The association of objectively determined physical activity behavior among adolescent female friends

The purpose of this study was to examine the extent to which physical activity among adolescent female friends is interdependent. The participants were 318 adolescent girls with a mean age of 16.0 years (range: 15-18 years). Pedometry was used to assess physical activity over 4 days. The relationship between an individual girl and her first-nominated reciprocal friend's physical activity level was moderate (r = 0.45, 90% confidence interval = 0.31, 0.56), when the friendship was nonreciprocal it was trivial (r = -.06, 90% confidence interval = -.36 .25). Friends'physical activity levels explained between 27% and 32% of an individual's pedometer-determined physical activity level. Reciprocity of friendship is an important variable to consider when understanding the relationship between adolescent female friends' physical activity. When friendships are reciprocal, there is a stronger relationship between friends' physical activity.     

A longitudinal assessment of the links between physical activity and physical self-worth in adolescent females

Abstract

A longitudinal framework was used to examine the hypotheses of (1) whether physical activity predicts changes in physical self-worth or (2) whether physical self-worth predicts changes in physical activity in adolescent girls. Participants (n=272) completed measures of physical self-worth and participation in physical activities at three different points spanning a two-year interval. A cross-lagged panel model using structural equation modelling analyses indicated that physical self-worth predicted subsequent physical activity and physical activity in turn predicted subsequent physical self-worth across time. Findings demonstrated a reciprocal relationship between physical self-worth and physical activity during early adolescence. This study supports the use of the reciprocal effects model (REM) in gaining an understanding of the cross-lagged relationships between physical self-worth and participation in physical activities amongst adolescent girls.     

The relationship between sport commitment and physical self-concept: Evidence for the self-enhancement hypothesis among adolescent females

ABSTRACT

Perceptions of physical self-concept are critical to physical activity participation. In line with the reciprocal effects model of causal ordering (REM), higher perceptions of physical self-concept can function as a facilitator to physical activity, and can arise as a result of engaging in physical activity. While this relationship has been predominantly tested in physical activity contexts, directional tests between physical self-concept and sport specific outcomes are limited. The current study aimed to evaluate the generalizability of the REM to sport commitment and physical self-concept in youth athletes. Over 24 months, adolescent females (N = 215) completed self-report questionnaires at Time 1 (T1) and two years later (Time 2; T2). Using structural equation modeling, the reciprocal effects model demonstrated that the path leading from T1 physical self-concept to T2 sport commitment was significant (p = .02), whereas the path leading from T1 sport commitment to T2 physical self-concept was not significant (p = .23). The results suggest a unidirectional relationship and may underscore the importance of focusing on the physical self-concept in the development of strategies geared towards improving adolescent female’s sport participation.     

Assessing parental impact on the sports participation of children: A socio-economic analysis of the UK

Abstract

This study examines the effects of parental attitudes on children's physical activity. A measure of parental attitude (their sport participation when being young) that is independent of the child's behaviour is needed. Using data from the sixth wave of the Taking Part Survey (n =14,002 adults and n =1116 children), a matching estimator analysis is conducted. The results reveal that there are substantial intergenerational transfers of behaviours, in particular for male adults and male children. Furthermore, while an effect is observed for female adults and male children, female children's sport participation is only marginally influenced by female adult's physical activity when growing up. The results imply that promoting sport to the younger generation seems to be a fruitful strategy in creating a sporting habit and promoting sport participation when being older. However, there are challenges to be overcome in promoting female participation.     

