The Effect of Creatine Nitrate and Caffeine Individually or Combined on Exercise Performance and Cognitive Function: A Randomized, Crossover, Double-Blind, Placebo-Controlled Trial.

This study examined the effect of creatine nitrate and caffeine alone and combined on exercise performance and cognitive function in resistance-trained athletes. In a double-blind, randomized crossover trial, twelve resistance-trained male athletes were supplemented with 7 days of creatine nitrate (5 g/day), caffeine (400 mg/day), and a combination of creatine nitrate and caffeine. The study involved twelve resistance-trained male athletes who initially provided a blood sample for comprehensive safety analysis, including tests for key enzymes and a lipid profile, and then performed standardized resistance exercises-bench and leg press at 70% 1RM-and a Wingate anaerobic power test. Cognitive function and cardiovascular responses were also examined forty-five minutes after supplementation. Creatine nitrate and caffeine that were co-ingested significantly enhanced cognitive function, as indicated by improved scores in the Stroop Word-Color Interference test (p = 0.04; effect size = 0.163). Co-ingestion was more effective than caffeine alone in enhancing cognitive performance. In contrast, no significant enhancements in exercise performance were observed. The co-ingestion of creatine nitrate and caffeine improved cognitive function, particularly in cognitive interference tasks, without altering short-term exercise performance. Furthermore, no adverse events were reported. Overall, the co-ingestion of creatine nitrate and caffeine appears to enhance cognition without any reported side effects for up to seven days.

Combined but Not Isolated Ingestion of Caffeine and Taurine Improves Wingate Sprint Performance in Female Team-Sport Athletes Habituated to Caffeine.

Previous studies have investigated caffeine (CAF) and taurine (TAU) in isolation and combined during exercise in males. However, the potential synergistic effect during high-intensity exercise remains unknown in female athletes. Seventeen female team-sport athletes participated (age: 23.4 ± 2.1 years; height: 1.68 ± 0.05 m; body mass: 59.5 ± 2.2 kg). All participants were habitual caffeine consumers (340.1 ± 28.6 mg/day). A double-blind randomized crossover design was used. Participants completed four experimental trials: (i) CAF and TAU (6 mg/kg body mass of CAF + 1 g of TAU), (ii) CAF alone; (iii) TAU alone; and (iv) placebo (PLA). Supplements were ingested 60 min before a 30-s Wingate Anaerobic Test (WAnT). Heart rate and blood lactate (BL) were measured before and immediately after the WAnT; and ratings of perceived exertion (RPE) were recorded immediately after the WAnT. Peak power (PP) was significantly higher following co-ingestion of CAF+TAU compared to PLA (p = 0.03) and TAU (p = 0.03). Mean power (MP) was significantly higher following co-ingestion of CAF+TAU compared to PLA (p = 0.01). No other differences were found between conditions for PP and MP (p > 0.05). There were also no observed differences in fatigue index (FI), BL; heart rate; and RPE between conditions (p > 0.05). In conclusion, compared to PLA the combined ingestion of 6 mg/kg of CAF and 1 g of TAU improved both PP and MP in female athletes habituated to caffeine; however; CAF and TAU independently failed to augment WAnT performance.

Effects of Beetroot Juice Supplementation on Cognitive Function, Aerobic and Anaerobic Performances of Trained Male Taekwondo Athletes: A Pilot Study.

