Karen E. French

The Use of Meta-Analysis in Exercise and Sport: A Tutorial.

Abstract Meta-analysis is a set of procedures used to quantify, integrate, and analyze the findings of a large number of research studies. It offers the advantage of quantifying effects from individual studies in addition to specifying the procedures the authors followed when reviewing the literature. Although meta-analysis has been demonstrated as a useful technique in exercise and sport research, and new and more appropriate statistical techniques for use in meta-analysis have been developed, these procedures are not widely used. This tutorial describes these advances and provides an example of their application to data from gender differences in throwing velocity during childhood and adolescence.

EFFECTS OF CONTEXTUAL INTERFERENCE ON RETENTION OF THREE VOLLEYBALL SKILLS

Previous research in motor learning has shown that random practice schedules facilitate retention and transfer of motor skills more than repetitive practice schedules. The purpose of this study was to investigate the generalizability of contextual interference effects. High school students (63 boys, 76 girls) from three physical education class periods were randomly assigned to one of three practice conditions, random, random-blocked, or blocked practice within a class period. Three teachers were randomly assigned to a practice group within a class period and taught a different practice condition each class period. There were nine groups with three practice groups per class period. Subjects practiced the volleyball forearm pass, set, or overhead serve for 30 trials every day for nine class periods. All subjects recorded scores for their practice trials each day during acquisition and were posttested after a 2-day retention interval. Analysis of variance indicated significant improvement in all groups but no significant effects of practice condition during acquisition or retention. These findings suggest that practice was long enough to produce change during acquisition. However, factors characteristic of physical education classes may reduce or mask contextual interference effects commonly observed in other settings.

Expert-novice differences in cognitive and skill execution components of youth baseball performance.

Previous research has shown that experts exhibit superior response selection and skill execution during performance in youth sport. The purpose of this study was to examine differences in cognitive and skill execution components of game performance in young baseball players (N = 159) with varying levels of expertise. Three levels of expertise (low-, average-, and high-skilled players) were identified at each age level (7, 8, 9, and 10 years of age). Game performance was videotaped, and measures of skill execution (throwing accuracy, throwing force, fielding, catching, batting average, and batting contact) and cognitive components (positioning, decisions) were developed from observational analysis. The results indicated that baseball skill execution during game play maximally discriminated expertise levels.

References for Motor Tasks—Gender Differences across Age in Motor Performance: A Meta-Analysis

In 1985 we published a meta-analysis of gender differences across age in motor performance in Psychological Bulletin, but it did not include an indexing of each motor task to the references from which it was obtained. This paper provides a table listing the 20 motor tasks and the references from which data for each task were taken. The range of tasks was from fundamental movements (e.g., catching, jumping, running, throwing) to motor fitness (e.g., agility, arm hang, balance, grip strength) to perceptual-motor abilities, (e.g., anticipation timing, fine eye-motor coordination, pursuit-rotor tracking, reaction time). The arm hang was represented in the fewest papers (n = 2) while the dash and long jump were most frequently referenced (n = 21).

Future Directions for Research on Expertise in Learning, Performance, and Instruction in Sport and Physical Activity

In reading and responding to the articles included in this theme issue of Quest, it becomes clear that there has been a burgeoning interest in research on expertise in sport and physical activity. An increasingly sophisticated knowledge base regarding both the nature of expertise and the constraints that limit the development of expertise has begun to accumulate. Despite the progress that has been made, the empirical database on pedagogical and motor experts remains limited; each of the articles provide more questions pertaining to expertise than findings. Our assessment is that the authors were successful in illuminating the necessity for continued research. In the sections that follow, we will attempt to describe a few of the many possible directions that research on expertise in pedagogy and sport learning might take.

Chapter 14 The Development of Expertise in Youth Sport

Publisher Summary This chapter reviews research regarding the development of expertise in youth sport. The focus is primarily on the development of cognitive skills and their relation to sport performance. The chapter presents the paradigms and findings from various areas of research on sport expertise in children and adults. The knowledge base and developmental processes associated with working memory and long term memory are discussed. The constraints on the development of cognitive and motor expertise in youth sport is highlighted. Studies examining modeling have shown that verbal strategies are particularly helpful for enhancing performance in young children. The longitudinal research and research on instructional influences offers the greatest promise. Experience alone does not translate into expertise. Research examining changes in knowledge, skill, and performance over short periods of time provide limited pieces of information. Sport expertise develops over considerable time and practice using the knowledge and skills. Many sport experts begin participation in childhood. Only by measuring changes in procedural knowledge and skill development over extended periods of time, can it be expected to uncover the changes in knowledge structures, the interaction of cognitive and motor processes, constraints on cognitive and motor performance, relations to improved performance, and instructional practices which facilitate performance.

