The development of motor competence during infancy and childhood is dependent upon and influenced by the growth and maturity characteristics of the child interacting with the environment in which a child is reared. Environmental opportunities and restraints for movement interact with the biological substrates of growth and maturation to determine the motor repertoire of the child. This paper provides a brief overview of motor development during infancy and early childhood and then highlights several specific areas and/or questions: critical evaluation of stages for specific movement patterns; extension of the dynamical systems framework; genotypic contributions to motor development; metabolic and physiological correlates of motor development; relationship of motor development to the growth of the brain, status at birth and early postnatal growth; and social contexts of motor development.
We examined the detraining effects on the exercise-induced changes of the distensibility and elastic components of the rat aorta. Exercised (E) and sedentary (S) rats were divided into two groups respectively (i.e., E1, E2, S1, and S2). The E1 and E2 ran in a wheel cage spontaneously for 16 weeks from 9 to 25 weeks old. The E1 and S1 were sacrificed at the end of the exercise period. The E2 and S2 were bred sedentarily for 15 weeks until 40 weeks old. The aortic incremental elastic modulus at extension ratio of 1.5 and the contents of polar amino acids and calcium in aortic elastin were significantly lower in E1 than in S1. The aortic incremental elastic modulus and polar amino acids content were increased with aging significantly in S2 but not significantly in E2, and accordingly, those values were significantly lower in E2 than in S2. The content of elastin calcium, however, was increased significantly not only in S2 but also E2. The increase was especially marked in E2, and then, there was no significant difference in the values between two groups. These results suggest that the aortic wall in exercise-trained rats may keep more distensible structure with lower elastic fiber degeneration for a long time compared with sedentary rats even after detraining. The reason why elastin calcium content in the exercise-trained rats was markedly increased after the detraining was remain to be investigated.
The purpose of this investigation was to examine the validity of the exercise intensity of which lactate increased 0.1 mmol/l from baseline level (METs@LAr+0.1), as for the practical assessment of lactate threshold (LT), in younger adults. Thirty-two apparently healthy younger adults (21±1yr., 167.5±10.2cm, 58.2±9.4kg) performed submaximal bench stepping test, in order to determine the LT and METs@LAr+0.1. The LT (8.6±1.1METs) and METs@LAr+0.1 (8.7±1.4METs) were not significantly different, with the strong correlation (r=0.925, p<0.001). The mean error (%), the standard error of estimation (%) and the total error were -0.1±0.6 METs (-0.5±6.7%), 0.44 METs (5.1%) and 0.53 METs, respectively. Furthermore the lower and upper limit of agreement were -1.1 METs (-13.2%) and 1.0 METs (11.6%), respectively. These results suggest that METs@LAr+0.1 can estimate the LT with ±15% of error. Thus the METs@LAr+0.1 may be a valid and useful assessment of LT in younger adults.
To examine how psychological variables influence adoption of physical activity/exercise, we conducted a cross-sectional study among Japanese employees based upon the idea of transtheoretical model. The study population consisted of 719 employees (male, 396, female, 323). Response rate of the males was 77.8% (n=308), among which 273 eligible male subjects (68.9%) were analyzed. The study questionnaire included demographic characteristics, physical activity/exercise measures, self-efficacy measures, and perceived benefit and barriers scales. Perceived benefit and barrier scales were classified into 8 factors (5 benefits and 3 barriers) by factor analyses. We found that only 8% of the subjects were in the action and maintenance stages of physical activity/exercise, and 27% of them in these two stages engaged in vigorous-intensity exercise and 73% of them engaged in moderate-intensity physical activity. We found that self-efficacy, “psychological benefit”, “social benefit”, “vital benefit” and “physical barrier” were psychological correlates of physical activity/exercise stages in male employees, especially, there was a consistent relationship between self-efficacy and the stage of physical activity/exercise. Our data suggest that health education for Japanese male employees should focus on strengthen self-efficacy and psychological factor-matched interventions through either engaging vigorous-intensity exercise or increasing physical activity in daily life.