Studies have shown that nitrate (NO3-)-rich beetroot juice (BJ) supplementation improves endurance and high-intensity intermittent exercise. The dose-response effects on taekwondo following BJ supplementation are yet to be determined. This study aimed to investigate two acute doses of 400 mg of NO3- (BJ-400) and 800 mg of NO3- (BJ-800) on taekwondo-specific performance and cognitive function tests compared with a placebo (PL) and control (CON) conditions. Eight trained male taekwondo athletes (age: 20 ± 4 years, height: 180 ± 2 cm, body mass: 64.8 ± 4.0 kg) completed four experimental trials using a randomized, double-blind placebo-controlled design: BJ-400, BJ-800, PL, and CON. Participants consumed two doses of BJ-400 and BJ-800 or nitrate-depleted PL at 2.5 h prior to performing the Multiple Frequency Speed of Kick Test (FSKT). Countermovement jump (CMJ) was performed before the (FSKT) and PSTT, whereas cognitive function was assessed (via the Stroop test) before and after supplementation and 10 min following PSTT. Blood lactate was collected before the CMJ tests immediately and 3 min after the FSKT and PSST; rating of perceived exertion (RPE) was recorded during and after both specific taekwondo tests. No significant differences (p > 0.05), with moderate and large effect sizes, between conditions were observed for PSTT and FSKT performances. In addition, blood lactate, RPE, heart rate, and CMJ height were not significantly different among conditions (p > 0.05). However, after the PSTT test, cognitive function was higher in BJ-400 compared to other treatments (p < 0.05). It was concluded that acute intake of 400 and 800 mg of NO3- rich BJ reported a moderate to large effect size in anaerobic and aerobic; however, no statistical differences were found in taekwondo-specific performance.

Effects of two different doses of carbohydrate ingestion on taekwondo-related performance during a simulated tournament.

BACKGROUND: Carbohydrate (CHO) ingestion enhances exercise performance; however, the efficacy of CHO intake on repeated bouts of exercise simulating a taekwondo tournament is unknown. Therefore, the purpose was to compare the effects of two different doses of CHO on a sports-specific kicking test during a simulated taekwondo tournament compared to placebo (PLA). METHODS: In a double-blind, randomized-placebo controlled, cross-over trial, eleven junior male professional taekwondo athletes (age: 16 ± 0.8 years, body mass: 55.3 ± 7.3 kg) ingested one of three solutions: (i) high dose (C45): 45 g of CHO (60 g∙h- 1), (ii) low dose (C22.5): 22.5 g of CHO (30 g∙h- 1; both solutions containing 2:1 glucose:fructose), or a PLA immediately following each kicking test. The kicking test was repeated 5 times, separated by 45 mins of rest, simulating a typical taekwondo competition day. Ratings of perceived exertion (RPE) and gastrointestinal discomfort (GI) scores were collected immediately after, and blood glucose before each test. RESULTS: The results revealed that C45 and C22.5 did not improve total, successful, or percentage of successful kicks compared to PLA (p > 0.05). Blood glucose was significantly higher following both CHO conditions compared with PLA across all five tests (p < 0.05). There were no differences between treatments or across tests for RPE (p > 0.05). CONCLUSION: CHO intake, independent of the dose, did not alter taekwondo kick performance during a simulated taekwondo tournament.

Short-term co-ingestion of creatine and sodium bicarbonate improves anaerobic performance in trained taekwondo athletes.

BACKGROUND: Creatine (CR) and sodium bicarbonate (SB) alone improve anaerobic performance. However, the ergogenic effects of CR and SB co-ingestion on taekwondo anaerobic performance remains unknown. METHODS: Forty trained taekwondo athletes (21 ± 1 y.; 180.5 ± 7.3 cm; 72.7 ± 8.6 kg) were randomized to: (i) CR and SB (CR + SB; 20 g of CR+ 0.5 g·kg- 1·d- 1 of SB), (ii) CR, (iii) SB, (iv) placebo (PLA), or (v) control (CON) for 5 days. Before and after supplementation, participants completed 3 bouts of a Taekwondo Anaerobic Intermittent Kick Test (TAIKT) to determine changes in peak power (PP), mean power (MP), and fatigue index (FI). Blood lactate (BL) was measured before, immediately following, and 3 min post-TAIKT. RESULTS: PP and MP increased over time (P < 0.05) following CR + SB, CR, and SB ingestion, with no changes in the PLA or CON groups. There was a greater increase over time in MP following CR + SB (Absolute Δ: 1.15 ± 0.28 W∙kg67) compared to CR (Absolute Δ: 0.43 ± 0.33 W∙kg67; P < 0.001) and SB (Absolute Δ: 0.73 ± 0.24 W∙kg67; P = 0.03). There were no significant time and condition effect for FI (P > 0.05). BL increased following exercise across all groups; however, CR + SB and SB post-exercise BL was lower compared to CR, PLA, and CON (P < 0.05). CONCLUSION: Short-term CR and SB alone enhance TAIKT performance in trained taekwondo athletes. Co-ingestion of CR and SB augments MP compared to CR and SB alone, with similar PP improvements.

