Nutritional Interventions to Improve Sleep in Team-Sport Athletes: A Narrative Review.

Athletes often experience sleep disturbances and poor sleep as a consequence of extended travel, the timing of training and competition (i.e., early morning or evening), and muscle soreness. Nutrition plays a vital role in sports performance and recovery, and a variety of foods, beverages, and supplements purportedly have the capacity to improve sleep quality and quantity. Here, we review and discuss relevant studies regarding nutrition, foods, supplements, and beverages that may improve sleep quality and quantity. Our narrative review was supported by a semi-systematic approach to article searching, and specific inclusion and exclusion criteria, such that articles reviewed were relevant to athletes and sporting environments. Six databases-PubMed, Scopus, CINAHL, EMBASE, SPORTDiscus, and Google Scholar-were searched for initial studies of interest from inception to November 2020. Given the paucity of sleep nutrition research in the athlete population, we expanded our inclusion criteria to include studies that reported the outcomes of nutritional interventions to improve sleep in otherwise healthy adults. Carbohydrate ingestion to improve sleep parameters is inconclusive, although high glycemic index foods appear to have small benefits. Tart cherry juice can promote sleep quantity, herbal supplements can enhance sleep quality, while kiwifruit and protein interventions have been shown to improve both sleep quality and quantity. Nutritional interventions are an effective way to improve sleep quality and quantity, although further research is needed to determine the appropriate dose, source, and timing in relation to training, travel, and competition requirements.

Evaluation of the Efficacy of Supplementation with Planox® Lemon Verbena Extract in Improving Oxidative Stress and Muscle Damage: A Randomized Double-Blind Controlled Trial.

Excessive exercise load can cause muscle soreness and fatigue, as well as inflammation and oxidative stress. Lemon verbena (Aloysia triphylla; Lippia citriodora) is often used as a spice in tea or beverages. Its leaves are rich in polyphenols, which have antioxidant and anti-inflammatory bioactivities. In the present study, we investigated whether supplementation with Planox® lemon verbena extract (LVE) could improve muscle damage and biochemical indicators after exhaustive exercise challenge. All subjects (30 males and 30 females) underwent a double-blind trial and were randomly divided into a placebo group (0 mg/human/day) and an LVE supplement group (400 mg/human/day), with gender-equal distribution. All subjects started supplementation 10 days before exhaustive exercise and continued it until all tests were completed. Before the intervention, after the exhaustive exercise, and on the following 3 days, the participants underwent 12-minute Cooper running/walking; blood collection; assessments of pain, muscle stiffness, maximum jump heights, and isometric maximum muscle strength. The results showed that supplementation with LVE effectively increased GPx and reduced CK, IL-6, 8-OHdG and muscle pain after the exhaustive exercise, but it had significant effect on strength recovery. In summary, LVE is a safe and edible natural plant extract that can reduce muscle damage and soreness after exercise. This trial was registered at clinicaltrials.gov as NCT04742244.

The Effects of Spirulina Supplementation on Redox Status and Performance Following a Muscle Damaging Protocol.

Spirulina plantensis is a popular supplement which has been shown to have antioxidant and performance enhancing properties. The purpose of this study was to evaluate the effects of spirulina supplementation on (a) redox status (b) muscle performance and (c) muscle damage following an eccentric bout of exercise that would induce muscle damage. Twenty-four healthy, recreationally trained males participated in the study and were randomly separated into two groups: a spirulina supplementation (6 g per day) and a placebo group. Both groups performed an eccentric bout of exercise consisting of 5 sets and 15 maximum reps per set. Blood was collected at 24, 48, 72 and 96 h after the bout and total antioxidant capacity (TAC) and protein carbonyls (PC) were assessed in plasma. Delayed onset muscle soreness (DOMS) was also assessed at the same aforementioned time points. Eccentric peak torque (EPT) was evaluated immediately after exercise, as well as at 24, 48, 72 and 96 h post exercise. Redox status indices (TAC and PC) did not change significantly at any time point post exercise. DOMS increased significantly 24 h post exercise and remained elevated until 72 h and 96 h post exercise for the placebo and spirulina group, respectively. EPT decreased significantly and immediately post exercise and remained significantly lower compared to baseline until 72 h post exercise. No significant differences between groups were found for DOMS and EPT. These results indicate that spirulina supplementation following a muscle damaging protocol does not confer beneficial effects on redox status, muscle performance or damage.

Effective Timing of Curcumin Ingestion to Attenuate Eccentric Exercise-Induced Muscle Soreness in Men.

