Preschool Home Environment and Classroom Behavior

A longitudinal investigation was made of the relationship between home-environment processes when children are between 3 and 5 years of age, and children’s classroom behavior in the primary grades. A generally moderate relationship was observed between the two sets of variables. Encouragement of social maturity showed the strongest relationship with classroom behavior, particularly patience, internal reliance, and inattentiveness. Of the seven classroom behavior variables examined, comprehension showed the largest number of significant relationships with early environment variables.     

Infants as Others: uncertainties,difficulties and (im)possibilities in researching infants’ lives

Increasingly, researchers are trying to understand what daily life is like for infants in non-parental care from the perspectives of the infants themselves. In this article, we argue that it is profoundly difficult, if not impossible, to know how infants experience their worlds with any certainty and, indeed, whether they do or do not possess well-worked out ‘perspectives’ on their experiences. Three key difficulties are discussed: firstly, the difficulty of interpreting non-verbal expressions and behaviour; secondly, the difficulty of knowing whether researchers’ constructions of the ‘infant’s perspective’ align with the infant’s experiences of their world; and, thirdly, the difficulty of providing opportunities for infants to disrupt researchers’ predetermined categories of understanding, meanings and expectations. Because of these difficulties, we argue that research endeavours to understand infants’ experiences in non-parental care should be seen as sites of ethical rather than epistemological practice.     

Upper and lower thresholds of fat-free mass index in a large cohort of female collegiate athletes

ABSTRACT

Fat-free mass index (FFMI) is a height-adjusted metric of fat-free mass which has been suggested as a useful method of body composition assessment in athletic populations. The purpose of this study was to determine sport-specific FFMI values and the natural upper threshold of FFMI in female athletes. 372 female collegiate athletes (Mean±SD; 20.03±1.55 years, 167.55±7.50 cm, 69.46±13.04 kg, 24.18±5.48% bodyfat) underwent body composition assessment via dual-energy x-ray absorptiometry. FFMI was adjusted to height via linear regression and sport-specific reference values were determined. Between-sport differences were identified using one-way ANOVA with Tukey post-hoc tests. Average FFMI was 18.82±2.08 kg/m²; height-adjusted values were not significantly different (p<0.05) than unadjusted values. FFMI in rugby athletes (20.09±2.23 kg/m²) was found to be significantly higher (p<0.05) than in gymnastics (18.62±1.12 kg/m²), ice hockey (17.96±1.04 kg/m²), lacrosse (18.58±1.84 kg/m²), swim & dive (18.16±1.67 kg/m²), and volleyball (18.04±1.13 kg/m²). FFMI in cross country (16.56±1.14 kg/m²) and synchronized swimming (17.27±1.47 kg/m²) was significantly lower (p<0.05) than in Olympic weightlifting (19.69±1.98 kg/m²), wrestling (19.15±2.47 kg/m²), and rugby. The upper threshold for FFMI in female athletes (97.5^th percentile) was 23.90 kg/m². These results can be used to guide personnel decisions and assist with long-term body composition, training, and nutritional goals.     

Qualitative Feasibility of Using Three Accelerometers With 2–3-Year-Old Children and Both Parents

Purpose: This study assessed mothers' opinions about the feasibility and acceptability of using the ActiGraph GT3X+, Actiheart, and activPAL3 with their 2- to 3-year-old children, as well as with themselves and their husbands/partners, for an 8-day period. Method: Six focus groups were run with Pakistani and White British mothers (n = 17), in English or Urdu, at Children's Centers in Bradford, United Kingdom. Each accelerometer was shown to the mothers while its characteristics and wearing procedures were explained. Mothers were then asked about their opinion on the feasibility of use with their toddlers, themselves, and husbands/partners, as well as their monitor preference. Data were transcribed verbatim and analyzed through thematic analysis. Results: The ActiGraph was the most preferred accelerometer for use with children, while the Actiheart was the least favorable. The ActiGraph was also the most preferred accelerometer for use with both mothers and fathers. Main issues raised included unsuitability of the Actiheart for fathers due to chest hair, discomfort due to the large size of the activPAL3 in relation to children's thighs, and children pulling off the Actiheart or tampering with the device if its presence was noticed (ActiGraph/Actiheart). Conclusion: The most preferred/accepted accelerometer overall was the ActiGraph GT3X+ for both children and parents. Issues raised with the devices have potential to impact recruitment and compliance rates of studies targeting this population, which highlights the importance of assessing the feasibility/acceptability of different devices with the target population ahead of planning research involving physical activity measurement.     

Factors Associated With Transitional Shifts in College Students' Physical Activity Behavior

The Transtheoretical Model (Prochaska & Marcus, 1994) has been widely used as a framework for understanding exercise behavior change. The purpose of this study was to clarify equivocal research findings reported for model predictions when examining stage movement over time rather than static stages and to provide some evidence of the construct validity of transitional stages. Participants were female (n = 285) and male (n = 243) undergraduates (M age = 19.9 years, SD = 2.7) who completed previously validated questionnaires twice, separated by 9 weeks, that assessed stage of change, exercise behavior, processes of change, pros and cons of exercise, and exercise self-efficacy. Participants were classified into one of five transitional shift groups based on their responses at baseline and follow up: (a) stable sedentary, (b) stable active, (c) activity adopters, (d) activity relapsers, and (e) perpetual preparers. Results of a 5 (group) x 2 (time) repeated measures (RM) analysis of variance (ANOVA) examining exercise behavior revealed a significant interaction (p < .001) and supported transitional stage classification, with activity adopters and stable actives increasing exercise over time and relapsers decreasing activity. Separate 5 (group) x 2 (time) RM ANOVAs examining model constructs revealed no significant interaction for cognitive processes of change; however, activity adopters and stable actives reported significant (p < .01) increases in the use of behavioral processes over time, while only the activity relapsers and perpetual preparers reported decreases. Activity relapsers also reported significant (p < .05) decreases in the pros of exercise. No significant interactions were found for the cons of exercise behavior. Unlike findings reported in cross-sectional studies, increases in self-efficacy did not accompany increases in exercise stage. The findings strongly support examination of stage movement classifications rather than static stages, as these transitions provide greater insight into the mechanisms of exercise behavior change.     

