-
1.
The Impact of Daytime Napping Following Normal Night-Time Sleep on Physical Performance: A Systematic Review, Meta-analysis and Meta-regression.
Boukhris, O, Trabelsi, K, Suppiah, H, Ammar, A, Clark, CCT, Jahrami, H, Chtourou, H, Driller, M
Sports medicine (Auckland, N.Z.). 2024;(2):323-345
-
-
Free full text
-
Abstract
BACKGROUND Daytime napping is used by athletes as a strategy to supplement night time sleep and aid physical performance. However, no meta-analytical overview regarding the impact of napping following a night of normal sleep (7-9 h) on physical performance is available. OBJECTIVE The aim of this study was to evaluate the effect of daytime napping following normal night-time sleep on physical performance in physically active individuals and athletes. METHODS This systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Seven electronic databases (i.e., PubMed, Web of Science, Scopus, SPORTDiscus, CINAHL, SCIELO, and EBSCOhost) were used to search for relevant studies that investigated the impact of daytime napping, following normal night-time sleep, on physical performance in physically active individuals and athletes, published in any language, and available before September 01, 2022. Studies that included assessments of any physical performance measures were included. QualSyst was used to assess the methodological quality of the studies. RESULTS Of 18 selected articles, 15 were of strong quality and 3 were of moderate quality. Compared with no-nap conditions, physically active individuals and athletes who napped experienced an increase in highest distance (effect size [ES] 1.026; p < 0.001) and total distance (ES 0.737; p < 0.001), and a decrease in fatigue index (ES 0.839, p = 0.008) during the 5-m shuttle run test (5MSRT). However, napping yielded no effect on muscle force (ES 0.175; p = 0.267). No effect of napping was found in one study that measured sprint performance and in two studies that measured performance during the 30-s Wingate test. Two of three studies reported an increase in jump performance after napping. Two of three studies reported an increase in repeated sprints after napping. One study reported an increase in upper-body power performance after napping, and napping was beneficial for endurance performance in one of two studies. CONCLUSION Following normal sleep, napping is beneficial for the performance of the 5MSRT, with no significant effect on muscle force. No firm conclusions can be drawn regarding other physical performance measures due to the limited number of studies.
-
2.
Recent advances in nano-fertilizers: synthesis, crop yield impact, and economic analysis.
Channab, BE, El Idrissi, A, Ammar, A, Dardari, O, Marrane, SE, El Gharrak, A, Akil, A, Essemlali, Y, Zahouily, M
Nanoscale. 2024;(9):4484-4513
Abstract
The escalating global demand for food production has predominantly relied on the extensive application of conventional fertilizers (CFs). However, the increased use of CFs has raised concerns regarding environmental risks, including soil and water contamination, especially within cereal-based cropping systems. In response, the agricultural sector has witnessed the emergence of healthier alternatives by utilizing nanotechnology and nano-fertilizers (NFs). These innovative NFs harness the remarkable properties of nanoparticles, ranging in size from 1 to 100 nm, such as nanoclays and zeolites, to enhance nutrient utilization efficiency. Unlike their conventional counterparts, NFs offer many advantages, including variable solubility, consistent and effective performance, controlled release mechanisms, enhanced targeted activity, reduced eco-toxicity, and straightforward and safe delivery and disposal methods. By facilitating rapid and complete plant absorption, NFs effectively conserve nutrients that would otherwise go to waste, mitigating potential environmental harm. Moreover, their superior formulations enable more efficient promotion of sustainable crop growth and production than conventional fertilizers. This review comprehensively examines the global utilization of NFs, emphasizing their immense potential in maintaining environmentally friendly crop output while ensuring agricultural sustainability.
-
3.
The impact of a 40-min nap on neuromuscular fatigue profile and recovery following the 5-m shuttle run test.
