Digit ratio (2D:4D) and muscular strength in adolescent boys

Using a cross-sectional design, this study quantified the relationship between the digit ratio (2D:4D) and muscular strength in 57 adolescent boys. 2D:4D was very likely a moderate negative correlate of handgrip strength, even after adjustment for age and body size. This result may reflect the organizational benefits of prenatal testosterone

Time changes in the body dimensions of male Australian Army personnel between 1977 and 2012

The aim of this study was to quantify time changes in the body dimensions of male Australian Army personnel. Following a systematic review, two studies were identified and matched for occupation and age (n = 669) with time changes in 12 absolute and 11 proportional body dimensions assessed between 1977 and 2010–12. Changes in means were expressed as absolute, percent and standardised changes, with changes in variability assessed visually and as the ratio of coefficients of variation (CVs). Time changes in absolute dimensions were typically positive (increases) and moderate in magnitude (median standardised change ± 95%CI: 0.53 ± 0.23), and while changes in proportional dimensions were typically negligible (median standardised change ± 95%CI: 0.16 ± 0.33), substantial changes(standardised changes ≥0.2 or ≤–0.2) were observed in several dimensions. Variability in body dimensions has also typically increased (median ratio of CVs ± 95%CI: 1.10 ± 0.07) and become more right-skewed. These findings have important implications for the design and acquisition of new military vehicles, body equipment and clothing

Relationships between digit ratio (2D:4D) and basketball performance in Australian men

Objective To investigate relationships between the digit ratio (2D:4D) and competitive basketball performance in Australian men. Methods Using an observational cross‐sectional design a total of 221 Australian basketball players who competed in the Olympic Games, International Basketball Federation World Championships/Cup, Australian National Basketball League, Central Australian Basketball League or socially had their 2D:4Ds measured. Analysis of variance was used to assess differences in mean 2D:4Ds between men playing at different competitive standards, with relationships between 2D:4Ds and basketball game‐related statistics assessed using Pearson\u27s product moment correlations in men playing at a single competitive standard. Results There were significant differences between competitive standards for the left 2D:4D following Bonferroni correction, but not for the right 2D:4D, with basketballers who achieved higher competitive standards tending to have lower left 2D:4Ds. No important correlations between 2D:4D and basketball game‐related statistics were found, with correlations typically negligible. Conclusions This study indicated that the 2D:4D can discriminate between basketballers competing at different standards, but not between basketballers within a single competitive standard using objective game‐related statistics

The relationship between ventilatory threshold and repeated-sprint ability in competitive male ice hockey players

Background/objective The relationship between ventilatory threshold (VT1, VT2) and repeated-sprint ability (RSA) in competitive male ice hockey players was investigated. Methods Forty-three male ice hockey players aged 18–23 years competing in NCAA Division I, NCAA Division III, and Junior A level participated. Participants performed an incremental graded exercise test on a skate treadmill to determine V˙ role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 14.4px; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative; \u3eV˙O2peak, VT1, and VT2 using MedGraphics Breezesuit™ software (v-slope). Participants performed an on-ice repeated shift (RSA) test consisting of 8-maximal skating bouts, lasting approximately 25 s and interspersed with 90 s of passive recovery, to determine first gate, second gate, and total sprint decrement (%dec). Pearson product-moment correlations and multiple regressions were used to assess relationships between ventilatory threshold variables (VT1, VT2, Stage at VT1, and Stage at VT2) and RSA (first gate, second gate, and total course decrement). Results Stage at VT2 was the only variable substantially correlated with first gate (r = −0.35; P \u3c 0.05), second gate (r = −0.58; P \u3c 0.001) and total course decrement (r = −0.42; P \u3c 0.05). Conclusion The results of this study demonstrated that VT is substantially associated with RSA, and VT2 is more strongly correlated with RSA than V˙ role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 14.4px; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative; \u3eV˙O2peak. This study suggests that longer duration high-intensity interval training at intensities that increase workrate at VT2 may lead to possible improvements in RSA

Temporal trends in the handgrip strength of 2,592,714 adults from 14 countries between 1960 and 2017: A systematic analysis

Background: Handgrip strength (HGS) is an excellent marker of functional capability and health in adults, although little is known about temporal trends in adult HGS. Objectives: The aim of this study was to systematically analyze national (country-level) temporal trends in adult HGS, and to examine relationships between national trends in adult HGS and national trends in health-related and socioeconomic/demographic indicators. Methods: Data were obtained from a systematic search of studies reporting temporal trends in HGS for adults (aged ≥20 years) and by examining national fitness datasets. Trends in mean HGS were estimated at the country-sex-age group level by best-fitting sample-weighted linear/polynomial regression models, with national and sub-regional (pooled data across geographically similar countries) trends estimated by a post-stratified population-weighting procedure. Pearson’s correlations quantified relationships between national trends in adult HGS and national trends in health-related and socioeconomic/demographic indicators. Results: Data from 10 studies/datasets were extracted to estimate trends in mean HGS for 2,592,714 adults from 12 high- and 2 upper-middle-income countries (from Asia, Europe and North America) between 1960 and 2017. National trends were few, mixed and generally negligible pre-2000, whereas most countries (75% or 9/12) experienced negligible-to-small declines ranging from an effect size of 0.05 to 0.27, or 0.6 to 6.3%, per decade post-2000. Sex- and age-related temporal differences were negligible. National trends in adult HGS were not significantly related to national trends in health and socioeconomic/demographic indicators. Conclusions: While trends in adult HGS are currently limited to 14 high- and upper-middle-income countries from 3 continents, adult HGS appears to have declined since 2000 (at least among most of the countries in this analysis), which is suggestive of corresponding declines in functional capability and health. PROSPERO registration number: CRD42013003678. KEY POINTS National (country-level) trends in adult handgrip strength (HGS) were few, mixed and generally negligible pre-2000, and generally negligible and indicated declines post-2000 Sex- and age-related temporal differences in adult HGS were negligible-to-small at the country level and negligible at the regional level National trends in adult HGS were not significantly related to national trends in health and socioeconomic/demographic indicator