Perception of Physical Activity Participation of Chinese Female Graduate Students: A Case Study

Purpose: Chinese female international students (CFIS) have been identified as one of the least physically active groups in the United States. In an effort to better understand this situation, this study's purpose was to examine CFIS in American higher education in terms of the meaning they assigned to physical activity and facilitators and barriers they experienced with regard to physical activity participation. Method: Twenty CFIS from a university in the Northwest region of the United States were recruited and interviewed. All of the interviews were conducted in Mandarin Chinese and translated and transcribed into English. The 1-on-1 semistructured interviews lasted between 45 min and 60 min each. Data were analyzed by NVivo8. Results: In terms of meaning, physical activity provided the participants with a break from their academic work, allowed them some alone time, and taught them a process for accomplishing other things in their lives. Major facilitators included social influences, ample available resources, their changing perceptions of femininity, and the need to improve or maintain health. Barriers included a lack of time, low self-efficacy, limited social support, cultural barriers, and a lack of “how-to” information. Conclusions: Understanding the physical activity experiences of CFIS is an important step in the process of promoting their long-term health and well-being. It may behoove universities with growing Chinese international student populations to add more cross-cultural content into their curriculums and fitness programs, increase awareness of cultural differences on campus, and increase accessibility to information in an effort to remove physical activity participation barriers experienced by CFIS.     

阶段变化模型在身体活动领域应用研究的综述:1998年至2012年

阶段变化模型于1998年首次引入我国,至今尚没有对基于该模型的身体活动研究成果进行过系统综述。对1998—2012年间,我国以此模型为基础进行的身体活动研究进行了综述;并论证了基于该模型,制订促进青少年每天锻炼一小时干预策略的可行性。在对知网等数据库的期刊论文进行计算机检索,并对符合检索条件论文的全文和参考文献进行人工检索后,114篇论文进入综述。论文被编码、分类,并使用半定量方法进行了分析。结果显示:阶段变化模型虽是我国锻炼心理学领域内备受关注的理论模型之一,但前期基于整体模型的研究和干预(或纵向)研究较少,模型在我国的适用性和应用性仍有待进一步检验。12项涉及青少年身体活动的研究中,基于整体模型的研究和干预研究各占不到一成,为后续研究提供的可参考结果极其有限。与青少年身体活动具有稳定关系的因素是性别、年级(年龄)和均衡决策。后续应考虑关注纵向设计、检验测量工具、针对不同性质被试以及基于整体模型进行研究;研究需明确界定身体活动和变化阶段的划分标准。基于阶段变化模型制定促进青少年参与体育锻炼干预策略的证据有限。     

Carbohydrate intake and ketosis in self-sufficient multi-stage ultramarathon runners

ABSTRACT

Ultra-endurance athletes accumulate an energy deficit throughout their events and those competing in self-sufficient multi-stage races are particularly vulnerable due to load carriage considerations. Whilst urinary ketones have previously been noted in ultra-endurance exercise and attributed to insufficient carbohydrate (CHO) availability, not all studies have reported concomitant CHO intake. Our aim was to determine changes in blood glucose and β-hydroxybutyrate concentrations over five days (240 km) of a self-sufficient multi-stage ultramarathon in combination with quantification of energy and macronutrient intakes, estimated energy expenditure and evaluation of energy balance. Thirteen runners (8 male, 5 female, mean age 40 ± 8 years) participated in the study. Glucose and β-hydroxybutyrate were measured every day immediately post-running, and food diaries completed daily. CHO intakes of 301 ± 106 g·day^?1 (4.3 ± 1.8 g·kg^?1·day^?1) were not sufficient to avoid ketosis (5-day mean β-hydroxybutyrate: 1.1 ± 0.6 mmol.L^?1). Furthermore, ketosis was not attenuated even when CHO intake was high (9 g·kg^?1·day^?1). This suggests that competing in a state of ketosis may be inevitable during multi-stage events where load reduction is prioritised over energy provisions. Attenuating negative impacts associated with such a metabolic shift in athletes unaccustomed to CHO and energy restriction requires further exploration.     

The influence of situational variables on ball possession in the English Premier League

Abstract

The aims of this study were twofold: (1) to examine the influence of situational variables on ball possession in elite soccer and (2) to quantify the variables that discriminate between high or low percentage ball possession teams (HPBPT and LPBPT) across different playing positions. Match performance data were collected from English Premier League matches using a multiple-camera system. Data were examined using linear regression, a 2 × 5 factorial analysis of variance and discriminant analysis. Playing against weak opposition was associated with an increase (P < 0.01) in time spent in possession while playing away decreased (P < 0.01) the time spent in possession by ~3%. Possession was increased (P < 0.01) when losing than winning or drawing. Finally, the better the ranking of a team, the higher (P < 0.01) the time spent in possession. The playing position effect was significant for all variables (P < 0.05); however, there were only interactions with team ball possession in some cases. The discriminant analysis identified functions for all five playing positions (P < 0.01). The variables that discriminated performance between HPBPT and LPBPT were different for various playing positions, although the number of successful passes was the most common discriminating variable. The results demonstrate that HPBPT and LPBPT developed different possession strategies during matches and that selected variables such as successful passes were identified to explain these data trends across various playing positions. Combinations of variables could be used to develop a probabilistic model for predicting time spent in possession by teams.