The purpose of this study was to determine the validity of a dynamic system model that predicts fluctuations in swim performance in junior female swimmers based on the dose-response relationship between training and performance. Two female swimmers, Sub.1 (age: 17 yrs, height: 168.0 cm, weight: 63 kg) and Sub.2 (age: 15yrs, height: 155.0 cm, weight: 51 kg) participated in this study. Their training and swim performance were monitored for 134 days. Training quantity was defined as a product of the intensity and distance of the swim training; intensity and distance were measured at every training session. Training intensity was determined by blood lactate levels and the unit of distance was kilometers. In order to determine swim performance, subjects were directed to perform a 200 m free-style swim test every 2 weeks. A dynamic system model that was composed of two exponential components (fitness component and fatigue componetnt) was applied to the relationship between training and performance. For each subject, parameters of the model were estimated using the non-linear least square method. Predicted performance by the model was compared with measured performance. For both subjects, the predicted values showed a significantly higher goodness of fit with measured performance (Sub.1: r² = 0.803; Sub.2: r² = 0.716). The range of prediction residual of the model was smaller than the range of random error in day-to-day, and there was no systematic bias in the distribution of prediction residuals. Therefore, the dynamic system model is judged to be a valid predictor of swim performance fluctuation in junior female swimmers.

　The reliability and validity of any test are important. However, it is difficult to determine both the reliability and validity of tests for young children’s motor ability. Therefore, the purpose of the present study was to elucidate issues in motor ability testing in order to develop new test items for young children. First, in order to assess the “Test Characteristics” of motor ability, reliability and validity were determined by administering a motor ability test to 304 young children (boys N=159, girls N=145) aged 2-6 years. Practicality was evaluated by teachers who actually conducted the motor ability tests. Next, the following five factors were extracted using defective principal component analysis with a Normal Varimax rotation: “reliability, validity and practicality”, “practicality without familiarity of young children”, “difficult for young children and general validity”, “acceptance for young children and practicality” and “reflection of young children’s daily life, practicality and validity”. Finally, the relationship between factor scores and movement patterns, physical fitness and measurement characteristics were examined using Quantification Theory Type I. The test items related to flexibility and using the trunk had high reliably, validity and practicality; however, items related to stability did not. The test items related to power and manipulation had low practicality, but were interesting to the young children. The test items that used upper limbs and were related to coordination and stability were difficult for young children, but had high validity. Items related to agility and combination had the opposite characteristics. Test items related to the trunk, muscular endurance and manipulation were not accepted by the young children and had low practicality. Combination and using the lower limbs and trunk had high validity and practicality and reflected young children’s daily life; however, agility showed contrary findings. For the development of new items for testing the motor ability of young children, the present findings are useful because few young children’s motor ability tests satisfy all “Test Characteristics”.

　The purpose of this study was to clarify the relationship between dynamic visual acuity and saccadic eye movement. Twenty-seven young adults, mean age 21.3±2.4 years, participated in this research. Electrooculography (EOG) was employed for analysis of the saccadic eye movement. Saccadic eye movements were recorded during measurements of dynamic visual acuity. Peak velocity, angle, and latency of saccadic eye movement were measured employing EOG. As a result, there were no relationships between dynamic visual acuity and peak velocity and angle of saccadic eye movement. However, there was significant correlation between dynamic visual acuity and latency of saccadic eye movement (at target velocity 49.5 rpm: r=-.734, p=.000, 47.6 rpm: r=-.619, p=.001, 45.1 rpm: r=-.538, p=.004, 42.5 rpm: r=-.600, p=.001, 40.0 rpm: r=-.478, p=.012). It was suggested that early start of saccadic eye movement is one of the important factors in the accurate discrimination of a moving target at high speed.

　The purpose of this study was to compare the dynamics of the relative intensity of maximal oxygen uptake (%VO²max) during 20-meter shuttle running test (SRT) with that during treadmill running test (TRT), and to determine the effect of the degree of turn skill to expired gas dynamics during SRT. Subjects were 4-male rugby players (RP), 4-male long-distance runners (LD) and 4-untrained males (UM). Initially, the maximal oxygen uptake (VO²max) of all subjects was measured. Subjects then underwent SRT and TRT. The protocols of SRT and TRT were the same except that there was turn motion in SRT. Subjects continued SRT until exhaustion, while they stopped TRT at the same time as in SRT. A portable metabolic cart (MetaMax 3B) measured ventilation, oxygen uptake (VO²), and carbon dioxide output (VCO²) throughout all exercise tests. Differences in expired gas dynamics between SRT and TRT were analyzed by general liner mixed model (GLMM) with three withinsubjects- factors (test-type, time, group). The relative intensity (%VO²max) of SRT was signifi cantly higher than that of TRT. The interactions (group*time) related to the degree of turn skill were not signifi cant in VO² (F^19,187 = 0.70, P = .812) and VCO² (F19,187 = 0.57, P = .922) dynamics. These results indicate that the relative intensity of SRT is high, and that the degree of turn skill does not infl uence VO² and VCO² dynamics during SRT.