Curcumin is known to have potent anti-inflammatory effects. We have reported that acute curcumin ingestion attenuates eccentric exercise-induced muscle damage. This study aimed to examine the effect of curcumin ingestion timing (before or after exercise) on the changes in muscle damage markers after eccentric exercise. In this randomized, single-blind, parallel design study, 24 healthy young men performed 30 maximal isokinetic (120º/s) eccentric contractions of the elbow flexors using an isokinetic dynamometer. Subjects were randomly assigned to ingest 180 mg/d of oral curcumin either 7 d before (PRE) or 4 d after exercise (POST) or 180 mg/d of oral placebo 4 d after exercise (CON). The maximal voluntary contraction (MVC) torque of the elbow flexors, elbow joint range of motion (ROM), muscle soreness, and serum creatine kinase (CK) activity were measured before, immediately after, and 1-4 d after exercise. Changes in these variables were compared over time. In the POST group, ROM were higher at 3-4 d and muscle soreness was lower at 3 d after exercise compared with the CON group (p<0.05). However, in the PRE group, there were no significant differences compared with the CON group in changes in ROM and muscle soreness. Meanwhile, there were no significant differences among the groups in terms of changes in MVC torque and serum CK activity. Our results suggest that curcumin ingestion after exercise had a more beneficial effect in attenuating muscle soreness.

Fibromyalgia and nutrition: Therapeutic possibilities?

Fibromyalgia (FM) is a complex chronic condition of unknown etiology, characterized by deep and widespread pain, sleep problems, cognitive impairment, fatigue, and other well-known functional symptoms. Recently, it has been proposed that an imbalance of nutritive components, including essential metal ions and vitamins, might play a critical role in the development of FM. Muscle pain has been associated with deficiencies in amino acids, magnesium, selenium, vitamins B and D, as well as with the harmful effects of heavy metals, such as mercury, cadmium, and lead. Research indicates that patients deficient in certain essential nutrients may develop dysfunction of pain inhibitory mechanisms together with fatigue and other FM symptoms. Additionally, mercury and other toxic elements may interfere with the bioavailability of essential nutrients. This review examines the many effects of metals and vitamins in pain evaluation of FM patients. Dietary guidance is therefore critical for FM patients to help them in correcting a suboptimal or deficient intake of essential nutrients. When optimal levels of nutrition are achieved, pain levels are usually lowered. Additional research is recommended in the field of FM and nutrition to disclose further possible relationships.

l-Carnitine Supplementation in Recovery after Exercise.

Given its pivotal role in fatty acid oxidation and energy metabolism, l-carnitine has been investigated as ergogenic aid for enhancing exercise capacity in the healthy athletic population. Early research indicates its beneficial effects on acute physical performance, such as increased maximum oxygen consumption and higher power output. Later studies point to the positive impact of dietary supplementation with l-carnitine on the recovery process after exercise. It is demonstrated that l-carnitine alleviates muscle injury and reduces markers of cellular damage and free radical formation accompanied by attenuation of muscle soreness. The supplementation-based increase in serum and muscle l-carnitine contents is suggested to enhance blood flow and oxygen supply to the muscle tissue via improved endothelial function thereby reducing hypoxia-induced cellular and biochemical disruptions. Studies in older adults further showed that l-carnitine intake can lead to increased muscle mass accompanied by a decrease in body weight and reduced physical and mental fatigue. Based on current animal studies, a role of l-carnitine in the prevention of age-associated muscle protein degradation and regulation of mitochondrial homeostasis is suggested.

Protein Supplementation During or Following a Marathon Run Influences Post-Exercise Recovery.

The effects of protein supplementation on the ratings of energy/fatigue, muscle soreness [ascending (A) and descending (D) stairs], and serum creatine kinase levels following a marathon run were examined. Variables were compared between recreational male and female runners ingesting carbohydrate + protein (CP) during the run (CPDuring, n = 8) versus those that were consuming carbohydrate (CHODuring,n = 8). In a second study, outcomes were compared between subjects who consumed CP or CHO immediately following exercise [CPPost (n = 4) versus CHOPost (n = 4)]. Magnitude-based inferences revealed no meaningful differences between treatments 24 h post-marathon. At 72 h, recovery [Δ(72 hr-Pre)] was likely improved with CPDuring versus CHODuring, respectively, for Physical Energy (+14 ± 64 vs -74 ± 70 mm), Mental Fatigue (-52 ± 59 vs +1 ± 11 mm), and Soreness-D (+15 ± 9 vs +21 ± 70 mm). In addition, recovery at 72 h was likely-very likely improved with CPPost versus CHOPost for Physical Fatigue, Mental Energy, and Soreness-A. Thus, protein supplementation did not meaningfully alter recovery during the initial 24 h following a marathon. However, ratings of energy/fatigue and muscle soreness were improved over 72 h when CP was consumed during exercise, or immediately following the marathon.

Minimal muscle damage after a marathon and no influence of beetroot juice on inflammation and recovery.