Measuring the effectiveness of offensive match-play in professional soccer

Abstract

The broader measures of offensive effectiveness, such as scoring opportunities and shots at goal, are commonly used as an alternative to goals scored due to the naturally low probability of scoring (about 1%) in soccer match-play. These measures may enable soccer practitioners to objectively see behind single match results, which are often influenced by chance. The purpose of this study was to examine the relationship between broader measures (scoring opportunities and score box possessions) and the ultimate measure (goals scored) of offensive effectiveness. We analysed data from videotapes of 163 of 182 (90%) matches played in the Norwegian men's professional league during the 2004 season. Multiple logistic regression analyses showed very similar results when comparing the effectiveness of different offensive tactics, regardless of which outcome was used. For example, counterattacks were more effective than elaborate attacks in producing goals (odds ratio OR=2.07, 95% confidence interval: 1.40 to 3.05), scoring opportunities (OR=2.30, 95% confidence interval: 1.28 to 4.15), and score box possessions (OR=2.12, 95% confidence interval: 1.39 to 3.25). The receiver-operating characteristic function statistical procedure was used to examine the association between each of the three measures of offensive effectiveness: scoring opportunities, score box possessions, and goals scored. No significant difference was observed between the area under the curve (AUC) for the broader measures (scoring opportunities and score box possessions) and the ultimate measure (goals scored) of offensive effectiveness. The 95% confidence interval of the AUC for both scoring opportunities (0.74–0.84) and score box possessions (0.68–0.76) includes the AUC for goals scored (0.74). Thus, the results are very similar regardless of which outcome measure for offensive effectiveness is used. This indicates that scoring opportunities and score box possessions (shooting opportunities) can be used as a proxy for goals scored when comparing the effectiveness of different playing tactics in soccer. Compared with goals scored, using scoring opportunities or score box possessions requires smaller match samples for meaningful analyses, and may therefore be more feasible alternatives.     

Physical activities during pregnancy and type of delivery in nulliparae

The aim of this study was to investigate changes in physical activity across pregnancy and the relationship between trimester-specific physical activity and unplanned caesarean sections (CSs). A cohort study design was carried out. A cohort of 150 pregnant women was established when they received prenatal care at 29–40 weeks of gestation at a medical centre in northern Taiwan. Participants were asked to recall the amounts of physical activity in which they had engaged in the three trimesters as assessed by the Pregnancy Physical Activity Questionnaire (PPAQ). Overall self-reported physical activity for the cohort decreased by 31% in the first trimester compared to the pre-gravid period, then increased in the second trimester and remained stable until delivery. A repeated measures analysis of variance was used to evaluate the data and revealed significantly more physical activity during the second trimester than in the first and third trimesters (F = 36.471, P = 0.000). In addition, there was a significant difference between normal spontaneous delivery and unplanned CS groups (F = 4.770, P = 0.031). Logistic regression determined that the odds ratio of undergoing a CS increased by 0.644 (95% confidence interval: 0.429–0.968) for women in the third trimester who performed low levels of physical activity. Results support the benefits of physical activity, and professionals are encouraged to provide pregnant women with information on recommendations for physical activity, particularly in terms of reducing unplanned CSs.     

Sport participation motivation in young adolescent girls: the role of friendship quality and self-concept

This study examined the factor structure of the Sport Friendship Quality Scale (SFQS; Weiss and Smith, 1999) and compared two models in which (a) self-worth mediated the relationship between physical self/friendship quality and sport commitment and (b) friendship quality and physical self-perceptions directly predicted self-worth and sport commitment. Female team sport participants (N = 227) between the ages of 11 and 14 years completed measures of sport commitment, enjoyment, athletic competence, physical attractiveness, self-worth, and friendship qualities. A confirmatory factor analysis found an inadequate fit for the SFQS, mainly due to problems with the loyalty and intimacy subscale. Separating the loyalty and intimacy factor into two subscales provided an adequate fit. Examination of the two structural models indicated that both models provided an adequate overall fit but that self-worth only weakly predicted sport commitment, suggesting the mediator model was impractical. Friendship quality had a weak relationship with self-worth and sport commitment. Results are discussed in light of issues in measuring sport friendship quality and future directions in this developing field.     

