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The time-of-day effect of exercise on human function remains largely equivocal. Hence, this study aimed to further analyze the existing evidence concerning diurnal variations in cardiorespiratory responses and endurance performance using a meta-analytic approach. Literature search was conducted through databases, including PubMed, CINAHL, and Google Scholar. Article selection was made based on inclusion criteria concerning subjects' characteristics, exercise protocols, times of testing, and targeted dependent variables. Results on oxygen uptake (VO2), heart rate (HR), respiratory exchange ratio, and endurance performance in the morning (AM) and late afternoon or evening (PM) were extracted from the chosen studies. Metaanalysis was conducted with the random-effects model. Thirty-one original research studies that met the inclusion criteria were selected. Meta-analysis revealed higher resting VO2 (Hedges' g = -0.574; p = 0.040) and resting HR (Hedges' g= -1.058; p = 0.002) in PM than in AM. During exercise, although VO2 remained indifferent between AM and PM, HR was higher in PM at submaximal (Hedges' g = -0.199; p = 0.046) and maximal (Hedges' g = -0.298; p = 0.001) levels. Endurance performance as measured by time-to-exhaustion or the total work accomplished was higher in PM than in AM (Hedges' g = -0.654; p = 0.001). Diurnal variations in VO2 appear less detectable during aerobic exercise. The finding that exercising HR and endurance performance were greater inPMthan in AMemphasizes the need to consider the effect of circadian rhythm when evaluating athletic performance or using HR as a criterion to assess fitness or monitor training. [ABSTRACT FROM AUTHOR]

Investigated recovery of maximal force and power following a 10-km race. Data collected on 10 healthy male distance runners pre-race, immediately post-race, and 48 hours later indicated that strength and power capabilities of these 10-km runners were for the most part restored 48 hours after the race. Only the hamstring muscle group was not fully recovered. (SM)

Examined the effects of ingesting the dietary supplement L- CARNIPURE on liver and renal function and blood hematology among healthy men. Analysis of blood samples indicated that there were no statistically significant differences between the L-CARNIPURE and placebo conditions for any variables examined, suggesting there are no safety concerns when ingesting 3g of L-CARNIPURE. (SM)

Abstract Comparison of protein intakes on strength, body composition and hormonal changes were examined in 23 experienced collegiate strength/power athletes participating in a 12-week resistance training program. Subjects were stratified into three groups depending upon their daily consumption of protein; below recommended levels (BL; 1.0 – 1.4 g·kg-1·day-1; n = 8), recommended levels (RL; 1.6 – 1.8 g·kg-1·day-1; n = 7) and above recommended levels (AL; > 2.0 g·kg-1·day-1; n = 8). Subjects were assessed for strength [one-repetition maximum (1-RM) bench press and squat] and body composition. Resting blood samples were analyzed for total testosterone, cortisol, growth hormone, and insulin-like growth factor. No differences were seen in energy intake (3,171 ± 577 kcal) between the groups, and the energy intake for all groups were also below the recommended levels for strength/power athletes. No significant changes were seen in body mass, lean body mass or fat mass in any group. Significant improvements in 1-RM bench press and 1-RM squat were seen in all three groups, however no differences between the groups were observed. Subjects in AL experienced a 22% and 42% greater change in Δ 1-RM squat and Δ 1-RM bench press than subjects in RL, however these differences were not significant. No significant changes were seen in any of the resting hormonal concentrations. The results of this study do not provide support for protein intakes greater than recommended levels in collegiate strength/power athletes for body composition improvements, or alterations in resting hormonal concentrations.

Abstract Background The purpose of this study was to examine the effect of nutritionally enriched JavaFit™ (JF) coffee (450 mg of caffeine, 1200 mg of garcinia cambogia, 360 mg of citrus aurantium extract, and 225 mcg of chromium polynicotinate) on resting oxygen uptake (VO2), respiratory exchange ratio (RER), heart rate (HR), and blood pressure (BP) in healthy and physically active individuals. Method Ten subjects (8 male, 2 female; 20.9 ± 1.7 y; 178.1 ± 10.4 cm; 71.8 ± 12.1 kg) underwent two testing sessions administered in a randomized and double-blind fashion. During each session, subjects reported to the Human Performance Laboratory after at least 3-h post-absorptive state and were provided either 354 ml (1.5 cups) of freshly brewed JF or commercially available caffeinated coffee (P). Subjects then rested in a semi-recumbent position for three hours. VO2 and HR were determined every 5 min during the first 30 min and every 10 min during the next 150 min. BP was determined every 15 min during the first 30 min and every 30 min thereafter. Area under the curve (AUC) analysis was computed for VO2, whereas a session-average was calculated for RER, HR and BP. Results Initial analysis revealed no significant differences. However, seven of the ten subjects were considered responders to JF (had a higher AUC for VO2during JF than P). Statistical analysis showed the difference between JF and P (12%) to be significantly different in these responders. In addition, the average systolic BP was higher (p < 0.05) in JF (118 ± 7 mmHg) than P (115 ± 8 mmHg) in both the total sample and the subgroup of responders. No differences in average HR and average diastolic BP were observed between JF and P in both the total sample and the subgroup of responders. Conclusion It appears that consuming a nutritionally-enriched coffee beverage may increase resting energy expenditure in individuals that are sensitive to the caffeine and herbal coffee supplement. In addition, this supplement also appears to affect cardiovascular dynamics by augmenting systolic arterial blood pressure.

