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Chung Gun Lee, Youngtae Cho and Seunghyun Yoo

Purpose:

Suicide is the leading cause of death among Korean adolescents. This study investigates the cross-sectional relations of physical activity with suicidal ideation and attempts in adolescents, simultaneously considering previously reported risk factors of suicide such as depression, stress, and body image.

Methods:

This study used the 2007 Korea Youth Risk Behavior Web-based Survey (KYRBWS). Four hundred middle schools and 400 high schools in Korea were monitored, and 74,698 students completed the questionnaire. Logistic regression analysis was conducted to investigate the relationship between physical activity and suicidal ideation and attempts, progressively adjusting for body image, depression and stress.

Results:

After controlling for body image, stress, and depression, the significant relationship between physical activity and suicidal ideation disappeared, and the only remaining relationship was a positive relationship between frequent vigorous physical activity and suicide attempts. No sex differences were found after adjusting for all the variables.

Conclusion:

Unlike the general expectation that physical activity protects adolescents from suicidal behaviors, the results from this study suggest that physical activity does not have protective effect. Korean adolescents who perform frequent vigorous physical activities are more likely to attempt suicide.

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Maïtel Botcazou, Christophe Jacob, Arlette Gratas-Delamarche, Sophie Vincent, Danièle Bentué-Ferrer, Paul Delamarche and Hassane Zouhal

The purpose of this study was to clarify the effect of sex on plasma catecholamine responses to sprint exercise in adolescents and adults. Thirty-six untrained participants took part in this study—9 girls and 10 boys (Tanner Stage 4) and 9 women and 8 men. Each participant performed a 6-s sprint test on a cycle ergometer. Plasma adrenaline (A) and noradrenaline (NA) concentrations were determined successively at rest (A0 and NA0), immediately after the 6-s sprint test (AEX and NAEX), and after 5 min of recovery (A5 and NA5). Peak power, expressed in absolute values or relative to body weight and fat-free mass, was significantly higher in boys than in girls and higher in men than in women (p < .001). No sex effect was observed in AEX in the adolescents, but the NA increase was significantly higher in boys in response to the 6-s sprint (p < .05). In adults, no sex difference was found in NAEX, but AEX was significantly higher in men than in women (p < .05). NAEX was significantly higher in women than in girls (p < .05), and AEX was significantly higher in men than in boys (p < .01). The results of this study suggest that male and female adolescents and young adults might exhibit different catecholamine responses to sprint exercise.

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Nancy L. Greer, Joseph Hamill and Kevin R. Campbell

Ground reaction force patterns during walking were observed in 18 children 3 and 4 years of age. The children walked barefoot at a self-chosen walking pace. Selected variables representing the vertical, anteroposterior, and mediolateral force components were evaluated. The results indicated that children in this age range contact the ground with greater vertical force measures relative to body mass than do adults. In addition, the minimum vertical force was lower, the transition from braking to propulsion occurred earlier, and the mediolateral force excursions were higher than typically found in adults. When the children were divided into groups on the basis of sex, differences were observed between those groups. The boys exhibited a greater difference in the vertical peak forces, a lower minimum force, a greater braking force, and a higher mediolateral force excursion value. The results indicated that children display a different ground reaction force pattern than do adults and that differences between boys and girls may be observed as early as ages 3 and 4 years.

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Alejandro Santos-Lozano, Ana M. Angulo, Pilar S. Collado, Fabian Sanchis-Gomar, Helios Pareja-Galeano, Carmen Fiuza-Luces, Alejandro Lucia and Nuria Garatachea

Most studies on aging and marathon have analyzed elite marathoners, yet the latter only represent a very small fraction of all marathon participants. In addition, analysis of variance or unpaired Student t tests are frequently used to compare mean performance times across age groups. In this report the authors propose an alternative methodology to determine the impact of aging on marathon performance in both nonelite and elite marathoners participating in the New York City Marathon. In all, 471,453 data points corresponding to 370,741 different runners over 13 race editions (1999–2011) were retrieved. Results showed that the effect of aging on marathon performance was overall comparable in both sexes, the effect of aging differed between the fastest and slowest runners in both sexes, and the magnitude of the sex differences was higher in the slowest runners than in the fastest ones. Current data suggest that the biological differences between sexes allow men to have better marathon performance across most of the human life span.

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Pedro Ángel Latorre-Román, Felipe García-Pinillos and David Mora-López

Purpose:

The purpose of this study was to examine age and sex differences in standing long jump (SLJ) and to determine norm-referenced values for Spanish preschool children.

Method:

A total of 3555 children, aged 3–6 years, participated in this study (1746 girls and 1809 boys). To measure explosive leg power, the SLJ was used.

Results:

In the analysis of reliability using test-retest with 86 children (48% boys, age = 56.22 ± 10.34 months), the following descriptive results were obtained (mean, SD): at pretest = 76.53 ± 20.20 cm, at retest = 74.56 ± 21.12 cm (p = .124), and an intraclass correlation coefficient = 0.913 (95% confidence interval = 0.866–0.943). Boys exhibited a greater performance than girls at 3- to 5-years old, but no significant differences were found at 6 years old. In whole group, the SLJ performance was higher with increased age. However, no significant differences were found between boys aged 5 and 6 years.

Conclusion:

This study provides references values for muscle strength assessment through SLJ test carried out on a large sample of Spanish preschoolers.