少年和成年业余长跑运动员急性耐力运动后心脏自主神经恢复观察研究

目的:观察少年和成年男子业余跑运动员一次急性耐力运动后心率变异(HRV)变化特征,并探讨运动后HRV变化生理学意义。方法:少年(14.4±1.3岁)与成年(25.7±2.8岁)受试者各10名,进行1次90min、强度为95%个体无氧阈强度跑台运动。在运动前、运动后15min以及运动后6h测定HRV。结果:运动后15min,TPLn、HFnu和HRV各时域指标明显低于运动前水平,LFnu和LF/HF显著升高;少年受试者HFnu降幅、LFnu和LF/HF升幅明显低于成年受试者(P<0.05)。运动后6h,HRV各指标均已恢复,其中,TPLn、SDNN、HFnu和RMSSD有反弹的迹象。运动后HFnu相对运动前的降幅与受试者年龄呈负相关关系(r=-0.645,P<0.01,n=20);另外,HFnu、TPLn相对运动前降低程度与运动前水平高度负相关(P<0.05,n=20)。结论:一次急性耐力运动后HRV出现短暂抑制现象,少年受试者运动后HRV降低幅度相对成年较低,可能与发育成熟度不同有关,急性运动后HRV变化可能是运动适应的生理表现。     

Sport Participation Motivation in Young Adolescent Girls

Abstract

This study examined the factor structure of the Sport Friendship Quality Scale (SFQS; Weiss & Smith, 1999) and compared two models in which (a) self-worth mediated the relationship between physical self/friendship quality and sport commitment and (b) friendship quality and physical self-perceptions directly predicted self-worth and sport commitment. Female team sport participants (N= 227) between the ages of 11 and 14 years completed measures of sport commitment, enjoyment, athletic competence, physical attractiveness, self-worth, and friendship qualities. A confirmatory factor analysis found an inadequate fit for the SFQS, mainly due to problems with the loyalty and intimacy subscale. Separating the loyalty and intimacy factor into two subscales provided an adequate fit. Examination of the two structural models indicated that both models provided an adequate overall fit but that self-worth only weakly predicted sport commitment, suggesting the mediator model was impractical. Friendship quality had a weak relationship with self-worth and sport commitment. Results are discussed in light of issues in measuring sport friendship quality and future directions in this developing field.     

Number of parous events affects the association between physical exercise and glycemic control among women with gestational diabetes mellitus: A prospective cohort study

BackgroundMultiparous women are at a higher risk of gestational diabetes mellitus (GDM) than primiparas. Physical activity during pregnancy has been shown to be beneficial for GDM, but there is little evidence on the association between physical activity and glycemic control among women with GDM, whether primiparas or multiparas. Thus, the objective of the present study was to examine the association between physical activity and glycemic control in women with GDM and to determine what, if any, effects result from number of parous events.MethodsA prospective cohort of 1162 women with GDM was recruited, with 604 multiparas (51.98%). The general linear model was used to calculate the risk difference and its 95% confidence interval (95%CI) to quantify the impact of parous events on glycemic control in pregnancy as well as the association between physical activity time and glycemic control.ResultsAmong 1162 women with GDM, the median daily activity time was 65 min (interquartile range (IQR): 45–90 min), and the abnormal plasma glucose (PG) percentage, calculated as number of abnormal PG tests divided by the total number of PG tests, was 40.00% (IQR: 22.22%–66.67%). The percentage of abnormal PG was stabilized and statistically lower with daily physical activity time exceeding 60 min among primiparas (IQR: 30.89%–44.43%) and exceeding 90 min among multiparas (ranged from 27.76% to 38.82%). After adjusting for potential confounders, primiparas tended to have a lower percentage of abnormal PG than do multiparas (rate difference = –0.39, 95%CI: –3.61 to 2.84). The same amount of physical activity time was significantly less effective for multiparas than for primiparas (trend p-value < 0.01).ConclusionIn women with GDM, being multiparous is associated with less effective glycemic control through physical activity, such that multiparas need more physical activity to achieve glycemic control at a similar level to primiparas.     

