Common questions and misconceptions about protein supplementation: what does the scientific evidence really show?

Protein supplementation often refers to increasing the intake of this particular macronutrient through dietary supplements in the form of powders, ready-to-drink shakes, and bars. The primary purpose of protein supplementation is to augment dietary protein intake, aiding individuals in meeting their protein requirements, especially when it may be challenging to do so through regular food (i.e. chicken, beef, fish, pork, etc.) sources alone. A large body of evidence shows that protein has an important role in exercising and sedentary individuals. A PubMed search of "protein and exercise performance" reveals thousands of publications. Despite the considerable volume of evidence, it is somewhat surprising that several persistent questions and misconceptions about protein exist. The following are addressed: 1) Is protein harmful to your kidneys? 2) Does consuming "excess" protein increase fat mass? 3) Can dietary protein have a harmful effect on bone health? 4) Can vegans and vegetarians consume enough protein to support training adaptations? 5) Is cheese or peanut butter a good protein source? 6) Does consuming meat (i.e., animal protein) cause unfavorable health outcomes? 7) Do you need protein if you are not physically active? 8) Do you need to consume protein ≤ 1 hour following resistance training sessions to create an anabolic environment in skeletal muscle? 9) Do endurance athletes need additional protein? 10) Does one need protein supplements to meet the daily requirements of exercise-trained individuals? 11) Is there a limit to how much protein one can consume in a single meal? To address these questions, we have conducted a thorough scientific assessment of the literature concerning protein supplementation.

Common questions and misconceptions about caffeine supplementation: what does the scientific evidence really show?

Caffeine is a popular ergogenic aid that has a plethora of evidence highlighting its positive effects. A Google Scholar search using the keywords "caffeine" and "exercise" yields over 200,000 results, emphasizing the extensive research on this topic. However, despite the vast amount of available data, it is intriguing that uncertainties persist regarding the effectiveness and safety of caffeine. These include but are not limited to: 1. Does caffeine dehydrate you at rest? 2. Does caffeine dehydrate you during exercise? 3. Does caffeine promote the loss of body fat? 4. Does habitual caffeine consumption influence the performance response to acute caffeine supplementation? 5. Does caffeine affect upper vs. lower body performance/strength differently? 6. Is there a relationship between caffeine and depression? 7. Can too much caffeine kill you? 8. Are there sex differences regarding caffeine's effects? 9. Does caffeine work for everyone? 10. Does caffeine cause heart problems? 11. Does caffeine promote the loss of bone mineral? 12. Should pregnant women avoid caffeine? 13. Is caffeine addictive? 14. Does waiting 1.5-2.0 hours after waking to consume caffeine help you avoid the afternoon "crash?" To answer these questions, we performed an evidence-based scientific evaluation of the literature regarding caffeine supplementation.

Monitoring training, performance, biomarkers, and psychological state throughout a competitive season: a case study of a triathlete.

INTRODUCTION: Ironman triathletes undergo high workloads during competition preparation which can result in nonfunctional overreaching or overtraining syndrome if not matched with adequate recovery. PURPOSE: The purpose of this case study was to observe changes in physiological and psychological status over the course of a competitive season in a free-living triathlete. METHODS: The subject was a 41-year-old triathlete competing in three 113.1-km events. Over the course of a 40-week period, the participant arrived at the laboratory every 4 weeks and underwent body composition testing via air displacement plethysmography, a blood draw for analysis of various biomarkers, and a treadmill-based lactate threshold test. Workload during training and competitions was monitored via a wearable heart rate-monitoring device. RESULTS: Throughout the season, training volume remained high (12.5 ± 3.4 h/week) and body mass and fat-free mass (FFM) continuously decreased, while biomarkers including cortisol, testosterone, and markers of immunological status exhibited minor changes. Laboratory performance remained relatively consistent, while competition performance continually improved. Following the completion of the competitive period, training volume decreased, FFM remained below baseline levels, free cortisol increased, and both free and total testosterone decreased. CONCLUSIONS: Workload and recovery seem to have been properly managed throughout the season, evidenced by minimal fluctuations in endocrine and immunological markers. The reason for changes observed in testosterone, cortisol, and body composition following the last competition is unclear, though it may be attributed to changes in stressors and recovery practices outside of training. It is recommended that athletes follow a structured plan during the transition period into the offseason to ensure recovery of physiological state and to set up a productive offseason.

Effects of Minimal-Equipment Resistance Training and Blood Flow Restriction on Military-Relevant Performance Outcomes.

