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  • Author: Zbigniew Jastrzębski x
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Damage to Liver and Skeletal Muscles in Marathon Runners During a 100 km Run With Regard to Age and Running Speed

Abstract

The purpose of this study was to determine: (1) whether damage to liver and skeletal muscles occurs during a 100 km run; (2) whether the metabolic response to extreme exertion is related to the age or running speed of the participant; (3) whether it is possible to determine the optimal running speed and distance for long-distance runners’ health by examining biochemical parameters in venous blood. Fourteen experienced male amateur ultra-marathon runners, divided into two age groups, took part in a 100 km run. Blood samples for liver and skeletal muscle damage indexes were collected from the ulnar vein just before the run, after 25, 50, 75 and 100 km, and 24 hours after termination of the run. A considerable increase in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) was observed with the distance covered (p < 0.05), which continued during recovery. An increase in the mean values of lactate dehydrogenase (LDH), creatine kinase (CK) and C-reactive protein (CRP) (p < 0.05) was observed with each sequential course. The biggest differences between the age groups were found for the activity of liver enzymes and LDH after completing 75 km as well as after 24 hours of recovery. It can be concluded that the response to extreme exertion deteriorates with age in terms of the active movement apparatus.

Open access
Impact of the Polymorphism Near MC4R (rs17782313) on Obesity- and Metabolic-Related Traits in Women Participating in an Aerobic Training Program

Abstract

The C/T polymorphism (rs17782313) mapped 188 kb downstream of the melanocortin-4 receptor gene (MC4R) shows a strong relationship with an increased body mass index (BMI) and the risk of type 2 diabetes. However, the information on polymorphism’s potential modifying effect on obesity- and metabolic-related traits achieved through training is still unknown. Therefore, we decided to check if selected body measurements observed in physically active participants would be modulated by the genotype. The genotype distribution was examined in a group of 201 Polish women measured for chosen traits before and after the completion of a 12 week moderate-intensive aerobic training program. A statistically significant relationship between the glucose level and the genotype was identified (p = 0.046). Participants with CC and CT genotypes had a higher glucose level during the entire study period compared with the TT genotype. However, our results did not confirm the relationship between the C allele and an increased BMI or other obesity-related traits. Additionally, we did not observe a near MC4R C/T polymorphism x physical activity interaction. However, our results revealed that majority of obesity-related variables changed significantly during the 12 week training program. The effect sizes (d) of these changes ranged from small to medium (d = 0.11-0.80), whereas the largest effect (d = 0.80; i.e. medium) was reported for the fat mass content (FM). We found a relationship between the near MC4R C/T polymorphism and an increased glucose level, and it is thus a candidate to influence type 2 diabetes. Interestingly, after the 12 week training program, participants with the C (risk) allele with fasting hyperglycemia had a normal glucose level. Although, this change was not statistically significant, it shows an important trend which needs further investigation.

Open access
Can Supplementation of Vitamin D Improve Aerobic Capacity in Well Trained Youth Soccer Players?

Abstract

There is no clear evidence that vitamin D effectively improves physical capacity in high-level athletes. The aim of this study was to confirm that vitamin D supplementation of soccer players during eight-week high-intensity training would have a significant effect on their aerobic capacity. The subjects were divided into two groups: the experimental one that was supplemented with vitamin D (SG, n = 20), and the placebo group (PG, n = 16), not supplemented with vitamin D. All the players were subjected to the same soccer training described as High-Intensity Interval Training (HIIT). The data of the vitamin D level, PWC170, lactate threshold (LT) were collected just before and after the intervention. A significant increase in vitamin D concentration (119%) was observed in the supplemented group, while the non-supplemented group showed a decrease of 8.4%. The studied subjects improved VO2max results by 20% in the SG, and by 13% in the PG. The improvement in velocity at the LT was similar in both groups. Results of this study show that vitamin D can have a positive, though moderate, effect on aerobic performance in players subjected to high-intensity training in the form of small-sided games for 8 weeks.

Open access
Does the MTHFR A1298C Polymorphism Modulate the Cardiorespiratory Response to Training?

Abstract

The 5,10-methylenetetrahydrofolate reductase gene (MTHFR) A1298C polymorphic variant is a candidate to explain the individual differences in trainability and response to exercise training. Therefore, the aim of the study was to verify whether the A1298C polymorphism influenced the aerobic and anaerobic performance as well as body and mass composition in young Polish women following low-high impact aerobic exercise training. Two hundred and one women aged 21 ± 1 years (range 19–24) were included in the study. All of them completed a 12-week exercise training program and were measured for selected somatic features, aerobic capacity and cardiorespiratory fitness indices as well as peak anaerobic power and anaerobic capacity, before and after the intervention. A mixed 2 x 2 ANOVA for 20 dependent variables grouped in three categories was conducted. No significant interaction of the genotype with training for body mass and body composition variables was observed. Although, there were three significant genotype x training interactions for maximal oxygen uptake variables, regardless of body mass i.e.: for VO2max (p < 0.05), HRmax (p < 0.0001) and HRAT/HRmax (p < 0.0001). Significantly greater improvement in VO2max was gained by the CC+AC group compared to the AA genotype group. The present results support the hypothesis that individual differences in trainability are at least in part determined by the genetic component and MTHFR A1298C seems to be one of the many polymorphisms involved.

Open access
Relationships Between the Expression of the ACTN3 Gene and Explosive Power of Soccer Players

Abstract

Muscle strength and maximal speed are factors determining athlete’s results during competition. Their association with ACTN3 gene activity has been documented. The purpose of this study was the analysis of ACTN3 gene expression during a 2 month training cycle of soccer players and its correlation with the countermovement jump (CMJ) and squat jump (SJ). The study group consisted of 22 soccer players (aged 17‐18). The study material included peripheral blood lymphocytes. The relative expression (RQ) of the ACTN3 gene was analyzed by qPCR and performed before and after the two‐month training cycle. Before the training cycle low expression levels of ACTN3 (median RQ = 0.95) were observed, yet after the training cycle they were elevated (median RQ = 1.98) ( p = 0.003). There was an increase in performance of both jumps: SJ (p = 0.020) and CMJ (p = 0.012) at the end of the training cycle. A simultaneous increase in the ACTN3 gene expression level and height in both jump tests was observed in 73% of athletes (p > 0.05). There were no significant relationships between the ACTN3 gene expression level and the results of the CMJ and SJ. However, explosive strength is a complex feature shaped by many different factors and it could be the reason why we did not observe correlations between these variables.

Open access