Effects of allometric scaling and isokinetic testing methods on the relationship between countermovement jump and quadriceps torque and power

Determination of the strongest possible relationship between isokinetic quadriceps and functional performance measurements in healthy females would allow sports medicine practitioners to establish normative values when examining muscular performance in injured females. Previous attempts to correlate both measurements have, however, produced inconsistent results. The purpose of this study was to examine the effects of allometric scaling, isokinetic testing velocities, reciprocal and non-reciprocal isokinetic testing on the relationship between countermovement jump (CMJ) and isokinetic quadriceps torque and power in recreational females athletes. Seventeen females (age 21.0 +/- 2.0 years, body mass index 19.5 +/- 1.0 kg x m(-2)) performed isokinetic quadriceps and CMJ tests. Isokinetic peak torque and average power were obtained reciprocally and non-reciprocally at 1.05 and 3.14 rad x s(-1), and were corrected for body mass by allometric modelling. Pearson product-moment correlation (r) was used to assess the relationship between the isokinetic parameters and the CMJ measurements. Coefficients of determination (r(2)) were calculated to determine the magnitude of common variance. The r-values for all non-allometrically modelled non-reciprocal parameters were greater (r = 0.58-0.63) than isokinetic parameters obtained reciprocally (r = 0.28-0.47). Using allometric scaling, non-reciprocal isokinetic data accounted for an additional 2-9% of the CMJ height variance, and statistically significant correlations were obtained at both 1.05 and 3.14 rad x s(-1). Allometrically scaled, non-reciprocal isokinetic peak torque and average power at 1.05 rad x s(-1) had the highest correlation with CMJ (r(2) = 0.49). At both 1.05 and 3.14 rad x s(-1), non-reciprocal quadriceps parameters correlated more closely with CMJ measurements than do reciprocal contractions. Normalization for body size by allometrically scaling may further improve correlations with CMJ performance.     

Six-year trends and intersectional correlates of meeting 24-Hour Movement Guidelines among South Korean adolescents: Korea Youth Risk Behavior Surveys, 2013–2018

BackgroundGrounded in intersectionality theory, this study examined the 6-year prevalence trend and correlates in meeting Canada's 24-Hour Movement Guidelines (Guidelines hereafter) in a nationally representative adolescent samples of South Korea (officially the Republic of Korea).MethodsSelf-reported, annually repeated cross-sectional data collected between 2013 and 2018 were used (n = 372,433, 12–17 years old, 47.9% females). Adolescents were categorized as meeting or not meeting different sets of physical activity, screen time (ST), and sleep recommendations within the Guidelines, separately for weekdays and weekend days. Intersectional correlates included sex and social class (i.e., family economic status, parental education level, and academic performance). Multiple logistic regression analyses were performed.ResultsOverall, the proportion of adolescents meeting physical activity, ST, and sleep recommendations were 5.3%, 60.3%, and 10.2% on weekdays and 5.3%, 28.2%, and 46.4% on weekend days, respectively. Between 2013 and 2018, no substantial changes were observed for meeting the physical activity or sleep recommendation, while meeting the ST recommendation was markedly lower in 2018. The proportion of meeting all 3 recommendations were 0.5% for weekdays and 0.8% for weekend days. Overall, compared to female adolescents, male adolescents were consistently associated with more favorable patterns of meeting different sets of recommendations, regardless of social class. Among females only, social class appeared to be not important or even detrimental in meeting different sets of recommendations. Being male, compounded with social class, was associated with meeting the ST recommendation.ConclusionLess than 1% of Korean adolescents met the overall Guidelines. Intersectionality-based analysis and intervention may be important in promoting healthy active lifestyles among South Korean adolescents.     

