Rotation,Translation, and Trajectory in Diving

Abstract

Theories causing rotation of the body in diving were critically reviewed and a statement relating angular momentum to both the angle of lean and the angle of force was presented. Equations were developed by which the partition of energy between rotation and translation could be computed.     

Effects of Different Durations of Physical Training on Cardiorespiratory Function,Body Composition,and Serum Lipids

Abstract

The purpose of the study was to determine the effects of 15, 30, and 45 min of conditioning on maximum performance and cardiorespiratory fitness variables, body composition, pulmonary function, and serum lipids. Subjects, ages 20 to 35, were 59 inmates at a California state prison. The conditioning included running and walking and was performed three days/week at approximately 85 to 90% max HR for 20 weeks. The distance covered per exercise session was approximately 1.75, 3.25, and 5.1 miles for the 15-, 30-, and 45-min groups, respectively.

Improvements in treadmill performance time. [Vdot]O₂ max, max O₂ pulse, diastolic blood pressure, and total skinfold fat were proportional to duration of the training session; i.e., the subjects training in the longer duration sessions showed the greater improvements. The control group showed no significant change during the same period. Compared to the control group, the 15-min group made significant reductions in resting HR, total skinfold fat, percent fat, and waist girth and increases in [Vdot]O₂ max, max O₂ pulse,[Vdot]_E max, and treadmill performance time. Vital capacity, FEV_1.0, and % FEV_1.0 remained relatively unchanged in all four groups, as did serum cholesterol and triglycerides. The 45-min group improved significantly more than the 15-min group in treadmill time, [Vdot]O₂ max, max O₂ pulse, resting systolic and diastolic blood pressures, and percent fat. In general, comparisons between the 15- and 30-min groups and between the 30- and 45-min groups failed to yield statistically significant differences.     

Comparative Effectiveness of Two Methods of Teaching Physical Education to Elementary School Girls

Abstract

This study was designed to determine whether there was a difference in the effectiveness of the traditional method and the movement exploration method of teaching physical education activities to elementary school girls. Four classes of fourth-grade girls (N = 67) were randomly assigned to the experimental conditions. A 2 × 2 × 3 factorial ANOVA with repeated measures on the last factor was used to analyze the data. The first factor consisted of the traditional and movement exploration teaching methods. The second was a combination of instructional time and retention time. The third was test period and had three levels: pretest, posttest, and retention test. Skills taught were gymnastics and tumbling, and basketball. It was concluded that a combination of methods should be used in teaching elementary school physical education activities, depending upon the activities to be taught. A four-week unit (two 50-min periods per week) is suggested as the appropriate length for nine and ten year olds.     

Relationship of Physique and Developmental Level to Physical Performance

Abstract

A study was made of the relationship of physique and developmental level, determined by use of the Wetzel Grid, to performance of junior high boys on four fitness tests: pull-ups, 50-yd. dash, standing broad jump, and softball throw. Subjects of different physique groups (heavy, medium, and thin) who were alike developmentally (accelerated, normal, and retarded) differed more markedly in performance than did subjects of different developmental levels who were alike with regard to physique. Subjects who were medium in physique and normal in development were the best performers. Subjects of heavy physique (many overweight) were the poorest performers. This would seem to indicate the need for a restudy of classification methods, particularly when norms are to be used for evaluating performance.     

对影响学龄儿童健康因素的研究

以1 215名学龄儿童为被试，以适度睡眠、合理饮食、口腔卫生、体育锻炼、防止久坐五类健康促进因素与冒险、越轨、吸烟、过量饮酒、冒险骑车五类健康危害因素为对象，对影响其健康因素的结构特点进行了分析.研究结果表明，学龄儿童的健康危害因素间具有显著的正相关，而健康促进因素间的关系则较为复杂.验证性因素分析结果也表明，学龄儿童健康因素的结构特点主要包含两个因素，其中健康生活习惯因素主要包括适度睡眠、合理饮食与口腔卫生三类健康促进因素;冒险生活方式因素则包括冒险、越轨、吸烟、过量饮酒、冒险骑车五类健康危害因素以及体育锻炼、防止久坐两类健康促进因素.以期建立较为全面、合理的学龄儿童健康因素的结构模型，减少影响学龄儿童的健康危害因素，增大影响学龄儿童的健康促进因素，促进学龄儿童的身心健康发展.