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Recent research findings have indicated that aerobic fitness and motor fitness are related to specific executive functions (EF). However, it is not clear whether the relationships of these fitness factors with executive functions are dependent on each other. The goal of this study was thus to investigate the relationship of aerobic fitness, motor fitness, and their interaction with EF in preadolescents. The sample consisted of 137 students (67 boys) aged 9-10 years. Physical fitness assessment included measures of aerobic fitness (20 m shuttle run test) and motor fitness (Hurdle and crawl test), while EF assessment encompassed measures of inhibition (Modified Stroop task), shifting (Smiley task) and updating (Letter memory task). The results showed that motor fitness was positively related to inhibition, r = .22, p < .05, while aerobic fitness was positively related to shifting r = .22, p < .05. Multiple regression and post hoc analyses indicated that aerobic fitness was positively related to shifting only when motor fitness was also high ([beta] = .44, p < .01). This pattern of results could indicate the potential relevance of high levels of both motor and aerobic fitness for EF., Author(s): Vladimir J. Milosevic [sup.1] , Ana Orlic [sup.1] , Danka Puric [sup.2] , Snezana Radisavljevic Janic [sup.1] , Dusanka Lazarevic [sup.1] , Ivana Milanovic [sup.1] Author Affiliations: (1) grid.7149.b, [...]

Estrogen influences myosin phosphorylation and post-tetanic potentiation in murine fast muscle. We tested the hypothesis that this influence is mediated by estrogen effects on skeletal myosin light chain kinase (skMLCK) activity. To this end, extensor digitorum longus muscles from female wildtype and skMLCK-absent ([skMLCK.sup.-/-]) mice were grouped as follows: ovariectomized with estrogen (E+), ovariectomized without estrogen (E-), sham surgery, and intact baseline. At 8 weeks of age, the ovariectomized groups were ovariectomized followed by implantation of either a 0.1 mg 17[beta]-estradiol (E+) or placebo pellet (E-). Two weeks later, muscles were isolated and suspended in vitro (25[degrees]C) for determination of regulatory light chain phosphorylation and post-tetanic potentiation. Regulatory light chain phosphorylation was not different across conditions within either genotype although wildtype values were significantly greater than [skMLCK.sup.-/-] values. Consistent with this, the potentiation of concentric twitch force was similar between E+ and E- groups within each genotype but wildtype values were greater than [skMLCK.sup.-/-] values. However, unaltered estradiol levels following ovariectomy, likely due to previously underappreciated confounds of mouse age, development, and growth during estrogen supplementation, prevented direct testing of the hypothesis. Future studies should note the importance of estrous cycles and continuing physiological developments of young adult mice when working with ovarian hormones. Key words: estrogen, myosin phosphorylation, potentiation, murine, fast twitch. Les restrogenes influencent la phosphorylation et la potentialisation post-tetanique de la myosine dans le muscle rapide de souris. Nous avons tente de verifier l'hypothese selon laquelle cette influence est mediee par les effets des restrogenes sur l'activite de la kinase des chaines legeres de la myosine squelettique (skMLCK pour <>). A cette fin, nous avons reuni des muscles extenseurs communs des orteils de souris femelles de type sauvage et avec absence de skMLCK ([skMLCK.sup.-/-]) dans les groupes suivants: ovariectomie avec restrogenes (E+), ovariectomie sans restrogenes (E-), intervention chirurgicale factice et intact au debut de l'etude. Les souris des groupes avec ovariectomie subissaient une ovariectomie a l'age de 8 semaines, suivie de l'implantation d'une pastille de 0,1 mg de 17[beta]-estradiol (E+) ou de placebo (E-). Deux semaines plus tard, les muscles etaient isoles et suspendus in vitro (25[degrees]C) afin d'etablir la phosphorylation de la chaine legere regulatrice et de la potentialisation post-tetanique. La phosphorylation de la chaine legere regulatrice n'etait pas differente d'un groupe a l'autre pour un meme genotype, mais les valeurs etaient nettement plus elevees pour le type sauvage que chez les [skMLCK.sup.-/-]. En accord avec cela, la potentialisation de la force de contraction concentrique etait semblable dans les groupes E+ et E- pour un meme genotype, mais les valeurs etaient plus elevees pour le type sauvage que chez les [skMLCK.sup.-/-]. Cependant, nous n'avons pas pu verifier l'hypothese directement en raison de l'absence de diminution des taux d'restradiol apres ovariectomie, probablement en raison de facteurs confondants sous-evalues quant a l'age, ainsi qu'au developpement et a la croissance des souris pendant la supplementation en restrogenes. Des etudes futures devraient remarquer l'importance du developpement en continu des cycles restraux et de la physiologie des jeunes souris adultes lors d'etudes portant sur les hormones ovariennes. [Traduit par la Redaction] Mots-cles: restrogenes, phosphorylation de la myosine, potentialisation, murin, contraction rapide., Introduction A muscle contraction is triggered by an influx of intracellular calcium ([Ca.sup.2+]) from the sarcoplasmic reticulum into the sarcoplasm (Ebashi and Endo 1968). In addition to activating the thin [...]

