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Thomas Rowland

Interest in the physiological responses to exercise unique to the pediatric age group has grown exponentially over the past 50 years. A number of issues surrounding children’s exercise have been particularly responsible for this trend, particularly a) recognition of the health benefits of exercise in youth, b) the growing involvement of young persons in highly intense levels of sports play, and c) the role that exercise may play in the diagnosis and management of children with chronic disease. As a consequence, current research to date has provided a comprehensive picture of the features specific to children’s response to exercise. Future challenges facing the field of pediatric exercise science involve translating this information into practical guidelines which can be applied to the realms of clinical medical practice, preventive health initiatives, and athletic training regimens which are appropriate for this age group.

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Nataphoom Benjanuvatra, Brian A. Blanksby and Bruce C. Elliott

Six 9-, 11-, and 13-year-old, anthropometrically matched males and females were towed on the water surface via a mechanical winch at 1.3 to 2.5 ms−1 in increments of 0.3 ms−1 during a prone streamlined glide. Passive drag force of the 13-year age group was significantly larger than that of the 9-year age group at 1.9, 2.2, and 2.5 ms−1, but not at 1.3-1.6 ms−1. While anthropometry did not feature in any regression equation at any age for passive drag at velocities of 1.3 and 1.6 ms−1, body mass was the best predictor of drag at 1.9 and 2.5 ms−1.

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Thomas J. Martinek and Joseph B. Griffith III

The purpose of this study was to describe the effect of age on specific psychological and behavioral measures of learned-helpless and mastery-oriented students. The study consisted of two age groups, younger and older, of learned-helplessness and mastery-oriented students. Within each age group, learned-helpless and mastery-oriented students were compared in terms of attributional profiles and levels of task persistence during instruction. Students were asked to view videotapes of their performances, to describe how they thought they did on each task, and to give reasons for their performance. Responses were classified into four attributional categories: (a) ability, (b) effort, (c) task difficulty, and (d) environment or luck. Persistence was also determined by looking at the number of times students would attempt a task. Attributional profiles and task persistence associated with the leamed-helpless condition was more prevalent with the older group than with the younger group.

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Lyle J. Micheli

The majority of injuries in exercising children affect the musculoskeletal system. These injuries result from two mechanisms: single, acute macrotrauma or repetitive microtrauma. The injuries resulting from repetitive microtrauma—overuse injuries—appear to be occurring with increased frequency in this age group. A number of risk factors for overuse injury from exercise have been identified, including training error, muscle imbalance, anatomic malalignment, footwear, surface, nutritional factors, and cultural factors. The development of scientific criteria for exercise prescription in this age group that will enhance fitness and avoid injury awaits techniques for noninvasive assessment of musculoskeletal tissue fitness. In the interim, many of these injuries can be prevented or decreased in severity by slow progression of exercise intensity and qualified adult supervision.

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Maria Paula Santos, Margarida Matos and Jorge Mota

This study aimed to describe seasonal variations in Portuguese adolescents’ physical activity, in organized and nonorganized physical activities, according to gender and age group. Data from the Portuguese second wave of the Health Behaviour in School-Aged Children (HBSC) study was used. The sample comprised 6,131 public school students ages 10 to 17 years (age = 14.0 ± 1.85 years old), and 51% were girls. Physical activity was measured by questionnaire and participants were categorized as “active” or “low active” according to their reported weekly participation in physical activity sessions. Participation in organized and nonorganized physical activities of all age groups was more frequent during the spring and summer period. Results suggest that appropriate strategies should be developed to promote involvement in sports and other physical activity, particularly organized physical activity programs, among adolescents throughout the year.

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Nobuyuki Inui and Yumi Katsura

We conducted an experiment to examine age-related differences in the control of force and timing in a finger-tapping sequence with an attenuated-force tap. Participants between 7 and 20 years old tapped on a load cell with feedback on practice trials. They were required to recall the force pattern (300 g, 300 g, 300 g, 100 g) and the intertap interval (400 ms) without feedback on test trials. Analysis indicated that the last attenuated tap affected the first three taps of the tapping sequence in adults and adolescents but not in children. Adults and adolescents appeared to respond with four taps as a chunk, resulting in a contextual effect on the timing of force control, but younger children had difficulty with such chunking. Further, adults and adolescents were able to more accurately produce individual force magnitudes to match target magnitudes than younger children. For the ratio of force in serial positions 1:4, 2:4, and 3:4, consequently, 7- to 8-year-old children had lower ratios than the other age groups. Although there was no difference among age groups for timing control of peak force to press duration as a control strategy of force, 7- to 8-year-old children spent more time to produce force than the other age groups. Peak force with a decreased force was more variable in the attenuated force serial position (4) than in the other serial positions in all five age groups. Peak force variability was particularly robust in younger children. These findings suggest that younger children have difficulty with both temporal and spatial (i.e., magnitude) components of force control.

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Tatiane Gorski, Thomas Rosser, Hans Hoppeler and Michael Vogt

Purpose:

To verify whether relative age effects (RAEs) occur among young male and female Swiss Alpine skiers of different age groups and performance levels. In addition, the efficacy of normalizing performance in physical tests to height and body mass to attenuate RAEs eventually present was tested.