ABSTRACT: Cintineo, HP, Chandler, AJ, Mastrofini, GF, Lints, BS, McFadden, BA, and Arent, SM. Effects of minimal-equipment resistance training and blood flow restriction on military-relevant performance outcomes. J Strength Cond Res 38(1): 55-65, 2024-This study compared minimal-equipment resistance training (RT) with and without blood flow restriction (BFR) to traditional-equipment RT on performance and body composition changes over 6 weeks. Reserve officers' training corps cadets and midshipmen (N = 54, 40.7% female) were randomized into traditional-equipment RT (TRAD), minimal-equipment RT (MIN), or minimal-equipment RT with BFR (MIN + BFR). Performance and body composition were assessed pretraining and post-training, and measures of intensity and workload were evaluated throughout. Performance assessments included the army combat fitness test (ACFT), countermovement vertical jump, 3RM bench press, and V̇O2max; body composition measures included body fat percentage, fat-free mass, and muscle and tendon thickness. All groups trained 4 days per week after a full-body routine. Data were analyzed by mixed-effects models (α = 0.05). Group-by-time interactions for 3RM deadlift and 3RM bench press (p < 0.004) showed larger improvements for TRAD compared with MIN and MIN + BFR. Time main effects for all other performance variables, body fat percentage, fat-free mass, and muscle thickness (p ≤ 0.035) indicated improvements in all groups. A group-by-time interaction for blood lactate (p < 0.001) and group main effects for heart rate (p < 0.001) and workload variables (p < 0.008) indicated higher intensity and workload for MIN and MIN + BFR compared with TRAD. A sex-by-time interaction for 3RM deadlift (p = 0.008) and sex-by-group-by-time interaction for 3RM bench press (p = 0.018) were also found. Minimal-equipment RT improved performance and body composition, although strength improvements were greater with traditional equipment. Minimal-equipment RT and minimal-equipment RT with BFR exhibited higher exertion levels than TRAD, although adaptations were similar. Overall, individuals can improve performance and body composition using portable, field-expedient RT equipment.

Effect of menstrual cycle and contraceptive pill phase on aspects of exercise physiology and athletic performance in female athletes: protocol for the Feminae international multisite innovative project.

The idiom 'more high-quality research is needed' has become the slogan for sport and exercise physiology-based research in female athletes. However, in most instances, it is challenging to address this gap of high-quality research in elite female athletes at a single study site due to challenges in recruiting enough participants with numerous menstrual cycle and contraceptive pill permutations. Accordingly, we have assembled an international multisite team to undertake an innovative project for female athletes, which investigates the effects of changes in endogenous and exogenous oestrogen and progesterone/progestins across the menstrual cycle and in response to second-generation combined monophasic contraceptive pill use, on aspects of exercise physiology and athletic performance. This project will employ the current gold-standard methodologies in this area, resulting in an adequately powered dataset. This protocol paper describes the consortium-based approach we will undertake during this study.

International Society of Sports Nutrition Position Stand: Effects of essential amino acid supplementation on exercise and performance.

Position Statement: The International Society of Sports Nutrition (ISSN) presents this position based on a critical examination of literature surrounding the effects of essential amino acid (EAA) supplementation on skeletal muscle maintenance and performance. This position stand is intended to provide a scientific foundation to athletes, dietitians, trainers, and other practitioners as to the benefits of supplemental EAA in both healthy and resistant (aging/clinical) populations. EAAs are crucial components of protein intake in humans, as the body cannot synthesize them. The daily recommended intake (DRI) for protein was established to prevent deficiencies due to inadequate EAA consumption. The following conclusions represent the official position of the Society: 1. Initial studies on EAAs' effects on skeletal muscle highlight their primary role in stimulating muscle protein synthesis (MPS) and turnover. Protein turnover is critical for replacing degraded or damaged muscle proteins, laying the metabolic foundation for enhanced functional performance. Consequently, research has shifted to examine the effects of EAA supplementation - with and without the benefits of exercise - on skeletal muscle maintenance and performance. 2. Supplementation with free-form EAAs leads to a quick rise in peripheral EAA concentrations, which in turn stimulates MPS. 3. The safe upper limit of EAA intake (amount), without inborn metabolic disease, can easily accommodate additional supplementation. 4. At rest, stimulation of MPS occurs at relatively small dosages (1.5-3.0 g) and seems to plateau at around 15-18 g. 5. The MPS stimulation by EAAs does not require non-essential amino acids. 6. Free-form EAA ingestion stimulates MPS more than an equivalent amount of intact protein. 7. Repeated EAA-induced MPS stimulation throughout the day does not diminish the anabolic effect of meal intake. 8. Although direct comparisons of various formulas have yet to be investigated, aging requires a greater proportion of leucine to overcome the reduced muscle sensitivity known as "anabolic resistance." 9. Without exercise, EAA supplementation can enhance functional outcomes in anabolic-resistant populations. 10. EAA requirements rise in the face of caloric deficits. During caloric deficit, it's essential to meet whole-body EAA requirements to preserve anabolic sensitivity in skeletal muscle.

Effects of fucoidan supplementation on inflammatory and immune response after high-intensity exercise.

