Rhodiola rosea supplementation on sports performance: A systematic review of randomized controlled trials.

The aim of this systematic review was to determine whether the supplementation with Rhodiola rosea (RR), an herb that has been used for centuries for its various properties, can have an effect on muscle damage and physical performance. The databases PubMed, Web of Science, and Cochrane Library were used to find studies published until March 2023. Randomized controlled trials, healthy participants, and no use of other supplements. The search strategy was conducted by two independent reviewers, and specific information was extracted from the selected studies. Thirteen studies were included with 263 participants (198 men and 65 women between 18 and 65 years old). Two studies followed acute supplementation, 5 chronic, and 6 combined both. The results were heterogenous, having 11 studies with some positive effects, while 2 studies show no effect in variables such as rating of perceive exertion, heart rate, antioxidant capacity, blood lactate, creatine kinase, or C-reactive protein. Two limitations were found, firstly, the difference between supplementation and exercise protocols, and secondly, the existence of unclear or high risk of bias in most of the studies included. Acute supplementation with RR has a positive effect on endurance performance and rating of perceived exertion (RPE). Chronic supplementation has a positive effect on anaerobic exercise performance, but not endurance exercise performance. Chronic supplementation may positively impact muscle damage during exercise. However, more high-quality studies are needed to firmly establish the clinical efficacy of RR.

Antioxidant vitamin supplementation on muscle adaptations to resistance training: A double-blind, randomized controlled trial.

OBJECTIVES: The aim of this study was to examine whether antioxidant vitamin supplementation with vitamin C (VitC) and vitamin E (VitE) affects the hypertrophic and functional adaptations to resistance training in trained men. METHODS: This was a double-blind, randomized controlled trial in which participants were supplemented daily with VitC and VitE ( n = 12) or placebo ( n = 11) while completing a 10-wk resistance training program accompanied by a dietary intervention (300 kcal surplus and adequate protein intake) designed to optimize hypertrophy. Body composition (dual-energy x-ray absorptiometry), handgrip strength, and one-repetition maximum (1-RM), maximal force (F0), velocity (V0), and power (Pmax) were measured in bench press (BP) and squat (SQ) tests conducted before and after the intervention. To detect between-group differences, multiple-mixed analysis of variance, standardized differences, and qualitative differences were estimated. Relative changes within each group were assessed using a paired Student's t test. RESULTS: In both groups, similar improvements were produced in BP 1-RM , SQ 1-RM SQ, and BP F0 (P < 0.05) after the resistance training program. A small effect size was observed for BP 1-RM (d = 0.53), BP F0 (d = 0.48), and SQ 1-RM (d = -0.39), but not for SQ F0 (d = 0.03). Dominant handgrip strength was significantly increased only in the placebo group (P < 0.05). According to body composition data, a significant increase was produced in upper body fat-free mass soft tissue (FFMST; P < 0.05) in the placebo group, whereas neither total nor segmental FFMST was increased in the vitamin group. Small intervention effect sizes were observed for upper body FFSMT (d = 0.32), non-dominant and dominant leg FFMST (d = -0.39; d = -0.42). Although a significant increase in total body fat was observed in both groups (P < 0.05) only the placebo group showed an increase in visceral adipose tissue (P < 0.05), showing a substantial intervention effect (d = 0.85). CONCLUSIONS: The data indicated that, although VitC/VitE supplementation seemed to blunt upper body strength and hypertrophy adaptations to resistance training, it could also mitigate gains in visceral adipose tissue elicited by an energy surplus.

Effect of ß-alanine and sodium bicarbonate co-supplementation on the body's buffering capacity and sports performance: A systematic review.

Muscle acidification is one of the main factors causing fatigue during exercise, thus compromising performance. The sport supplements beta alanine (ß-A) and sodium bicarbonate (SB) are thought to enhance the effects of the body's buffer systems by reducing H+ concentrations. The aim of this systematic review was to analyze the effects of ß-A and SB co-supplementation on the organism's buffering capacity and sport performance. The databases PubMed, Web of Science, Medline, CINAHL and SPORTDiscus were searched until November 2021 following PRISMA guidelines. Randomized controlled trials, at least single-blind, performed in athletes of any age were considered. Nine studies including a total of 221 athletes were identified for review. Athletes were supplemented with ß-A and SB while they performed exercise tests to assess physical performance and buffer capacity. Five of the nine studies indicated there was some additional improvement in buffering capacity and performance with co-supplementation, while one study concluded that the effect was comparable to the added effects of the individual supplements. According to the results of the studies reviewed, we would recommend ß-A and SB co-supplementation during high intensity exercises lasting between 30 s and 10 min.