Methods:

The Swiss Ski Power Test consists of anthropometric measures and physical tests for coordination and speed, endurance, and strength and has been used since 2004 to evaluate 11- to 19-y-old Swiss competitive Alpine skiers. The authors analyzed the distribution of 6996 tests performed by 1438 male and 1031 female Alpine skiers between 2004 and 2011 according to the athletes’ respective relative age quartiles. Differences in anthropometric measures and performance in physical tests according to quartile were assessed, and the possibility of attenuating eventual RAEs on performance by normalization of results to height and body mass was tested.

Results:

RAEs were found among all female and male age groups, with no differences between age groups. While performance level did not affect RAE for male skiers, it influenced RAE among female skiers. RAEs also influenced results in all physical tests except upper-limb strength. Normalization of results to body mass attenuated most RAEs identified.

Conclusion:

Small RAEs are present among young Swiss competitive Alpine skiers and should be taken into account in training and selection settings to prevent the waste of possible future talents. When ranking junior athletes according to their performance in physical tests, normalization of results to body mass decreases the bias caused by RAEs.

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Arthur H. Bossi, Guilherme G. Matta, Guillaume Y. Millet, Pedro Lima, Leonardo C. Pertence, Jorge P. de Lima and James G. Hopker

Purpose:

To describe pacing strategy in a 24-h running race and its interaction with sex, age group, athletes’ performance group, and race edition.

Methods:

Data from 398 male and 103 female participants of 5 editions were obtained based on a minimum 19.2-h effective-running cutoff. Mean running speed from each hour was normalized to the 24-h mean speed for analyses.

Results:

Mean overall performance was 135.6 ± 33.0 km with a mean effective-running time of 22.4 ± 1.3 h. Overall data showed a reverse J-shaped pacing strategy, with a significant reduction in speed from the second-to-last to the last hour. Two-way mixed ANOVAs showed significant interactions between racing time and both athlete performance group (F = 7.01, P < .001, ηp 2 = .04) and race edition (F = 3.01, P < .001, ηp 2 = .02) but not between racing time and either sex (F = 1.57, P = .058, ηp 2 < .01) or age group (F = 1.25, P = .053, ηp 2 = .01). Pearson product–moment correlations showed an inverse moderate association between performance and normalized mean running speed in the first 2 h (r = –.58, P < .001) but not in the last 2 h (r = .03, P = .480).

Conclusions:

While the general behavior represents a rough reverse J-shaped pattern, the fastest runners start at lower relative intensities and display a more even pacing strategy than slower runners. The “herd behavior” seems to interfere with pacing strategy across editions, but not sex or age group of runners.

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Norikazu Hirose and Chikako Nakahori

Purpose:

To describe cross-sectional age differences in change-of-direction performance (CODp) in female football players and investigate the relationship between CODp and linear-sprint speed, muscle power, and body size.

Methods:

A sample of 135 well-trained female football players was divided into 8 age groups. Anthropometry (height, body mass, and lean body mass) and athletic performance (10-m sprint speed, 10-m × 5-CODp, and 5-step bounding distance) were compared to determine interage differences using ANOVA. Then, the participants were divided into 3 age groups: 12- to 14-y-olds, 15- to 17-y-olds, and ≥ 18 y-olds. Simple- and multiple-regression analyses were conducted to determine the correlation between CODp and the other measurement variables in each age group.

Results:

Age-related differences were found for CODp (F = 10.41, P < .01), sprint speed (F = 3.27, P < .01), and bounding distance (F = 4.20, P < .01). Post hoc analysis revealed that the CODp of 17-y-old players was faster than that of 16-y-old players (P < .01), with no interage differences in sprint speed and bounding distance. Sprint speed and bounding distance were weakly correlated with CODp in 15- to ≥18-y-old players, but only sprint speed was correlated with CODp in 12- to 14-y-old players.

Conclusions:

CODp improves from 16 to 17 y of age in female players. Linear-sprint speed, muscle power, and body size were weakly correlated with the age differences in CODp.

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Shamly Austin, Haiyan Qu and Richard M. Shewchuk

Objective:

To examine whether age bias exists in physicians’ recommendations for physical activity among individuals with arthritis.

Methods:

A cross-sectional sample with 33,071 U.S. adults, 45 years or older with physician-diagnosed arthritis was obtained from 2007 Behavioral Risk Factor Surveillance System Survey. We used logistic regression to examine physicians’ recommendations for physical activity as a function of age controlling for gender, race, education, marital status, employment, income, health insurance, personal physician, emotional support, body mass index, activity limitations, health status, and comorbidities.

Results:

Majority of individuals were females (65%), White (85%), had annual household income < $50,000 (67%), and with comorbidities (86%). Respondents were approximately equal across age groups: middle-aged group (53%) and older group (47%). About 36% were obese and 44% had activity limitations, and 44% did not receive any physicians’ recommendations for physical activity. Results from logistic regression indicated older adults (≥ 65 years old) were less likely (OR = 0.87; 95% CI, 0.82−0.92) to receive physicians’ recommendations for physical activity compared with the middle-aged group (45−64 years old).

Conclusions:

This study indicates that although the benefits associated with the physical activity is well recognized, there is age bias in physicians’ recommendations for physical activity.