MET values for youth, but was limited because about two-thirds of the values were actually adult-based and only 1 MET value was provided for all age groups ( 12 ). To update the Youth Compendium with youth-based values, a method is needed that expresses the energy cost of physical activities and
Karin A. Pfeiffer, Kathleen B. Watson, Robert G. McMurray, David R. Bassett, Nancy F. Butte, Scott E. Crouter, Stephen D. Herrmann, Stewart G. Trost, Barbara E. Ainsworth, Janet E. Fulton, David Berrigan and For the CDC/NCI/NCCOR Research Group
Kosuke Kojima, Christopher L. Brammer, Tyler D. Sossong, Takashi Abe and Joel M. Stager
swimmers remains to be determined. As there is a tendency for training paradigms to rapidly trickle down from the elite, collegiate swimming programs, it is not surprising to find that RST is becoming increasingly common in age-group swimming programs. However, because of the limited data regarding the
Thomas A. Perks
confounding age and cohort effects, where researchers use differences between age groups to make possibly erroneous generalizations about change over time. By contrast, studies using longitudinal data—which are required if one wishes to assess how individuals change—offer more qualified assessments. However
Brian A. Blanksby, Jennifer R. Simpson, Bruce C. Elliott and Keith McElroy
Because turning can account for one-third of breaststroke race time in 25 m pools, it is possible that enhancing turning techniques can improve performance significantly. Underwater video cameras and a force platform were used to analyze turning techniques of 23 age-group breaststrokers during three 50 m push-start, maximum-effort swims. The criterion measure was the time elapsed between passing the 5 m mark on the approach and departure from the wall (5 m round-trip time [RTT]). Correlations revealed significant commonality of variance (p < .01) between the 5 m RTT and the 2.5 m RTT, 50 m time, average single-stroke velocity, peak reaction force, pivot time, impulse, peak horizontal velocity off the wall, arm and leg split-stroke resumption distances, surfacing distance, surfacing time, and horizontal velocity, height, and mass of the subjects. All swimmers achieved a net gain at the turn in that the mean 5 m RTT (20% of the distance) represented 18.26% of the total swimming time. Following stepwise regression, a successful turn was predicted by the equation 17.113 - 0.322 surfacing distance - 0.036 height - 0.723 surfacing horizontal velocity + 0.723 pivot time - 0.65 peak horizontal velocity.
S. Jill Black and Maureen R. Weiss
Based on Barter's competence motivation theory, this study examined the relationships between perceived coaching behaviors and (a) perceptions of ability and (b) motivation in competitive age-group swimmers. Male and female athletes (N=312) assessed their coaches' behaviors and their own ability and motivation using self-report measures. Multivariate analyses indicated that significant relationships were found for males, females, 12–14-year-olds, and 15-18-year-olds. Variables contributing most importantly to the relationships differed depending upon gender and age group. In general, coaches who were perceived as giving more frequent information following desirable performances, and more frequent encouragement combined with information following undesirable performances, were associated with athletes who perceived higher levels of success, competence, enjoyment, and preference for optimally challenging activities. These results indicate that young athletes' self-perceptions and motivation are significantly related to the quantity and quality of coaching feedback they receive for performance successes and errors.
Daniel Gould, Robert C. Eklund, Linda Petlichkoff, Kirsten Peterson and Linda Bump
This study examined psychological correlates of performance in youth wrestlers by replicating and extending the findings of Scanlan et al. (18). A secondary purpose was to replicate and extend work on antecedents of pre- and postcompetitive state anxiety. A total of 202 youth wrestlers, ages 13 and 14, completed a background questionnaire assessing demographic characteristics, trait anxiety, achievement orientations, and characteristic prematch cognitions prior to participating in an age-group wrestling tournament. Prematch performance expectancies and prematch state anxiety were also assessed 10 to 20 minutes before Rounds 1 and 2 of the tournament. Postmatch assessments of satisfaction and state anxiety were conducted immediately after both bouts. Results partially replicated those of Scanlan et al. (18), that is, wrestlers who performed best had more years of experience and higher prematch performance expectancies. Pre- and postmatch competitive state anxiety antecedent variables of trait anxiety, prematch performance expectancies, and parental-pressure-to-participate anxiety were also replicated.
Eduardo A. Abade, Bruno V. Gonçalves, Nuno M. Leite and Jaime E. Sampaio
To provide the time–motion and physiological profile of regular training sessions (TS) performed during the competitive season by under-15 (U15), under-17 (U17), and under-19 (U19) elite-level Portuguese soccer players.
One hundred fifty-one elite players of U15 (age 14.0 ± 0.2 y, n = 56), U17 (age 15.8 ± 0.4 y, n = 66), and U19 (age 17.8 ± 0.6 y, n = 29) participated in the study during a 9-wk period. Time–motion and body-impact data were collected using GPS technology (15 Hz) across 38 randomly selected TS that resulted in a total of 612 samples. In addition, heart rate (HR) was continuously monitored (1 Hz) in the selected TS.
