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The main objective of this study was to assess the ergogenic effect of N-acetylcysteine (NAC) on myotendinous isometric force production in physically active people after being subjected to a fatigue protocol. Twenty-three physically active people were randomly divided into the following two groups: NAC (n = 12; age = 26.8 ± 4.5 years, height = 173.1 ± 7.2 cm, and weight = 75.5 ± 7.5 kg), who received 2400 mg oral NAC, and control (n = 11; age = 23.4 ± 5.8 years, height = 175.9 ± 4.5 cm, and weight = 72.3 ± 9.9 kg), who received a placebo, for eight days. The isometric force production was assessed pre- and post-NAC supplementation during a maximal voluntary contraction test (MVC) and also during a fatigue protocol composed of seven sets of ten maximal isometric contraction repetitions of 5 s, with 5 s of rest between repetitions and 20 s between sets. No differences were observed between the groups in the force production values at any moment, and no side effects were found after NAC supplementation. After supplementation, a significant decrease in force was observed in both groups, but this significant loss of force started one set later in the NAC group compared to the control group (4th set vs. 5th set), which could be an ergogenic effect of the treatment. Therefore, oral daily supplementation with 2400 mg of NAC for eight days, could delay the decrease in force production during an isometric exercise protocol and without adverse side effects. [ABSTRACT FROM AUTHOR]

Simple Summary: Exposure to hypoxia may negatively affect cognitive performance. The aim of this systematic review and meta-analysis was to determine the effects of acute hypoxic exposure in simulated altitude in healthy adults on reaction time, response accuracy, memory, and attention. After a review and meta-analysis of the 37 studies analyzed, it appears that acute hypoxic exposure in simulated altitude produces impairment in reaction time, accuracy response, and memory in different cognitive tests in healthy adults. Nevertheless, attention shows no significant changes under hypoxic exposure in simulated altitude. Therefore, hypoxia training under controlled conditions could be a promising approach to avoid an impaired cognitive response in individuals who are frequently exposed to hypoxic environments. The neurocognitive response following hypoxia has received special interest. However, it is necessary to understand the impact of acute hypoxic exposure induced by simulated altitude on cognitive performance. This study aimed to determine the effects of acute hypoxic exposure in simulated altitude in healthy adults on reaction time, response accuracy, memory, and attention. Five electronic databases were searched. The inclusion criteria were: (1) Experimental studies involving a hypoxia intervention induced by a hypoxic air generator to determine the effects on cognitive performance; and (2) Conducted in adults (males and/or females; aged 18–50 years) without pathologies or health/mental problems. Four meta-analyses were performed: (1) reaction time, (2) response accuracy, (3) memory, and (4) attention. Finally, 37 studies were included in the meta-analysis. Hypoxia exposure induced detrimental effects on reaction time (standard mean difference (SMD) −0.23; 95% confidence interval (CI) −0.38–−0.07; p = 0.004), response accuracy (SMD −0.20; 95% CI −0.38–−0.03; p = 0.02), and memory (SMD −0.93; 95% CI: −1.68–−0.17; p = 0.02). Nevertheless, attention was not affected during hypoxia exposure (SMD −0.06; 95% CI: −0.23–0.11; p = 0.47). Acute exposure to hypoxia in controlled lab conditions appears to be detrimental to cognitive performance, specifically in reaction time, response accuracy, and memory. [ABSTRACT FROM AUTHOR]

Regular sport practice could prevent age-related changes in tendinous tissues. The purpose of the study was to investigate the effect of regular badminton practice on patellar and Achilles tendon mechanical properties in senior competitive badminton players (>35 years old) and to compare the results with physically active people matched by age. One hundred ninety-two badminton players and 193 physically active people were divided by age into four groups, between 35 and 44 (U45), between 45 and 54 (U55), between 55 and 64 (U65), and over 65 (O65) years old. A LogiqS8 transducer in elastography mode and a MyotonPRO myotonometer were used to assess patellar and Achilles mechanical properties. Achilles tendon stiffness was higher in the control group than the badminton players for the U45, U55, and O65 age groups (p <.01). Also, the elastography index was higher in the control group than the badminton players for the U45, U55, U65, and O65 age groups (p <.05). In conclusion, regular badminton practice could prevent the decline in mechanical properties of the patellar and Achilles tendons. [ABSTRACT FROM AUTHOR]

