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William Bell

The purpose of the present study was to investigate the pubertal characteristics of a group of specialist association football (soccer) players (N = 22) between the ages of 12.3 and 15.3 years. Pubertal status was assessed by direct observation of pubic hair (PH), and peak height velocity (PHV) was assessed using graphic procedures. The ages at which the various stages of PH were reached did not differ between playing positions or between players as a whole and the control group. The length of the interval between sequential stages of PH was about a year and between PH2 and PH5 was 2.5 years. Correlations between the age at PHV and each of the pubertal stages were generally high. It was concluded that the influence of participation in competitive association football had no significant effect on the attainment and progress of pubertal development beyond that expected by normal growth.

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Kristel Võsoberg, Vallo Tillmann, Anna-Liisa Tamm, Toivo Jürimäe, Meeli Saar, Katre Maasalu, Inga Neissaar, Evelin Lätt and Jaak Jürimäe

The aim of this study was to describe longitudinal changes in body composition, leptin, adiponectin, and ghrelin over a 36-month period in prepubertal rhythmic gymnasts (RG) and their age-matched untrained controls (UC) entering into puberty. Thirty-five RG (8.0 ± 0.6 yrs) and 33 UC (8.2 ± 0.6 yrs) were followed at 12-month intervals for the next 3 years. Height, weight, pubertal stage, body composition, leptin, adiponectin, and ghrelin were measured at each time points. The pubertal development over the next 36 months was slower in the RG compared with UC. Leptin was increased in UC and remained unchanged in RG over 3-year study period (3.7 ± 3.6 vs. 0.2 ± 1.1 ng/ml; p < .05). In RG, baseline leptin was negatively correlated with the change in body fat percentage over a 36-month period (r = −0.34; p < .05). The change in adiponectin over the study period was negatively correlated with the change in BMI (r = −0.43; p < .05). RG had relative leptin deficiency per body fat mass. In conclusion, relatively high leptin concentration at the beginning of puberty may predict those girls who do not increase their body fat percentage through coming years and therefore may have increased risk for delayed puberty.

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Birgitta L. Baker and Kirsten K. Davison

Background:

This study examined predictors of perceived athletic competence and subsequent physical activity in a longitudinal sample of adolescent girls.

Methods:

A sample of 149 girls was assessed at ages 9, 11, and 13. Perceived athletic competence (PAC) was measured at all ages. Nonaesthetic versus aesthetic sport participation, body fat percentage, and breast development were measured at age 9. Accelerometers were used to measure girls’ moderate-to-vigorous physical activity (MVPA) at age 13.

Results:

Girls who participated in nonaesthetic sports at age 9 reported higher PAC at age 11 than those who participated in only aesthetic sports, while more advanced breast development at age 9 was associated with greater relative declines in PAC between ages 11 and 13. Both age 11 PAC and the relative change in PAC between ages 11 and 13 were significant positive predictors of age 13 MVPA. Results were independent of age 9 socioeconomic status and self-reported physical activity.

Conclusion:

Perceived athletic competence is a suitable target for intervention efforts designed to increase adolescent girls’ physical activity. Particular attention should be focused on girls who are overweight or experiencing puberty. Participation in nonaesthetic sports may be particularly important in the development of PAC.

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Jaak Jürimäe

Physical exercise is known to regulate energy balance. Important to this regulatory system is the existence of several peptides that communicate the status of body energy stores to the brain and are related to the body fatness including leptin, adiponectin and ghrelin. These hormones assist in regulating energy balance as well as somatic and pubertal growth in children. It appears that rather few studies have investigated the responses of leptin, adiponectin and ghrelin to acute exercise and these studies have demonstrated no changes in these peptides as a result of exercise. Leptin levels are decreased and may remain unchanged advancing from prepuberty to pubertal maturation in young male and female athletes. A limited number of studies indicate that adiponectin levels are not different between prepubertal and pubertal athletes and untrained controls. However, in certain circumstances circulating adiponectin could be increased in young athletes after onset of puberty as a result of heavily increased energy expenditure. Ghrelin levels are elevated in young sportsmen. However, pubertal onset decreases ghrelin levels in boys and girls even in the presence of chronically elevated energy expenditure as seen in young athletes. Ghrelin may also be used as an indicator of energy imbalance across the menstrual cycle in adolescent athletes. There are no studies with high-molecular-weight adiponectin and only very few studies with acylated ghrelin responses to acute exercise and chronic training have been performed in young athletes. Since these forms of adiponectin and ghrelin have been thought to be bioactive forms, further studies with these specific forms of adiponectin and ghrelin are needed. In conclusion, further studies should be conducted to investigate the response of these hormones to acute and chronic negative energy balance to better understand their role in regulating energy balance during growth and maturation in young athletes.

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Sharon Ann Plowman

This paper describes the effects of exercise training on the somatic, skeletal, and sexual maturation of children. Young athletes of both sexes grow at the same rate and to the same extent as young nonathletes. However, there is evidence that the pubertal development of young female athletes may be delayed. Menarche is more consistently late than either thelarche or pubarche. Genetic and environmental factors are explored in an attempt to determine causative mechanisms. Longitudinal training data are needed for both boys and girls on a variety of physical and hormonal variables. Until such data are available, it is recommended that all children engage in regular physical activity but that maturational progress be monitored in those involved in strenuous competitive training.