Boukhris, O, Zghal, F, Trabelsi, K, Suppiah, H, Ammar, A, Jahrami, H, Hsouna, H, Abdessalem, R, Glenn, JM, Chtourou, H, et al
Journal of sleep research. 2024;(1):e14052
Abstract
This study aims to investigate the impact of a 40-min nap opportunity on perceived recovery, exertion, and maximal voluntary isometric contraction (MVIC) following the 5-m shuttle run test (5SRT), after 1 night of normal sleep. In a randomised, counterbalanced, cross-over design, 17 trained men (mean [SD] age 20 [3] years, height 173 [6] cm, body mass 68 [6] kg) performed a 5SRT under two conditions: a 40-min nap opportunity and no-nap condition. After both conditions, electromyography signals during a 5-s isometric knee extension were recorded before and immediately after the 5SRT. Two electrical nerve stimulations at the femoral nerve were measured during and after the MVIC. Force, voluntary activation level, M-wave amplitudes, potentiated twitch, and electromyography signals (root mean square) were measured during each MVIC. Perceived exertion was recorded after each repetition of the test and perceived recovery was determined after the end of the MVIC. Compared to the no-nap condition, the 40-min nap resulted in significant enhancements in both the highest distance (p < 0.01, Δ = +7.6%) and total distance (p < 0.01, Δ = +7.5%). Before and after exercise, values for MVIC, root mean square, M-wave amplitudes, and voluntary activation level were improved after the 40-min nap opportunity compared to no-nap condition (all p ≤ 0.01). Values for perceived exertion and recovery were improved after the 40-min nap opportunity in comparison with no-nap condition (p ≤ 0.01). A 40-min nap opportunity improved repeated high-intensity short-term maximal performance, perceived recovery, associated neuromuscular responses, and reduced perceived fatigue. Therefore, our findings suggest that central and peripheral processes are involved in the improvements of 5SRT performance after napping.
-
4.
Branched-Chain Amino Acids Supplementation and Post-Exercise Recovery: An Overview of Systematic Reviews.
Salem, A, Trabelsi, K, Jahrami, H, AlRasheed, MM, Boukhris, O, Puce, L, Bragazzi, NL, Ammar, A, Glenn, JM, Chtourou, H
Journal of the American Nutrition Association. 2024;(4):384-396
Abstract
Objective: This overview of systematic reviews (OoSRs) aimed, firstly, to systematically review, summarize, and appraise the findings of published systematic reviews with or without meta-analyses that investigate the effects of branched-chain amino acids (BCAA) on post-exercise recovery of muscle damage biomarkers, muscle soreness, and muscle performance. The secondary objective was to re-analyze and standardize the results of meta-analyses using the random-effects Hartung-Knapp-Sidik-Jonkman (HKSJ) method.Methods: The methodological quality of the reviews was assessed using A Measurement Tool to Assess Systematic Reviews 2.We searched on five databases (i.e., PubMed, Web of Science, Scopus, SPORTDiscus, ProQuest) for systematic reviews with or without meta-analyses that investigated the effects of BCAA supplementation on the post-exercise recovery of muscle damage biomarkers, muscle soreness, and muscle performance.Results: Eleven systematic reviews (seven with meta-analyses) of individual studies were included. Evidence suggests BCAA ingestion attenuates creatine kinase (CK) levels (medium effects) and muscle soreness (small effects) immediately post-exercise and accelerates their recovery process, with trivial-to-large effects for CK levels and small-to-large effects for muscle soreness. BCAA supplementation has no effect on lactate dehydrogenase, myoglobin, and muscle performance recovery. The re-analyses with HKSJ method using the original data reported a slight change in results significance, concluding the same evidence as the original results. The major flaws found in the analyzed reviews were the absence of justification for excluding studies, and the lack of provision of sources of funding for primary studies and sources of conflict of interest and/or funding description.Conclusions: BCAA supplementation is an effective method to reduce post-exercise muscle damage biomarkers, particularly CK levels, and muscle soreness, with no effect on muscle performance. Future systematic reviews with/without meta-analyses, with greater methodological rigor, are needed.
-
5.
Attenuating Muscle Damage Biomarkers and Muscle Soreness After an Exercise-Induced Muscle Damage with Branched-Chain Amino Acid (BCAA) Supplementation: A Systematic Review and Meta-analysis with Meta-regression.
