Can sport-specific training affect vertical jumping ability during puberty?

Vertical jumping ability (VJ) is an important component for successful performance in various team sports such as volleyball, basketball, and soccer. There is evidence that the sport-specific training in these sports may affect the development of VJ throughout the developmental years. Thus, the main objective of this study was to investigate the sport-related effect (volleyball, basketball, soccer) on vertical jumping ability (VJ) and on the stretch-shortening cycle (SSC) during puberty. 320 boys (12-15 years old) - 80 basketball players (BP), 80 soccer players (SP), 80 volleyball players (VP) and 80 non-athletes (NA) - participated in the present study. VJ was evaluated by the squat jump (SJ) and countermovement jump (CMJ) tests, and the contribution of SSC was calculated. The SJ and CMJ were significantly higher in VP vs. NA at the age of 12 years old and significantly greater in all sports vs. NA at the age of 13, 14 and 15 years. Furthermore, 15-year-old VP demonstrated significantly higher SJ and CMJ compared with BP and SP (p<0.01), whereas no differences were observed between BP and SP (p>0.05). Finally, pairwise comparisons revealed non-significant sport- and age-related differences (p > .05) in SSC. The pattern of age-related increase in VJ is different between athletes and non-athletes during puberty. Furthermore, sport-specific training adaptations are evident at the age of 15 years old where VP demonstrate greater VJ than BP and SP, while in younger age groups, there are no significant differences in VJ between athletes of different sports.

Strength Profile of Hip Abductor and Adductor Muscles in Youth Elite Soccer Players.

The main objective of this study was to provide an extensive isokinetic profile of the hip joint in youth soccer players, where the literature is limited. Additionally, this study investigated the effect of age on isokinetic peak torque values of hip abductor and adductor muscles and on reciprocal muscle group torque ratios in youth soccer players at different angular velocities (30 vs. 90o/s) and muscle actions (concentric vs. eccentric). Sixty young elite male soccer players were assigned into three equal groups (n = 20): children, young adolescents and older adolescents, and performed five maximal concentric and eccentric hip-abductions and adductions at 30o/s and 90o/s. The results showed a significant increase (p < 0.05) in peak torque values from childhood to adolescence, with the exception of young adolescents vs. older adolescents where no differences were observed. The reciprocal ratios were not affected by age, but improved with an increase in angular velocity with the exception of the CON/ECC ratio that was higher at 30o/s. The data presented in this study provide an extensive isokinetic profile of hip abductor and adductor muscle strength in youth soccer players to assist both coaches and sports medicine professionals in strength monitoring and training.

The effect of professional dietary counseling: elite basketball players eat healthier during competition days.

BACKGROUND: Literature suggests that dietary intake of elite athletes may differ between training and competition days. In addition, despite the importance of nutrition in sports and the popularity of basketball, studies on the diet of basketball players are scarce. Therefore, the aim of the present study was to assess dietary intake and diet quality in training and competition days in a team of elite basketball players receiving daily professional nutritional counseling. METHODS: One elite basketball team (N.=15) participating in EuroLeague volunteered for the study. The team employed a certified dietitian, responsible for providing individualized nutritional evaluation and counseling, dietary planning and supervision of the diet of all the players. Dietary intake was assessed using 24-hour recalls and the Healthy Eating Index (HEI) was then calculated. RESULTS: All players exhibited adequate (i.e., >80) HEI score (raw and adjusted for energy intake [EI]), on both training and competition days. Although daily energy, carbohydrate and protein intakes were greater during training compared to competition days (26.0 [21.7, 26.4] vs. 19.5 [19.3, 22.1] MJ, 7.6±1.5 vs. 6.8±0.9 g/kg of body weight [BW] and 2.6±0.6 vs. 2.2±0.2 g/kg BW, respectively; all P<0.05), HEI score (raw and adjusted for EI) was lower in training compared to competition days (92.9 [82.1, 93.2] vs. 94.0 [94.0, 94.0] and 89.7 [88.4, 89.7] vs. 92.7 [91.7, 92.8], respectively; all P≤0.001) due to lower total grains, whole grains and total vegetables consumption and greater saturated fats consumption (P<0.05). CONCLUSIONS: Elite basketball players receiving daily nutritional counseling by certified sports dietitians exhibit adequate diet quality, with the highest possible observed during competition days.

Prediction of VO2max from a new field test based on portable indirect calorimetry.

We assessed the validity and reliability of the new 15m square shuttle run test (SST) for predicting laboratory treadmill test (TT) maximal oxygen uptake (VO(2 max)) compared to the 20 m multistage shuttle run test (MST) in 45 adult males. Thirty participants performed a TT and a SST once to develop a VO( 2max) prediction model. The remaining 15 participants performed the TT and MST once and the SST twice for cross-validation purposes. Throughout testing V O(2max) was determined via portable indirect calorimetry while blood lactate concentration was assessed at the fifth recovery minute. Comparisons of TT V O(2 max) (51.3+/-3.1 ml kg(-1)min(-1)) with SST measured (51.2+/-3.2 ml kg(-1)min(-1)) and predicted (50.9+/-3.3 ml kg(-1)min(-1)) V O(2 max) showed no differences while TT blood lactate was higher compared to SST (10.3+/-1.7 mmol vs. 9.7+/-1.7 mmol, respectively). In contrast, MST measured (53.4+/-3.5 ml kg(-1)min(-1)) and predicted (57.0+/-4.5 ml kg(-1)min(-1)) V O(2 max) and blood lactate (11.2+/-2.0 mmol) were significantly higher compared to TT. No test-retest differences were detected for SST measured and predicted V O(2 max) and blood lactate. It is concluded that the SST is a highly valid and reliable predictive test for V O(2 max).