Purpose: The purpose of this study was to examine divided attention over a large age range by looking at the effects of 3 nonspeech tasks on concurrent speech motor performance. The nonspeech tasks were designed to facilitate measurement of bidirectional interference, allowing examination of their sensitivity to speech activity. A cross-sectional design was selected to explore possible changes in divided-attention effects associated with age. Method: Sixty healthy participants were separated into 3 groups of 20: younger (20s), middle-aged (40s), and older (60s) adults. Each participant completed a speech task (sentence repetitions) once in isolation and once concurrently with each of 3 nonspeech tasks: a semantic decision linguistic task, a quantitative-comparison cognitive task, and a manual motor task. The nonspeech tasks were also performed in isolation. Results: Data from speech kinematics and nonspeech task performance indicated significant task-specific divided attention interference, with divided attention affecting speech and nonspeech measures in the linguistic and cognitive conditions and affecting speech measures in the manual motor condition. There was also a significant age effect for utterance duration. Conclusions: The results increase what is known about bidirectional interference between speech and other concurrent tasks as well as age effects on speech motor control., Speech is a highly sophisticated feat of fine motor performance. However, research has shown that speech production can be affected in subtle but measureable ways by the concurrent performance of [...]

Purpose: This study compared pragmatic language in youths (9-17 years) with autism spectrum disorder (ASD) and those with typical development (TD) on the Yale in vivo Pragmatic Protocol (YiPP), a semistructured, dynamic conversational assessment. Method: Participants (n = 118) were divided into groups based on age and diagnosis. Each completed the YiPP, which included 4 pragmatic domains (discourse management, communicative functions, conversational repair, presupposition). The participant's response to each probe was scored correct or incorrect; incorrect scores elicited cues from the examiner, and level of cue required for a correction was also scored. Results: The YiPP showed high reliability and internal consistency, with moderate concurrent validity, sensitivity, and specificity. The group with ASD performed worse overall on YiPP probes compared to their TD counterparts on both error (d = 0.96) and cue (d = 0.91) scores. Item analyses revealed greater gaps between older students with ASD and their TD peers than between the 2 younger groups. Conclusions: These data suggest that a probe measure designed to assess pragmatic abilities in children with ASD within a conversational context has some validity for contributing to diagnostic classification and can identify specific areas of pragmatic vulnerabilities as part of a clinical assessment., A core feature, and one of the primary diagnostic symptoms, of autism spectrum disorder (ASD) is a qualitative impairment in communication (American Psychiatric Association, 2000). Current estimates suggest that a [...]

Abstract This study aimed to quantify articulation rate among Hebrew speaking children and adolescents across a wide age range, and to assess whether age-related differences vary according to metric. One [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.addbeh.2010.07.002 Byline: Michael Chaiton, Joanna Cohen, Jennifer O'Loughlin, Juergen Rehm Keywords: Smoking; Depressive symptoms; Adolescents; Longitudinal; Self-medication Abstract: Smoking to alleviate negative affect or improve physiological functioning (i.e., self-medication) is one explanation for the association between depression and smoking in adolescents. This study tests whether using cigarettes to improve mood or physiological functioning is associated with the onset, and change over time, of elevated depressive symptoms. Data were drawn from the Nicotine Dependence in Teens study which followed 1293 participants initially aged 12-13years in Montreal, Canada every three months for five years. The subsample included 662 adolescents who had been current smokers (reported smoking during the previous three months) at any point during the study. Survival analysis was used to test whether self-medication scores predicted onset of elevated depressive symptoms. Changes over time in depressive symptom scores relative to self-medication scores were modeled in growth curve analyses controlling for sex and number of cigarettes smoked per week. Smokers who reported higher self-medication scores had higher depressive symptom scores. The interaction between self-medication scores and the acceleration rate in depressive symptom scores was significant and negative, suggesting that participants with higher self-medication scores had decelerated rates of change in depression over time compared to participants with lower self-medication scores. Smoking appears to be ineffective at reducing depressive symptoms. These findings are consistent with a version of the Positive Resource Model that suggests that smoking will not lower depressive symptoms, but could slow the rate of change over time. Alternatively, the perceived positive benefits may be the result of alleviation of symptoms of withdrawal and craving resulting from abstinence. The self-medication scale may identify a population at risk of increased levels of depressive symptoms.