Salem, A, Ben Maaoui, K, Jahrami, H, AlMarzooqi, MA, Boukhris, O, Messai, B, Clark, CCT, Glenn, JM, Ghazzaoui, HA, Bragazzi, NL, et al
Sports medicine - open. 2024;(1):42
-
-
Free full text
-
Abstract
BACKGROUND Branched-chain amino acid (BCAA) supplementation is one of the most popular strategies used by the general population and athletes to reduce muscle soreness and accelerate the recovery process of muscle damage biomarkers after an intense exercise or training session. OBJECTIVES This systematic review and meta-analysis investigated the effects of BCAA supplementation on muscle damage biomarkers and muscle soreness after exercise-induced muscle damage (EIMD). METHODS The systematic literature search for randomized controlled trials was conducted using seven databases, up to September 13th, 2022. The eligibility criteria for selecting studies were as follows: studies performed on healthy active participants, using BCAA at least once, controlled with a placebo or control group, performing resistance or endurance exercises, and followed up at least once post-EIMD. The methodological quality of the studies was assessed using the "SIGN RCT checklist". Random-effects meta-analyses were processed to compute the standardized mean difference (Hedges' g). Meta-regression analyses were completed with daily and total dosage and supplementation as continuous moderator variables. RESULTS Of the 18 studies included in this meta-analysis, 13 were of high quality and five were of acceptable quality. Our results revealed BCAA supplementation elicits a significant effect on reducing creatine kinase (CK) levels immediately (g = - 0.44; p = 0.006) and 72 h (g = - 0.99; p = 0.002), but not 24 h, 48 h, and 96 h post-EIMD. Additionally, a significant effect on delayed onset of muscle soreness (DOMS) was identified at 24 h (g = - 1.34; p < 0.001), 48 h (g = - 1.75; p < 0.001), 72 h (g = - 1.82; p < 0.001), and 96 h (g = - 0.82; p = 0.008), but not immediately post-EIMD. No significant effect was found on lactate dehydrogenase (LDH) levels at any time point. Meta-regression indicated higher daily and total dosages of BCAA, and longer supplementation periods were related to the largest beneficial effects on CK (total dosage and supplementation period) at 48 h, and on DOMS at 24 h (only daily dosage). CONCLUSION The overall effects of BCAA supplementation could be considered useful for lowering CK and DOMS after EIMD, but not LDH. The longer supplementation period prior to the EIMD could be more effective for CK and DOMS reduction.
-
6.
Optimizing Short-Term Maximal Exercise Performance: The Superior Efficacy of a 6 mg/kg Caffeine Dose over 3 or 9 mg/kg in Young Female Team-Sports Athletes.
Bougrine, H, Ammar, A, Salem, A, Trabelsi, K, Jahrami, H, Chtourou, H, Souissi, N
Nutrients. 2024;(5)
Abstract
Caffeine (CAF) is among the most extensively researched dietary supplements worldwide. However, little is known about the relationship between dosage and performance enhancement, particularly in female athletes. This study aimed to explore the effects of three different CAF dosages (3 mg·kg-1, 6 mg·kg-1, and 9 mg·kg-1) on high-intensity exercise and the prevalence of undesirable side effects related to these doses among female team-sports athletes. All participants (n = 16; age: 16.9 ± 0.6 y; height: 1.64 ± 0.1 m; BMI: 21.6 ± 1.5 kg·m-2) were mild CAF consumers. This study had a randomized, crossover, double-blind design in which each athlete performed four experimental sessions after ingesting either a placebo (PLAC), 3 mg·kg-1 CAF (CAF-3), 6 mg·kg-1 CAF (CAF-6), or 9 mg·kg-1 of CAF (CAF-9), with an in-between washout period of at least 72 h. In each experimental session, 60 min after ingesting the capsules, participants underwent a countermovement jumps test (CMJ), modified agility t-test (MATT), repeated sprint ability (RSA) test, and a rating of perceived exertion (RPE) and completed the CAF side effects questionnaire. Our findings revealed that in comparison to the PLAC condition, the MATT, RSAmean, and RSAbest performances were significantly greater only under the CAF-6 and CAF-9 conditions. Although the RPE scores remained unchanged, CMJ performance improved under all CAF conditions. All the performance outcomes were better for the CAF-6 and CAF-9 conditions than for the CAF-3 condition. Notably, no significant difference between the CAF-6 and CAF-9 conditions was observed for any of these parameters despite the highest incidence of side effects being noted for the CAF-9 condition. In summary, our findings highlight the recommendation for a moderate CAF dosage of 6 mg·kg-1 rather than 3 or 9 mg·kg-1 to enhance various aspects of short-term maximal performance in mild-CAF-consumer female team-sports athletes while mitigating the occurrence of adverse CAF side effects.
-
7.
Effects of Various Caffeine Doses on Cognitive Abilities in Female Athletes with Low Caffeine Consumption.