α-Actinin-3 is a protein with a structural role at the sarcomeric Z-line in skeletal muscle. As it is only present in fast-type muscle fibers, α-actinin-3 is considered a key mechanical component to produce high-intensity muscle contractions and to withstand external tension applied to the skeletal muscle. α-Actinin-3 is encoded by the gene ACTN3, which has a single-nucleotide polymorphism (p.R577X; rs1815739) that affects the expression of α-actinin-3 due to the presence of a stop codon. Individuals homozygous for the 577R allele (i.e., RR genotype) and RX heterozygotes express functional α-actinin-3, while those homozygous for the 577X (i.e., XX genotype) express a non-functional protein. There is ample evidence to support the associations between the ACTN3 genotype and athletic performance, with higher frequencies of the 577R allele in elite and professional sprint and power athletes than in control populations. This suggests a beneficial influence of possessing functional α-actinin-3 to become an elite athlete in power-based disciplines. However, no previous investigation has determined the frequency of the ACTN3 genotypes in elite badminton players, despite this sport being characterized by high-intensity actions of intermittent nature such as changes of direction, accelerations, jumps and smashes. The purpose of this study was to analyze ACTN3 R577X genotype frequencies in professional badminton players to establish whether this polymorphism is associated with elite athlete status. A total of 53 European Caucasian professional badminton players competing in the 2018 European Badminton Championships volunteered to participate in the study. Thirty-one were men (26.2 ± 4.4 years) and twenty-two were women (23.4 ± 4.5 years). Chi-squared tests were used to analyze the differences in the distribution of ACTN3 genotypes (RR, RX and XX) between categories and sexes. The ACTN3 RR genotype was the most frequent in the sample of professional badminton players (RR = 49.1%, RX = 22.6% and XX = 28.3%). None of the badminton players ranked in the world's top ten possessed the XX genotype (RX = 60%, RR = 40%). The distribution of the ACTN3 genotypes was similar between male and female professional badminton players (men: RR = 45.2%, RX = 25.8% and XX = 29.0%; women: RR = 54.5%, RX = 18.2% and XX = 27.3%; χ2 = 0.58; p = 0.750). The distribution of the ACTN3 genotypes in badminton players was different from the 1000 genome database for the European population (χ2 = 15.5; p < 0.001), with an overrepresentation of the RR genotype (p < 0.05) and an underrepresentation of the RX genotype (p < 0.01). In conclusion, the expression of functional α-actinin-3, associated with RR and RX genotypes in the ACTN3 gene may confer an advantage for reaching the status of elite athlete in badminton, and especially the world's top-ten ranking. Large-scale studies with different ethnic backgrounds are needed to confirm the association of the R allele of ACTN3 with badminton performance. [ABSTRACT FROM AUTHOR]