Muscle hypertrophy induced by N-3 PUFA supplementation in absence of exercise: a systematic review of randomized controlled trials.

The use of omega-3 polyunsaturated fatty acids (n-3 PUFA) has been studied in physically active population, however, there is a lack of information about the effects of n-3 PUFA supplementation on people with a sedentary behavior or who are undergoing a period of limb immobilization. This systematic review aims to examine the effect of n-3 PUFA on lean mass and muscle protein synthesis (MPS) in absence of physical training. The PubMed, Web of Science, MEDLINE, CINAHL and SPORTDiscus databases were searched following the PRISMA guidelines. Only randomized controlled trials, at least single blind, performed with sedentary humans were considered. Seven studies on a total of 192 individuals were included. Five of the six studies which measured changes in skeletal muscle volume and mass showed higher values with n-3 PUFA. Only two studies measured skeletal muscle protein expression. Both showed beneficial effects of supplementation in muscle protein fractional synthesis rate (FSR), while no effect of n-3 PUFA was observed for mechanistic target of rapamycin (mTOR) and kinase protein (Akt). In addition, ribosomal protein S6 kinase 1 (p70s6k) improved with n-3 PUFA only in one study. Finally, the two studies which measured the skeletal muscle gene expression observed no effect of supplementation.

Effects of Nitrate Supplementation on Muscle Strength and Mass: A Systematic Review.

ABSTRACT: Anderson, OK, Martinez-Ferran, M, Lorenzo-Calvo, J, Jiménez, SL, and Pareja-Galeano, H. Effects of nitrate supplementation on muscle strength and mass: a systematic review. J Strength Cond Res 36(12): 3562-3570, 2022-This systematic review examines the effect of dietary nitrate supplementation (SUP) on muscle strength and hypertrophy when combined with physical exercise. The databases PubMed, Web of Science, and MEDLINE were searched for full-text articles published between January 2000 and June 2020. For inclusion, studies had to report on the effects of SUP administered as acute or chronic doses together with a standardized exercise protocol on muscle strength and hypertrophy compared with placebo in healthy adults who were sedentary, physically active, or professional athletes. Twelve studies (1,571 subjects) were finally selected. In 5 studies, the SUP regime was acute, and in 7, it was chronic. SUP was nitrate-rich beetroot juice in 9 studies, a potassium nitrate capsule in 1, and increased dietary nitrate in 2. Ingested nitrate was 64-1,200 mg. Of the 12 studies, 6 observed an ergogenic effect of SUP compared with placebo. These findings indicate that muscle strength gains are possible provided the dose, format, frequency, period, and exercise test are appropriate. Best results were observed with a minimum acute dose of 400 mg of nitrate provided as beetroot juice/shot taken 2-2.5 hours before exercise involving low- and high-intensity muscle contractions. This SUP regime seems to improve muscle efficiency in terms of reduced phosphocreatine and energy costs (P-magnetic resonance spectroscopy) and improved time to exhaustion.

Effects of Acute Vitamin C plus Vitamin E Supplementation on Exercise-Induced Muscle Damage in Runners: A Double-Blind Randomized Controlled Trial.

Considering the existing controversy over the possible role of acute antioxidant vitamins in reducing exercise-induced muscle damage (EIMD), this doubled-blind, randomized and controlled trial aimed to determine whether supplementation with vitamins C and E could mitigate the EIMD in endurance-trained runners (n = 18). The exercise protocol involved a warm-up followed by 6 to 8 bouts of 1 km running at 75% maximum heart rate (HRmax). Two hours before the exercise protocol, participants took the supplementation with vitamins or placebo, and immediately afterwards, blood lactate, rate of perceived exertion and performance were assessed. At 24 h post-exercise, CK, delayed onset muscle soreness and performance were determined (countermovement jump, squat jump and stiffness test). The elastic index and vertical stiffness were calculated using a stiffness test. Immediately after the exercise protocol, all participants showed improved maximum countermovement jump, which only persisted after 24 h in the vitamin group (p < 0.05). In both groups, squat jump height was significantly greater (p < 0.05) immediately after exercise and returned to baseline values after 24 h. The elastic index increased in the vitamin group (p < 0.05), but not in the placebo group. In both groups, lactate levels increased from pre- to immediately post-exercise (p < 0.05), and CK increased from pre- to 24 h post-exercise (p < 0.05). No significant differences between groups were observed in any of the variables (p > 0.05). Vitamin C and E supplementation does not seem to help with EIMD in endurance-trained individuals.

