## 5 The Roles of Creatine, Caffeine, Phosphate, Beta-Alanine and Carnitine
### Caffeine  
Caffeine, a stimulant that is found in almost every adult's diet, has long been known to improve athletic performance. Adenosine receptor antagonism, higher endorphin release, better neuromuscular functionality, enhanced attentiveness and a decreased impression of effort during exercise are among the processes behind these improvements [150]. Caffeine supplementation has a long research history in a variety of performance procedures, such as endurance-based circumstances, strength exercises and/or repeat-sprint activities. Current research on the efficiency of reduced caffeine doses, fluctuations in the timing of consumption before and/or during exercise, and the dearth of a requirement for the expelled time for productivity impact enhancement are all worth noting [150]. Caffeine supplementation has been shown to boost physical performance during period exercise trials, including treadmill running to exhaustion [151] and resistance training repetitions to defeat [152]. Additionally, ergogenic effects are frequently observed in competitive contexts, including actual or laboratory-simulated time trials (TTs). [PERSON] et al. [153] reported that caffeine consumption supplied a mean substantial advantage of \(\sim\)3.2 percent when given before and/or during endurance-based TT workouts of varying duration (5-150 min) across a multitude of exercise modalities in a systematic review of 33 trials. Caffeine dosages of \(\sim\)3-6 mg/kg of body mass (BM) in the form of anhydrous caffeine were frequently employed in studies claiming its benefits and were taken 60 minutes prior to exercise. Intriguingly, both habitual caffeine users and nonusers should certainly expect performance outcomes [154], with a recent study finding that high repetitive daily caffeine consumption (351 \(\pm\) 139 mg/day) is closely linked to equivalent absolute and relative outcome advantages with low or adequate routine caffeine consumption [155]. Caffeine consumption at low levels during endurance training has also been demonstrated to improve productivity. In fact, following 80 minutes of preload cycling, 100-200 mg (-1.5-2.9 mg/kg BM) of caffeine combined with a carbohydrate-electrolyte solution resulted in a 4-7% enhancement during a following TT performed in 26-28 minutes [156]. Moreover, 200-300 mg of caffeine given as a sugar substance at the 10-kilometer mark of a 30 km cycling TT was demonstrated to boost average power output (+3.8%) for the final 10 km of the task, as well as provide a 4% improvement in peak sprint power production at the conclusion [157]. A double-blind study performed on ten elite judokas demonstrated improvement in training parameters such as number of throws and a lower fatigue index, combined with a better biochemical profile, after caffeine supplementation [158]. Another study performed on 18 judokas showed that caffeine at a dose of 4 mg/kg resulted in better performance and a lower rating of perceived exertion [159]. A meta-analysis of nine studies including 109 combat athletes found increased performance and glycolytic activity after caffeine supplementation [160].  
In the WADA monitoring program, caffeine remains one of the most utilized stimulants in sports. The results of several studies also demonstrate its efficacy in sustaining better performance in combat sports, especially in aerobic conditions.