The purpose of this study was to investigate the effects of non-throwing arm on trunk and throwing arm movements in baseball pitching. Ten right-handed collegiate baseball players were asked to throw baseballs under two conditions, the normal and the restricted conditions. Under the restricted condition, non-throwing arm was fixed to the trunk by a rubber band. Their motions were analyzed by three-dimensional high-speed motion analysis and compared between two conditions. Under the restricted condition, upper torso rotated more counterclockwise and trunk twist angle decreased, at the instant of stride foot contact on the ground. It might be because the moment of inertia of upper torso and upper extremities along the trunk axis was smaller without non-throwing arm movement. Additionally, the maximum angular velocities of shoulder internal rotation and elbow extension as well as pitched ball velocity were lower under the restricted condition. When trunk twist, which stretches trunk rotator musculature, is small, the energy exerted by the musculature and transferred to throwing arm would decrease. Therefore, non-throwing arm in baseball pitching motion is considered to contribute to enhance pitched ball velocity by controlling the moment of inertia of upper torso and upper extremities along the trunk axis.
A procedure of inverse dynamics was developed to adjust the body segmental parameter values to individual subjects. Newton's second law was utilized, which states that a resultant force vector (the sum of all forces acting on a rigid body) can be calculated from the mass of the body and the acceleration vector of the center of mass of the body. By comparing the measured resultant force and the calculated resultant force, it was possible to evaluate the errors that exist in body segmental parameter values. These errors were minimized through simulated annealing numerical optimization that searched for the optimal values of body segmental parameters. A three-dimensional neuromusculoskeletal model was used to generate error-free sets of kinematic and kinetic data. Two types of jumping motion, i.e., squat jumping and countermovement jumping, were generated through forward dynamic computer simulation. In the process of analysis, randomly generated errors were introduced into body segmental parameter values, i.e., the mass and the location of the center of mass of each segment. The procedure developed in this study successfully reduced the errors in those body segmental parameter values. The average error for the mass was 0.97% whereas the average error for the location of the center of mass was 6.04%.
The kinetic factors to maintain the curve skating velocity of long distance speed skaters were investigated by measuring the changes in blade reaction forces due to fatigue. Eight male long distance speed skaters performed 4000 m skating at maximal effort with an instrumented sensor klapskate. The skaters were videotaped with two synchronized video cameras (60 fields/s) in the mid portion of the curve by using a panning DLT technique. Push-off forces of the left leg and three-dimensional coordinates of the segment endpoints and blades during the left stroke over the 4000 m distance were measured at two points: 650 m and 3450 m. The blade reaction forces (BRF) were defined as the vertical and horizontal components in the coordinate system fixed on the ice, and used to calculate impulse. There were no significant differences in the peak value and impulse of the vertical component of the BRF between the measurements taken at the above two points while those of the horizontal component in the first half were larger than those of the second half. There were significant positive relationships between the peak value and impulse of the horizontal component and the velocity of the center of mass (r=0.721; 0.677, p<0.01). These results indicate that minimizing the decrease in the horizontal impulse of the BRF during the left stroke could be one of important factors to maintain the skating velocity in the curve.
The purpose of this study was to investigate the kinetic characteristics of backward giant swing on parallel bars (PB) compared with those of backward giant swing on horizontal bar (HB). The subjects were six male skillful university gymnasts. Their performances of PB and HB were videotaped with a digital video camera to calculate the knee, shoulder, and hip joint angle, joint torque, joint power, and mechanical work from two-dimensional coordination of the body landmarks. The mechanical negative work done by hip extension torque leading to hang phase of PB were larger than those of HB. During upward phase from hang, the shoulder extension torque of PB was exerted longer period of time than HB, with the result that mechanical positive work done by shoulder extension torque of PB was larger than that of HB. For effective training of backward giant swing on parallel bars, the coach has to recognize their characteristic differences from those of horizontal bar.
