The Brazilian Twin Registry.

The Brazilian Twin Registry (BTR) was established in 2013 and has impelled twin research in South America. The main aim of the initiative was to create a resource that would be accessible to the Brazilian scientific community as well as international researchers interested in the investigation of the contribution of genetic and environmental factors in the development of common diseases, phenotypes, and human behavior traits. The BTR is a joint effort between academic and governmental institutions from Brazil and Australia. The collaboration includes the Federal University of Minas Gerais (UFMG) in Brazil, the University of Sydney and University of Melbourne in Australia, the Australian Twin Registry, as well as the research foundations CNPq and CAPES in Brazil. The BTR is a member of the International Network of Twin Registries. Recruitment strategies used to register twins have been through participation in a longitudinal study investigating genetic and environmental factors for low back pain occurrence, and from a variety of sources including media campaigns and social networking. Currently, 291 twins are registered in the BTR, with data on demographics, zygosity, anthropometrics, and health history having been collected from 151 twins using a standardized self-reported questionnaire. Future BTR plans include the registration of thousands of Brazilian twins identified from different sources and collaborate nationally and internationally with other research groups interested on twin studies.

The Charles Perkins Centre's Twins Research Node.

Twins can help researchers disentangle the roles of genes from those of the environment on human traits, health, and diseases. To realize this potential, the Australian Twin Registry (ATR), University of Melbourne, and the Charles Perkins Centre (CPC), University of Sydney, established a collaboration to form the Twins Research Node, a highly interconnected research facility dedicated specifically to research involving twins. This collaboration aims to foster the adoption of twin designs as important tools for research in a range of health-related domains. The CPC hosted their Twins Research Node's launch seminar entitled 'Double the power of your research with twin studies', in which experienced twin researchers described how twin studies are supporting scientific discoveries and careers. The launch also featured twin pairs who have actively participated in research through the ATR. Researchers at the CPC were surveyed before the event to gauge their level of understanding and interest in utilizing twin research. This article describes the new Twins Research Node, discusses the survey's main results and reports on the launch seminar.

Structural and functional predictors of drop vertical jump.

This investigation was designed to determine if relatively small manipulations of squat load and the inclusion of selected morphologic variables might augment the explained variance in vertical jump (VJ) displacement. Fifty-two university students (27 women and 25 men) with weight training experience served as subjects. All were assessed for body fat percentage (BF%), height, body weight (BW), leg length (LL), ankle range of motion, and quadriceps angle (Q-angle). Additionally, subjects performed drop vertical jumps (DVJs) and both countermovement jump (CMJ) squats and static jump (SJ) squats at 20, 30, and 40% of their back squat 1 repetition maximum (1RM). A preliminary analysis revealed that DVJcm for all subjects (28.1 +/- 6.64; mean +/- SD) was most highly correlated with both CMJ @ 30% 1RM (CMJ30PP) and SJ @ 20% 1RM (SJ20PP) (r = 0.84, p < 0.001). Forced multiple regression was then used to determine which variables contributed to VJ displacement. The greatest variability explained (83%) used a CMJ: DVJcm = 20.311 + (0.008) (CMJ30PP) - (0.346) (BW). When the same variables were used to calculate separate gender-based regressions, the explained variance in DVJcm (men = 33.0 +/- 5.34 cm; women = 23.4 +/- 3.79 cm) was 68% for men and 64% for women. These findings suggest that jump squat peak power at a light load is a good predictor of VJ and that its training-induced augmentation would likely improve VJ. The addition of BW to the equation explained slightly more variability in DVJcm than in BF%. Because excess amounts of either would be an additional load to be moved against gravity (fat in general or skeletal muscle in the upper torso), it follows that relatively high levels of either might be expected to attenuate VJ performance.

Reach height and jump displacement: implications for standardization of reach determination.

Vertical jump performance is often assessed using jump-and-reach tests. The exact procedure used for determining standing reach height and jump height has a large effect on the resultant displacement. The purpose of this investigation was to determine the influence of 4 methods of standing reach height measurement and Vertec jump height measurement against 2 force plate methods of jump displacement determination (impulse and flight-time methods). Fifteen men with various training backgrounds performed 2 each of countermovement, restricted (no arm swing) and static start vertical jumps. Reach height was determined using 4 methods; either a 1- or overlapped 2-hand reach, flat footed or with plantar flexion. All jumps were performed on a force platform. The best jump of each type based on Vertec displacement was used for analysis. Repeated-measures of analysis of variance for each jump type was used for analysis with Bonferroni post hoc for pairwise comparisons of jump measurement style. All jump displacements for similar types were significantly intercorrelated with a minimum r-value of 0.84. Impulse vs. flight time was the only pairwise comparison of measurement type for which similar values were noted. The one-hand reach with plantar flexion was the method of reach that was closest to the impulse and flight-time methods, and thus should be the preferred choice when using jump-and-reach tests to determine jump displacement. In all cases, the Vertec overestimates the displacement of the COM based on force plate methods. When comparing groups of individuals from different data sets, one must consider both the method of reach height (if performed) and jump displacement to make valid comparisons. If plantar flexion with a 1-hand reach is not used during reach measurement, jump displacement will be erroneously high.