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Purpose: (1) To examine the comparability, i.e., discriminatory power, in a preschooler test (PREFIT 20-m shuttle-run test) and the 20mSRT-Original in 5-6-year-olds; (2) to provide an equation to estimate VO2max from the 20mSRT-PREFIT.Methods: 138 participants aged 5-6 years performed the 20mSRT-PREFIT and the 20mSRT-Original in a counterbalanced order. Total test duration, completed stages, maximum speed and maximum heart rate were registered.Results: Participants finished stages from 2-10 in the 20mSRT-PREFIT, whereas stages 1-5 were completed in the 20mSRT-Original and a null was registered, showing the original version a lower discriminatory power. We also observed that the higher the cardiorespiratory fitness level the more comparable were the tests, i.e., - 0.04 km h-1 difference between tests in the fittest participants (i.e., maximum speed ≥ 9.5 km h-1). Using the original equation proposed by Leger and colleagues in 1988 and based on the estimation regression of maximum speed in the 20mSRT-Original from the PREFIT version, we computed a new equation to estimate VO2max from the 20mSRT-PREFIT: Y = 44.657 + 1.795X 1   - 2.601X 2  + 0.0852X 1 X 2 (r = 0.77; r 2 = 0.59; SEE = 1.25 ml kg-1 min-1 or 2.59% of estimated mean VO2max = 48.38 ml kg-1 min-1), where X 1 is the 20mSRT-PREFIT maximum speed (km h-1) and X 2 is the age of participants. The 20mSRT-PREFIT resulted in a significantly higher maximum heart rate than the 20mSRT-Original.Conclusions: The 20mSRT-PREFIT has higher discriminatory power than the 20mSRT-Original. Our study provides for the first time an opportunity to estimate VO2max in preschoolers and children based on the 20mSRT-PREFIT maximum speed and the age of participants. [ABSTRACT FROM AUTHOR]

We studied the association of 55 polymorphisms in the PPP3CA, PPP3CB, PPP3CC, PPP3R1 and PPP3R2 genes with both (1) the pre-training levels and (2) responsiveness to endurance training (18 weeks), of echocardiographic variables. The latter were measured both before and after the training program at each of the following time points: before (rest), during and after cycle-ergometry exercise. Subjects were healthy young Chinese men of Han origin [n = 102; mean (SD) age: 19 ± 1 years]. To assess genotype:phenotype associations at pre-training, we used a one-factor (genotype) ANOVA for each polymorphism. To assess the association between each polymorphism and the training responsiveness of cardiac phenotypes, we used a two-factor (genotype x training) ANOVA with repeated measures. All multiple comparisons were corrected for mass significance. For genotype:phenotype associations at pre-training, we only found a significant association between the rs3763679 polymorphism (PPP3CB) and resting heart rate. As for genotype associations with trainability of cardiac phenotypes, we found the following significant associations (i.e. significant genotype × training interaction effect): (1) rs1879793, rs1075534, rs7430, rs2461483 and rs10108011 (PPP3CC) and cardiac output/stroke volume after exercise; and (2) rs1407877 (PPP3R2) and ejection fraction at 50 W. The findings suggest that polymorphisms in the calcineurin genes might be among the numerous potential genetic variant candidates that can help explaining human variations in the pre-training levels or trainability of cardiac phenotype traits. [ABSTRACT FROM AUTHOR]

Polymorphisms in calcineurin genes are candidates to explain individual variations in endurance phenotype traits owing to the pivotal role that the calcineurin signaling pathway plays in the regulation of important cardiac and skeletal muscle phenotypes such as slow myosin heavy chain expression, skeletal muscle oxidative capacity or cardiac hypertrophy. We studied the possible association of 55 polymorphisms in the calcineurin gene isoforms PPP3CA, PPP3CB, PPP3CC, PPP3R1 and PPP3R2 with both baseline levels and responsiveness to a 18-week endurance training program of maximal oxygen uptake (VO(2)max) and running economy (RE) in healthy young Chinese men [n = 102; mean (SD) age 19 +/- 1 years] of Han origin. We used two-way (genotype, training) ANOVA for repeated measures to compare baseline and trainability of VO(2)max and RE among genotypes of the aforementioned polymorphisms. We found a significant association between (a) baseline VO(2)max and the rs2850965 and rs3804423 polymorphisms in the PPP3CA gene; (b) training responsiveness of VO(2)max and both the rs3804358 polymorphism (PPP3CA) and the rs4671887 polymorphism (PPP3R1); and (c) training responsiveness of RE and rs3739723 (PPP3R2). Though more research is needed, our findings suggest that polymorphisms in the calcineurin genes might be among the numerous potential genetic variant candidates that, together with other factors (e.g., environment, complex genetics interactions), can help explaining human variations in endurance exercise phenotype traits. [ABSTRACT FROM AUTHOR]

The NOS3 gene is a candidate to explain individual variations in health and exercise related phenotypes. We compared genotypic and allelic frequencies of the NOS3 -786 T/C polymorphism (rs2070744) in three groups of men of the same Caucasian (Spanish) descent: (i) elite endurance athletes (cyclists, runners; N = 100); (ii) elite power athletes (jumpers, throwers, sprinters; N = 53) and (iii) non-athletic controls (N = 100). The frequency of the TT genotype was significantly higher in power athletes (57%) than in the endurance (33%, P = 0.017) or control group (34%, P = 0.026). The frequency of the T allele was also higher in power sportsmen (71%) than in their endurance (55%, P = 0.003) and control referents (56%, P = 0.015). No differences were observed between control and endurance groups. In summary, the -786 T/C polymorphism of the NOS3 gene seems to be associated with elite performance in power-oriented athletic events (throwing, jumping, sprinting), with the T allele exerting a beneficial effect. The mechanism by which this allele variant might benefit power performance remains to be elucidated. [ABSTRACT FROM AUTHOR]