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Summary Objectives This review aims to analyze the available data, mainly the most recent, regarding L-carnitine supplementation and exercise performance, in order to understand if L-carnitine can still be considered an ergogenic supplement. Moreover, it also aims to briefly analyze other potential uses, more specifically the effects on weight loss, recovery after exercise and aging. News A literature search, using the online scientific databases PubMed and Scopus, was conducted to identify studies related to L-carnitine supplementation and athletic performance. The discovery that skeletal muscle carnitine content can be increased through oral supplementation in humans represented a significant progress in this area. More recently, due to this discovery, new research has been done to investigate whether L-carnitine supplementation could have an impact on fuel metabolism. However, the inconsistency of results led to a change in the focus of research, shifting towards the investigation of the impact L-carnitine could have on the process of recovery after exercise and on aging. Prospects and projects In future research, this new area needs to be more explored. Nevertheless, the study of the L-carnitine supplementation impact on fuel selection during exercise should continue and it is crucial to use athletes. Conclusion Despite some performance benefits have been demonstrated, more research needs to be done. Presently, the available data is still not enough to widely recommend the use of L-carnitine supplements with the aim of improving exercise performance. [ABSTRACT FROM AUTHOR]

Summary Objectives This review article aimed to summarize the current state of understanding on creatine supplementation for soccer players. In other words, it investigated the beneficial (and potentially negative) effects of this supplementation on sport-specific skills and performance in soccer players. Furthermore, this article accordingly discussed the safest and most recommended protocols for the consumption of creatine by these athletes. News Studies have shown that creatine supplementation can have positive effects on sprint and vertical jump performances in soccer players. This supplementation may also enhance soccer players’ muscle strength and adaptation to a high-intensity training regimen. Besides, creatine may be able to enhance muscle glycogen (as well as phosphocreatine) storage, reduce oxidative stress, and improve muscular repair and hypertrophy. Interestingly, creatine supplementation does not seem to affect aerobic performance. Prospects and projects Soccer players could take creatine during pre-season training (3 to 5 g/day) in order to help them endure a high-intensity training regimen and enhance their muscular strength and adaptation resulting from strength and/or resistance training. A lower dosage (less than 3 g/day) might also be sufficient and beneficial during the season in case of fatigue, in order to sustain adequate levels of phosphocreatine and glycogen in the muscles. Occasional intakes (about 3 g) before games and/or extenuating practices could also give a physical and mental boost to the players. Conclusion Most of the studies measured the effects of creatine on skills or physical performances in isolation from the true athletic demands of soccer match play. In conclusion, there is still a need for more research in order to determine whether creatine supplementation is ergogenic regarding the (aerobic) capacity to repeat (very) high-intensity actions, more particularly during competitive soccer. [ABSTRACT FROM AUTHOR]

Summary Objectives The purpose of this study was to investigate the spontaneous use of protein and carbohydrate supplements (PCS) in amateurs practicing resistance training in gyms, and determine whether the intake of this type of supplement in practice can have beneficial effects on energy balance and body composition. Equipment and methods Sixty-seven men followed the same resistance training for 8 weeks. They were assigned to two groups: (i) 27 consuming protein and carbohydrate supplements (GC), and (ii) 40 not consuming dietary supplements (GNC). All the participants attended four experimental sessions, underwent anthropometric measurements and bioelectrical impedance analysis, and kept dietary and physical activity diaries. The GC group also recorded their spontaneous intakes of protein and carbohydrate supplements. Results Both groups significantly gained body mass ( P < 0.001), GC more than GNC ( P < 0.001 at week 8). These gains were explained by increased fat mass in GC, while the GNC lost fat mass. No significant differences in lean body mass were found between the two groups. PCS energy seems to raise the energy balance in the GC group relative to the GNC group ( P < 0.001). Moreover, the change in fat body mass in GC was positively correlated with energy balance ( P < 0.01), and energy balance was positively correlated with PCS energy intake ( P < 0.01). Spontaneous intake of protein and carbohydrate supplements by this population was thus strongly associated with an increase in body fat mass over the course of the training period, without any beneficial change in the gain of lean body mass. This might be because protein requirements were already largely covered by diet without supplementation. Conclusion The spontaneous use of protein and carbohydrate supplements (PCS) by recreational users practicing resistance training at gyms induced no positive effects on body composition. We advocate more nutritional education to enhance nutritional status and learn how to use protein and carbohydrate supplements in the light of dietary needs and food intake. [ABSTRACT FROM AUTHOR]