Bougrine, H, Ammar, A, Salem, A, Trabelsi, K, Jahrami, H, Chtourou, H, Souissi, N
Brain sciences. 2024;(3)
Abstract
Caffeine (CAF), a prevalent psychoactive stimulant, is believed to potentially enhance cognitive ability. However, studies on the effects of various doses are limited and yield inconsistent results, particularly in female athletes. Therefore, we aimed to assess the association between three different dosages of CAF intake (low, moderate, and high) and cognitive skills in female athletes with low CAF consumption. This study had a randomized, crossover, double-blind design in which each athlete performed four experimental sessions after ingesting either a placebo (PLAC), 3 mg·kg-1 of CAF (3 mg of CAF), 6 mg·kg-1 of CAF (6 mg of CAF), or 9 mg·kg-1 of CAF (9 mg of CAF) with an in-between washout period of at least 72 h. Following a 60 min window post-capsule consumption, fourteen female athletes (age: 17.4 ± 0.8 years) were assessed through various cognitive tests, namely, simple reaction time (SRT), choice reaction time (CRT), and attentional task (AT) tests, along with the mental rotation test (MRT). Additionally, they were required to complete a questionnaire about the undesirable side effects of CAF. Our results indicated that, compared to those of PLAC, the SRT, CRT, and AT performance were significantly improved following the administration of both 3 mg of CAF and 6 mg of CAF. While the greatest enhancement was observed after consuming 3 mg of CAF, no significant differences were found between the effects of 3 mg and 6 mg of CAF. Interestingly, MRT performance did not improve with any of the CAF dosages. Moreover, the ingestion of 9 mg of CAF did not enhance cognitive skills and was linked to the highest occurrence of CAF-related side effects. In conclusion, our results highlight the recommendation for a low CAF dosage of 3 mg·kg-1, in contrast to a higher dose of 6 mg·kg-1 or 9 mg·kg-1 of CAF, to enhance various aspects of cognitive performance in female athletes with low CAF consumption without adverse side effects.
-
8.
Dietary Intake and Body Composition During Ramadan in Athletes: A Systematic Review and Meta-Analysis With Meta-Regression.
Trabelsi, K, Ammar, A, Boukhris, O, Glenn, JM, Clark, CCT, Stannard, SR, Slater, G, Żmijewski, P, Driss, T, Ben Saad, H, et al
Journal of the American Nutrition Association. 2023;(1):101-122
Abstract
The aim of this research was to evaluate the effect of Ramadan observance on dietary intake and body composition in adult athletes. This was a systematic review and meta-analysis. Data sources used were PubMed, Web of Science, Scopus, and Taylor and Francis. Eligibility criteria for selecting studies were as follows: single-group, pre-/post-Ramadan, with or without control group, conducted in athletes aged ≥19 years training at least twice a week, and published in any language before August 25, 2021. Studies assessing dietary intake and/or body composition were deemed eligible. The methodological quality of studies was assessed using QualSyst. Nine studies evaluated dietary intake; 4 of these were rated as strong quality and the remaining as moderate. Of the 17 selected studies evaluating body composition, 7 were of strong quality and the remaining 10 were rated as moderate. Compared to pre-Ramadan, energy (number of studies, K = 7; number of participants, N = 78; g = -0.781; 95% confidence interval [CI], -1.416 to -0.145; p = 0.016), carbohydrate (K = 5; N = 50; g = -1.643; 95% CI, -2.949 to -0.336; p = 0.014), and water (K = 4; N = 39; g = -1.081; 95% CI, -1.371 to -0.790; p = 0.000) intakes decreased during Ramadan. However, fat (K = 5; N = 50; g = -0.472; 95% CI, -1.085 to 0.140; p = 0.131) and protein (K = 5; N = 60; g = -0.574; 95% CI, -1.213 to -0.066; p = 0.079) intakes remained unchanged. Compared to pre-Ramadan, body mass (K = 16; N = 131; g = -0.262; 95% CI, -0.427 to -0.097; p = 0.002) and body fat percentage (K = 8; N = 81; g = -0.197; 95% CI, -0.355 to -0.040; p = 0.014) decreased in the fourth week of Ramadan. Lean body mass did not change during Ramadan (K = 4; N = 45; g = -0.047; 95% CI, -0.257 to 0.162; p = 0.658). Carbohydrate and total water intake decreased with the observance of Ramadan, but fat and protein intake were unchanged. Continued training of athletes during Ramadan was associated with a decreased body mass and body fat percentage, but not lean body mass, toward the end of the fasting month. Key pointsRamadan fasting decreases body mass and body fat percentage of athletes, but not lean body mass.Longer durations of fasting could provoke more pronounced decrements in body mass.Carbohydrate and total water intake decreased during Ramadan in athletes.Future studies, with greater methodological rigor, are required to better discern changes in dietary intake and body composition during Ramadan. Supplemental data for this article is available online at https://doi.org/10.1080/07315724.2021.2000902 .