Interaction Between Caffeine and Creatine When Used as Concurrent Ergogenic Supplements: A Systematic Review.

There is some controversy regarding the interactions between creatine (CRE) and caffeine (CAF) supplements. The aim of this systematic review was to study whether such ergogenic interaction occurs and to analyze the protocol to optimize their synchronous use. The PubMed, Web of Science, MEDLINE, CINAHL, and SPORTDiscus databases were searched until November 2021 following the PRISMA guidelines. Ten studies were included. Three studies observed that CRE loading before an acute dose of CAF before exercise did not interfere in the beneficial effect of CAF, whereas one study reported that only an acute supplementation (SUP) of CAF was beneficial but not the acute SUP of both. When chronic SUP with CRE + CAF was used, two studies reported that CAF interfered in the beneficial effect of CRE, whereas three studies did not report interaction between concurrent SUP, and one study reported synergy. Possible mechanisms of interaction are opposite effects on relaxation time and gastrointestinal distress derived from concurrent SUP. CRE loading does not seem to interfere in the acute effect of CAF. However, chronic SUP of CAF during CRE loading could interfere in the beneficial effect of CRE.

N-3 PUFA as an ergogenic supplement modulating muscle hypertrophy and strength: a systematic review.

There is growing evidence that suggests that n-3 polyunsaturated fatty acids (PUFA) may improve physical performance when combined with proper training through modulation of muscle hypertrophy, muscle strength, and delayed onset muscle soreness (DOMS). This systematic review aims to examine the effect and optimal dosage of n-3 PUFA supplementation on muscle hypertrophy, muscle strength, and DOMS when combined with physical exercise. The PubMed, Web of Science, MEDLINE Complete, CINAHL and SPORTDiscus databases were searched following the PRISMA guidelines. Randomized controlled trials performed with healthy humans were considered. Fifteen studies with a total of 461 individuals were included in this systematic review. All of them measured muscle function (short physical performance test, range of motion (ROM), electromechanical delay (EMD), muscle echo intensity or muscle quality) and DOMS. Fourteen studies evaluated muscle strength and only six assessed muscle hypertrophy. Our results demonstrated that n-3 PUFA does not improve muscle hypertrophy, muscle strength or skeletal muscle biomarkers of inflammation and muscle damage beyond the benefits obtained by the training itself. Nevertheless, n-3 PUFA improves DOMS recovery and muscle function (measured by ROM, EMD and muscle quality).

Supplementation with Vitamins C and E and Exercise-Induced Delayed-Onset Muscle Soreness: A Systematic Review.

Muscle damage induced by exercise may have several consequences such as delayed-onset muscle soreness, a side-effect of the release of free radicals during oxidative stress. To mitigate the oxidative stress cascade, the oral intake of antioxidants has been assessed by several research groups. This review examines whether supplementation with vitamin C and/or vitamin E is able to prevent or attenuate delayed-onset muscle soreness after eccentric exercise. The PubMed, Web of Science, Medline, and Embase databases were searched to identify studies meeting the inclusion criteria: primary randomized control trials, healthy male and female participants aged 16-80 years, and an intervention consisting of the intake of vitamin C and/or vitamin E without other supplements plus a controlled eccentric exercise regimen. Further requirements were the measurement of muscle soreness or markers of delayed-onset muscle soreness. All original full-text articles in English or translated into English published from January 2000 to June 2020 were considered for this review. Fourteen studies were finally identified, including 280 participants, 230 men, and 50 women aged 16-30 years. All participants were healthy individuals with different starting levels of physical activity. Supplementation was acute in two studies and chronic in 12, and its consisted of vitamin C in eight studies, vitamin E in two studies, and both in four studies. Only in 3 of the 14 studies was muscle soreness found to be significantly reduced in response to vitamin C and/or vitamin E supplementation at all time points when compared to the placebo group. Despite some studies showing the beneficial effects of chronic supplementation with these vitamins on muscle soreness manifesting 24-72 h after eccentric exercise, the evidence is so far insufficient to confirm that the intake of antioxidant vitamins is able to minimize delayed-onset muscle soreness in this context.

Vitamin D and cardiovascular health.

