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However, players' fatigue was more noticeable in shorter and more frequent sprints. Heart rate responses and local use of O2 showed a similar activity of aerobic reactions through the different exercises. During the sprints, players' SmO2 fell to 40% and recovered to the level of about 80% during passive rest intervals without showing differences in both modalities. This suggests that both types of sprint exercises can similarly stimulate aerobic metabolism. © 2020 Rūtenis Paulauskas, Paulius Kamarauskas, Ričardas Nekriošius, Nicholas Malcolm Bigwood, published by Sciendo.Personality traits, especially in sport are modulatory factors of athletes' behavior - his/ her conscientiousness, the will to achieve an aim, perseverance and motivation of activity. Not only are biological predispositions related to anatomical or biochemical traits of success, but they are also largely determined by personality traits that result from genetic factors. In our research we joined tests of athlete's personality in correlation with genotypes of the dopamine transporter (DAT1) gene polymorphism. The selection of this polymorphism was based on previous reports connecting the influence of dopamine with motivation and numerous arguments supporting its correlation with human behavior. We observed significant differences among polymorphisms DAT 9/9, 9/10, 10/10 in terms of proportion of particular genotypes between athletes and the control group. We also found significant differences in the NEO FFI sten scale for conscientiousness. We noticed that anxiety was related with genotypic variants of DAT1, specifically the 9/10 VNTR variant, which conditioned lower levels of anxiety in the group of tested athletes. By contrast, the lower sten value of agreeability was statistically significant for the group of athletes that were carriers of the 10/10 VNTR genotype. Heterozygous 9/10 VNTR among athletes showed lower levels of anxiety in comparison with the control group, whereas agreeability determined using the NEO FFI scale represented a lower value among athletes that had the 10/10 polymorphism. We may thus conclude that the presence of polymorphic variants of the dopamine transporter gene corresponds to athletes' personality traits. © 2020 Monika Michałowska-Sawczyn, Milena Lachowicz, Anna Grzywacz, Aleksandra Suchanecka, Jolanta Chmielowiec, Krzysztof Chmielowiec, Jakub Chycki, Grzegorz Trybek, Piotr Żmijewski, Paweł Cięszczyk, published by Sciendo.The aim of this study was to investigate the effects of oral branched-chain amino acids (BCAAs) intake on muscular (creatine kinase and myoglobin) and central (serotonin) fatigue during an incremental exercise protocol and to determine the time to exhaustion. Sixteen male long-distance runners (25.7 ± 2.0 yrs) performed two trials, 14 days apart. Using a double-blind, placebo-controlled, randomised crossover design, participants ingested either 20 g of BCAAs (BCAA trial) or a placebo 1 hour prior to performing an incremental exercise session on a treadmill. The starting speed was 8 km/h and this was increased by 1 km/h every 5 minutes until volitional exhaustion. Blood analysis indicated that plasma levels of serotonin were lower in the BCAA trial (259.3 ± 13.5 ng/ml) than the placebo trial (289.1 ± 14.5 ng/ml) (p less then 0.05). There was a similar pattern of results for free fatty acid (p less then 0.05). The creatine kinase level was higher in the BCAA trial (346.1 ± 33.7 U/L) than the placebo trial (307.3 ± 30.2 U/L). No significant difference between trials was observed regarding the level of myoglobin (p = 0.139). Time to exhaustion was longer in the BCAA trial (50.4 ± 2.3 min) than the placebo trial (46.6 ± 3.2 min). In conclusion, oral intake of 20 g of BCAAs 1 hour prior to an incremental treadmill exercise session increased time to exhaustion, probably due to the reduction in serotonin concentration. Avapritinib manufacturer As myoglobin levels were within the normal range in both trials, we conclude that the participants did not reach muscular fatigue. © 2020 Mohammad Fayiz AbuMoh'd, Laila Matalqah, Zainalabidden Al-Abdulla, published by Sciendo.The objective of the present study was to analyze (based on gender and the style of swimming) the kinematic parameters of the transition phase between underwater swimming and surface swimming after the push-off start in competitive national swimmers. Seventy-four swimmers participating in the Spanish Swimming Championships were filmed and analyzed by DLT-2D photogrammetry during the start with the push-off in crawl, backstroke and butterfly styles. Between genders there were small differences in the distance and speed of transition. The male swimmers travelled greater distances (0.84 ± 0.04 vs. 0.66 ± 0.04 m, η2 = 0.05, F = 10.34, p less then 0.001) and they were faster (1.59 ± 0.03 vs. 1.38 ± 0.03 m/s, η2 = 0.08, F = 19.54, p less then 0.001) in the transition phase than female swimmers. Among styles there were greater differences in time (η2 = 0.47, F = 94.50, p less then 0.001) and transition distance (η2 = 0.38, F = 67.08, p less then 0.001), than in speed (η2 = 0.05, F = 5.63, p less then 0.001). During the backstroke push-off, swimmers spent more time (0.88 ± 0.04 s) and distance (1.17 ± 0.05 m), this being the slowest style (1.37 ± 0.04 m/s). In butterfly, athletes used less time (0.26 ± 0.03 s) and distance (0.39 ± 0.05 m) whereas crawl was the fastest of all (1.57 ± 0.04 m/s). These results allow the phase of transition from underwater to surface swimming to be characterized and to provide useful data for competitive swimmers and coaches to improve performance. © 2020 Alfonso Trinidad, Santiago Veiga, Enrique Navarro, Alberto Lorenzo, published by Sciendo.We aimed to compare dynamic exercise performance between hip extension exercises with different knee angles and between knee flexion exercises with different hip angles, and to investigate the recruitment pattern of the hamstrings in each exercise. Seven men performed 4 isokinetic exercises (3 maximal concentric contractions at 30°/s (peak torque) and 30 maximal concentric contractions at 180°/s (total work)) hip extension with the knee fully extended (HEke) and with the knee flexed at 90° (HEkf) and knee flexion with the hip fully extended (KFhe) and with the hip flexed at 90° (KFhf). The recruitment pattern of the hamstrings was evaluated in each exercise using magnetic resonance imaging (T2 calculation). The HEke condition showed significantly greater peak torque than the HEkf condition (p less then 0.05). The KFhf condition had significantly greater peak torque and total work values than the KFhe condition (p less then 0.05). Although the biceps femoris long head, semitendinosus, and semimembranosus had significantly increased post-exercise T2 values in the HEke (p less then 0.