Vitamin D Status and its Relation to Exercise Performance and Iron Status in Young Ice Hockey Players

Objectives The aim was to examine the association between serum vitamin D concentration and isometric strength of various muscle groups, vertical jump performance, and repeated sprint ability in young ice hockey players. The secondary aim was to determine the association between vitamin D deficiency and indices of iron status. Methods Fifty male ice hockey players (17.2±0.9 years) participated in this cross-sectional study. Exercise performance was evaluated using isometric strength measures of upper and lower extremities, vertical jump performance and repeated sprint ability (RSA). Blood samples were collected for the determination of serum 25-hydroxyvitamin D (25(OH)D) and multiple indicies of iron status. Results The mean serum 25(OH)D concentration was 30.4 ng-ml-1 and ranged from 12.5 to 91.4 ng-ml-1. Eleven participants (22%) had vitamin D deficiency and 20 athletes (40%) had vitamin D insufficiency. Serum 25(OH)D concentration was not positively correlated with isometric muscle strength, vertical jump performance, or RSA after adjusting for age, training experience, fat mass, fat free mass and height. Serum 25(OH)D concentration was not associated with indices of iron status. Conclusion Vitamin D insufficiency is highly prevalent in ice hockey players, but 25(OH)D concentration but it is not associated with exercise performance or indices of iron status

Relationship between ACTN3 R577X polymorphism and maximal power output in elite Polish athletes

Background and objective: The main purpose of this study was to examine the association between ACTN3 R577X polymorphism and the ability to produce peak power in young male athletes from various sports. Our hypothesis was that the ACTN3 R577X polymorphism is associated with jumping performance and athletes with RR genotype have better scores in tests than athletes with XX or RX genotype independently of the sport discipline. Materials and methods: Two hundred young Polish male participants representing different disciplines were recruited for this study. Genotyping for ACTN3 gene was performed using polymerase chain reaction. The power output of lower extremities and the height of rise of the body mass center during vertical jumps were measured on a force plate. Results: The genotype distribution of the ACTN3 gene did not differ significantly between groups of athletes. The significant difference in height of counter-movement jump was found between athletes with RR and XX genotype (0.446 ± 0.049 m vs. 0.421 ± 0.036 m, respectively, P = 0.026). The ACTN3 RR genotype was associated with greater muscle power and height of jump in young male athletes. Conclusions: These results suggest that the ACTN3 gene may play a significant role in determining muscle phenotypes. However, this gene is only one of many factors which could contribute to athletes’ performance and muscle phenotypes

Relationship between ACTN3 R577X polymorphism and maximal power output in elite Polish athletes

Background and objective: The main purpose of this study was to examine the association between ACTN3 R577X polymorphism and the ability to produce peak power in young male athletes from various sports. Our hypothesis was that the ACTN3 R577X polymorphism is associated with jumping performance and athletes with RR genotype have better scores in tests than athletes with XX or RX genotype independently of the sport discipline. Materials and methods: Two hundred young Polish male participants representing different disciplines were recruited for this study. Genotyping for ACTN3 gene was performed using polymerase chain reaction. The power output of lower extremities and the height of rise of the body mass center during vertical jumps were measured on a force plate. Results: The genotype distribution of the ACTN3 gene did not differ significantly between groups of athletes. The significant difference in height of counter-movement jump was found between athletes with RR and XX genotype (0.446 ± 0.049 m vs. 0.421 ± 0.036 m, respectively, P = 0.026). The ACTN3 RR genotype was associated with greater muscle power and height of jump in young male athletes. Conclusions: These results suggest that the ACTN3 gene may play a significant role in determining muscle phenotypes. However, this gene is only one of many factors which could contribute to athletes’ performance and muscle phenotypes

Vitamin D status and its relation to exercise performance and iron status in young ice hockey players

<div><p>Objectives</p><p>The aim was to examine the association between serum vitamin D concentration and isometric strength of various muscle groups, vertical jump performance, and repeated sprint ability in young ice hockey players. The secondary aim was to determine the association between vitamin D deficiency and indices of iron status.</p><p>Methods</p><p>Fifty male ice hockey players (17.2±0.9 years) participated in this cross-sectional study. Exercise performance was evaluated using isometric strength measures of upper and lower extremities, vertical jump performance and repeated sprint ability (RSA). Blood samples were collected for the determination of serum 25-hydroxyvitamin D (25(OH)D) and multiple indicies of iron status.</p><p>Results</p><p>The mean serum 25(OH)D concentration was 30.4 ng·ml^-1 and ranged from 12.5 to 91.4 ng·ml^-1. Eleven participants (22%) had vitamin D deficiency and 20 athletes (40%) had vitamin D insufficiency. Serum 25(OH)D concentration was not positively correlated with isometric muscle strength, vertical jump performance, or RSA after adjusting for age, training experience, fat mass, fat free mass and height. Serum 25(OH)D concentration was not associated with indices of iron status.</p><p>Conclusion</p><p>Vitamin D insufficiency is highly prevalent in ice hockey players, but 25(OH)D concentration but it is not associated with exercise performance or indices of iron status.</p></div

Descriptive characteristics for all ice hockey players (n = 50).

<p>Descriptive characteristics for all ice hockey players (n = 50).</p

Pearson’s and partial correlations between exercise performance and (log of) 25(OH)D concentration (n = 50).

<p>Pearson’s and partial correlations between exercise performance and (log of) 25(OH)D concentration (n = 50).</p

Pearson’s and partial correlations between exercise performance and Iron concentration (n = 50).

<p>Pearson’s and partial correlations between exercise performance and Iron concentration (n = 50).</p

Correlations between indices of iron status and (log of) 25(OH)D concentration (n = 50).

<p>Correlations between indices of iron status and (log of) 25(OH)D concentration (n = 50).</p