The relationship between evaluative concerns and sport competition state anxiety among youth skiers

Thirty-four youth competitive skiers (mean age = 13.74 years) completed measures of social evaluative concern and competitive anxiety. Consistent with past research, regression analyses showed that cognitive anxiety was related to performance-specific evaluative concerns. However, contrary to current conceptualizations of sport competition anxiety, somatic anxiety was correlated with concerns about evaluation of other non-performance aspects of ski racing. Competitive skiers were most concerned about parents' and friends' evaluations of their performance, and other competitors' and friends' evaluations of their skiing in general. These findings are discussed in relation to the theory and management of sport competition state anxiety.     

Attraction to Physical Activity in Urban Schoolchildren: Parental Socialization and Gender Influences

Abstract

The purpose of this study was to gain a better understanding of the contribution of parental socialization processes and gender to children's interest in physical activity using Eccles' expectancy-value model of motivation. An additional purpose was to examine the nature of these relationships among children of a lower socioeconomic level, a sample that has been underrepresented in pediatric exercise research to date. Fourth- through sixth-grade children (N = 107) from a large metropolitan school district were participants in this study and completed questionnaires assessing attraction to physical activity, perceived physical competence, and perceptions of their parents' physical activity beliefs and behaviors. Multivariate regression analyses revealed a significant relationship between parental socialization processes and children's perceived physical competence and attraction to physical activity. Gender differences were also identified and were primarily related to liking of the exertional characteristics of physical activity and exercise. These findings are consistent with theory and research regarding parental and gender-role socialization during childhood.     

Accelerometry to Assess Preschooler's Free-Play: Issues with Count Thresholds and Epoch Durations

This study examines the utility of current accelerometer threshold definitions and epoch durations for physical activity intensity classification in preschool-aged children. Using video footage of children engaged in active play, directly observed 1-sec epoch physical activity intensity scores were derived from a modified version of the Children's Activity Rating Scale, averaged into 15-sec epochs (corresponding to the accelerometer scale), and compared to accelerometer-measured classifications. Overall, 6,540 individual 1-sec epochs were captured and classified from six children, yielding 429 time-matched 15-sec epoch physical activity intensity classifications from both methods. Children participated in 25 distinct physical activity behaviors and spent 75% of free-play in one intensity level for ≤5 sec. The maximum amount of time spent participating in an activity prior to changing activity intensity was 98 sec. Agreement between methods was generally poor (overall: κ = .22; child range: κ = .00 to .66), and the difference between methods was significantly asymmetrical (McNemar's test overall: p = .01). Accelerometer thresholds and epoch durations used to classify preschoolers' physical activity intensity yielded biased estimates in the current study. Further investigation is necessary to establish optimal physical activity measurement methods with this population.     

Discriminant analysis of anthropometric and biomotor variables among elite adolescent female athletes in four sports

The aim of this study was to identify anthropometric and biomotor variables that discriminated among groups of elite adolescent female athletes aged 14.3 +/- 1.3 years (mean +/- s) from four different sports (tennis, n = 15; swimming, n = 23; figure skating, n = 46; volleyball, n = 16). The anthropometric variables included body mass, height, bi-epicondylar breadth of the distal extremity of the humerus and femur, maximal girth of the calf and biceps and the sum of five adipose skinfolds. The biomotor variables were maximal aerobic power, muscular endurance and flexibility of the trunk. Discriminant analysis revealed three significant functions (P < 0. 05). The first discriminant function primarily represented differences between figure skaters and all other groups of athletes. The other two underlined anthropometric and biomotor differences between swimmers and volleyball players and between tennis players and swimmers, respectively. After validation, the analysis showed that 88% of the athletes were correctly classified in their respective sports. Our model confirms that elite adolescent female athletes show physical and biomotor differences that clearly distinguish them according to their particular sport.     