-
9.
Effects of home confinement on physical activity, nutrition, and sleep quality during the COVID-19 outbreak in amateur and elite athletes.
Taheri, M, Irandoust, K, Reynoso-Sánchez, LF, Muñoz-Helú, H, Cruz-Morales, KN, Torres-Ramírez, R, Mirmoezzi, M, Youzbashi, L, Mirakhori, F, Dergaa, I, et al
Frontiers in nutrition. 2023;:1143340
Abstract
INTRODUCTION Despite the progress in the management of the pandemic caused by COVID-19, it is necessary to continue exploring and explaining how this situation affected the athlete population around the world to improve their circumstances and reduce the negative impact of changes in their lifestyle conditions that were necessitated due to the pandemic. The aim of this study was to analyze the moderating influence of physical activity (PA) and dietary habits on the impact of the COVID-19 pandemic experience on sleep quality in elite and amateur athletes. MATERIALS AND METHODS A total of 1,420 elite (40.1%) and amateur (59.9%) athletes (41% women; 59% men) from 14 different countries participated in a cross-sectional design study. Data were collected using a battery of questionnaires that identified sociodemographic data, sleep quality index, PA levels, dietary habits, and the athletes' perception of their experience during the COVID-19 pandemic. Means and standard deviations were calculated for each variable. The analysis of variances and the correlation between variables were carried out with non-parametric statistics. A simple moderation effect was calculated to analyze the interaction between PA or dietary habits on the perception of the COVID-19 experience effect on sleep quality in elite and amateur athletes. RESULTS The PA level of elite athletes was higher than amateur athletes during COVID-19 (p < 0.001). However, the PA level of both categories of athletes was lower during COVID-19 than pre-COVID-19 (p < 0.01). In addition, amateurs had a higher diet quality than elite athletes during the pandemic (p = 0.014). The perception of the COVID-19 experience as controllable was significantly higher (p = 0.020) among elite athletes. In addition, two moderating effects had significant interactions. For amateur athletes, the PA level moderated the effect of controllable COVID-19 experience on sleep quality [F (3,777) = 3.05; p = 0.028], while for elite athletes, the same effect was moderated by dietary habits [F (3,506) = 4.47, p = 0.004]. CONCLUSION Elite athletes had different lifestyle behaviors compared to amateurs during the COVID-19 lockdown. Furthermore, the relevance of maintaining high levels of PA for amateurs and good quality dietary habits by elite athletes was noted by the moderating effect that both variables had on the influence of the controllable experience during the COVID-19 pandemic on sleep quality.
-
10.
Does Beetroot Supplementation Improve Performance in Combat Sports Athletes? A Systematic Review of Randomized Controlled Trials.
Delleli, S, Ouergui, I, Messaoudi, H, Trabelsi, K, Glenn, JM, Ammar, A, Chtourou, H
Nutrients. 2023;(2)
Abstract
While studies on dietary nitrate (NO3-) supplementation and its impact on combat sports performance are increasing, finite conclusions from currently available investigations remain unclear. Thus, the present systematic review examined the acute and chronic ergogenic effect(s) of dietary nitrate intake from beetroot on different aspects of combat sports performance. A systematic search for randomized placebo-controlled studies investigating the effects of beetroot supplementation on combat sports outcomes was performed through Scopus, PubMed/MEDLINE, Web of Science, Scielo, Sport Discus, and Cochrane Library databases up to 2 January 2023. The different terms related to beetroot and to combat sports were connected in the search strategies using the Boolean operators 'AND' and 'OR'. A total of nine studies with good methodological quality (based on the Cochrane risk of bias tool) fulfilled the inclusion criteria. Seven studies used an acute supplementation strategy, while the other two studies utilized chronic supplementation. Findings showed beetroot intake may be an effective tool to improve oxidative metabolism and muscle force production (i.e., isokinetic and isometric) in combat sports athletes. However, these effects may depend on the population, intake duration, muscle group activated, and exercise type. Future studies are required to (1) understand the effects on female athletes and (2) elucidate the impacts of dosing protocols and specific exercise modalities for enhancing combat sports performance.