INTRODUCTION: High-intensity exercise (HIE) can damage the musculotendon complex and impact the immune response, resulting in post-exercise inflammation. Sufficient rest and recovery will improve muscular resilience against future damaging bouts; however, HIE with minimal durations of rest is common in athletic competitions that facilitate persistent inflammation and immune dysregulation. Fucoidans are fucose-rich sulfated polysaccharides with demonstrated anti-inflammatory and pro-immune responses. Fucoidans may improve inflammation and immune responses, which may prove beneficial for individuals who regularly engage in repeated HIE. The research purpose was to investigate the safety and efficacy of fucoidans on inflammatory and immune markers following HIE. METHODS: Eight male and eight female participants were randomized into a double-blind, placebo-controlled, counterbalanced, crossover design study and supplemented with 1 g/day fucoidan from Undaria pinnatifida (UPF) or placebo (PL) for 2 weeks. Supplementation periods concluded with HIE testing, followed by 1 week of washout. HIE involved one > 30 s Wingate anaerobic test (WAnT) and eight 10 s WAnT intervals. Blood was drawn pre-exercise, immediately post-exercise, 30 min, and 60 min post-exercise to assess immune and inflammatory markers. Blood markers, peak power (PP), and mean power (MP) were analyzed using a 2 (condition) × 4 (time) design. Significance was set at α = .05. RESULTS: A time-by-condition interaction was observed for interleukin-6 (p = .01) and interleukin-10 (p = .008). Post hoc analysis revealed greater interleukin-6 and interleukin-10 concentrations at 30 min post HIE with UPF supplementation (p = .002 and p = .005, respectively). No effects of condition were observed for all blood markers or performance outcomes with UPF supplementation (p > .05). Main effects of time were observed for white blood cells, red blood cells, red cell distribution width, mean platelet volume, neutrophils, lymphocytes, monocytes, eosinophils, basophils, natural killer cells, B and T-lymphocytes, CD4 and CD8 cells (p < .05). DISCUSSION: No adverse events were reported throughout the study period, indicating a positive safety profile of UPF. While notable changes in biomarkers occurred up to 1 hr post HIE, few differences were observed between supplementation conditions. There did appear to be a modest effect of UPF on inflammatory cytokines potentially warranting further investigation. However, fucoidan supplementation did not influence exercise performance.

International society of sports nutrition position stand: nutritional concerns of the female athlete.

Based on a comprehensive review and critical analysis of the literature regarding the nutritional concerns of female athletes, conducted by experts in the field and selected members of the International Society of Sports Nutrition (ISSN), the following conclusions represent the official Position of the Society: 1. Female athletes have unique and unpredictable hormone profiles, which influence their physiology and nutritional needs across their lifespan. To understand how perturbations in these hormones affect the individual, we recommend that female athletes of reproductive age should track their hormonal status (natural, hormone driven) against training and recovery to determine their individual patterns and needs and peri and post-menopausal athletes should track against training and recovery metrics to determine the individuals' unique patterns. 2. The primary nutritional consideration for all athletes, and in particular, female athletes, should be achieving adequate energy intake to meet their energy requirements and to achieve an optimal energy availability (EA); with a focus on the timing of meals in relation to exercise to improve training adaptations, performance, and athlete health. 3. Significant sex differences and sex hormone influences on carbohydrate and lipid metabolism are apparent, therefore we recommend first ensuring athletes meet their carbohydrate needs across all phases of the menstrual cycle. Secondly, tailoring carbohydrate intake to hormonal status with an emphasis on greater carbohydrate intake and availability during the active pill weeks of oral contraceptive users and during the luteal phase of the menstrual cycle where there is a greater effect of sex hormone suppression on gluconogenesis output during exercise. 4. Based upon the limited research available, we recommend that pre-menopausal, eumenorrheic, and oral contraceptives using female athletes should aim to consume a source of high-quality protein as close to beginning and/or after completion of exercise as possible to reduce exercise-induced amino acid oxidative losses and initiate muscle protein remodeling and repair at a dose of 0.32-0.38 g·kg-1. For eumenorrheic women, ingestion during the luteal phase should aim for the upper end of the range due to the catabolic actions of progesterone and greater need for amino acids. 5. Close to the beginning and/or after completion of exercise, peri- and post-menopausal athletes should aim for a bolus of high EAA-containing (~10 g) intact protein sources or supplements to overcome anabolic resistance. 6. Daily protein intake should fall within the mid- to upper ranges of current sport nutrition guidelines (1.4-2.2 g·kg-1·day-1) for women at all stages of menstrual function (pre-, peri-, post-menopausal, and contraceptive users) with protein doses evenly distributed, every 3-4 h, across the day. Eumenorrheic athletes in the luteal phase and peri/post-menopausal athletes, regardless of sport, should aim for the upper end of the range. 7. Female sex hormones affect fluid dynamics and electrolyte handling. A greater predisposition to hyponatremia occurs in times of elevated progesterone, and in menopausal women, who are slower to excrete water. Additionally, females have less absolute and relative fluid available to lose via sweating than males, making the physiological consequences of fluid loss more severe, particularly in the luteal phase. 8. Evidence for sex-specific supplementation is lacking due to the paucity of female-specific research and any differential effects in females. Caffeine, iron, and creatine have the most evidence for use in females. Both iron and creatine are highly efficacious for female athletes. Creatine supplementation of 3 to 5 g per day is recommended for the mechanistic support of creatine supplementation with regard to muscle protein kinetics, growth factors, satellite cells, myogenic transcription factors, glycogen and calcium regulation, oxidative stress, and inflammation. Post-menopausal females benefit from bone health, mental health, and skeletal muscle size and function when consuming higher doses of creatine (0.3 g·kg-1·d-1). 9. To foster and promote high-quality research investigations involving female athletes, researchers are first encouraged to stop excluding females unless the primary endpoints are directly influenced by sex-specific mechanisms. In all investigative scenarios, researchers across the globe are encouraged to inquire and report upon more detailed information surrounding the athlete's hormonal status, including menstrual status (days since menses, length of period, duration of cycle, etc.) and/or hormonal contraceptive details and/or menopausal status.