Effects of Different Doses of Caffeinated Coffee on Muscular Endurance, Cognitive Performance, and Cardiac Autonomic Modulation in Caffeine Naive Female Athletes.

Caffeine is widely consumed among elite athletes for its well-known ergogenic properties, and its ability to increase exercise performance. However, studies to date have predominantly focused on the anhydrous form of caffeine in male participants. The aim of the study was to investigate the effect of caffeinated coffee ingestion on lower-upper body muscular endurance, cognitive performance, and heart rate variability (HRV) in female athletes. A total of 17 participants (mean ± standard deviation (SD): age = 23 ± 2 years, body mass = 64 ± 4 kg, height = 168 ± 3 cm) in a randomized cross-over design completed three testing sessions, following the ingestion of 3 mg/kg/bm of caffeine (3COF), 6 mg/kg/bm of caffeine (6COF) provided from coffee or decaffeinated coffee (PLA) in 600 mL of hot water. The testing results included: (1) repetition number for muscular endurance performance; (2): reaction time and response accuracy for cognitive performance; (3): HRV parameters, such as standard deviation of normal-to-normal (NN) intervals (SDNN), standard deviation of successive differences (SDSD), root mean square of successive differences (RMSSD), total power (TP), the ratio of low- and high-frequency powers (LF/HF), high-frequency power (HF), normalized HF (HFnu), low-frequency power (LF), and normalized LF (LFnu). A one-way repeated measures ANOVA revealed that 3COF (p = 0.024) and 6COF (p = 0.036) improved lower body muscular endurance in the first set as well as cognitive performance (p = 0.025, p = 0.035 in the post-test, respectively) compared to PLA. However, no differences were detected between trials for upper body muscular endurance (p = 0.07). Lastly, all HRV parameters did not change between trials (p > 0.05). In conclusion, ingesting caffeinated coffee improved lower body muscular endurance and cognitive performance, while not adversely affecting cardiac autonomic function.

Caffeine and sodium bicarbonate supplementation alone or together improve karate performance.

BACKGROUND: The ergogenic properties of acute caffeine (CAF) and sodium bicarbonate (NaHCO3) ingestion on athletic performance have been previously investigated. However, each sport has unique physiological and technical characteristics which warrants optimizing supplementations strategies for maximizing performance. This study examined the effects of CAF and NaHCO3 ingestion on physiological responses and rate of perceived exertion during a Karate-specific aerobic test (KSAT) in competitive karatekas. METHODS: In a double-blind, crossover, randomized placebo-controlled trial, eight Karatekas underwent five experimental conditions including control (CON), placebo (PLA), CAF, NaHCO3, and CAF + NaHCO3 before completing KSAT. Capsules containing 6 mg/kg BW CAF were consumed 50 min prior to a KSAT whilst 0.3 g/kg BW NaHCO3 was consumed for 3 days leading to and 120, 90, and 60 min prior to a KSAT. Time to exhaustion (TTE), rate of perceived exertion (RPE), and blood lactate (BL) were measured before, immediately after and 3 min following KSAT. RESULTS: TTE was significantly greater following CAF, NaHCO3, and CAF + NaHCO3 consumption compared to PLA and CON. However, the differences between CAF, NaHCO3, and CAF + NaHCO3 were not statistically significant (p > 0.05). BL increased significantly from baseline to immediately after and 3 min following KSAT in all conditions (p < 0.01), while RPE at the end of KSAT was not significantly different between conditions (p = 0.11). CONCLUSIONS: Karate practitioners may benefit from the ergogenic effects of CAF and NaHCO3 when consumed separately or together.

