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Background Post-activation potentiation (PAP) is the phenomenon by which muscular performance is enhanced in response to a conditioning stimulus. PAP has typically been evidenced via improved counter movement jump (CMJ) performance. This study examined the effects of PAP, with and without prior caffeine ingestion, on CMJ performance. Methods Twelve male professional soccer players (23 ± 5 years) performed two trials of plyometric exercises and sled towing 60 min after placebo or caffeine ingestion (5 mg.kg − 1 ) in a randomized, counterbalanced and double-blinded design. CMJ performance was assessed at baseline and 1, 3 and 5 min after the conditioning stimulus (T1, T3 and T5, respectively). Results Two way ANOVA main effects indicated a significant difference in jump height after the PAP protocol (F[3, 11] = 14.99, P  < 0.001, partial η2 = 0.577). Analysis also indicated a significant difference in CMJ performance across conditions, with caffeine eliciting a greater response (F[1, 11] = 10.12, P  = 0.009, partial η2 = 0.479). CMJ height was increased at T1, T3 and T5 in caffeine condition (5.07%, 5.75% and 5.40%, respectively; P  < 0.01) compared to baseline. In the placebo condition, jump performance was increased at T3 (4.94%; P  < 0.01) only. Jump height was higher in caffeine condition on T1, T3 and T5 ( P  < 0.05) but not on baseline ( P  > 0.05) compared to placebo. Conclusions The results of this study suggest that acute plyometric and sled towing stimuli enhances jump performance and that this potentiation is augmented by caffeine ingestion in male soccer players.

This study aimed to verify the effects of congested fixture and matches’ participation on internal and external workload indexes in professional Brazilian soccer players. Rate of perceived exertion-based training load (sRPE), distance- and accelerometry-based measures were daily monitored over 119 training sessions and 33 matches performed by 29 male outfield players. Weeks were classified as congested (n = 11, two or more matches within a 7-day period) and regular (n = 10, one match or less within a 7-day period). The players were divided based on the matches’ participation: (1) players who played ≥ 60 min (G1); (2) players who played < 60 min (G2); (3) players who did not participate of the match (G3). The findings showed that independent of the levels of participation during the matches, regular weeks presented greater acute, monotony, and strain indices for internal and external workload measures than congested weeks. The G1 presented the highest values for most of the workload indices in both regular and congested weeks, except for monotony indices (internal and external load) that G2 showed greater values than G1 and G3. Coaches and practitioners should plan the training “doses” to reduce disparities of these different match’s participation and congested schedule weeks.

Mixed martial arts (MMA) is a combat sport where competitors utilize strikes (punches, kicks, knees, and elbows) and submission techniques to defeat opponents in a cage or ring. The aim of this study was to investigate the effect of acute caffeine ingestion on punching performance by professional MMA athletes. The study used a double-blind, counterbalanced, crossover design. Eleven professional MMA competitors (27.6 ± 4.3 years and 83.5 ± 7.8 kg of body weight) ingested a dose of caffeine (5 mg·kg−1) or placebo 60 min prior to three sets of punching. Each set consisted of 15 s, at which participants were asked to perform straight punches with maximum strength and frequency with his dominant arm. After each set, a 45 s recovery time was applied. Using a force transducer attached to a cushioned plate, the punch frequency, and mean and maximal punch force was measured. The readiness to invest in both physical (RTIPE) and mental (RTIME) effort was assessed prior to the protocol, and the rating of perceived exertion (RPE) was recorded after. Caffeine ingestion did not result in increased punching frequency, mean and maximum punch force, RTIPE, RTIME, and RPE when compared to the placebo condition. Based on these results, acute caffeine ingestion did not improve punching performance in professional MMA athletes.