International society of sports nutrition position stand: energy drinks and energy shots.

Position Statement: The International Society of Sports Nutrition (ISSN) bases the following position stand on a critical analysis of the literature regarding the effects of energy drink (ED) or energy shot (ES) consumption on acute exercise performance, metabolism, and cognition, along with synergistic exercise-related performance outcomes and training adaptations. The following 13 points constitute the consensus of the Society and have been approved by the Research Committee of the Society: Energy drinks (ED) commonly contain caffeine, taurine, ginseng, guarana, carnitine, choline, B vitamins (vitamins B1, B2, B3, B5, B6, B9, and B12), vitamin C, vitamin A (beta carotene), vitamin D, electrolytes (sodium, potassium, magnesium, and calcium), sugars (nutritive and non-nutritive sweeteners), tyrosine, and L-theanine, with prevalence for each ingredient ranging from 1.3 to 100%. Energy drinks can enhance acute aerobic exercise performance, largely influenced by the amount of caffeine (> 200 mg or >3 mg∙kg bodyweight [BW-1]) in the beverage. Although ED and ES contain several nutrients that are purported to affect mental and/or physical performance, the primary ergogenic nutrients in most ED and ES based on scientific evidence appear to be caffeine and/or the carbohydrate provision. The ergogenic value of caffeine on mental and physical performance has been well-established, but the potential additive benefits of other nutrients contained in ED and ES remains to be determined. Consuming ED and ES 10-60 minutes before exercise can improve mental focus, alertness, anaerobic performance, and/or endurance performance with doses >3 mg∙kg BW-1. Consuming ED and ES containing at least 3 mg∙kg BW-1 caffeine is most likely to benefit maximal lower-body power production. Consuming ED and ES can improve endurance, repeat sprint performance, and sport-specific tasks in the context of team sports. Many ED and ES contain numerous ingredients that either have not been studied or evaluated in combination with other nutrients contained in the ED or ES. For this reason, these products need to be studied to demonstrate efficacy of single- and multi-nutrient formulations for physical and cognitive performance as well as for safety. Limited evidence is available to suggest that consumption of low-calorie ED and ES during training and/or weight loss trials may provide ergogenic benefit and/or promote additional weight control, potentially through enhanced training capacity. However, ingestion of higher calorie ED may promote weight gain if the energy intake from consumption of ED is not carefully considered as part of the total daily energy intake. Individuals should consider the impact of regular coingestion of high glycemic index carbohydrates from ED and ES on metabolic health, blood glucose, and insulin levels. Adolescents (aged 12 through 18) should exercise caution and seek parental guidance when considering the consumption of ED and ES, particularly in excessive amounts (e.g. > 400 mg), as limited evidence is available regarding the safety of these products among this population. Additionally, ED and ES are not recommended for children (aged 2-12), those who are pregnant, trying to become pregnant, or breastfeeding and those who are sensitive to caffeine. Diabetics and individuals with preexisting cardiovascular, metabolic, hepatorenal, and/or neurologic disease who are taking medications that may be affected by high glycemic load foods, caffeine, and/or other stimulants should exercise caution and consult with their physician prior to consuming ED. The decision to consume ED or ES should be based upon the beverage's content of carbohydrate, caffeine, and other nutrients and a thorough understanding of the potential side effects. Indiscriminate use of ED or ES, especially if multiple servings per day are consumed or when consumed with other caffeinated beverages and/or foods, may lead to adverse effects. The purpose of this review is to provide an update to the position stand of the International Society of Sports Nutrition (ISSN) integrating current literature on ED and ES in exercise, sport, and medicine. The effects of consuming these beverages on acute exercise performance, metabolism, markers of clinical health, and cognition are addressed, as well as more chronic effects when evaluating ED/ES use with exercise-related training adaptions.

