Health-enhancing physical activity and sedentary behaviour in children and adolescents

We provide a wide-ranging review of health-related physical activity in children and adolescents using a behavioural epidemiology framework. In contrast to many other reviews, we highlight issues associated with true sedentary behaviours alongside physically active behaviours. Specifically, we review the evidence concerning the links between physical activity and cardiovascular disease, overweight and obesity, psychosocial measures, type II diabetes, and skeletal health. Although the evidence is unconvincing at times, several factors lead to the conclusion that promoting physical activity in youth is desirable. A review of the prevalence of physical activity and sedentary behaviours shows that many young people are active, but this declines with age. A substantial number are not adequately active for health benefits and current trends in juvenile obesity are a cause for concern. Prevalence data on sedentary behaviours are less extensive but suggest that total media use by young people has not changed greatly in recent years. Most children and adolescents do not exceed recommended daily hours of TV viewing. Physical activity is unrelated to TV viewing. We also identified the key determinants of physical activity in this age group, highlighting demographic, biological, psychological, behavioural, social and environmental determinants. Interventions were considered for school, family and community environments. Finally, policy recommendations are offered for the education, governmental, sport and recreation, health, and mass media sectors.     

The Physical Education Predisposition Scale: Preliminary development and validation

Abstract

The main aim of this study was to develop and test psychometrically the Physical Education Predisposition Scale, to assess secondary school students' cost–benefit assessment of physical education (PE) participation (PE attitude affective and attitude cognitive) and self-perceptions (PE perceived competence and self-efficacy). Secondary aims were to explore how the two variables were related, and to investigate age and gender differences. Altogether, 315 Year 8 and 9 students (aged 12–14 years) from four North West England schools completed the Physical Education Predisposition Scale. Principal components analysis revealed the presence of a simple two-factor solution explaining 60.7% of the variance. Factor 1 (labelled Perceived PE Worth) reflected attitude affective and attitude cognitive (α = 0.91), and factor 2 (Perceived PE Ability) represented perceived competence and self-efficacy (α = 0.89). Significant positive correlations were observed between the factors (r = 0.67 to 0.71, P < 0.001). Boys scored significantly higher than girls on Perceived PE Worth (P < 0.001) and Perceived PE Ability (P = 0.02). Similarly, Year 8 students scored significantly higher than Year 9 students on Perceived PE Worth (P = 0.005) and Perceived PE Ability (P < 0.001). Our results support the potential of the Physical Education Predisposition Scale as a concise measurement tool for use in the PE setting, for both teachers and researchers.     

The effect of induced alkalosis and submaximal cycling on neuromuscular response during sustained isometric contraction

Abstract

The aim of this study was to determine if inducing metabolic alkalosis would alter neuromuscular control after 50 min of standardized submaximal cycling. Eight trained male cyclists (mean age 32 years, s = 7; [Vdot]O_2max 62 ml · kg^?1 · min^?1, s = 8) ingested capsules containing either CaCO₃ (placebo) or NaHCO₃ (0.3 g · kg^?1 body mass) in eight doses over 2 h on two separate occasions, commencing 3 h before exercise. Participants performed three maximal isometric voluntary contractions (MVC) of the knee extensors while determining the central activation ratio by superimposing electrical stimulation both pre-ingestion and post-exercise, followed by a 50-s sustained maximal contraction in which force, EMG amplitude, and muscle fibre conduction velocity were assessed. Plasma pH, blood base excess, and plasma HCO₃ were higher (P < 0.01) during the NaHCO₃ trial. After cycling, muscle fibre conduction velocity was higher (P < 0.05) during the 50-s sustained maximal contraction with NaHCO₃ than with placebo (5.1 m · s^?1, s = 0.4 vs. 4.2 m · s^?1, s = 0.4) while the EMG amplitude remained the same. Force decline rate was less (P < 0.05) during alkalosis-sustained maximal contraction and no differences were shown in central activation ratio. These data indicate that induced metabolic alkalosis can increase muscle fibre conduction velocity following prolonged submaximal cycling.     