It has been suggested that histidine-containing dipeptide carnosine (β-alanyl-L-histidine), which is believed to act as a cytosolic buffering agent, is present predominantly in skeletal muscle. The purpose of this study was to investigate the effects of sprint training (30-s maximal cycle ergometer sprinting) on muscle carnosine concentration. Six untrained males trained 2 days per week for 8 weeks on an electronic-braked cycle ergometer. Muscle biopsy samples were taken from the vastus lateralis before and two days after the last training session and were analyzed for carnosine concentration by the use of an amino acid autoanalyzer. The carnosine concentration was significantly increased after sprint training (P < 0.05). The mean power during 30-s maximal cycle ergometer sprinting was significantly increased following training. When dividing the 30-s sprinting into 6 phases (0-5, 6-10, 11-15, 16-20, 21-25, 26-30 s), the magnitude of increase in mean power was significantly larger for the last 2 phases than the first phase (P < 0.05). These results suggest that the increases in skeletal muscle carnosine concentration following sprint training may be associated with the increase in sustainability of high power during 30-s maximal cycle ergometer sprinting.
We had previously shown that performing a single set of resistance exercise at 50% of 1 repetition maximum (RM) added after a high-intensity, low-repetition exercise (strength-type regimen) greatly enhanced growth hormone (GH) secretion [Goto et al. (2003)]. The present study aimed to investigate the effect of an additional set at 50% to 20% of 1RM after a strength-type regimen on anabolic hormone secretion. Eight male subjects performed bilateral knee extension exercises using a strength-type regimen (5 sets at 90% of 1RM, with 3-min rests), and other 3 types of regimens, in which 1 set of exercise at either 50%, 30% or 20% of 1RM was added immediately after the strength-type regimen (defined as C50-type, C30-type and C20-type regimens, respectively). Concentrations of serum GH, testosterone and blood lactate were measured before and after exercises. The number of repetitions in the added set showed a significant dependence on the exercise intensity: 82.3 times in C20-type > 46.1 times in C30-type > 22.6 times in C50-type (p ≤ 0.05). Post-exercise GH concentrations were significantly (p ≤ 0.05) higher in C50- and C30-type regimens than in the strength-type regimen, whereas no significant difference was observed between C20- and strength-type regimens. Testosterone did not change in any types of regimen. These results indicated that performing a single set of exercise at low intensity added after a strength-type regimen caused a significant increase in GH concentration. However, such an effect might be diminished when the intensity of the additional exercise was extremely low (below 20% of 1RM).
The purpose of this study was to examine the validity of a soccer defending skill scale (SDSS) measured by the location of players in soccer games using structural equation modeling. The samples were 469 defending performances in the final of FIFA World Cup Korea / Japan 2002™ (Brazil vs. Germany), which were determined by distances, and angles, between attackers and defenders, and the number of players. Results for the general CFA model consisting of the selected 9 items indicated a good fit to the data (CFI= .994, RMSEA= .032). The causal structure model of the defending skills was statistically valid (CFI= .991, RMSEA= .037). The multidimensional CFA model indicated a much better fit to the data than the general CFA model (χ2 = 17.378 with 8 df, p < 0.05). It was concluded that the SDSS with 9 items successfully was able to measure the game performance according to the causal structure of the tactical defending phase, and the SDSS was able to measure multi-dimensional abilities consisting of the defending phase and the defending object.