Climate changes, mostly related to high temperature, are predicted to have major negative impacts on coffee crop yield and bean quality. Recent studies revealed that elevated air [CO ] mitigates the impact of heat on leaf physiology. However, the extent of the interaction between elevated air [CO ] and heat on coffee bean quality was never addressed. In this study, the single and combined impacts of enhanced [CO ] and temperature in beans of cv. Icatu were evaluated. Plants were grown at 380 or 700 μL CO L air, and then submitted to a gradual temperature rise from 25°C up to 40°C during ca. 4 months. Fruits were harvested at 25°C, and in the ranges of 30-35 or 36-40°C, and bean physical and chemical attributes with potential implications on quality were then examined. These included: color, phenolic content, soluble solids, chlorogenic, caffeic and -coumaric acids, caffeine, trigonelline, lipids, and minerals. Most of these parameters were mainly affected by temperature (although without a strong negative impact on bean quality), and only marginally, if at all, by elevated [CO ]. However, the [CO ] vs. temperature interaction strongly attenuated some of the negative impacts promoted by heat (e.g., total chlorogenic acids), thus maintaining the bean characteristics closer to those obtained under adequate temperature conditions (e.g., soluble solids, caffeic and -coumaric acids, trigonelline, chroma, Hue angle, and color index), and increasing desirable features (acidity). Fatty acid and mineral pools remained quite stable, with only few modifications due to elevated air [CO ] (e.g., phosphorous) and/or heat. In conclusion, exposure to high temperature in the last stages of fruit maturation did not strongly depreciate bean quality, under the conditions of unrestricted water supply and moderate irradiance. Furthermore, the superimposition of elevated air [CO ] contributed to preserve bean quality by modifying and mitigating the heat impact on physical and chemical traits of coffee beans, which is clearly relevant in a context of predicted climate change and global warming scenarios.

The increasing demand of organic agriculture (OA) is based on the consumer’s belief that organic agricultural products are healthier, tastier and more nutritious. The effect of OA and conventional agriculture (CA) methods on the elemental compositions of green and red sweet peppers were studied. The highest concentrations of Ca, Cu, K and P occur in peppers from OA in both states of ripeness, with emphasis on Ca and K contents. Furthermore, the principal component analysis (PCA), points out to a clear separation, regarding concentrations, between peppers from OA and CA. The average fruit weight is higher in OA, 141 g versus 112 g in CA. Regarding productivity, CA reaches a value of 30.1 t/ha, 7% higher than the value observed for OA, i.e., 28 t/ha. Peppers from CA, exhibited greater protein content than those which originated from OA, regardless of the ripening stage, but not more ashes. Regarding nutritional ratios, the ripening stage and the production mode, can be important for an adequate choice regarding a more balanced Ca/P ratio, and the studied variety contained high Ca values ranging between 1009 and 1930 mg.kg−1. The PCA analysis also revealed that Mn and Fe are inversely correlated, confirming the importance of the Mn/Fe ratio evaluation in nutritional studies.

Thirteen genotypes of durum wheat were grown in two different environments in Portugal. Grain and ash mineral profile, as well as protein content, test weight, and grain ash content were evaluated. Genotype, environment, and their interaction explains the variation in the quality traits, with the environment having the highest influence. Mineral profile analysis was performed by the μ-EDXRF system: macroelements (K, P, Ca, Cl, and S) represented 99% of the total concentration detected in the grain samples, while microelements represented up to 2% of the total concentration when analyzing the ash samples (Fe, Mn, Zn, Cu, Si, Rb, Sr, and Ti). Almost every element found in the grain and ash analysis was affected by the environment. Only K and Ca in the grain had higher concentrations in the environment with water scarcity, while the concentrations of all the detected elements except for Si and Sr were higher in the ashes in this environment. Regarding the genotype, P, S, and Cu grain concentrations were not affected by the environment. The highest grain mineral concentration was found for Gingão, suggesting a better mineral uptake and/or translocation-to-grain capacity. However, regarding the technological quality, most of the genotypes presented ash content values above the maximum specified threshold.

The contamination of abandoned mining areas is a problem worldwide that needs urgent attention. Phytoremediation emerges as a successful method to extract different contaminants from the soil. In this context, Eucalyptus globulus plants growing in soils artificial contaminated with arsenic (As) were used to access its phytoremediation capabilities. The effects of As on photosynthetic performance were monitored through different physiological parameters, whereas the uptake and translocation of As and the putative effects on calcium, iron, potassium, and zinc levels on plants were evaluated by X-ray fluorescence analysis. Root system is the major accumulator organ, while the translocation to the above-ground organs is poor. In the end of the experiment, the root biomass of plants treated with 200 μg As mL−1 is 27% and 49.7% lower than equivalent biomass from plants treated with 100 μg As mL−1 and control plants, respectively. Each plant can accumulate 8.19 and 8.91 mg As after a 6-month period, when submitted to 100 As and 200 As, respectively. It seems to exist an antagonistic effect of As on Zn root uptake by E. globulus. In general, the tested concentrations do not influence negatively plant metabolism, indicating that this species is suitable for plantation in contaminated areas.