Relative Effects of Isokinetic and Plyometric Training on Vertical Jumping Performance

Forty-eight volunteer males were randomly assigned to one of three groups. Group I trained with isokinetic exercises, Group II trained with plyometric exercises, and Group III was the control. Subjects in the training groups trained three times per week for 8 weeks. The isokinetic group performed three sets of 10 repetitions per set of leg presses each training session. The plyometric group performed three sets of 10 repetitions per set of depth jumps from a height of 34 inches, with added resistance beginning with weeks 3, 5, and 7 of 10, 15, and 20 pounds, respectively. Prior to and at the end of the training period, all subjects were given a vertical jump-and-reach test. Covariance analysis was used to compare posttest scores with the effect of pretest differences removed. Results showed both training groups improved significantly in vertical jump capacity; however, no significant difference existed between training groups.     

African American and European American Mothers' Beliefs about Negative Emotions and Emotion Socialization Practices

OBJECTIVE: Mothers' beliefs about their children's negative emotions and their emotion socialization practices were examined. DESIGN: Sixty-five African American and 137 European American mothers of 5-year-old children reported their beliefs and typical responses to children's negative emotions, and mothers' emotion teaching practices were observed. RESULTS: African American mothers reported that the display of negative emotions was less acceptable than European American mothers, and African American mothers of boys perceived the most negative social consequences for the display of negative emotions. African American mothers reported fewer supportive responses to children's negative emotions than European Americans and more nonsupportive responses to children's anger. African American mothers of boys also reported more nonsupportive responses to submissive negative emotions than African American mothers of girls. However, no differences were found by ethnicity or child gender in observed teaching about emotions. Group differences in mothers' responses to negative emotions were explained, in part, by mothers' beliefs about emotions. CONCLUSIONS: Differences in beliefs and practices may reflect African American mothers' efforts to protect their children from discrimination.     

Cognitive validity of students’ self-reports of classroom mastery goal structure: What students are thinking and why it matters

Cognitive interviews were employed to systematically examine the cognitive validity of self-report survey items extensively used to assess classroom mastery goal structure. In a sample of elementary and middle school students, items were identified that functioned according to their intended meaning and those eliciting less accurate interpretations as conceptually defined by mastery goal structure cognitive validity criteria. Evidence suggested that items framed to focus on students’ teachers (i.e., teacher goals) were more cognitively valid than were items that focused students on their classroom context. Items with abstract terms yielded less accurate interpretations. We discuss implications of determining the cognitive validity of scales used to assess achievement goal structure and related self-report instruments.     

Examining Samoan language development in Samoan bilingual students＇ understanding of texts in English

This paper examines language development of Samoan students in bilingual contexts in Aotearoa, New Zealand. In the absence of valid and standardized assessments tools in Samoan, one was designed to test reading comprehension and oral language development for Samoan students using common narratives as a base. For reading comprehension, the tool used a listening comprehension format to avoid possible decoding limitations and provided a gradient of difficulty with a surprising drop in both oral and reading comprehension at year 7. This drop was attributed to a change in competencies of some students entering the bilingual classroom at year 7. For example, the mixed levels of both L 1 （Samoan） oral and L1 （Samoan） reading comprehension within and across years of schooling likely reflects the varied provision in the Samoan bilingual classes and the variations across cohorts in different degrees of bilingualism. We argue that this might be due to the make up of the two schools of which one was an Intermediate school of years 7 and 8 students and, the other was a full primary school with students from years 4 to 8. The patterns suggest two general instructional needs in Samoan bilingual classrooms. One is the need to develop metacognitive components and the need for deliberate and explicit instruction to build awareness of strategies and effectiveness. The other is the ubiquitous need identified in reading comprehension instruction generally to develop vocabulary both through oral and written forms. There was a highly significant relationship between L 1 oral at L1 reading comprehension levels reflecting a general relationship found in other studies of monolingual in L2 （English） contexts.