Adjusting athletes' body mass index to better reflect adiposity in epidemiological research

Abstract

The aim of the present study was to identify when body mass index (BMI) is unlikely to be a valid measure of adiposity in athletic populations and to propose a simple adjustment that will allow the BMI of athletes to reflect the adiposity normally associated with non-athletic populations. Using data from three previously published studies containing 236 athletes from seven sports and 293 age-matched controls, the association between adiposity (sum of 4 skinfold thicknesses, in millimetres) and BMI was explored using correlation, linear regression, and analysis of covariance (ANCOVA). As anticipated, there were strong positive correlations (r = 0.83 for both men and women) and slope parameters between adiposity and BMI in age-matched controls from Study 1 (all P < 0.001). The standard of sport participation reduced these associations. Of the correlations and linear-regression slope parameters between adiposity and BMI in the sports from Studies 2 and 3, although still positive in most groups, less than half of the correlations and slope parameters were statistically significant. When data from the three studies were combined, the ANCOVA identified that the BMI slope parameter of controls (5.81 mm · (kg · m^?2)^?1) was greater than the BMI slope parameter for sports (2.62 mm · (kg · m^?2)^?1) and middle-distance runners (0.94 mm · (kg · m^?2)^?1) (P < 0.001). Based on these contrasting associations, we calculated how the BMI of athletes can be adjusted to reflect the same adiposity associated with age-matched controls. This simple adjustment allows the BMI of athletes and non-athletes to be used with greater confidence when investigating the effect of BMI as a risk factor in epidemiological research.     

Effect of cluster set configurations on power clean technique

Abstract

The purpose of this investigation was to examine the effects of cluster set configurations on power clean technique. Ten male, recreational weightlifters performed three sets of six repetitions at 80% of one repetition max with 0 (P0), 20 (P20) or 40 seconds (P40) inter-repetition rest. During the first and second set of P0, the catch and first pull were in a more forward position during repetition 6 as compared to repetition 1, respectively. During the second set of P40, differences in horizontal displacement were found between repetitions 1 and 6 for the second pull and the loop. During the third set of P40, differences in horizontal displacement were found between repetitions 1 and 6 for the first pull, transition, and beginning of the second pull. No differences in horizontal displacement were found between repetitions 1 and 6 during P20. During each set of P0, vertical displacement decreased between repetitions 1 and 6 (1.02 ± 0.07 m vs. 0.94 ± 0.06 m; Mean ± s). Cluster set configurations led to the maintenance of vertical displacement throughout all sets. The results demonstrate cluster set configurations with greater than 20 seconds inter-repetition rest maintain weightlifting technique to a greater extent than a traditional set configuration.     

Modifications to the Bassin Anticipation Timer

Abstract

The purpose of this study was to ascertain and to analyze the attitudes of men and women undergraduate students at the University of California, Santa Barbara, concerning the desirability of intensive athletic competition for girls and women. In January 1966, a questionnaire and an attitude inventory were administered to a random stratified sample of 300 undergraduate students. The attitude inventory consisted of 38 statements which were divided into four categories— social-cultural, mental-emotional, physical, and personality. Two hundred and eighty-four questionnaires and attitude inventories (94.7 percent) were completed and were submitted to statistical analysis.

Although the population was found to be favorable in attitude, the range of scores indicated that considerable differences of opinion existed concerning the desirability of athletic competition for girls and women.     

Stimulus Velocity,Duration and Uncertainty as Determiners of Response Structure and Timing Accuracy

Abstract

The present experiments examined the effects of stimulus velocity, stimulus duration, and stimulus uncertainty on the spatial-temporal structure and timing accuracy of coincident timing responses. The results of Experiment 1 indicated that the response structure for aimed movements differed from that of ballistic movements but response accuracy was comparable for both movement conditions. However, when information concerning the stimulus velocity was provided, the responses to the faster stimuli (i.e., stimuli of shorter duration) appeared to be “speeded up” copies of those to slower stimuli and response accuracy increased as the stimulus velocity increased (i.e., stimulus duration decreased). When the stimulus velocity was not known, subjects initiated a common response for approximately 260 msec and response accuracy appeared to decrease as the stimulus velocity increased (i.e., stimulus duration decreased). Experiment 2 indicated that the stimulus duration rather than the stimulus velocity was the major determiner of both the spatial-temporal structure and timing accuracy and that a very fast and a very slow stimulus will be responded to similarly when the stimulus duration remains constant.     