The purpose of this research is to identify a dynamic factor structure of an athlete's perceived condition fluctuation using a dynamic factor analysis (DFA) and a confirmatory factor analysis (CFA). The subject of the study was an athlete who represented Japan in the women's race walking in the 2002 Asian Games. The subject made records of 15 items concerning perceived conditions, training, and basic lifestyle habits everyday for 714 days on QC sheets for conditions that she created herself. As factor analysis from an exploratory standpoint, a DFA using a maximum likelihood method and an orthogonal rotation by varimax method was applied, and common factors of perceived condition fluctuation was extracted with consideration given to time lag. Furthermore, CFA by structural equation modeling was applied to identify a dynamic factor structure of perceived condition fluctuation. Based on the coefficient of autocorrelation and the coefficient of partial autocorrelation of the variables, it was found best to use avariance-covariance matrix of Lag 1 in DFA. Three factors of weather conditions, sleeping, and getting up were extracted in all lags. However, training factor was extracted in Lag 0 only and perceived condition factor in Lag 1 only. The fit index of the dynamic factor structure model of perceived conditions where five factors were hypothesized was favorable. It was concluded that perceived condition fluctuation is a dynamic factor structure that was influenced from change in time.
At the heart of a culture lies a certain view of the body, and this view decides which perceptual experiences the culture chooses to value. In trying to achieve those experiences, certain principles for moving and handling the body are established, and these principles then set the standards for the mastery of essential skills that penetrate through all fields of art, creating a rich foundation from which the culture can flourish. The culture of traditional Japan, which disintegrated at the hands of the Meiji Restoration, indeed possessed such a structure. The idea of the body, the shared perceptual experiences, and the principles of movement that existed in traditional Japanese culture were radically different from those that arrived from the West and have been blindly disseminated by the Japanese government ever since the Meiji Restoration. This paper discusses the feeble underpinnings of modern Japan as a culture built upon the destruction of its own traditions, and explores the possibility of giving birth to a new culture by looking into the structure of its lost traditional culture.
The necessity of recognising an ideological basis for overcoming the crisis of modern sport symbolised by doping is set out in this paper. The first part provides the consideration of the influences which doping brings to sport. The second section examines a means for conquering the crisis of sport. The third and final section considers the dimension of achievement, which is different from excellence, and proposes the ideological basis for conquering the crisis of modern sport based on the development of a new sports culture, different from modern sport in its quality, is proposed.
The purpose of this study was to examine the effects of “Momentum” and “Climate” in P. E. class on students' formative evaluation. Data was collected through observation of 60 P. E. classes at elementary school. Momentum of P. E. class was evaluated by the observation instrument of “Learning Engagement in the Motor Learning Scenes”, while climate of P. E. class was evaluated by the observation instrument of “Students' Human Relationship and Affective Behaviors” developed by Hirano et al (1997). The learning outcomes were assessed by “Questionnaire for Students' Formative Evaluation” standardized by Takahashi et al (1994). Main findings were as follows, 1) The multiple regression analysis revealed 6 factors that connected with “Momentum” and “Climate” had big effects on P. E. classes. Especially, off-task behaviors as a component of “Momentum” and negative behaviors of human relationship as a component of “Climate” had significantly negative effects on students' formative evaluation. Only positive behaviors of human relationship showed a significantly positive effect on it. 2) Even in analyzing the gymnastics classes and the ball-game classes separately, the above general tendency was found similarly. However, only in the ball-game classes negative behaviors of human relationship and negative behaviors of affection showed significantly negative effects on students' evaluation, 3) It was suggested that the teaching strategies for reducing off-task behaviors and negative behaviors of human relationship and those for increasing positive behaviors of human relationship were important to realize the effective teaching in P. E. highly evaluated by students.