The principal source of vitamin D in humans is its biosynthesis in the skin through a chemical reaction dependent on sun exposure. In lesser amounts, the vitamin can be obtained from the diet, mostly from fatty fish, fish liver oil and mushrooms. Individuals with vitamin D deficiency, defined as a serum level of 25 hydroxyvitamin D < 20 ng/dl, should be supplemented. Vitamin D deficiency is a prevalent global problem caused mainly by low exposure to sunlight. The main role of 1,25 dihydroxyvitamin D is the maintenance of calcium and phosphorus homeostasis. However, vitamin D receptors are found in most human cells and tissues, indicating many extra-skeletal effects of the vitamin, particularly in the immune and cardiovascular (CV) systems. Vitamin D regulates blood pressure by acting on endothelial cells and smooth muscle cells. Its deficiency has been associated with various CV risk factors and appears to be linked to a higher mortality and incidence of CV disease (CVD). Several mechanisms have been proposed relating vitamin D deficiency to CV risk factors such as renin-angiotensin-aldosterone system activation, abnormal nitric oxide regulation, oxidative stress or altered inflammatory pathways. However, in the latest randomized controlled trials no benefits of vitamin D supplementation for CVD have been confirmed. Although more work is needed to establish the protective role of vitamin D in this setting, according to current evidences vitamin D supplements should not be recommended for CVD prevention.

Role of Oral and Gut Microbiota in Dietary Nitrate Metabolism and Its Impact on Sports Performance.

Nitrate supplementation is an effective, evidence-based dietary strategy for enhancing sports performance. The effects of dietary nitrate seem to be mediated by the ability of oral bacteria to reduce nitrate to nitrite, thus increasing the levels of nitrite in circulation that may be further reduced to nitric oxide in the body. The gut microbiota has been recently implicated in sports performance by improving muscle function through the supply of certain metabolites. In this line, skeletal muscle can also serve as a reservoir of nitrate. Here we review the bacteria of the oral cavity involved in the reduction of nitrate to nitrite and the possible changes induced by nitrite and their effect on gastrointestinal balance and gut microbiota homeostasis. The potential role of gut bacteria in the reduction of nitrate to nitrite and as a supplier of the signaling molecule nitric oxide to the blood circulation and muscles has not been explored in any great detail.

Influence of Nitrate Supplementation on Endurance Cyclic Sports Performance: A Systematic Review.

Endurance can be defined as the capacity to maintain one's velocity or power output for the longest possible time. Maintaining such activity can lead to the onset of fatigue. Dietary nitrate supplementation produces an ergogenic effect due to the improvement of mitochondrial oxygen efficiency through a reduction in the oxygen cost of exercise that increases vasodilation and blood flow to the skeletal muscle in recreationally active subjects. However, the effects of dietary nitrate supplementation on well-trained endurance athletes remain unclear; such supplementation could affect more performance areas. In the present study, a systematic review of the literature was conducted to clarify the use and effects of nitrate as a dietary supplement in endurance athletes trained in cyclic sports (repetitive movement sports). A systematic search was carried out following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in the databases of SCOPUS, Web of Science (WOS), Medline (PubMed), and Sport Discus from 1 January 2010 to 30 November 2019. Twenty-seven studies were included in the study. The methodological quality of the articles was assessed using the McMaster Critical Review Form. Statistically significant ergogenic results were obtained in 8 (29.63%) of the 27 studies investigated, with significant results obtained for cardiorespiratory parameters and performance measures. Improvement in exercise tolerance was obtained, which could help with exhaustion over time, while the improvement in exercise economics was not as clear. Additionally, the dose necessary for this ergogenic effect seems to have a direct relationship with the physical condition of the athlete. The acute dose is around 6-12.4 mmol/day of nitrate administered 2-3 h before the activity, with the same amount given as a chronic dose over 6-15 days. Further studies are required to understand the factors that affect the potential ergogenic impacts of nitrate on athletic performance among endurance athletes.

Inspiratory Muscle Training in Intermittent Sports Modalities: A Systematic Review.

The fatigue of the respiratory muscles causes the so-called metabolic reflex or metaboreflex, resulting in vasoconstriction of the blood vessels in the peripheral muscles, which leads to a decrease in respiratory performance. Training the respiratory muscles is a possible solution to avoid this type of impairment in intermittent sports. The objective of this systematic review was to evaluate the results obtained with inspiratory muscle training (IMT) in intermittent sports modalities, intending to determine whether its implementation would be adequate and useful in intermittent sports. A search in the Web of Science (WOS) and Scopus databases was conducted, following the Preferred Reporting Elements for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The methodological quality of the articles was assessed using the PEDro (Physiotherapy Evidence Database) scale. In conclusion, the introduction of specific devices of IMT seems to be a suitable method to improve performance in intermittent sports, mainly due to a reduction of the metaboreflex, fatigue sensation, and dyspnea. The ideal protocol would consist of a combination of acute and chronic treatment, and, even if IMT is done daily, the duration will not exceed one hour per week.