External-Focus Feedback Benefits Free-Throw Learning in Children.

Purpose: Considerable research supports the motor-learning advantage associated with an external focus of attention; however, very few studies have attempted to generalize these findings to children especially with attentional focus feedback. Therefore, the purpose of this study was to determine the effect of attentional focus feedback on motor learning in children. Method: Boys (n = 14) and girls (n = 14) aged 9 to 11 years old were randomly assigned to 1 of 2 gender-stratified groups: (a) internal-focus feedback or (b) external-focus feedback. Following initial instructions and task demonstration, participants performed 100 modified free throws over 2 days while receiving feedback statements respective to their attentional focus condition. Approximately 24 hr later, participants performed a retention test consisting of 20 additional free throws. Participants were also asked to respond to a retrospective verbal report at the end of each day to serve as a manipulation check. Results: Results of the analysis revealed a statistically significant learning advantage for participants receiving external-focus feedback, and retrospective verbal reports provide support for the self-invoking trigger and constrained action hypotheses. Conclusions: Future research should continue to incorporate retrospective verbal reports and explore potential causal links between internal attentional focus and self-evaluation.

Somatic comparisons at four ages of South Korean females and females of other Asian groups

Somatic data were collected during April 1997 on 156 females ages 6, 9, 13, and 15 years, residing in urban Pusan, South Korea, and on 158 age peers residing in rural regions surrounding the city. Comparisons were made between urban and rural groups for measures of body size and form, skinfold thicknesses, the body mass index (BMI), and estimated arm muscle area (ARM). Age at menarche was retrospectively reported by the 13‐ and 15‐year‐olds. The data were analyzed in 2 (urban‐rural) × 3 (age) analyses of variance with an alpha level of P < 0.05. Age differences were evident for all dimensions. A significant main effect for urban–rural differences was found for stature, lower limb height, upper limb height, shoulder width, hip width, triceps skinfold, ARM, skelic index, and the trunk width index. Regardless of age, urban children were larger than rural children. Similar means were obtained for the BMI in urban and rural girls. Age at menarche was consistent with recent results; however, the rural sample (12.4 years) was significantly earlier than the urban sample (13.1 years). Compared with data collected four decades ago, present‐day 6‐, 9‐, 13‐, and 15‐year‐old females are taller and heavier at every age, indicating secular gains. Pusan females are similar in stature to age peers in Taiwan, Japan, and Hong Kong, and taller than the Chinese. Am. J. Hum. Biol. 11:735–744, 1999.

Somatic comparisons of urban and rural Russian boys, ages 6, 9, and 15 years, living in St. Petersburg and surrounding areas

Somatic data were collected during September 1991 on 280 males, ages 6, 9, and 15 years, residing in urban St. Petersburg, Russia, and in rural regions surrounding the city. Comparisons are made between urban and rural groups for measures of body size and form, skinfold thicknesses, body mass index (BMI), and estimated arm muscle area (ARM). The data were analyzed in 2 (urban‐rural) × 3 (age) analyses of variance, with an alpha level of P < 0.05.

Somatic comparisons at three ages of South Korean males and males of other Asian groups

Somatic data were collected during July 1995 on 154 males, ages 6, 9, and 15 years, residing in urban Pusan, South Korea, and on 157 age peers residing in rural regions surrounding the city. Comparisons are made between urban and rural groups for measures of body size and form, skinfold thicknesses, the body mass index (BMI), and estimated arm muscle area (ARM). The data were analyzed in 2 (urban‐rural) × 3 (age) analyses of variance with an alpha level of P < 0.05. Age differences were evident for all dimensions. A significant main effect for urban‐rural differences was found for stature, sitting height, lower limb height, upper limb length, arm girth, calf girth, shoulder width, hip width, body weight, and the sum of skinfolds. Regardless of age, urban children were larger than rural children. The interaction was nonsignificant. Except for the trunk width index, urban and rural boys did not differ on measures of body form. Similar means were obtained for the BMI and ARM in urban and rural boys. Compared with data collected four decades ago, present day 6, 9, and 15 year old males are taller and heavier at every age, indicating secular gains. Pusan males are similar in stature to age peers in Taiwan and Japan, and taller than the Chinese. Am. J. Hum. Biol. 9:493–503, 1997.