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Maria L. Zonderland, Wietze B.M. Erich, Wouter Kortlandt and D. Willem Erkelens

A 3-year controlled intervention was used to study the influence of physical activity on the plasma lipid and apoprotein profile of 10-year-old Dutch schoolchildren. Twice-a-year measurements were taken of height, weight, body composition (skinfolds), pubertal development (Tanner stages), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), triglycerides (TG), apoproteins A-I and B (immunoturbidimetry), and participation in physical activities. The effect of the intervention was analyzed with a MANOVA. The intervention did not affect the level of the lipids and apoproteins of the boys. In the girls, the intervention led to a smaller increase of TG and a larger decrease of apoprotein A-I. There may be two explanations for the limited intervention effect. First, it may be due to the healthy baseline plasma lipid and apoprotein profile, which leaves little room for improvement. Second, the exercise intensity during the physical education classes may have been too low to bring about the desired effect.

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Ying Sun, Jing An, Xi Wang, Ping Zu and Fang-Biao Tao

Background:

The study aims to understand the possible gender difference in the associations between physical activity and depressive symptoms during pubertal transition.

Methods:

Participants were 30,399 children and adolescents of Han ethnicity from urban and rural areas in 8 cities in China. Physical activity (PA) and depressive symptom was assessed by adapted Youth Risk Behavior Survey and Children Depression Inventory (CDI), respectively. Pubertal development was assessed by trained physicians.

Results:

In China, over 30% boys and 40% girls reported having no vigorous PA (VPA) or moderate PA (MPA) in the past week. In girls, participating in VPA 1 to 2 days/week showed protective effect for depressive symptoms; whereas in boys, participating in MPA 1 to 2 days/week showed protective effect for depressive symptoms at and after genital stage III (G3).

Conclusions:

Moderate frequency (1 to 2 days/week) in PA undertaken might be encouraged to prevent depressive symptoms among adolescents.

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Eleni Michopoulou, Alexandra Avloniti, Antonios Kambas, Diamanda Leontsini, Maria Michalopoulou, Symeon Tournis and Ioannis G. Fatouros

This study determined dietary intake and energy balance of elite premenarcheal rhythmic gymnasts during their preseason training. Forty rhythmic gymnasts and 40 sedentary age-matched females (10–12 yrs) participated in the study. Anthropometric profile and skeletal ages were determined. Dietary intake and physical activity were assessed to estimate daily energy intake, daily energy expenditure, and resting metabolic rate. Groups demonstrated comparable height, bone age, pubertal development, resting metabolic rate. Gymnasts had lower body mass, BMI, body fat than age-matched controls. Although groups demonstrated comparable daily energy intake, gymnasts exhibited a higher daily energy expenditure resulting in a daily energy deficit. Gymnasts also had higher carbohydrate intake but lower fat and calcium intake. Both groups were below the recommended dietary allowances for fiber, water, calcium, phosphorus and vitamin intake. Gymnasts may need to raise their daily energy intake to avoid the energy deficit during periods of intense training.

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Noreen D. Willows, Susan K. Grimston, Delia Roberts, David J. Smith and David A. Hanley

This study assessed serum ferritin, hemoglobin, and hematocrit among 107 physically active young people 9 to 18 years of age. Tanner stage (TS) of puberty was assessed and subjects were categorized as prepubertal (TS 1), midpubertal (TS 2, 3, and 4, excluding menarcheal females) and going through their rapid growth phase, or late pubertal (TS 5 and menarcheal females) and having completed their rapid growth phase. Midpubertal females had a lower hematocrit than late pubertal females, but there were no significant differences in serum ferritin or hemoglobin between pubertal groups. Late pubertal males had hemoglobin and hematocrit values that were higher than among prepubertal males, but serum ferritin did not differ. At late puberty the males had significantly higher serum ferritin, hemoglobin, and hematocrit compared with late pubertal females, and females in late puberty were more likely to have marginal iron stores compared with males at the same stage of pubertal development. Midpubertal and late pubertal females reported a diet low in absorbed iron, which could contribute to their poorer iron status.

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Ailsa G. Niven, Samantha G. Fawkner, Ann-Marie Knowles and Claire Stephenson

This cross-sectional study examined the relationship between physical self-perceptions (PSPs), maturation, and physical activity and compared the strength of the relationships of biological and chronological age with PSPs in early adolescent girls (N = 208; mean age = 11.83 ± 0.39 years). Participants completed the Physical Activity Questionnaire for Older Children, the Children’s Physical Self-Perception Profile, and the Pubertal Development Scale. Results indicated that PSPs were significantly and moderately correlated with physical activity. There were no differences in physical activity between maturation stages. Girls who were in the early stages of maturation had significantly more positive perceptions of body attractiveness and physical self-worth than girls in the mid stages of maturation. There was no evidence of a relationship between PSPs and chronological age. This study provided further support for the relationship between PSPs and physical activity and the relationship between maturation and aspects of PSPs. In this age group, maturation does not appear to be related to physical activity or the PSPs most strongly influential on physical activity behavior.