Hormonal Contraceptives Do Not Influence Concussion Recovery in Collegiate Athletes: Data from the NCAA-DoD CARE Consortium.

INTRODUCTION: The hormonal withdrawal hypothesis suggests that progesterone reduction in women after concussion may lead to greater symptom burden and longer recoveries. Current evidence indicates that hormonal stability after head injury may be an important moderator of postconcussive recovery. Thus, female athletes using hormonal contraceptives (HC) may exhibit better recovery profiles as their hormone levels are artificially stabilized. Our investigation sought to examine the relation between HC use and concussion outcomes in female student-athletes. METHODS: This longitudinal study examined concussion outcomes from female student-athletes participating in the NCAA-DoD CARE Consortium Research Initiative, including academic years 2014 to 2020. Eighty-six female collegiate athletes reporting HC use (HC+) were group matched on age, body mass index, race/ethnicity, sport contact level, concussion history, and current injury characteristics (i.e., amnesia, loss of consciousness) to 86 female collegiate athletes reporting no HC use (HC-). All participants had sustained a concussion and completed the Sport Concussion Assessment Tool, 3rd edition Symptom Scale, Brief Symptom Inventory-18, and Immediate Post-concussion Assessment and Cognitive Testing at preinjury baseline, 24 to 48 h postinjury, and when cleared for unrestricted return to play. To provide an index of recovery trajectory, days between injury and unrestricted return to play were calculated. RESULTS: Groups did not differ on length of recovery, postconcussion symptoms, psychological health, or cognitive assessments. No differences were observed between groups on any measure when accounting for baseline levels of performance. CONCLUSIONS: Our findings suggest that HC use does not influence recovery trajectory, symptoms, or recovery of cognitive function after concussion.

Power, Endurance, and Body Composition Changes Over a Collegiate Career in National Collegiate Athletic Association Division I Women Soccer Athletes.

ABSTRACT: McFadden, BA, Bozzini, BN, Cintineo, HP, Hills, SP, Walker, AJ, Chandler, AJ, Sanders, DJ, Russell, M, and Arent, SM. Power, endurance, and body composition changes over a collegiate career in National Collegiate Athletic Association Division I women soccer athletes. J Strength Cond Res 37(7): 1428-1433, 2023-The purpose of this study was to determine longitudinal changes in fitness and body composition throughout athletes' 4-year collegiate soccer careers. Performance testing occurred before preseason during freshman, sophomore, junior, and senior year in 17 female Division I soccer players. Body composition was assessed through air-displacement plethysmography to determine percent body fat (%BF), fat-free mass (FFM), and body mass (BM). Maximal countermovement vertical jump height was assessed through contact mat using arm swing (CMJ AS ) and hands-on-hips (CMJ HOH ) methods to calculate power (CMJ watts / HOHwatts ). Aerobic capacity (V̇ o2 max) and ventilatory threshold (VT) were assessed by indirect calorimetry during a maximal graded exercise test on a treadmill. Linear mixed models were used to assess changes across academic years ( p < 0.05). No changes occurred in %BF, BM, V̇ o2 max, VT, CMJ AS , or CMJ watts . A time main effect was seen for FFM ( p = 0.01) with increases from freshman to senior ( p = 0.02). Time main effects were observed for CMJ HOH ( p < 0.001) and CMJ HOHwatts ( p < 0.001) with increases from freshman to junior (CMJ HOH,p = 0.001; CMJ HOHwatts , p = 0.02) and senior (CMJ HOH , p < 0.001; CMJ HOHwatts , p = 0.003) as well as sophomore to senior (CMJ HOH , p < 0.001; CMJ HOHwatts , p = 0.02). Countermovement vertical jump with hands on hips also increased from sophomore to junior ( p = 0.005). The lower FFM and power capabilities as freshmen compared with upperclassman indicate a potential limited readiness. Coaches and training staff should account for these developmental differences when entering the preseason. Adequate conditioning programs before starting a collegiate program may help build a fitness foundation and prepare freshmen athletes to compete at the same level as their upperclassmen counterparts.

An Examination of Depression, Anxiety, and Self-Esteem in Collegiate Student-Athletes.

Mental health research exists for student-athletes in the areas of depression, anxiety, and self-esteem prevalence. However, updated prevalence rates and assessment of risks across sports, academic status, and genders are needed. Filling the gaps in research assists in the creation of patient-centered mental health screening and interventions designed for student-athletes. Therefore, the purpose is to examine the prevalence of depression, anxiety, and self-esteem in collegiate student-athletes and differences between sex, academic status, and sport type, and identify associations for risks. Using a cross-sectional design, collegiate student-athletes were surveyed to assess for risks of depression, anxiety, and self-esteem. With the use of SPSS, Chi-square analyses and multinomial logistic regressions were used. Student-athletes (22.3%) were at risk for depression, anxiety (12.5%), and low self-esteem (8%). No significant differences were found for sex, academic status, and sport type for depression or self-esteem; however, significant differences occurred for state and trait anxiety by sex. A significant association for depression and anxiety risk was found with females at risk. Depression and anxiety are present within student-athletes, regardless of sport type. Females are at a higher risk; however, all student-athletes would benefit from the creation of validated, patient-centered mental health screenings and psychotherapeutic interventions.