Abián-Vicén, J, Martínez, F, Jiménez, F, and Abián, P. Effects of eccentric single-leg decline squat training performed with different execution times on maximal strength and muscle contraction properties of the knee extensor muscles. J Strength Cond Res 36(11): 3040–3047, 2022—The eccentric phase of the single-leg decline squat (SLDSe) has been described as a method to maximally load the knee extensor and has been used as an easy and effective rehabilitation exercise for patellar tendinopathy. The purpose of this study was to examine the impact of 6-week SLDSe training with 2 technical execution times on changes related to strength and muscle contractile properties. Thirty-six healthy volunteers were randomly divided into 3 groups: a control group (CG, n = 13, no training), a slow training group (n = 11, SLDSe in 6 seconds), and a fast training group (n = 12, SLDSe in 3 seconds). Subjects completed a 6-week SLDSe training program (80% of eccentric one repetation maximum [1RM]) 3 days a week. Pre, post, and 6-week follow-up of maximal dynamic and isometric strength and muscle contractile properties were assessed. After 6 weeks, training maximal loads showed a significant increase (p < 0.05) in 1RM of the SLDSe (∼92–95%), the concentric peak torque at 180°·s−1 (∼38%) and 60°·s−1 (∼25%), and the extension isometric peak torque (∼12%), with no differences between both experimental groups. Moreover, a decrease (p < 0.05) was found in the contraction time of the vastus medialis (VM) and the response time of the 3 analyzed quadriceps muscles. After the 6-week detraining period, there was a decrease in strength in all tests and in both experimental groups (1RM = 28–37%, isometric and isokinetic tests = 7–17%) and all contractile properties returned to baseline, except for the response time of the vastus lateralis in the fast training group and the contraction time of the VM in the STG. In conclusion, the SLDSe training protocol produced significant increases in muscle strength, showing important neuromuscular changes regardless of the technical execution time. It was also found that the training reduced the response and contraction time of the knee extensor musculature. [ABSTRACT FROM AUTHOR]

Context: Although caffeine is one of the most commonly used substances in combat sports, information about its ergogenic effects on these disciplines is very limited. Purpose: To determine the effectiveness of ingesting a moderate dose of caffeine to enhance overall performance during a simulated Brazilian jiu-jitsu (BJJ) competition. Methods: Fourteen elite BJJ athletes participated in a double-blind, placebo-controlled experimental design. In a random order, the athletes ingested either 3 mg/ kg body mass of caffeine or a placebo (cellulose, 0 mg/kg) and performed 2 simulated BJJ combats (with 20 min rest between them), following official BJJ rules. Specific physical tests such as maximal handgrip dynamometry, maximal height during a countermovement jump, permanence during a maximal static-lift test, peak power in a bench-press exercise, and blood lactate concentration were measured at 3 specific times: before the first combat and immediately after the first and second combats. The combats were video-recorded to analyze fight actions. Results: After the caffeine ingestion, participants spent more time in offensive actions in both combats and revealed higher blood lactate values (P < .05). Performance in all physical tests carried out before the first combat was enhanced with caffeine (P < .05), and some improvements remained after the first combat (eg, maximal static-lift test and bench-press exercise; P < .05). After the second combat, the values in all physical tests were similar between caffeine and placebo. Conclusions: Caffeine might be an effective ergogenic aid for improving intensity and physical performance during successive elite BJJ combats. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effectiveness of a caffeinated energy drink to enhance physical performance in elite junior tennis players. In 2 different sessions separated by 1 wk, 14 young (16 ± 1 y) elite-level tennis players ingested 3 mg caffeine per kg body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed a handgrip-strength test, a maximal-velocity serving test, and an 8 × 15-m sprint test and then played a simulated singles match (best of 3 sets). Instantaneous running speed during the matches was assessed using global positioning (GPS) devices. Furthermore, the matches were videotaped and notated afterward. In comparison with the placebo drink, the ingestion of the caffeinated energy drink increased handgrip force by ~4.2% ± 7.2% (P = .03) in both hands, the running pace at high intensity (46.7 ± 28.5 vs 63.3 ± 27.7 m/h, P = .02), and the number of sprints (12.1 ± 1.7 vs 13.2 ± 1.7, P = .05) during the simulated match. There was a tendency for increased maximal running velocity during the sprint test (22.3 ± 2.0 vs 22.9 ± 2.1 km/h, P = .07) and higher percentage of points won on service with the caffeinated energy drink (49.7% ± 9.8% vs 56.4% ± 10.0%, P = .07) in comparison with the placebo drink. The energy drink did not improve ball velocity during the serving test (42.6 ± 4.8 vs 42.7 ± 5.0 m/s, P = .49). The preexercise ingestion of caffeinated energy drinks was effective to enhance some aspects of physical performance of elite junior tennis players. [ABSTRACT FROM AUTHOR]