This study examined whether beetroot juice (BTJ) would attenuate inflammation and muscle damage following a marathon. Using a double blind, independent group design, 34 runners (each having completed ca. ∼16 previous marathons) consumed either BTJ or an isocaloric placebo (PLA) for 3 days following a marathon. Maximal isometric voluntary contractions (MIVC), countermovement jumps (CMJ), muscle soreness, serum cytokines, leucocytosis, creatine kinase (CK), high sensitivity C-reactive protein (hs-CRP), and aspartate aminotransferase (AST) were measured pre, post, and 2 days after the marathon. CMJ and MIVC were reduced after the marathon (P < 0.05), but no group differences were observed (P > 0.05). Muscle soreness was increased in the day after the marathon (BTJ; 45 ± 48 vs. PLA; 46 ± 39 mm) and had returned to baseline by day 2, irrespective of supplementation (P = 0.694). Cytokines (interleukin-6; IL-6, interleukin-8, tumour necrosis factor-α) were increased immediately post-marathon but apart from IL-6 had returned to baseline values by day 1 post. No interaction effects were evident for IL-6 (P = 0.213). Leucocytes increased 1.7-fold after the race and remained elevated 2 days post, irrespective of supplement (P < 0.0001). CK peaked at 1 day post marathon (BTJ: 965 ± 967, and PLA: 1141 ± 979 IU·L-1) and like AST and hs-CRP, was still elevated 2 days after the marathon (P < 0.05); however, no group differences were present for these variables. Beetroot juice did not attenuate inflammation or reduce muscle damage following a marathon, possibly because most of these indices were not markedly different from baseline values in the days after the marathon.

Effect of tart cherry juice on recovery and next day performance in well-trained Water Polo players.

BACKGROUND: Tart Montmorency cherries contain high concentrations of phytochemicals and anthocyanins, which have recently been linked to improved athletic recovery and subsequent performance. To date however, previous work reporting promising results has focused on land-based endurance sports, with any potential benefits to team sports remaining unknown. As such, this investigation set-out to examine the effect of supplemental tart cherry juice (CJ) on recovery and next day athletic performance in highly-trained water-based team sport athletes over seven days. METHODS: In a randomised, double-blind, repeated measures, crossover design, nine male Water Polo athletes were supplemented with CJ or a placebo equivalent (PLA) for six consecutive days. Prior to, and at the completion of the supplementation period, water-based performance testing was conducted. On day 6, participants also undertook a fatiguing simulated team game activity. Venous blood samples were collected (Pre-exercise: day 1, 6 and 7; Post-exercise: day 6) to investigate markers of inflammation [Interleukin-6 (IL-6); C-reactive protein (CRP)] and oxidative stress [Uric Acid (UA); F2-Isoprostane (F2-IsoP)]. A daily diary was also completed (total quality of recovery, delayed onset muscle soreness) as a measure of perceptual recovery. RESULTS: In both conditions, day 6 post-exercise IL-6 was significantly higher than pre-exercise and day 7 (p < 0.05); CRP was greater on day 7 as compared to day 6 pre- and post-exercise (p < 0.05); F2-IsoP was significantly lower on day 7 as compared to day 1 and day 6 (p < 0.05); UA remained unchanged (p > 0.05). No differences were found for any performance or recovery measures. CONCLUSIONS: The lack of difference observed in the blood markers between groups may reflect the intermittent, non-weight bearing demands of Water Polo, with such activity possibly unable to create a substantial inflammatory response or oxidative stress (over 7 days) to impede performance; thereby negating any potential beneficial effects associated with CJ supplementation. TRIAL REGISTRATION: This trial was registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR). Registration number: ACTRN12616001080415. Date registered: 11/08/2016, retrospectively registered.

Branched-chain aminoacid supplementation attenuates a decrease in power-producing ability following acute strength training.

BACKGROUND: This study aimed to investigate the effects of branched-chain amino acid (BCAA) supplementation on recovery of power-producing ability following a strength training (ST) session. METHODS: Eleven resistance-trained males, performed baseline measures of a countermovement jump (CMJ) and a seated shot-put throw (SSPT). In a counterbalanced fashion, participants were provided with either 20-g of BCAA or a placebo. Each dose was divided into two equal quantities and consumed before and after a ST session consisting of various multi-joint barbell exercises. For both conditions, the CMJ and SSPT were repeated at 24-h post-ST, in addition participants attributed their perceived muscle soreness level via a 200-mm visual analogue scale. RESULTS: Following ST there were significant decrements in CMJ (baseline; 55.2±7.4-cm, BCAA; 52.8±5.9-cm placebo; 50.6±7.3-cm) and SSPT (baseline; 4.55±0.56-m, BCAA; 4.37±0.61-m, placebo; 4.22±0.64-m) for both conditions in comparison to baseline values (P<0.05). However, BCAA was shown to attenuate the decrements in CMJ and SSPT performance compared to placebo (P<0.05). Muscle soreness was significantly increased following ST for both conditions, however there were no differences in attributed values following BCAA and placebo ingestion. CONCLUSIONS: BCAA administered acutely before and following intensive ST attenuates a decrease in power-producing ability experienced by resistance-trained males. The apparent small but significant effects on functional power suggest that BCAA is an effective ergogenic aid for athletes who require augmented recovery of power-producing ability following intensive ST.