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Joaquin A. Barrios and Danielle E. Strotman

The prevalence of medial knee osteoarthritis is greater in females and is associated with varus knee alignment. During gait, medial knee osteoarthritis has been linked to numerous alterations. Interestingly, there has been no research exploring sex differences during walking in healthy individuals with and without varus alignment. Therefore, the gait mechanics of 30 asymptomatic individuals with varus knees (15 females) and 30 normally-aligned controls (15 females) were recorded. Gait parameters associated with medial knee osteoarthritis were analyzed with two-factor analyses of variance. In result, varus males exhibited the greatest peak knee adduction moments, while normal females showed the greatest peak hip adduction angles and pelvic drop excursions. By sex, females exhibited greater peak hip adduction angles and moments and greater pelvic drop excursion, but lesser peak knee adduction angles. By alignment type, varus subjects exhibited greater peak knee adduction angles and moments, midstance knee flexion angles and excursion, and eversion angles and lateral ground reaction forces, but lesser peak hip adduction angles. In conclusion, females generally presented with proximal mechanics related to greater hip adduction, whereas males presented with more knee adduction. Varus subjects demonstrated a number of alterations associated with medial knee osteoarthritis. The differential sex effects were far less conclusive.

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Anne Jobling

This longitudinal research examined the development of motor proficiency in 99 children with Down syndrome born in Brisbane from 1973 to 1984. The Bruininks-Oseretsky Test of Motor Proficiency (BOTMP) was used to assess motor proficiency, and the Stanford-Binet L-M was used to obtain a measure of general intelligence. Although significant progress on the BOTMP subtest scores occurred with age for most subtests, this was related to mental age (MA) rather than chronological age (CA). Progress related to CA was associated with upper limb coordination and upper limb speed and dexterity subtests from CA 10 to 12 years, not from 12 to 16 years. There were considerable inter- and intraindividual differences on subtest items. A cluster analysis of 263 assessments revealed no one profile of strengths and weaknesses. Two distinct profiles were found with high scores in either the visual–motor or the running speed and agility subtests, with balance scores at a low level of proficiency in both clusters. Across the study groupings, sex differences were also evident.

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Danielle Symons Downs, Jennifer S. Savage and Jennifer M. DiNallo

Background:

Scant research has examined the determinants of primary exercise dependence symptoms in youth. Study purposes were to examine sex differences across leisure-time exercise behavior, motivation, and primary exercise dependence symptoms in youth and the extent to which exercise behavior and motivation predicted exercise dependence within the Self-Determination Theory framework.

Methods:

Adolescents (N = 805; mean age = 15 years; 46% girls) completed measures of exercise behavior, motivation, and exercise dependence in health/PE classes.

Results:

One-way ANOVA revealed boys scored higher than girls on leisure-time exercise behavior, exercise dependence symptoms, and most of the exercise motivation subscales. Hierarchical regression analyses indicated a) sex, exercise behavior, motivation, and their interaction terms explained 39% of the variance in primary exercise dependence; b) Integrated Regulation and Introjected Regulation were important determinants of exercise dependence; and c) sex moderated the contributions of External Regulation for predicting exercise dependence such that boys in the high and low external regulation groups had higher symptoms than girls in the high and low external regulation groups.

Conclusions:

These preliminary findings support the controlled dimensions of Integrated Regulation (boys, girls), Introjected Regulation (boys, girls), and External Regulation (boys only) are important determinants of primary exercise dependence symptoms.

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Élvio R. Gouveia, José A. Maia, Gaston P. Beunen, Cameron J. Blimkie, Ercília M. Fena and Duarte L. Freitas

The purposes of this study were to generate functional-fitness norms for Portuguese older adults, to determine age and sex differences, and to analyze the physical activity–associated variation in functional fitness. The sample was composed of 802 older adults, 401 men and 401 women, age 60–79 yr. Functional fitness was assessed using the Senior Fitness Test. Physical activity level was estimated via the Baecke questionnaire. The P50 values decreased from 60 to 64 to 75 to 79 yr of age. A significant main effect for age group was found in all functional-fitness tests. Men scored significantly better than women in the chair stand, 8-ft up-and-go, and 6-min walk. Women scored significantly better than men in chair sit-and-reach and back scratch. Active participants scored better in functional-fitness tests than their average and nonactive peers. This study showed a decline in functional fitness with age, better performance of men, and increased proficiency in active participants.

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Bart C. Bongers, Maarten S. Werkman, Donna Blokland, Maria J.C. Eijsermans, Patrick van der Torre, Bart Bartels, Olaf Verschuren and Tim Takken

Purpose:

To determine criterion validity of the pediatric running-based anaerobic sprint test (RAST) as a nonsophisticated field test for evaluating anaerobic performance in healthy children and adolescents.

Methods:

Data from 65 healthy children (28 boys and 37 girls between 6 and 18 years of age, mean ± SD age: 10.0 ± 2.8 years) who completed both the pediatric RAST and the 30-s Wingate anaerobic test (WAnT) on a cycle ergometer in a randomized order were analyzed. Peak power (PP) and mean power (MP) were the primary outcome measures for both tests.

Results:

There were no significant sex-differences in PP and MP attained at the pediatric RAST and the WAnT. Age was strongly correlated to pediatric RAST and WAnT performance (Spearman’s rho values ranging from 0.85 to 0.90, with p < .001 for all coefficients). We found high correlation coefficients between pediatric RAST performance and WAnT performance for both PP (Spearman’s rho: 0.86; p < .001) and MP (Spearman’s rho: 0.91; p < .001).

Conclusion:

The pediatric RAST can be used as a valid and nonsophisticated field test for the assessment of anaerobic performance in healthy children and adolescents. For clinical evaluative purposes, we suggest to use MP of the pediatric RAST when assessing glycolytic power in the absence of the WAnT.