; CAS 53.71 ± 5.42 bpm; p = 0.99; HRV: PLA 98.24 ± 34.01 ms; CHO 99.14 ± 34.08 ms; ALA 103.91 ± 31.48 ms; CAS 103.05 ± 34.60 ms; p = 0.54; SREC: PLA 65.93 ± 20.40; CHO 65.64 ± 19.22; ALA 64.73 ± 17.06; CAS 60.93 ± 19.76; p = 0.43).Conclusion PSF, specifically a 40 g protein bolus, does not negatively affect objective or subjective sleep quality or recovery in elite female athletes. In addition, α-lactalbumin (43% α-Lactalbumin) does not influence sleep more than other pre-sleep protein options. PSF may provide a valuable opportunity to meet calorie and macronutrient needs, especially protein, essential for supporting recovery and adaptation in this population, without impacting sleep.

Background The menopausal transition is characterized by hormonal shifts, particularly a decline in estrogen, which is associated with increased fat mass and reduced lean body mass. Adequate caloric and protein intake is essential for preserving muscle mass and mitigating these body composition changes. This preliminary analysis examined total energy and protein intake (g/kg body weight) across pre-menopausal, peri-menopausal, and post-menopausal women.Methods An anonymous online survey was conducted in resistance-trained females, aged 30–75 years old, using Qualtrics software (Qualtrics, Provo, UT, USA) to document fitness, nutrition, and hormone replacement therapy (HRT) practices during the menopause transition. This preliminary analysis focused on two nutrition-related close-ended questions: “How many calories do you consume (on average) each day?” and “How many grams of protein do you consume (on average) each day?.” Relative protein intake was reported in grams per kilogram of body weight (g/kg). Data is reported with descriptive statistics to estimate mean calorie and relative protein intake per menopausal group and analyzed via one-way ANOVA to compare intake across groups.Results There were 1,719 and 1,854 responses for total calorie and protein intakes, respectively. Participants self-reported their menopausal status, with 13.7% identifying as pre-menopausal, 44.5% as peri-menopausal, and 41.9% as post-menopausal. Average estimated caloric intake was the highest in pre-menopausal women (1861 ± 305.9 kcal), followed by peri-menopausal (1823.8 ± 321.6 kcal), and lowest in post-menopausal women (1741.3 ± 333.2 kcal), who consumed significantly fewer calories than both other groups (p < 0.001). No significant difference was found between pre-menopausal and peri-menopausal women (p = 0.228). Average relative protein intake followed a similar trend: highest in pre-menopausal (1.65 ± 0.53 g/kg), then peri-menopausal (1.63 ± 0.48 g/kg), and lowest in post-menopausal women (1.53 ± 0.55 g/kg), who consumed significantly less than both groups (p = 0.004 and p < 0.001, respectively). Differences between pre-menopausal and peri-menopausal women were not significant (p = 0.696).Conclusion Post-menopausal women reported to consume significantly fewer calories and less protein relative to their body weight compared to pre-menopausal and peri-menopausal women, who did not differ significantly from each other. While menopausal status appears to be associated with reduced dietary intake, it is important to note that overall, participants reported protein intakes within the recommended range (1.4–2.0 g/kg) for resistance-trained individuals to build or maintain lean mass. In addition to focusing on menopausal status, future research should investigate whether higher protein intakes are necessary to counteract anabolic resistance associated with aging.

OBJECTIVE: To estimate anterior cruciate ligament reconstruction (ACLR) return-to-play (RTP) factors and proportions across all National Collegiate Athletics Association (NCAA) sports. DESIGN: Systematic review with prognosis and etiology components. LITERATURE SEARCH: Two independent reviewers searched PubMed, Cochrane Library, and Embase databases using terms related to RTP, ACLR, and NCAA for articles published up to June 30, 2023. STUDY SELECTION CRITERIA: Articles were included if RTP proportions or factors affecting RTP were reported and if the study population included NCAA collegiate athletes recovering from an ACLR. DATA SYNTHESIS: The proportion represents the total number of athletes who returned to play after ACLR over the total number of ACLR athletes from each cohort. The cumulative proportion represents the aggregated total from each included study. When eligibility information was available (ie, athletes in their final year of eligibility), RTP proportions were adjusted. The Newcastle-Ottawa Scale (NOS) was used to assess the study quality and scored by 2 raters. RESULTS: Nine studies were included. RTP criteria varied across the studies. Proportions of RTP ranged from 69% to 92%, with a cumulative RTP proportion after ACLR of 84% (628/745). The primary factors associated with the proportion of RTP were scholarship status, competitive eligibility remaining, depth chart position, and surgical graft type. CONCLUSIONS: The cumulative proportion of RTP was 84% and was associated with patient-specific and operative factors. Psychological and functional factors were not routinely reported, and rehabilitation protocols were unknown. Data were not explicitly available for any athletes outside of Division I. The criteria for RTP after ACLR varied. J Orthop Sports Phys Ther 2024;54(10):1-9. Epub 10 September 2024. https://doi.org/10.2519/jospt.2024.12483.

