Aims: To compare the effects of 2 and 5 min of passive static stretching (SS) on stiffness and blood flow in the rectus femoris in adolescent athletes using shear wave elastography (SWE) and superb microvascular imaging (SMI).Material and methods: This prospective study included 20 male athletes with median age of 14.5 (12.5–16.5) years. The subjects were divided into two groups based on the SS duration as follows: 2 min (n=10) and 5 min (n=10). At rest and after 2 and 5 min of SS, stiffness and blood flow values were compared in the rectus femoris for each group. Inter-operator reliability was also analysed.Results: There was no significant difference between resting and 2 min of SS in terms of stiffness. The stiffness values decreased significantly from resting to 5 min of SS. The blood flow increased significantly from resting to 2 and 5 min of SS. Inter-operator reliability was moderate to perfect for SWE and SMI measurements (ICC: 0.52–0.83).Conclusions: SWE and SMI can be used to acquire reliable quantitative data about muscle stiffness and blood flow in adolescents. While stiffness parameters significantly decreased from resting after only 5 min, blood flow significantly increased both after 2 and 5 min. For physical rehabilitation protocols, 5 min of SS may be chosen to reduce stiffness. For competitions, 2 min of SS may be sufficient for warm-up exercise because it increases the blood flow optimally. Five min of SS may be preferred for the cool-down exercise to enhance recovery.

Aims: Athletic performance in basketball comprises the contributions of anaerobic and aerobic performance. The aim was to investigate the effects of passive muscle stiffness, using shear wave elastography (SWE), as well as muscle thickness, and body mass index (BMI), on both aerobic and anaerobic performances in adolescent female basketball players.Material and methods: Anaerobic and aerobic (VO2max) performance was assessed using the vertical jump and shuttle run tests, respectively, in 24 volunteer adolescent female basketball players. Passive muscle stiffness of the rectus femoris (RF), gastrocnemius medialis (GM), gastrocnemius lateralis (GL) and soleus muscles were measured by SWE, and the thickness of each muscle was assessed by gray scale ultrasound. The BMI of each participant was also calculated. The relationship between vertical jump and VO2max values, and those of muscle stiffness, thickness, and BMI were investigated via Pearson’s correlation and multivariate linear regression analysis.Results: No significant correlation was observed between muscle stiffness and VO2max or vertical jump (p>0.05). There was significant negative correlation between GL thickness and VO2max (p=0.026), and soleus thickness and VO2max (p=0.046). There was also a significant negative correlation between BMI and VO2max (p=0.001). Conclusions: This preliminary work can be a reference for future research. Although our article indicates that passive muscle stiffness measured by SWE is not directly related to athletic performance, future comprehensive studies should be performed in order to illuminate the complex nature of muscles. The maintenance of lower muscle thickness and optimal BMI may be associated with better aerobic performance.

We aimed to analyze the allelic distribution of solute carrier family-6 member-4 promoter region in Turkish athletes. Recent studies showed the association of lesser expressing "S" allele with anxiety. Genotype percentages for LL, LS and SS genotypes were found as 46, 35 and 19, respectively. 38% of the males had LL, %38 had LS and 24% had SS genotypes. Percentages of LL, LS and SS genotypes were 54, 31 and 15 in females, respectively. 15 (58%) male and 18 (69%) females had L, 11 (42%) male and 8 (31%) females had S alleles. Variations in the association of the SLC6A4 alleles with neuropsychiatric disorders according to different nationalities have been reported. This is the first report showing that LL genotype and L allele in Turkish athletes was more frequent than SS genotype and S allele.

In the present study, the effect of ACE rs1799752 polymorphism on maximal oxygen consumption (VO_2max) in ice hockey players was analyzed. For this reason, 21 male National Ice Hockey players, aged between 18-25, were recruited for the study. The conventional polymerase chain reaction (PCR) was used on the genotype rs1799752 polymorphism. The VO_2max values were calculated by using the 20m Shuttle Run tests. The numbers and percentages of the II, ID and DD genotypes were 9 (%43), 7 (%33), and 5 (%24), respectively. The allelic distribution for I and D alleles was found to be 25 (60%) and 17 (40%), respectively. The mean VO_2max of all the athletes was calculated as 47.52 ml. The mean VO_2max of the II, ID, and DD genotypes were 49.74ml, 47.34 ml, and 46.43 ml, respectively. We found that the oxygen utilization capacity increased from the DD genotype to the II genotype. However, this increase was not statistically significant (p> 0.05). In order to confirm our findings, it is recommended that larger prospective studies depending on the effect of the relevant polymorphisms needed to be carried out.