The total distances covered (m) were higher in U17 (4648.3 ± 831.9), followed by U19 (4212.5 ± 935.4) and U15 (3964.5 ± 725.4) players (F = 45.84, P < .001). Total body impacts and relative impacts were lower in U15 (total: 490.8 ± 309.5, F = 7.3, P < .01), but no differences were identified between U17 (total: 584.0 ± 363.5) and U19 (total: 613.1 ± 329.4). U19 players had less high- and very-high-intensity activity (above 16 km/h; F = 11.8, P < .001) and moderate-intensity activity (10.0–15.9 km/h; F = 15.07, P < .001). HR values showed significant effects of zone (F = 575.7, P < .001) and interaction with age group (F = 9.7, P < .001), with pairwise differences between all zones (zone 1, <75%; zone 2, 75–84.9%; zone 3, 85–89.9%; zone 4, ≥90%). All players spent most of their time below 75% HRmax (U15, ~50%; U17, ~42%; U19, ~50%).
Results showed high variability between TS, refraining from identifying meaningful trends when measuring performance, although different demands were identified according to age group. The U15 TS were less physiologically demanding, probably because of increased focus on small-sided games to develop basic tactical principles and technical skills. The focus on game-like situations imposed higher external and internal workloads on U17 and U19 players.
Leonard M. Wankel and Philip S.J. Kreisel
A 10-item Thurstonian paired comparison inventory pertaining to factors underlying sport enjoyment was administered to 822 youth sport participants. The sample included participants at four age levels (7-8, 9-10, 11-12, and 13-14 years) from the three sports, soccer (n = 330), baseball (n = 176), and hockey (n = 343). Considerable consistency was found across both sport and age levels in the relative importance of the different enjoyment factors. Factors that were interpreted as being intrinsic to the sport activity (excitement of the sport, personal accomplishment, improving one's skills, testing skills against others, and just doing the skills) were consistently rated as being most important, whereas more extrinsic or outcome-related factors (pleasing others, winning rewards, winning the game) were consistently rated least important of the 10 factors. The social items “being on a team” and “being with friends” were consistently of intermediate importance. The results are interpreted in terms of contemporary views of intrinsic motivation, and suggestions are offered both for future research and for youth sport practice.
Pedro Figueiredo, Ana Silva, António Sampaio, João Paulo Vilas-Boas and Ricardo J. Fernandes
The aim of this study was to evaluate the determinants of front crawl sprint performance of young swimmers using a cluster analysis. 103 swimmers, aged 11- to 13-years old, performed 25-m front crawl swimming at 50-m pace, recorded by two underwater cameras. Swimmers analysis included biomechanics, energetics, coordinative, and anthropometric characteristics. The organization of subjects in meaningful clusters, originated three groups (1.52 ± 0.16, 1.47 ± 0.17 and 1.40 ± 0.15 m/s, for Clusters 1, 2 and 3, respectively) with differences in velocity between Cluster 1 and 2 compared with Cluster 3 (p = .003). Anthropometric variables were the most determinants for clusters solution. Stroke length and stroke index were also considered relevant. In addition, differences between Cluster 1 and the others were also found for critical velocity, stroke rate and intracycle velocity variation (p < .05). It can be concluded that anthropometrics, technique and energetics (swimming efficiency) are determinant domains to young swimmers sprint performance.
Antonio García de Alcaraz, David Valadés and José M. Palao
To assess the evolution of the volleyball’s game demands throughout players’ development in men’s volleyball.
A total of 150 sets and 6.671 rallies were analyzed. The sample was composed of 30 sets each by under-14, under-16, under-19, national senior, and international senior teams (1.291, 1.318, 1.310, 1.372, and 1.380 rallies for each category, respectively). Sets included in the sample were stratified and then randomly selected. The variables studied included play time, rest time, rallies played, jumps, hits, types of ball contact, types of game interruptions, performance of the game phases, and performance of the actions. Student t and Mann Whitney U tests were used to analyze specific differences between categories.
The results showed significant reductions in the play times of the rally (from 8.91 to 6.79 s) and the set (6 min 23 s to 4 min 30 s), significant increases in the rest times of the rally (19.64 to 26.53 s) and the set (13 min 44 s to 20 min 27 s), and a significant increase in the number of jumps per set (113.5 to 181.3). Significant improvements in the reception performance (1.57 to 2.45 out of 3), attack performance (2.13 to 2.67 out of 4), and side-out-phase success (48.4% to 69.6%) were found. Throughout the players’ development, data show an increase in the speed, intensity, and efficacy of the side-out phase.
The findings provide reference values to guide athletes’ development and to monitor training and matches both physically and technically tactically.