Determination of the swing technique characteristics and performance outcome relationship in golf driving for low handicap female golfers

Abstract

Previous studies on the kinematics of the golf swing have mainly focused on group analysis of male golfers of a wide ability range. In the present study, we investigated gross body kinematics using a novel method of analysis for golf research for a group of low handicap female golfers to provide an understanding of their swing mechanics in relation to performance. Data were collected for the drive swings of 16 golfers using a 12-camera three-dimensional motion capture system and a stereoscopic launch monitor. Analysis of covariance identified three covariates (increased pelvis–thorax differential at the top of the backswing, increased pelvis translation during the backswing, and a decrease in absolute backswing time) as determinants of the variance in clubhead speed (adjusted r ² = 0.965, P < 0.05). A significant correlation was found between left-hand grip strength and clubhead speed (r = 0.54, P < 0.05) and between handicap and clubhead speed (r = ?0.612, P < 0.05). Flexibility measures showed some correlation with clubhead speed; both sitting flexibility tests gave positive correlations (clockwise: r = 0.522, P < 0.05; counterclockwise: r = 0.711, P < 0.01). The results suggest that there is no common driver swing technique for optimal performance in low handicap female golfers, and therefore consideration should be given to individual swing characteristics in future studies.     

Schooling Taiwan's aboriginal baseball players for the nation

One of the major challenges that faces nation-builders in postcolonial societies is the incorporation of subaltern groups, particularly aboriginal peoples, into a collective national project. One vehicle for addressing this challenge is sport with schools being amongst the most important venues. This article offers an empirical study of the role of aboriginal players in Taiwanese baseball. By examining the schooling and historic achievements of aboriginal players in the Nenggao and Hongye teams and the role of aboriginal players during the more recent post-martial law period, the study challenges some commonly held views concerning the relationship between baseball and Taiwanese national identity. In particular, the article analyzes the role of the state in its use of baseball to support the co-option of aboriginal players for the nation-building project. The study concludes that the state, regardless of which ruling elite is in power, has consistently manipulated Taiwan's indigenous peoples, not least through the education system, in order to achieve certain political objectives, specifically in relation to nation-building. Furthermore, although baseball remains an important avenue for the social and economic advancement of individual aborigines, recurrent scandals linked to exploitation have been consistent characteristics of state policy.     

一份极有价值的关于华人数学教育的著作--评《华人如何学习数学:局内者之研究》

《华人如何学习数学:局内者之研究》是一本从不同情景和角度出发,研究关于华人学生的数学教学的指南.全书分4个部分,20章,574页.它的出版表明数学教育可以从对相关国家在数学测试中的各自表现提出一些简单的问题进入一些更具挑战性和更有意义的研究领域.     

The Significance of Gender Boundaries in Preadolescence: Contemporary Correlates and Antecedents of Boundary Violation and Maintenance

Previous research has established the importance of gender boundaries as a normative aspect of development in middle childhood. Here, the nature and importance of gender boundaries as an individual differences construct was explored. Ratings of gender boundary violation and gender boundary maintenance were made of 47 10–11-year-old children participating in a series of summer day camps. These ratings were supported by videotape-based behavior codings of gender boundary violating behaviors and by live observations of sheer number of associations with members of the opposite gender. In addition, considerable external validation of these individual differences was obtained. Children low on gender boundary violation and (especially) children high on boundary maintenance were independently judged by camp counselors to be socially competent. They also were found to be higher on a friendship variable, based on observation. Those who violated boundary were especially unpopular with peers, based on a child interview. Finally, boundary violation and maintenance were related to attachment history and to early measures of parent-child generational boundary distortions.     

The construction of experience: a longitudinal study of representation and behavior

Continuity in relationship representation and developmental links between relationship representation and behavior from infancy to late adolescence were examined using longitudinal data from a risk sample (N = 185). Significant correlations were found among diverse representational assessments (e.g., interview, drawing, projective narrative) and between representational and concurrent observational measures of relationship functioning. Structural equation models were analyzed to investigate the relations among caregiving experience in infancy; relationship representation and experience in early childhood, middle childhood, and early adolescence; and socioemotional functioning in adolescence. A model representing interactive contributions of representational and behavioral experience represented the data significantly better than a model representing noninteractive contributions. Findings support an organizational developmental view that socioemotional adaptation arises from the progressive construction of mutually informing expectations and experience.