This longitudinal investigation examined the shift from use of a marking time to an alternating stepping pattern by young children. A set of twin males was videotaped between ages 37 and 46 months climbing stairs of 3.8-17.8 cm height. One boy began to alternate consistently on the highest steps at 41 months, the other at 46 months. Anthropometries (leg lengths) and a measure of foot overshoot (maximum height of the foot over the stair) were used to investigate the timing of the shift for the 2 boys. Magnitude of overshoot decreased with age and with increased use of the more advanced pattern. Immature balance and an initial need to visually guide the foot to the next step may be important factors in the timing of the pattern shift.
Kathleen Williams, Lavon Williams and H. Scott Strohmeyer
Tara K. Scanlan and Michael W. Passer
Identification of factors influencing expectancies of successful performance in competitive youth sports is important to understanding the way in which children perceive and respond to this evaluative achievement situation. Therefore, in this field study involving 10- to 12-year-old female soccer players, intrapersonal factors affecting players' pregame personal performance expectancies were first identified. Soccer ability and self-esteem were found to be related to personal performance expectancies, but competitive trait anxiety was not Second, the impact of game outcome, the previously mentioned intrapersonal variables, and the interaction of game outcome and intrapersonal variables was examined by determining players' postgame team expectancies in a hypothetical rematch with the same opponent. The postgame findings showed that winning players evidenced higher team expectancies than tying and losing players. Moreover, the expectancies of tying players were low and, in fact, similar to those of losers. The results of this study successfully replicated and extended previous findings with young male athletes.
Michelle McCalpin, Blair Evans and Jean Côté
Competitive engineering is a process whereby sport organizations modify the rules, facilities, and equipment involved in sport to facilitate desirable athlete outcomes and experiences. Competitive engineering is being increasingly adopted by youth sport organizations with empirical evidence positively supporting its influence on skill development and performance. The purpose of this study was to explore young female athletes’ experiences in their modified soccer environment. Seventeen recreational and competitive soccer players, aged 8–11, participated in semistructured photo elicitation interviews that featured several visual qualitative methods (i.e., athlete-directed photography, drawing exercises, and pile-sorting) to facilitate insight on their sport environments. Results revealed that the athletes’ competitively engineered soccer experience was perceived as being a distinct environment that emphasized personal development, positive relationships, and the underlying enjoyment of sport. These findings shed light of how youth sport structure modifications influence the athletes’ experiences, providing practical implications to further promote positive youth sport experiences.
Mary Jo MacCracken and Robert E. Stadulis
Dynamic balance performance of young children (ages 4, 6, and 8) was assessed in three social situations: alone (only with tester present); coaction (one other child performing at the same time); and spectators (five other observer children present). Within each age and gender, children (N = 120) were classified as of higher or lower comparative skill. Each balance task performed (walking forward and backward on a line, a narrow beam or a wide beam) was classified as representing easier or more difficult tasks for each child individually. Findings (p ≤ .05) indicated that the facilitation effects of social situations strengthened over age, with spectators producing increments in performance for children of higher skill (especially boys) and decrements in performance for the lower skilled children (both boys and girls). Coaction resulted in positive effects regardless of skill level.
Guellich Arne, Seiler Stephen and Emrich Eike
To describe the distribution of exercise types and rowing intensity in successful junior rowers and its relation to later senior success.
36 young German male rowers (31 international, 5 national junior finalists; 19.2 ± 1.4 y; 10.9 ± 1.6 training sessions per week) reported the volumes of defined exercise and intensity categories in a diary over 37 wk. Training categories were analyzed as aggregates over the whole season and also broken down into defined training periods. Training organization was compared between juniors who attained national and international senior success 3 y later.
Total training time consisted of 52% rowing, 23% resistance exercise, 17% alternative training, and 8% warm-up programs. Based on heart rate control, 95% of total rowing was performed at intensities corresponding to <2 mmol·L-1, 2% at 2 to 4 mmol·L-1, and 3% at >4 mmol·L-1 blood lactate. Low-intensity work remained widely unchanged at ~95% throughout the season. In the competition period, the athletes exhibited a shift within <2 mmol exercise toward lower intensity and within the remaining ~5% of total rowing toward more training near maximal oxygen consumption (VO2max) intensity. Retrospectively, among subjects going on to international success 3 y later had their training differed significantly from their peers only in slightly higher volumes at both margins of the intensity scope.
The young world-class rowers monitored here exhibit a constant emphasis on low-intensity steady-state rowing exercise, and a progressive polarization in the competition period. Possible mechanisms underlying a potential association between intensity polarization and later success require further investigation.