The exercise metabolome: acute aerobic and anaerobic signatures.

Background: Exercise modality differentially alters body composition and physical performance. Metabolic changes underlying these outcomes can be tracked through assessment of circulating metabolites. Here, global responses to an acute bout of aerobic or anaerobic exercise were compared in the serum of male and female subjects using a discovery-based metabolomics platform. Methods: On separate days, 40 healthy, active participants completed 45 min of aerobic cycling or resistance exercise, and blood samples were collected at rest, immediately after (T1) and 1 hour post-exercise (T2) to examine the serum metabolomic landscape. Results: The two exercise metabolomes appeared more similar than different in this healthy cohort. Overall, metabolomic signatures of both exercise modalities were markedly altered from rest at T1, and returned toward baseline by T2. Metabolomic perturbations at T1 and the T1-T2 rate of recovery post-exercise were greater following aerobic cycling than resistance exercise. Shared signatures included elevations in purine metabolism, substrate catabolism and mobilization, and inflammatory signaling. Aerobic exercise resulted in greater substrate diversity and use of fatty acids, whereas resistance exercise displayed higher purine turnover and glycolytic flux. Discussion: Individual metabolite differences between conditions were seen in magnitude but not direction. Metabolomic signatures of the exercise responses appeared fairly robust across exercise modalities. An initial perturbation and subsequent shift toward recovery by an hour post-exercise defined the signature in our healthy cohort. The expedited recovery following aerobic cycling may be explained by globally elevated lipid metabolism.

Effects of caffeine, methylliberine, and theacrine on vigilance, marksmanship, and hemodynamic responses in tactical personnel: a double-blind, randomized, placebo-controlled trial.

Background: Tactical athletes require fast reaction times (RT) along with high levels of vigilance and marksmanship performance. Caffeine has been shown to improve these measures but also results in increased blood pressure and jitteriness. Research on other purine alkaloids, such as methylliberine and theacrine, has suggested they do not increase blood pressure or jitteriness to the same extent, but their impact on tactical performance is unknown. Methods: A between-subjects, randomized, placebo-controlled design was used to test the effects of placebo (PLA), 300 mg caffeine (CAF), and a combination of 150 mg caffeine, 100 mg methylliberine, and 50 mg theacrine (CMT) on RT and marksmanship along with hemodynamic and arousal measures following a sustained vigilance task in tactical personnel (n = 48). Following consumption of the supplement, participants underwent a 150-min protocol consisting of two rounds. Each round began with leisurely reading followed by a 30-min vigilance task before beginning two trials of movement and marksmanship tasks. Hemodynamics and felt arousal were assessed throughout the protocol. Composite Z-scores were calculated for overall performance measures at each timepoint, and mixed-effects models were used to assess differences in RT, accuracy, and composite Z-scores along with hemodynamics and felt arousal. An α-level of 0.05 was used to determine statistical significance, and Cohen's d was used to quantify effect sizes. Results: A Group-by-Time interaction for vigilance RT (P = 0.038) indicated improvements for both CAF and CMT from round 1 to round 2 (P < 0.01) while PLA did not change (P = 0.27). No Group main effects or Group-by-Time interactions were found for movement or marksmanship performance (P > 0.20). Group main effects for systolic (SBP; P = 0.001) and diastolic blood pressure (DBP; P = 0.028) indicated higher SBP in CAF (P = 0.003, d= 0.84) and CMT (P = 0.007, d= 0.79) compared to PLA but only higher DBP in CAF (P = 0.025, d= 0.74). No Group-by-Time interaction or Group main effect was found for felt arousal (P > 0.16). Conclusions: These findings suggest similar benefits on RT during a vigilance task between CAF, containing 300 mg caffeine, and CMT above PLA, though CAF resulted in slightly less favorable hemodynamic changes. This study is the first to provide data showing similar efficacy of combined caffeine, methylliberine, and theacrine compared to double the caffeine dose consumed alone on vigilance RT but without a significant rise in DBP above PLA in tactical personnel.

A qualitative report of the perceptions of the COVID-19 pandemic from collegiate student-athletes.