Time restricted feeding (TRF) as a form of intermittent fasting (IF) has gained popularity because its ability to reduce body mass (BM) without an emphasis on caloric restriction. However, how this dietary protocol may affect health, fitness, and performance in a relatively healthy cohort remains less clear. The purpose of this article was to systematically review the current literature concerning the effect of TRF on anthropometric, metabolic, and fitness parameters in normal-weight adults and overweight and obese individuals. A systematic search of English literature was conducted through databases including PubMed, CINAHL, and Google Scholar. The search was facilitated by using various combinations of key words related to nutritional interventions, i.e., IF and TRF, and outcomes of interest, i.e., BM, body composition, glucose, insulin, lipid, fitness, and performance. The article selection was made based on the inclusion and exclusion criteria concerning the participants' characteristics, study design, intervention protocols, and targeted dependent variables. Twenty-three full-text longitudinal randomized and nonrandomized controlled studies were selected for this review. Our analysis indicates that TRF can reduce BM and improve nutrient metabolism in both normal- and over-weight individuals. TRF does not appear to alter protein synthesis and fat-free mass nor hamper aerobic fitness and muscular performance among physically active individuals including athletes. In conclusion, TRF as a more easily adaptable form of IF is a promising dietary approach to improving body composition and metabolic health while maintaining fitness and muscular function. However, more research is needed before this dietary protocol can be fully recommended for athletes especially those competing in sports that demand strength and power. Time-restricted feeding (TRF) differs from other fasting protocols due to its emphasis on restricting eating window rather than caloric intake and can be more easily adopted by simply skipping a meal. Its deemphasis on caloric restriction appeals to many young and physically active individuals wanting to optimize body composition but needing sufficient energy to support their physical training and daily activity. Much of what is known regarding the impact of TRF on fitness and athletic performance was derived from studies that use the Ramadan fasting protocol, which differs from TRF in terms of protocol duration and feeding schedule. This review concludes that TRF is a promising dietary approach to improving body composition and metabolic health while maintaining fitness and muscular function in both normal- and over-weight individuals. Due to limited evidence concerning TRF and athletic performance, more research is needed before this dietary protocol can be fully recommended for athletes especially those competing in sports that demand strength and power. [ABSTRACT FROM AUTHOR]

Physical education (PE) provides a unique opportunity for school-age youth to establish health habits, although some young athletes are exempt from PE and others do not participate because of a concern regarding the lingering effects of fatigue on after-school fitness performance. The purpose of this study was to examine the acute effects of different PE lessons on after-school fitness performance in young athletes. Twenty athletes (14-18 years) participated in 3 different PE lessons that consisted of aerobic exercise (AE), resistance training (RT), or basketball skill training (BS). Fitness performance was assessed after-school following each lesson and after a control day without PE. There were no significant differences in flexibility (34.1 [+ or -] 6.5, 34.7 [+ or -] 1.3, 33.5 [+ or -] 7.2, and 33.6 [+ or -] 7.3 cm), vertical jump (46.3 [+ or -] 14.7, 46.2 [+ or -] 13.6, 46.4 [+ or -] 13.4, and 45.6 [+ or -] 14.2 cm), long jump (175.0 [+ or -] 36.4, 174.2 [+ or -] 36.3, 172.7 [+ or -] 35.8, and 171.9 [+ or -] 34.7 cm), medicine ball toss (348.9 [+ or -] 121.8, 342.0 [+ or -] 120.6, 353.9 [+ or -] 123.6, and 348.4 [+ or -] 129.1 cm), proagility shuttle run (5.8 [+ or -] 0.5, 5.7 [+ or -] 0.53, 5.8 [+ or -] 0.52, and 5.8 [+ or -] 0.5 seconds), 20-m sprint (3.7 [+ or -] 0.4, 3.7 [+ or -] 0.4, 3.7 [+ or -] 0.3, and 3.7 [+ or -] 0.3 seconds), and 200-m sprint (36.3 [+ or -] 4.7, 35.1 [+ or -] 4.0, 35.9 [+ or -] 5.9, and 35.4 [+ or -] 5.4 seconds) after AE, RT, BS, or the control day, respectively. These findings suggest that an exercise lesson or skill-based PE class will not have an adverse effect on after-school fitness performance in adolescent athletes. KEY WORDS youth, sport, physical activity, fatigue; recovery