Melissa Hodge, Mary Hovinga, Kelley Gabriel, Linda Snetselaar, John Shepherd, Linda Van Horn, Victor Stevens, Brian Egleston, Alan Robson, Seungyoun Jung and Joanne Dorgan
This study prospectively investigates associations between youth moderate-to-vigorous-intensity physical activity (MVPA) and body composition in young adult women using data from the Dietary Intervention Study in Children (DISC) and the DISC06 Follow-Up Study. MVPA was assessed by questionnaire on 5 occasions between the ages 8 and 18 years and at age 25-29 years in 215 DISC female participants. Using whole body dual-energy x-ray absorptiometry (DXA), overall adiposity and body fat distribution were assessed at age 25-29 years by percent body fat (%fat) and android-to-gynoid (A:G) fat ratio, respectively. Linear mixed effects models and generalized linear latent and mixed models were used to assess associations of youth MVPA with both outcomes. Young adult MVPA, adjusted for other young adult characteristics, was significantly inversely associated with young adult %fat (%fat decreased from 37.4% in the lowest MVPA quartile to 32.8% in the highest (p-trend = 0.02)). Adjusted for youth and young adult characteristics including young adult MVPA, youth MVPA also was significantly inversely associated with young adult %fat (β=-0.40 per 10 MET-hrs/wk, p = .02) . No significant associations between MVPA and A:G fat ratio were observed. Results suggest that youth and young adult MVPA are important independent predictors of adiposity in young women.
Søren E. Larsen, Henrik S. Hansen, Karsten Froberg and Jens Rokkedal Nielsen
This study investigated a group of young elite cyclists at the age of 19–20 years. The cardiac characteristics, left ventricular function and structure, after long-term and high intensity endurance training, were examined by echocardiography during resting conditions. In comparison with an age-matched control group, the elite cyclists had significantly lower systolic blood pressure, heart rate, and total body fat and a significantly higher physical fitness. Left ventricular mass, left ventricular mass indexed for differences in body size, and both systolic and diastolic dimensions of the left ventricle were increased significantly in the elite cyclist group. No significant difference was found in left ventricular function. Left ventricular diastolic function was examined (E/A-ratio, E = early passive, A = late active, atriale induced transmitral diastolic flow) and showed no significant difference between the two groups in spite of the structural changes observed in the left ventricular structure. We conclude that structural but not functional cardiac changes can be observed in elite cyclists when examined during resting conditions.
Sabine Felser, Martin Behrens, Susanne Fischer, Mario Baeumler, Ralf Salomon and Sven Bruhn
To investigate differences in muscle activation of both legs between the straight and the curve and changes in muscle activity during a 1000-m time trial (TT) and their relationship to the change in skating velocity in 9 young short-track speed skaters. The authors recorded skating times and EMG data from different leg muscles during maximum-effort skating trials on the straight and in the curve, as well as during a 1000-m TT.
Muscle activation differs between the straight and the curves and between legs; ie, average activities of selected muscles of the right leg were significantly higher during skating through the curves than in the straights. This could not be observed for the left leg. The reduction in speed during the 1000-m TT highly correlates with the decrease in the muscle activity of both the tibialis anterior and the rectus femoris of the right leg. Muscle recruitment is different in relation to lap section (straight vs curve) and leg (right vs left leg). The decreased muscle activity of the tibialis anterior and rectus femoris of the right leg showed the highest relationships with the reduction in skating speed during the 1000-m TT.
Nicholas D. Parr, Chris J. Hass and Mark D. Tillman
Cellular phone texting has become increasingly popular, raising the risk of distraction-related injuries. The purpose of this study was to compare alterations in gait parameters during normal gait as opposed to walking while texting. Thirty able-bodied young adults (age = 20 ± 2 y, height = 171 ± 40 cm, mass = 61.7 ± 11.2 kg) who reported texting on a regular basis were tested using an 11-camera optical motion capture system as they walked across an 8 m, obstacle-free floor. A reduction in velocity (P < .05) was seen along with additional significant changes in spatial and temporal parameters. Specifically, step width and double stance time increased, while toe clearance, step length, and cadence decreased. Although many of the changes in spatial and temporal parameters generally accompany slowed gait, the complex distraction task used here may have amplified these potentially deleterious effects. The combination of the slower gait velocity and decrease in attention to the surrounding environment suggests that an individual who is texting while walking could be at a greater risk of injury. Tripping injuries while texting could be more likely due to the decreased toe clearance. In addition, increased step width may increase the likelihood of stepping on an unstable surface or colliding with obstacles in close proximity.
Jorge E. Morais, António J. Silva, Daniel A. Marinho, Vítor P. Lopes and Tiago M. Barbosa
To develop a performance predictor model based on swimmers’ biomechanical profile, relate the partial contribution of the main predictors with the training program, and analyze the time effect, sex effect, and time × sex interaction.
91 swimmers (44 boys, 12.04 ± 0.81 y; 47 girls, 11.22 ± 0.98 y) evaluated during a 3-y period. The decimal age and anthropometric, kinematic, and efficiency features were collected 10 different times over 3 seasons (ie, longitudinal research). Hierarchical linear modeling was the procedure used to estimate the performance predictors.
Performance improved between season 1 early and season 3 late for both sexes (boys 26.9% [20.88;32.96], girls 16.1% [10.34;22.54]). Decimal age (estimate [EST] –2.05, P < .001), arm span (EST –0.59, P < .001), stroke length (EST 3.82; P = .002), and propelling efficiency (EST –0.17, P = .001) were entered in the final model.
Over 3 consecutive seasons young swimmers’ performance improved. Performance is a multifactorial phenomenon where anthropometrics, kinematics, and efficiency were the main determinants. The change of these factors over time was coupled with the training plans of this talent identification and development program.