Comparison of Hydrostatic Weighing at Residual Volume and Total Lung Capacity in Children

Abstract

The influence of perceptions of the motivational climate and perceived ability on situational motivation and the physical activity behavior of 213 male and 229 female adolescent physical education students (M age= 12.56 years; SD = 0.96) was examined over a 3-day period. A significant age by gender interaction emerged, with physical activity declining from the sixth to eighth grade. The decline was more pronounced among female than male students. Perceptions of a mastery climate were strongly related to more self-determined forms of situational motivation. In contrast, perceptions of a performance climate were strongly related to less self-determined forms of situational motivation. Results of a hierarchical regression analysis revealed gender, perceived ability, and perceptions of a mastery climate to explain a significant amount of variance in physical activity. These findings suggest that promoting a mastery oriented motivational climate in physical education will foster self-determined situational motivation and physical activity.     

Physical activity and situational motivation in physical education: influence of the motivational climate and perceived ability

The influence of perceptions of the motivational climate and perceived ability on situational motivation and the physical activity behavior of 213 male and 229 female adolescent physical education students (M age = 12.56 years; SD = 0.96) was examined over a 3-day period. A significant age by gender interaction emerged, with physical activity declining from the sixth to eighth grade. The decline was more pronounced among female than male students. Perceptions of a mastery climate were strongly related to more self-determined forms of situational motivation. In contrast, perceptions of a performance climate were strongly related to less self-determined forms of situational motivation. Results of a hierarchical regression analysis revealed gender, perceived ability, and perceptions of a mastery climate to explain a significant amount of variance in physical activity. These findings suggest that promoting a mastery oriented motivational climate in physical education will foster self-determined situational motivation and physical activity.     

Cognitive Interviewing: A Qualitative Tool for Improving Questionnaires in Sport Science

This study sought to determine whether body fat percentage estimates using an inexpensive bioelectrical impedance analysis (BIA) device (Tanita TBF-521, Tanita Corp, of America, Arlington Heights, IL) could be freely substituted for those obtained utilizing skinfolds (method equivalence). Data were analyzed from measurements on 38 children age 6 to 12 years. Random effect intraclass correlation (r = .930; 95% confidence interval [CI] = .87 to .96), fixed effect intraclass correlation (r = .932; 95% CI = .87 to .96), and least-products regression supported the equivalence of the 2 methods. The technical error between the 2 methods (3.7; coefficient of variation = 12.2%) was small and also supported the equivalence of the two methods. The ability of the BIA device to categorize into normal and obese categories when compared to the skinfold technique was also impressive (κ = .95; 95% CI = .73 to .99). However, the results of the limits of agreement analysis showed that the approximate 95% CI for the differences between methods was wide (-9.1 to 11.4).     

Effects of Instructional Physical Activity Courses on Overall Physical Activity and Mood in University Students

Purpose: The aim of this research was to assess the association between university-based instructional physical activity (PA) courses and changes in overall PA levels and negative mood and their interrelations. The study also sought to determine the amount of change in PA required to significantly improve mood in course enrollees. Method: Participants were university students initially completing PA below the level recommended for health who were either presently enrolled in an elective instructional PA course (treatment group, n = 52, 69% female) or not presently enrolled in such a course (comparison group, n = 32, 69% female). Validated surveys assessed volumes of PA completed per week and overall negative mood from baseline to course end. Mediation analyses assessed group effects on mood through PA changes and reciprocal relations between PA and mood changes. Results: There was a significantly greater increase in PA and significantly more reduction in negative mood in the treatment group. Change in PA completely mediated the relationship between group and change in negative mood, and change in mood completely mediated the relationship between group and PA. These findings indicated a reciprocal, mutually reinforcing relationship between changes in PA and mood. An increase in PA of at least 2 days/week was associated with a significant reduction in negative mood, with no greater effect for more increase. Conclusions: Results provided an improved understanding of the effects of university-based instructional PA courses and how they might be leveraged to improve students’ mental health and possibly contribute to their academic success.