Abstract The purpose of this study was to examine the effects of a school-based plyometric training program (i.e., Plyo Play) on children's fitness performance. Forty children (8 to 11 yrs) [...]

Perceived yet often misunderstood demands of a sport, overt benefits of anabolic drugs, and the inability to be offered any effective alternatives has fueled anabolic drug abuse despite any consequences. Motivational interactions with many situational demands including the desire for improved body image, sport performance, physical function, and body size influence and fuel such negative decisions. Positive countermeasures to deter the abuse of anabolic drugs are complex and yet unclear. Furthermore, anabolic drugs work and the optimized training and nutritional programs needed to cut into the magnitude of improvement mediated by drug abuse require more work, dedication, and preparation on the part of both athletes and coaches alike. Few shortcuts are available to the athlete who desires to train naturally. Historically, the NSCA has placed an emphasis on education to help athletes, coaches, and strength and conditioning professionals become more knowledgeable, highly skilled, and technically trained in their approach to exercise program design and implementation. Optimizing nutritional strategies are a vital interface to help cope with exercise and sport demands (516-518). In addition, research-based supplements will also have to be acknowledged as a strategic set of tools (e.g., protein supplements before and after resistance exercise workout) that can be used in conjunction with optimized nutrition to allow more effective adaptation and recovery from exercise. Resistance exercise is the most effective anabolic form of exercise, and over the past 20 years, the research base for resistance exercise has just started to develop to a significant volume of work to help in the decision-making process in program design (187,248,305). The interface with nutritional strategies has been less studied, yet may yield even greater benefits to the individual athlete in their attempt to train naturally. Nevertheless, these are the 2 domains that require the most attention when trying to optimize the physical adaptations to exercise training without drug use. Recent surveys indicate that the prevalence of androgen use among adolescents has decreased over the past 10-15 years (154,159,246,253,370,441,493). The decrease in androgen use among these students may be attributed to several factors related to education and viable alternatives (i.e., sport supplements) to substitute for illegal drug use. Although success has been achieved in using peer pressure to educate high school athletes on behaviors designed to reduce the intent to use androgens (206), it has not had the far-reaching effect desired. It would appear that using the people who have the greatest influence on adolescents (coaches and teachers) be the primary focus of the educational program. It becomes imperative that coaches provide realistic training goals for their athletes and understand the difference between normal physiological adaptation to training or that is pharmaceutically enhanced. Only through a stringent coaching certification program will academic institutions be ensured that coaches that they hire will have the minimal knowledge to provide support to their athletes in helping them make the correct choices regarding sport supplements and performance-enhancing drugs. The NSCA rejects the use of androgens and hGH or any performance-enhancing drugs on the basis of ethics, the ideals of fair play in competition, and concerns for the athlete's health. The NSCA has based this position stand on a critical analysis of the scientific literature evaluating the effects of androgens and human growth hormone on human physiology and performance. The use of anabolic drugs to enhance athletic performance has become a major concern for professional sport organizations, sport governing bodies, and the federal government. It is the belief of the NSCA that through education and research we can mitigate the abuse of androgens and hGH by athletes. Due to the diversity of testosterone-related drugs and molecules, the term androgens is believed to be a more appropriate term for anabolic steroids.