Background/Objectives: A pilot study was conducted to investigate the effect of four weeks of creatine monohydrate (CrM) on vascular endothelial function in older adults. Methods: In a double-blind, randomized crossover trial, twelve sedentary, healthy older adults were allocated to either the CrM or placebo (PL) group for four weeks, at a dose of 4 × 5 g/day for 5 days, followed by 1 × 5 g/day for 23 days. Macrovascular function (flow-mediated dilation [FMD%], normalized FMD%, brachial-ankle pulse wave velocity [baPWV], pulse wave analysis [PWA]), microvascular function (microvascular reperfusion rate [% StO2/sec]), and biomarkers of vascular function (tetrahydrobiopterin [BH4], malondialdehyde [MDA], oxidized low-density lipoprotein [oxLDL], glucose, lipids) were assessed pre- and post-supplementation with a four-week washout period. Results: CrM significantly increased FMD% (pre-CrM, 7.68 ± 2.25%; post-CrM, 8.9 ± 1.99%; p < 0.005), and normalized FMD% (pre-CrM, 2.57 × 10−4 ± 1.03 × 10−4%/AUCSR; post-CrM, 3.42 × 10−4 ± 1.69 × 10−4%/AUCSR; p < 0.05), compared to PL. Microvascular reperfusion rates increased following CrM (pre-CrM, 2.29 ± 1.42%/sec; post-CrM, 3.71 ± 1.44%/sec; p < 0.05), with no change following PL. A significant reduction in fasting glucose (pre-CrM, 103.64 ± 6.28; post-CrM, 99 ± 4.9 mg/dL; p < 0.05) and triglycerides (pre-CrM, 99.82 ± 35.35; post-CrM, 83.82 ± 37.65 mg/dL; p < 0.05) was observed following CrM. No significant differences were observed for any other outcome. Conclusions: These pilot data indicate that four weeks of CrM supplementation resulted in favorable effects on several indices of vascular function in older adults.

Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the use of a ketogenic diet in healthy exercising adults, with a focus on exercise performance and body composition. However, this review does not address the use of exogenous ketone supplements. The following points summarize the position of the ISSN: 1. A ketogenic diet induces a state of nutritional ketosis, which is generally defined as serum ketone levels above 0.5 mM. While many factors can impact what amount of daily carbohydrate intake will result in these levels, a broad guideline is a daily dietary carbohydrate intake of less than 50 grams per day. 2. Nutritional ketosis achieved through carbohydrate restriction and a high dietary fat intake is not intrinsically harmful and should not be confused with ketoacidosis, a life-threatening condition most commonly seen in clinical populations and metabolic dysregulation. 3. A ketogenic diet has largely neutral or detrimental effects on athletic performance compared to a diet higher in carbohydrates and lower in fat, despite achieving significantly elevated levels of fat oxidation during exercise (similar to 1.5 g/min). 4. The endurance effects of a ketogenic diet may be influenced by both training status and duration of the dietary intervention, but further research is necessary to elucidate these possibilities. All studies involving elite athletes showed a performance decrement from a ketogenic diet, all lasting six weeks or less. Of the two studies lasting more than six weeks, only one reported a statistically significant benefit of a ketogenic diet. 5. A ketogenic diet tends to have similar effects on maximal strength or strength gains from a resistance training program compared to a diet higher in carbohydrates. However, a minority of studies show superior effects of non-ketogenic comparators. 6. When compared to a diet higher in carbohydrates and lower in fat, a ketogenic diet may cause greater losses in body weight, fat mass, and fat-free mass, but may also heighten losses of lean tissue. However, this is likely due to differences in calorie and protein intake, as well as shifts in fluid balance. 7. There is insufficient evidence to determine if a ketogenic diet affects males and females differently. However, there is a strong mechanistic basis for sex differences to exist in response to a ketogenic diet.

This study sought to investigate the effect of cold ambient temperature on subcutaneous abdominal adipose tissue (SCAAT) lipolysis and blood flow during steady-state endurance exercise in endurance-trained cyclists. Ten males (age: 23 ± 3 years; peak oxygen consumption: 60.60 ± 4.84 ml·kg−1·min−1; body fat: 18.4% ± 3.5%) participated in baseline lactate threshold (LT) and peak oxygen consumption testing, two familiarization trials, and two experimental trials. Experimental trials consisted of cycling in COLD (3 °C; 42% relative humidity) and neutral (NEU; 19 °C; 39% relative humidity) temperatures. Exercise consisted of 25 min cycling at 70% LT and 25 min at 90% LT. In situ SCAAT lipolysis and blood flow were measured via microdialysis. Heart rate, core temperature, carbohydrate and fat oxidation, blood glucose, and blood lactate were also measured. Heart rate, core temperature, oxygen consumption, and blood lactate increased with exercise but were not different between COLD and NEU. SCAAT blood flow did not change from rest to exercise or between COLD and NEU. Interstitial glycerol increased during exercise (p < .001) with no difference between COLD and NEU. Fat oxidation increased (p < .001) at the onset of exercise and remained elevated thereafter with no difference between COLD and NEU. Carbohydrate oxidation increased with increasing exercise intensity and was greater at 70% LT in COLD compared to NEU (p = .030). No differences were observed between conditions for any other variable. Cycling exercise increased SCAAT lipolysis but not blood flow. Ambient temperature did not alter SCAAT metabolism, SCAAT blood flow, or fat oxidation in well-trained cyclists, though cold exposure increased whole-body carbohydrate oxidation at lower exercise intensities.