Do Antioxidant Vitamins Prevent Exercise-Induced Muscle Damage? A Systematic Review.

Free radicals produced during exercise play a role in modulating cell signaling pathways. High doses of antioxidants may hamper adaptations to exercise training. However, their benefits are unclear. This review aims to examine whether vitamin C (VitC) and/or vitamin E (VitE) supplementation (SUP) prevents exercise-induced muscle damage. The PubMed, Web of Science, Medline, CINAHL, and SPORTDiscus databases were searched, and 21 articles were included. Four studies examined the effects of acute VitC SUP given pre-exercise: in one study, lower CK levels post-exercise was observed; in three, no difference was recorded. In one study, acute VitE SUP reduced CK activity 1 h post-exercise in conditions of hypoxia. In three studies, chronic VitE SUP did not reduce CK activity after an exercise session. Chronic VitE SUP did not reduce creatine kinase (CK) concentrations after three strength training sessions, but it was effective after 6 days of endurance training in another study. Chronic SUP with VitC + E reduced CK activity post-exercise in two studies, but there was no such effect in four studies. Finally, three studies described the effects of chronic VitC + E SUP and long-term exercise, reporting dissimilar results. To conclude, although there is some evidence of a protective effect of VitC and/or VitE against exercise-induced muscle damage, the available data are not conclusive.

Neuromuscular Electrical Stimulation: A New Therapeutic Option for Chronic Diseases Based on Contraction-Induced Myokine Secretion.

Myokines are peptides known to modulate brain neuroplasticity, adipocyte metabolism, bone mineralization, endothelium repair and cell growth arrest in colon and breast cancer, among other processes. Repeated skeletal muscle contraction induces the production and secretion of myokines, which have a wide range of functions in different tissues and organs. This new role of skeletal muscle as a secretory organ means skeletal muscle contraction could be a key player in the prevention and/or management of chronic disease. However, some individuals are not capable of optimal physical exercise in terms of adequate duration, intensity or muscles involved, and therefore they may be virtually deprived of at least some of the physiological benefits induced by exercise. Neuromuscular electrical stimulation (NMES) is emerging as an effective physical exercise substitute for myokine induction. NMES is safe and efficient and has been shown to improve muscle strength, functional capacity, and quality of life. This alternative exercise modality elicits hypertrophy and neuromuscular adaptations of skeletal muscles. NMES stimulates circulating myokine secretion, promoting a cascade of endocrine, paracrine, and autocrine effects. We review the current evidence supporting NMES as an effective physical exercise substitute for inducing myokine production and its potential applications in health and disease.

Supplements with purported effects on muscle mass and strength.

PURPOSE: Several supplements are purported to promote muscle hypertrophy and strength gains in healthy subjects, or to prevent muscle wasting in atrophying situations (e.g., ageing or disuse periods). However, their effectiveness remains unclear. METHODS: This review summarizes the available evidence on the beneficial impacts of several popular supplements on muscle mass or strength. RESULTS: Among the supplements tested, nitrate and caffeine returned sufficient evidence supporting their acute beneficial effects on muscle strength, whereas the long-term consumption of creatine, protein and polyunsaturated fatty acids seems to consistently increase or preserve muscle mass and strength (evidence level A). On the other hand, mixed or unclear evidence was found for several popular supplements including branched-chain amino acids, adenosine triphosphate, citrulline, ß-Hydroxy-ß-methylbutyrate, minerals, most vitamins, phosphatidic acid or arginine (evidence level B), weak or scarce evidence was found for conjugated linoleic acid, glutamine, resveratrol, tribulus terrestris or ursolic acid (evidence level C), and no evidence was found for other supplements such as ornithine or α-ketoglutarate (evidence D). Of note, although most supplements appear to be safe when consumed at typical doses, some adverse events have been reported for some of them (e.g., caffeine, vitamins, α-ketoglutarate, tribulus terrestris, arginine) after large intakes, and there is insufficient evidence to determine the safety of many frequently used supplements (e.g., ornithine, conjugated linoleic acid, ursolic acid). CONCLUSION:  In summary, despite their popularity, there is little evidence supporting the use of most supplements, and some of them have been even proven ineffective or potentially associated with adverse effects.