Potato (Solanum tuberosum L.) is an important global food crop, being greatly valued for its high carbohydrate content and nutritional profile. In response to the world population’s rapid growth and the increasing need for nutritionally enhanced food quality, potato biofortification has become a key focus of agronomic research. This study investigated the effect of calcium (Ca) biofortification on two potato cultivars (Picasso and Rossi) cultivated in Portugal, assessing its impact on the photosynthetic functioning and the Ca content and distribution of tubers. At the beginning of the tuberization stage, seven foliar applications of CaCl2 or Ca-EDTA at 12 kg ha−1 were performed. The application of Ca-EDTA led to an increased Ca content in peeled tubers of Picasso (37%) and Rossi (16%), and 88% and 79% in unpeeled tubers, in the same cv. order and as compared to their controls, with Ca predominantly accumulating in the epidermis/peel region. Photosynthetic performance was negatively impacted by the Ca-EDTA treatment in Picasso but not in Rossi, which was reflected in the significant declines in net photosynthesis (Pn) and maximal (Fv/Fm) and actual (Fv′/Fm) photochemical efficiency of photosystem II. Additionally, both genotypes showed negative impacts (greater in Picasso) on the quantum yield of non-cyclic electron transport (Y(II)) and photochemical quenching (qL) after five foliar applications. This contrasted with the absence of negative impacts under the use of CaCl2, which resulted in 17.1% (Picasso) and 29.5% (RFossi) increase in Ca content in peeled tubers, without any significant differences between the unpeeled tubers of both cvs. Moreover, only with CaCl2, the tuber weight and yield were not negatively impacted. These findings pointed out that, although with a lower Ca increase in the tubers, CaCl2 was the best suitable option for the Ca biofortification of these cvs. at the applied doses.

In worldwide production, rice is the second-most-grown crop. It is considered a staple food for many populations and, if naturally enriched in Se, has a huge potential to reduce nutrient deficiencies in foodstuff for human consumption. This study aimed to develop an agronomic itinerary for Se biofortification of Oryza sativa L. (Poaceae) and assess potential physicochemical deviations. Trials were implemented in rice paddy field with known soil and water characteristics and two genotypes resulting from genetic breeding (OP1505 and OP1509) were selected for evaluation. Plants were sprayed at booting, anthesis and milky grain phases with two different foliar fertilizers (sodium selenate and sodium selenite) at different concentrations (25, 50, 75 and 100 g Se·ha−1). After grain harvesting, the application of selenate showed 4.9–7.1 fold increases, whereas selenite increased 5.9–8.4-fold in OP1509 and OP1505, respectively. In brown grain, it was found that in the highest treatment selenate or selenite triggered much higher Se accumulation in OP1505 relatively to OP1509, and that no relevant variation was found with selenate or selenite spraying in each genotype. Total protein increased exponentially in OP1505 genotype when selenite was applied, and higher dosage of Se also increased grain weight and total protein content. It was concluded that, through agronomic biofortification, rice grain can be enriched with Se without impairing its quality, thus highlighting its value in general for the industry and consumers with special needs.

The aim of this study is to evaluate the elemental composition of fifteen algae-based supplements commonly sold in the Portuguese market, by energy dispersive X-ray fluorescence. Despite the fact that the majority of Kelp samples were a good source of iodine, the levels observed might well contribute to an excess in the human body, which can cause dysfunction of the thyroid gland. Furthermore, the presence of lead in Sea spaghetti, Arame, Hijiki and Wakame caused a considerable risk to public health vis a vis possible ingestion of a high daily dose. Regarding arsenic, great variability was observed in all the samples with concentrations equal to or above 60 μg/g in the case of Arame, KelpJ and Hijiki. Although algae mainly accumulate organic arsenic, some also contain high levels of its inorganic form, as is commonly pointed out for Hijiki. Thus, regular ingestion of these supplements must also take into account the mentioned facts. There is no doubt that these supplements are also good sources of other nutrients, but the lack of accurate regulations and control should alert consumers to avoid indiscriminate use of these types of products.