We estimated international/national temporal trends in sit-ups performance for children and adolescents, and examined relationships between national trends in sit-ups performance and national trend...

The association between 25(OH)D concentration and fat mass (FM) after adjusting for covariates. Methods Data were collected for 53 junior and collegiate ice hockey players residing near Minneapolis, MN (44.9° N) during the off-season (May 16 to June 28). Liquid chromatography-tandem mass spectrometry was used to assess 25(OH)D concentration, and hydrostatic weighing was used to determine FM. Dietary intake and endogenous synthesis of vitamin D were evaluated via a questionnaire. Results Twenty (37.7%) athletes possessed insufficient 25(OH)D concentrations (<32 ng·mL−1). Log-transformed 25(OH)D concentration was inversely associated with FM in the athletes (r = −0.52, n = 51, P = 0.001). After controlling for measured covariates using sequential linear regression, the adjusted R2 change value indicated that 8.1% of the variability in (log of) 25(OH)D concentration was predicted by FM (P = 0.005). Conclusions The findings of this study demonstrate an inverse association between FM and vitamin D status after adjusting for environmental, dietary, and anthropometric predictors in a sample population of athletes. Athletes with higher levels of adiposity may be at increased risk of poor vitamin D status....

Purpose: To estimate temporal trends in broad jump performance for United States youth, a marker of muscular fitness and health. Method: Electronic databases, topical systematic reviews, and personal libraries were systematically searched for studies reporting descriptive standing broad jump data for apparently healthy United States youth (age 10–17 years). Temporal trends at the sex-age level were estimated using sample-weighted regression models associating the year of testing to mean jump performance, with national trends standardized to the year 1985 using a post-stratified population-weighting procedure. Results: Collectively, there was a small increase of 12.6 cm (95%CI: 12.5 to 12.7) or 7.9% (95%CI: 7.1 to 8.6) in 65,527 United States youth between 1911 and 1990. Increases were greater for girls (change in means [95% CI]: 17.1 cm [16.9 to 17.3]; 11.4% [10.7 to 12.2]) compared to boys (change in means [95% CI]: 8.5 cm [8.3 to 8.7]; 4.6% [3.8 to 5.4]), but did not differ between children (10–12 years) and adolescents (13–17 years). Increases in broad jump performance were not always uniform across time, with steady and progressive increases observed for boys and children, respectively, and a diminishing rate of increase observed for girls and adolescents. Conclusions: Muscular fitness is a good marker of health, so greater broad jump performance from 1911 to 1990 may reflect corresponding changes in health. Routine assessment of broad jump performance may be useful to monitor trends in health and muscular fitness of United States youth due to its practicality, scalability, and predictive utility.

The relationship between ventilatory threshold (VT1, VT2) and repeated-sprint ability (RSA) in competitive male ice hockey players was investigated. 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 ˙ O_2peak, 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). Stage at VT2 was the only variable substantially correlated with first gate (r = -0.35; P < 0.05), second gate (r = -0.58; P < 0.001) and total course decrement (r = -0.42; P < 0.05). The results of this study demonstrated that VT is substantially associated with RSA, and VT2 is more strongly correlated with RSA than V ˙ O_2peak. This study suggests that longer duration high-intensity interval training at intensities that increase workrate at VT2 may lead to possible improvements in RSA.