Muscle Carnosine Concentration with the Co-Ingestion of Carbohydrate with ß-alanine in Male Rats.

Muscle carnosine is an intracellular buffer. The intake of ß-alanine, combined with carbohydrate and protein, enhanced carnosine loading in human muscle. The aim of the present study was to examine if muscle carnosine loading was enhanced by ß-alanine intake and co-ingestion of glucose in male rats. Thirty-six male rats were divided into three groups and supplemented for four weeks: ß-alanine (ßA group, 1.8% ß-alanine in drinking water), ß-alanine and glucose (ßAGL group, 1.8% ß-alanine and 5% glucose in drinking water), and control (C group, drinking water). During the supplementation period, rats were exercised (20 m·min-1, 10 min·day-1, 4 days·week-1 for 4 weeks). Muscle carnosine concentration was quantified in soleus (n = 12) and rectus femoris (n = 6) muscles using high-performance liquid chromatography. In soleus muscle, carnosine concentration was 2.24 ± 1.10, 6.12 ± 1.08, and 6.93 ± 2.56 mmol/kg dw for control, ßA, and ßAGL, respectively. In rectus femoris, carnosine concentration was 2.26 ± 1.31, 7.90 ± 1.66, and 8.59 ± 2.33 mmol/kg dw for control, ßA, and ßAGL respectively. In each muscle, ßA and ßAGL resulted in similar carnosine increases compared to the control. In conclusion, ß-alanine intake for four weeks, either alone or with glucose co-ingestion, equally increased muscle carnosine content. It appears that the potential insulin response to fluid glucose intake does not affect muscle carnosine loading in male rats.

Co-ingestion of Nutritional Ergogenic Aids and High-Intensity Exercise Performance.

Many sports involve repeated bouts of high-intensity exercise. High-intensity exercise is compromised, however, by the early onset of exercise-induced fatigue. Metabolic by-products, ion dysbalance and amount of phosphocreatine are considered the main peripheral causes of fatigue during high-intensity exercise. Intake of nutritional ergogenic aids is commonplace to enhance performance of high-intensity exercise by offsetting the potential mechanisms of fatigue. Creatine, probably one of the best known nutritional aids to enhance performance of high-intensity exercise, has convincingly substantiated its ergogenic potential. Although multi-ingredient supplements are now common, the justification for effectiveness is mostly based on observations with single intake of those ingredients. In this narrative review, the main focus is on the evidence of the effect of co-ingestion of ergogenic aids on performance of high intensity exercise for which the single intake has shown beneficial effects on high-intensity performance.

Effect of Four Weeks of ß-alanine Supplementation on Muscle Carnosine and Blood Serum Lactate during Exercise in Male Rats.

ß-alanine (BA) supplementation may increase muscle buffering capacity and affect physiological responses during exercise. We examined the effects of 4 weeks of BA supplementation on muscle carnosine and serum lactate in male rats. Rats (n = 24, age: 2 months, body weight: 265±22 g) were divided into a BA supplementation or control group. Along with aerobic acclimatization exercise (15 m·min(-1), 8-10 min·day(-1), 4 days·week(-1) for 4 weeks), the BA group had access to BA powder in their drinking water (1.8%) with the control group having access to plain water for 4 weeks. After 4 weeks, rats ran on a treadmill at speeds of 15, 20, 25, 30, and 35 m·min(-1), respectively, each for 4 min, in order to measure post-exercise serum lactate. Muscle carnosine and serum lactate levels were measured with high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbant assay (ELISA) procedures, respectively. Following BA supplementation, carnosine content in the m.rectus femoris increased by 117% (p < .01) and serum lactate decreased by 7.4% (p < .01). It was concluded that ß-alanine supplementation increases muscle carnosine content and reduces serum lactate; these changes may indicate an adaptation of rat skeletal muscles to postpone peripheral muscle fatigue during high-intensity exercise.