Context: The COVID-19 pandemic led to an abrupt disruption in access to services and personnel for collegiate student-athletes in the spring and summer of 2020. We sought to identify the effects of this unprecedented change by examining the psychological well-being, changes to normal routines, and return-to-play considerations of current student-athletes in order to guide support for both current and future student-athletes who may face similar situations. Methods: We utilized a phenomenological approach to interview a purposeful sample of eighteen collegiate student-athletes (7 males, 11 females; mean age = 20 years) from across the United States. The participants were interviewed using a semi-structured interview protocol, which was audio recorded and transcribed verbatim using Zoom. The data were then analyzed and coded by a 3-person team via the consensual qualitative research tradition. Results: Four domains emerged after data analysis: 1) ambiguity, 2) perspective, 3) bonding and cohesion, and 4) resource utilization. Participants discussed ambiguity in terms of eligibility and participation questions, academic changes, and varying COVID-19 policies. Participants shared a wide range of perspectives, from apprehension at the onset of the pandemic, to excitement when returning to campus and competition. They shared how bonding and team development were affected due to a lack of socialization and that support system dynamics between family, coaches, and teammates were strengthened. When describing resource utilization, participants discussed the use of personnel and supplies to help them adjust to changes in facility and space availability. The identification and utilization of resources enabled them to establish a "new normal" for their academics, workouts, and hobbies during the pandemic. Conclusions: Collegiate student-athletes realized the seriousness of the pandemic and utilized their resources and support systems to adjust their routines and keep a positive attitude during COVID-19. At the same time, some student-athletes struggled with these changes. Personnel should be aware of these effects to provide care and prevent future negative effects.

Racial differences in running and landing measures associated with injury risk vary by sex.

It is unknown whether running and landing mechanics differ between racial groups despite injury disparities between African Americans (AA) and white Americans (WA). This study aimed to identify potential racial differences in running and landing mechanics and understand whether anthropometric, strength, and health status factors contribute to these differences. Venous blood samples, anthropometry, lower-extremity strength, and health status assessments were collected (n = 84, 18-30y). Three-dimensional motion capture and force plate data were recorded during 7 running and 7 drop vertical jump trials. Racial effects were determined, and regression models evaluated explanatory factors. AA females ran with longer stance times (p = 0.003) than WA females, while AA males ran with smaller loading rates (p = 0.046) and larger peak vertical ground reaction forces (p = 0.036) than WA males. Frontal plane knee range of motion during landing was greater in AA females (p = 0.033) than WA females; larger waist circumference and weaker knee extension strength accounted for this significance. Although outcome measures were associated with physiologic, anthropometric, and activity measures, their explanatory power for race was ambiguous, except for knee range of motion in females. Modifiable factors explaining racial effects during landing in females are potential intervention targets to reduce racial health disparities in running and landing injuries.

Investigation of Eating Disorder Risk and Body Image Dissatisfaction among Female Competitive Cheerleaders.

Social agents associated with cheerleading environments are increasingly linked to body image dissatisfaction (BID) and eating disorders (ED). This study examined ED risk across team type, squad type, and position. An additional purpose determined BID in clothing type (daily clothing, midriff uniform, and full uniform), and meta-perceptions from the perspective of peers (MP peers), parents (MP parents), and coaches (MP coaches). Female cheerleaders (n = 268) completed an online survey which included demographics, the Eating Attitudes Test-26, and pathogenic behavior questions. Body image perceptions were assessed by using the Sex-Specific Figural Stimuli Silhouettes. Overall, 34.4% of cheerleaders (n = 268; mean age: 17.9 ± 2.7 years) exhibited an ED risk. Compared to All-Star cheerleaders, college cheerleaders demonstrated significant higher ED risk (p = 0.021), dieting subscale scores (p = 0.045), and laxative, diet pill, and diuretic use (p = 0.008). Co-ed teams compared to all-girl teams revealed higher means for the total EAT-26 (p = 0.018) and oral control subscale (p = 0.002). The BID in clothing type revealed that cheerleaders wanted to be the smallest in the midriff option (p < 0.0001, η2 = 0.332). The BID from meta-perception revealed that cheerleaders felt that their coaches wanted them to be the smallest (p < 0.001, η2 = 0.106). Cheerleaders are at risk for EDs and BID at any level. Regarding the midriff uniform, MP from the perspective of coaches showed the greatest difference between perceived and desired body image.

Examination of the Prevalence of Female Athlete Triad Components among Competitive Cheerleaders.

The purpose of this study was to examine individual and combined Female Athlete Triad components within collegiate cheerleaders, an at-risk group. Cheerleaders (n = 19; age: 20.3 ± 1.2 years) completed anthropometric measurements, health history questionnaires, resting metabolic rate, the eating disorder inventory-3 and symptom checklist, blood sample, and DXA scan. Participants completed dietary and exercise logs for 7 days and used heart rate monitors to track daily and exercise energy expenditure. Proportions were calculated for low energy availability (LEA) risk, disordered eating risk, and pathogenic behaviors. Chi-square analysis was used to determine the difference between cheerleaders who experience low EA with or without disordered eating risk. All cheerleaders demonstrated LEA for the days they participated in cheerleading practice, 52.6% demonstrated LEA with eating disorder risk and 47.4% demonstrated LEA without eating disorder risk, 52.6% self-reported menstrual dysfunction, 14% experienced menstrual dysfunction via hormonal assessment, and 0% demonstrated low bone mineral density. Overall, 47.7% presented with one Triad component, 52.6% demonstrated two Triad components using self-reported menstrual data, and 10.5% demonstrated two Triad components using hormonal assessments. All cheerleaders displayed LEA. These findings support the need for increased education on the individual components of the Triad and their potential consequences by qualified personal.

