REVIEW | doi:10.20944/preprints202101.0334.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: ergogenic aid; dietary supplement; youth; athletes
Online: 18 January 2021 (12:36:24 CET)
Creatine is a popular ergogenic aid among athletic populations with consistent evidence indicating that creatine supplementation also continues to be commonly used among adolescent populations. In addition, the evidence base supporting the therapeutic benefits of creatine supplementation for a plethora of clinical applications in both adults and children continues to grow. Among pediatric populations, a strong rationale exists for creatine to afford therapeutic benefits pertaining to multiple neuromuscular and metabolic disorders, with preliminary evidence for other subsets of clinical populations as well. Despite the strong evidence supporting the efficacy and safety of creatine supplementation among adult populations, less is known as to whether similar physiological benefits extend to children and adolescent populations, and in particular those adolescent populations who are regularly participating in high-intensity exercise training. While limited in scope, studies involving creatine supplementation and exercise performance in adolescent athletes generally report improvements in a number of ergogenic outcomes with limited evidence of ergolytic properties and consistent reports indicating no adverse events associated with supplementation. The purpose of this article is to summarize the rationale, prevalence of use, performance benefits, clinical applications, and safety of creatine use in children and adolescents.
ARTICLE | doi:10.20944/preprints201804.0168.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: nutritional supplements; tennis; ergogenic aids; amateurs
Online: 12 April 2018 (14:16:39 CEST)
Literature on the use of nutritional supplements (NS) in tennis players is scarce. The objective of the present study was to evaluate NS consumption in a group of men's tennis players who participated in the 2016 Andalusian team championship. A total of 70 questionnaires from 7 different clubs were registered. The questionnaire was previously designed and evaluated through piloting in which the validity of the content, its application, its structure and its presentation were observed. The results showed that 100% of the sample group was in favor of NS consumption within the law, 88.6% claimed to have consumed them at some time and 61.4% presently consume them. The NS most consumed by study participants were sports drinks (69.35%), energy bars (29%), a vitamin complex (19.35%), protein (serum) (17.74%) and creatine (14.51%). A high percentage of NS consumers thought that they had obtained positive results from NS consumption. The percentages and the findings regarding NS consumption in the present study were similar to the contributions made by other studies which evaluated supplementation in athletes, although with some subtle differences.
ARTICLE | doi:10.20944/preprints201807.0411.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: ergogenic aid; muscle glycogen; substrate oxidation; GLUT4
Online: 23 July 2018 (10:38:14 CEST)
We investigated whether post-exercise capsinoids (CSN) supplementation could enhance muscle glycogen resynthesis via GLUT4/Akt expressions in human skeletal muscle. Nine male college students (aged 21.4±0.2 years, BMI 21.9±1.3 kg/m2, VO2max 47.1±1.8 ml/kg/min) participated in this crossover designed study, and completed a 60-min cycling exercise at 70% VO2max. Immediately after exercise, participants consumed high-carbohydrate diet (2 g carb/kg bodyweight) with CSN (12 mg, single dosage) or placebo. Biopsied muscle samples (vastus lateralis) were obtained immediately (0h) and 3h after exercise. Blood and expired gas samples were collected before and after exercise. We found oral CSN supplementation immediately after exercise was unable to enhance glycogen resynthesis in exercised human skeletal muscle. Despite, CSN could alter the energy reliance on fat oxidation during post-exercise recovery, based on gaseous exchange measurement (NEFA and glycerol). We further identified no significant differences in postprandial glucose/insulin area under curve in both trials. Western blot data showed no significant response of p-Akt/Akt ratio with CSN during post-exercise recovery. Inconsistent with glycogen levels, muscle GLUT4 expression was significantly elevated at 3h in CSN trial. Our findings emphasize the necessity of further evidences to confirm the ergogenic properties of CSN in connection with glycogen recovery in exercised human skeletal muscle.
REVIEW | doi:10.20944/preprints202010.0227.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Intermittent occlusion; Blood flow occlusion; Sports; Ergogenic; Ischemic postconditioning
Online: 12 October 2020 (10:42:36 CEST)
It has been demonstrated that brief cycles of ischemia followed by reperfusion (IR) applied before exercise can improve performance and, IR intervention, applied immediately after exercise (post-exercise ischemic conditioning – PEIC) exerts a potential ergogenic effect to accelerate recovery. Thus, the purpose of this systematic review with meta-analysis was to identify the effects of PEIC on exercise performance, recovery and the responses of associated physiological parameters, such as creatine kinase, perceived recovery and muscle soreness, over 24 h after its application. From 3281 studies, six involving 106 subjects fulfilled the inclusion criteria. Compared to sham (cuff administration with low pressure) and control interventions (no cuff administration), PEIC led to faster performance recovery (p=0.004; ES=-0.49) and lower increase in creatine kinase (p<0.001; ES=-0.71) and muscle soreness (p<0.001; ES=-0.89) over 24 h. The effectiveness of this intervention is more pronounced in subjects with low/moderate fitness level and at least a total time of 10 min of ischemia (e.g. 2 cycles of 5 min) is necessary to promote positive effects.
ARTICLE | doi:10.20944/preprints202304.0631.v1
Subject: Social Sciences, Other Keywords: caffeine; New Zealand blackcurrant; anthocyanins; ergogenic; supplement; performance; endurance; sports
Online: 20 April 2023 (08:25:40 CEST)
The use of isolated supplements to enhance performance is widespread among athletes. The aim of this study was to increase knowledge about the combined effects of caffeine and New Zealand blackcurrant (NZBC) dietary supplements. In this study, two subjects each underwent four phases of four sessions in a double-blind and randomized alternating treatment single-case design. After a 3-week pre-test phase, the supplement combinations of placebo/placebo, caffeine/placebo (5 mg/kg), NZBC/placebo (600 mg), and caffeine/NZBC (5 mg/kg + 600 mg) were taken and weekly performance tests were conducted to examine their effects on relative power (W/kg) during a 20-minute time trial on a bicycle. Data were analyzed descriptively and using the Tau-U calculator from Single Case Research. The ergogenic effect of caffeine was confirmed in both subjects, with increases of 3.3% and 6.5%, while the positive effect of NZBC on performance was only seen in one subject (13.4%). The combination of caffeine and NZBC again increased performance in both subjects (2.2% and 19.2%), but the data only showed an additive effect of the supplements in one subject. Further studies are required to confirm or refute this evidence of the synergistic effects of these supplements.