Our aim in this study was to examine the association between breastfeeding duration and cardiorespiratory fitness, isometric strength, and explosive strength during adolescence. A total of 2567 adolescents (1426 girls) from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) cross-sectional study aged 12.5-17.5 y were included. Information about duration of any and exclusive breastfeeding was obtained retrospectively by means of a parental questionnaire. The 20-m shuttle run, handgrip strength, and standing long jump tests were used to assess physical fitness. Significant differences among the categories of breastfeeding duration were tested using ANCOVA after adjusting for a set of potential confounders: gestational and current age, birth weight, sexual maturation, fat mass, fat-free mass, maternal education, parental weight status, country, smoking behavior, and days of vigorous physical activity. Longer breastfeeding (either any or exclusive) was associated with a higher performance in the standing long jump test in both boys and girls (P < 0.001), regardless of fat mass, fat-free mass, and the rest of potential confounders. In adolescents who were breastfed for 3-5 mo or [greater than or equal to]6 mo, the risk of having a standing long jump performance below the 5th percentile was reduced by half compared with those who were never breastfed [odds ratio (OR) = 0.54, 95% CI = 0.30-0.96, P < 0.05; and OR = 0.40, 95% CI = 0.22-0.74, P < 0.01, respectively). These findings suggest a role of breastfeeding in determining lower body explosive strength during adolescence. J. Nutr. 140: 1989-1995, 2010. doi: 10.3945/jn.110.123596.

The aim of this study was to examine acute physiological responses and time-motion characteristics associated with 4 soccer-specific small-sided game (SSG) formats (3 vs. 4 players, 3 vs. 3 players + floater, 5 vs. 6 players, and 5 vs. 5 players + floater) and 4 rule changes in elite youth soccer players. Sixteen male youth soccer players (mean [+ or -] SD: age = 15.6 [+ or -] 0.8 years, stature = 170.8 [+ or -] 6.6 cm, body mass = 67.5 [+ or -] 6.2 kg, and 20-m shuttle run estimated [[??]O.sub.2]max = 57.4 [+ or -] 3.7 ml x [kg.sup.-1] x [min.sup.-1]) participated in the study, in which heart rate (HR), rating of perceived exertion (RPE), blood lactate ([La.sup.-]), and time-motion characteristics were recorded. The rule change requiring extra sprint running had a greater effect on the time-motion characteristics than all other rule modifications but no effect on acute %HRmax, [La.sup.-], and RPE. Rule changes had no effect on RPE. Fixed underload teams (i.e., lower number of players compared with the opponent team) recorded a significantly higher RPE compared with the fixed overload teams, although there were no differences in %HRmax and [La.sup.-]. The major practical findings are that subtle changes in SSGs playing rules can influence the physiological, perceptual, and time-motion responses in young elite soccer players. Rules that are related to a team's chances of scoring may improve player motivation and thereby increase training intensity during SSGs. There were no differences between fixed and variable formats in terms of physiological and perceptual responses, although both may provide useful technical-tactical training. Coaches should take care in designing different soccer SSGs as each rule or game format change may influence exercise intensity independently. KEY WORDS overload, game format, rule modifications, sprints

The purpose of the present study was to examine the association among different measures of lower body muscular strength in children, and the association between measures of lower- and upper-body muscular strength. The study population comprises 94 (45 girls) healthy Caucasian children aged 6-17 years. Children performed several lower body explosive muscular strength tests (i.e., standing long jump [SLJ], vertical jump, squat jump, and countermovement jump) and upper body muscular strength tests (i.e., throw basketball, push-ups, and isometric strength exercises). The association among the study tests was analyzed by multiple regression. The SU was strongly associated with other lower body muscular strength tests ([R.sup.2] = 0.829-0.864), and with upper body muscular strength tests ([R.sup.2] = 0.694-0.851). The SLJ test might be therefore considered a general index of muscular fitness in youth. The SLJ test is practical, time efficient, and low in cost and equipment requirements. KEY WORDS fitness, field tests, children, adolescents