Psychological and Physiological Changes in Response to the Cumulative Demands of a Women's Division I Collegiate Soccer Season.

ABSTRACT: McFadden, BA, Walker, AJ, Bozzini, BN, Hofacker, M, Russell, M, and Arent, SM. Psychological and physiological changes in response to the cumulative demands of a women's division I collegiate soccer season. J Strength Cond Res 36(5): 1373-1382, 2022-This study sought to determine the effects of a women's collegiate soccer season on psychological markers, biomarkers, sleep, and performance. Athletes participated in maximal countermovement vertical jump height (CMJ) assessments and biomarker monitoring in conjunction with subjective measures of psychological wellness and sleep questionnaires before preseason (S1) and every 4 weeks following (S2, S3, and S4). Training was monitored during practices and games using global positioning satellite systems and heart rate technology. Total training load was highest from S1 to S2, decreased from S2 to S3 (effect size [ES] = -2.5; p < 0.001), and remained stable from S3 to S4. CMJ declined at S2 (ES1-2 = -0.51; p = 0.001) and returned to baseline at S3. Increases from S1 to S2 were seen for creatine kinase (ES1-2 = 1.74), free testosterone (ES1-2 = 1.27), total testosterone (ES1-2 = 3.5), and free cortisol (ES1-2 = 0.88) (p < 0.03) before returning to baseline by S3 and S4 (free cortisol). Total cortisol was elevated throughout the season before declining at S4 (ES1-4 = -0.41; p = 0.03). Iron declined from S1 to S2 (ES1-2 = -0.73; p = 0.01) and returned to baseline values at S4, whereas growth hormone declined at S2 (ES1-2 = -0.50; p = 0.01) and remained depressed. Interleukin-6 increased at S4 (ES1-4 = 0.71; p = 0.02). Total training distress decreased from S1 to S2 (ES1-2 = -0.38; p = 0.02), returned to baseline by S3, and increased by S4 (ES1-4 = 0.57; p = 0.01). No changes were observed in markers of sleep (p > 0.05). Biomarkers showed notable changes after the highest workload period (S1-S2), which coincided with CMJ decrements. Biomarker perturbations preceded declines in subjective psychological wellness (S4) which occurred in the latter half of the season, indicating an accumulation of fatigue as the season progressed.

Serum myokine levels after linear and flexible non-linear periodized resistance training in overweight sedentary women.

This study compared the capacity of linear-(LP) and non-linear periodized (NLP) resistance training to improve select myokines and metabolic parameters in overweight sedentary women. An additional purpose was to compare these variables between the overweight and lean women. Fitness- and age-matched overweight women between 28 and 43 years old were randomly allocated to LP (body fat [BF]% = 38.7 ± 2.6, n = 10), NLP (BF% = 39.3 ± 2.4, n = 9) and control (BF% = 39.8 ± 2.6, n = 9) groups. Lean women (BF% = 29.1 ± 2.3, n = 16) matched for age and fitness were also included for baseline comparison. Resistance training programmes (12 weeks, 3 d.wk-1, 9 exercises, 60-90% of 1-repetition maximum [1RM]) were performed with different periodization schemes. Glucose, insulin, interleukin (IL)-7, IL-15, and insulin-like growth factor (IGF)-1 levels were measured at baseline and after training. Overweight subjects had significantly lower IL-15, IGF-1 and higher insulin, glucose, and insulin resistance (homeostasis model assessment, HOMA-IR) than lean subjects at baseline (all, P < .05). IL-15 and VO2max increased significantly after NLP compared with CON, which was accompanied by a significant decrease in HOMA-IR (all, P < .03). Muscular endurance improved significantly in both models after training compared to CON (all, P < .01), but it increased more in NLP than in LP (P = .01). Both training protocols were equally effective at reducing BF% and increasing IGF-1, IL-7, muscle mass and bench press 1RM (P < .01). It appears that LP and NLP are both effective strategies for improving health markers in overweight women, but LP is not as effective as NLP to improve IL-15, HOMA-IR and aerobic capacity.HighlightsOverweight women had a significantly lower IL-15 and IGF-1 compared to lean encounters, but no significant difference was noted for maximal strength, aerobic capacity, muscle mass, IL-7 and neutrophil/lymphocyte ratio.Twelve weeks of either linear or flexible non-linear periodized resistance training resulted in reduction in BF% and neutrophil/lymphocyte ratio, and increased IGF-1, IL-7, muscle mass and bench press 1RM, with no difference between the two training protocols.Linear protocol is not as effective as non-linear protocol to improve IL-15, HOMA-IR and aerobic capacity.