The purpose of this study was to examine performance differences between starters and nonstarters and between different playing positions in collegiate female lacrosse athletes. Twenty-two subjects playing on a two-time defending National Champion National Collegiate Athletic Association Division III female lacrosse team volunteered to participate in this study. Subjects were examined during the preseason period and participated in a total of 5 testing sessions, separated by at least 72 hours. Subjects were tested on their 1 repetition maximum (1RM) (bench press and squat), vertical jump, Wingate anaerobic power test (WANT), 30-second sprint using a nonmotorized treadmill, maximal aerobic capacity, 40-yd sprint, T-drill, and pro-agility test. No significant differences were observed between starters and nonstarters in any performance variable. Anthropometric analysis revealed that attackers were 15.7% (p < 0.05) heavier than midfielders. A significant difference (10.3%) between defenders and midfielders was seen in 1RM squat, while no other strength differences were noted. Attackers were more powerful in the WAnT (both peak and mean power) than both defenders (19.6 and 13.4%, respectively) and midfielders (21.2 and 13.4%, respectively). No significant differences were noted between the groups in any speed or agility measure. Although physical performance characteristics were not different between starters and nonstarters, results indicate that attackers are heavier and more powerful than the other positions and midfielders appear to be weaker in lower-body strength relative to the other positions in lacrosse. KEY WORDS performance testing, strength, power, speed, agility

The purpose of the present study was to examine the independent and combined effects of resistance and treadmill sprint training on maximal sprint velocity and power. Twenty-five male athletes (age = 19.8 [+ or -] 1.5 years, height = 181.2 [+ or -] 7.9 cm, body mass = 88.9 [+ or -] 10.9 kg) were matched for 30-m sprint times and assigned to 1 of 3 training groups: 1) sprint training only (ST), 2) resistance training only (RT), or 3) combined sprint and resistance training (SRT) for 7 weeks. Periodized resistance training was performed 4 d x [wk.sup.-1] (3-4 sets of 6-10 repetitions). The treadmill sprint training program was performed 2 d x [wk.sup.-1] and consisted of 8-12 sets of maximal sprints for 40-60 m at 0-25% of each athlete's body mass, with rest intervals of 2-3 minutes on a treadmill that was user driven and that enabled loading via a magnetic braking system. Peak 30-m sprint times, power and average velocity attained during maximal sprint trials on the treadmill, and 1 -repetition maximum (1RM) squat were determined pre and post training. The 30-m sprint times improved significantly only in the SRT group, and a trend for improvement (p = 0.06) was observed in the ST group. All groups significantly increased treadmill sprint velocity. However, the SRT and ST groups increased significantly more than RT. Only the SRT group increased treadmill sprint peak power. All training groups increased 1RM squat strength significantly by 6.6-8.4 kg, with no differences observed between groups. The results of this study showed that 7 weeks of sprint training on a newly designed treadmill resulted in significant kinematic and kinetic improvements in sprint performance. Of practical significance, treadmill sprint training enhanced land-based sprint performance. KEY WORDS maximal strength, periodization, resisted sprinting, speed

Recovery from an American football game has had limited study. The purpose of this study was to examine markers of skeletal muscle tissue damage and circulating anabolic and catabolic hormones to gain insight into the recovery process from Friday until Monday, when a new practice week begins. Twenty-eight National Collegiate Athletic Association Division I football players gave consent to participate in the investigation in the ninth game of the season. Sixteen players started the game and played the entire game (PL), and 12 others did not play and were on the bench during the game (DNP). Each player had fasted blood samples obtained at the same time of day between 1000 and 1200 hours the day before the game (Friday; T1), 18-20 hours after the game (Sunday; T2), and then 42-44 hours after the game (Monday; T3). Blood samples were analyzed for concentrations of creatine kinase (CK), lactate dehydrogenase (LDH), myoglobin, testosterone, and cortisol. The PL players showed significantly (p [less than or equal to] 0.05) increased concentrations of CK (T2 > T1 and T3), myoglobin (T2 > T1 and T3), and LDH (T2 > T1). In contrast, DNP players showed significant differences in cortisol (T3 < T1 and T2) and testosterone:cortisol (T3 > T1). Few changes were observed in testosterone and cortisol changes, indicating stability of the anabolic/catabolic hormones. In conclusion, these data indicate that participation in a college football game late in the season results in some degree of tissue damage but with minimal hormonal responses, which seem to have stabilized at resting concentrations without predominance of cortisol's catabolic presence. As previously noted in the literature, some type of 'contact adaptation' to the season may have occurred with regard to tissue damage responses. However, by the ninth game of a season, players do carry soft tissue damage levels above resting ranges into subsequent games, indicating that recovery should be monitored, with coaches being careful with scheduling scrimmage and full-contact drills. How such data implicate overuse injuries remains unclear, considering that hormonal status in this study was highly stable, with catabolic influences minimized by the high level of athlete conditioning. These data again support that high-level conditioning can stabilize anabolic and catabolic hormonal signals and limit acute soft tissue injury, making cerebral concussion (acute and chronic) and traumatic injury the biggest threats to a student-athlete's health and well-being during an American football game. Key Words competition, contact sports, collision injury, endocrine, performance, recovery, skeletal muscle