The purpose of this study was to investigate the relationship between excess CO2 output during and after short duration-intensive exercise and skeletal muscle characteristics (i.e., muscle fiber type, muscle capillary density and muscle buffering capacity). Twelve healthy males (age; 22.4±2.9 years, height; 172.3±5.8 cm, weight; 65.0±4.8 kg) performed 30-s maximal cycle ergometer sprinting. Excess CO2 output during and after exercise was obtained through respiratory gas analysis. Excess CO2 output per unit of time (ExcessVCO2) was calculated by subtracting VO2 from VCO2 during and after exercise. Muscle biopsy samples were taken from the right vastus lateralis muscle, and then muscle fiber type, muscle capillary density and muscle buffering capacity were measured. ExcessCO2 calculated as the sum of ExcessVCO2 from the onset of exercise until 15 min after exercise was not significantly correlated with any muscle fiber types, while it was significantly correlated with capillary-to-fiber ratio (r = 0.791, p < 0.01). A significant negative correlation was also demonstrated between ExcessCO2-to-La peak ratio and muscle buffering capacity (r = -0.645, p < 0.05). These results suggest that ExcessCO2 during and after short duration-intensive exercise is affected by the amount of H+ buffered by nonbicarbonate system and the amount of H+ diffusion from muscle to blood depending on the development of muscle capillaries.
This research was conducted for the purpose of studying the influence of exercise training on the level of SOD mRNA expression in human lymphocytes. 10 first-year high school boys (age 15-16), members of the high-school football club, were subjected to exercise training for a period of 3 months; using a bicycle ergometer before and after the exercise training, maximal exercise test was conducted. The subjects trained 2 hours a day, 6 days a week over the span of 3 months, as a regular part of their club activities. Blood samples were taken before and immediately after maximal exercise test before and after training, at rest and after training at the end of 1 month, 2 months and the end of the training period; expression of manganese-SOD (Mn-SOD) mRNA and copper-zinc SOD (Cu/Zn SOD) mRNA in their lymphocytes was measured. Results showed significant increases in both maximal oxygen uptake (VO2max) and maximal voluntary ventilation (MVV), (p<0.001 and p<0.01, respectively), and the physiological effects of exercise training were verified. No significant changes were seen in expression of Mn-SOD and Cu/Zn-SOD mRNA at rest as a result of training. In maximal exercise tests, Cu/Zn-SOD mRNA expression levels showed no significant changes either before or after exercise training. Although Mn-SOD mRNA expression levels showed significant increases before exercise training in comparison to before maximal exercise test (p<0.05), significant changes after exercise training were not observed. From these results, the effects of exercise training on lymphocyte SOD mRNA were demonstrated to exert beneficial effects on Mn-SOD functions for an acute bout of exercise rather than on SOD mRNA expression at rest.
The present study examined the relationship between exercise motivational profiles and stages of exercise behavior change. Four hundred and eighty-six Japanese adults participated in this study. In the first analysis, a cluster analysis identified four meaningful clusters in exercise motivational profiles. The first cluster was labeled the ‘self-determined motivation profile’ as the participants in this cluster had relatively high levels of intrinsic motivation and identified regulation. The second was the ‘moderate motivation profile’ with moderate scores on all measured motivational variables. The third was the ‘nonself-determined motivation profile’ as subjects in this group demonstrated higher nonself-determined motivation than self-determined motivation. The last cluster was the ‘amotivation profile’, which consisted of participants who had the highest scores in amotivation, and the lowest scores in intrinsic motivation and identified regulation. The second analysis explored how motivational profiles are related to stages of exercise behavior change. Participants in the first cluster were most likely to be classified in the maintenance stage. The results from this study provided the foundation for successful strategies to develop exercise adherence in adults focusing on motivational profiles.
The present research examined the interaction between the skill level of a model (an expert or learning model) and a learning schedule (alternating observation and practice; or concentrated observation and practice, respectively) on acquiring a new bimanual pattern of 90 degrees relative phase. Five groups were compared: alternating-expert, alternating-learning, concentrated-expert, concentrated-learning and physical practice only. The concentrated-learning group performed better than alternating-expert, alternating-learning, as well as physical practice only learning schedule groups in retention tests. This seemed to arise from the effectiveness of concentrated observation throughout the improvement processes exhibited by the learning model.
In this study, sport harassment is defined as harassment situated in sport. The aims of the study were to identify behaviors considered to be a form of sport harassment in the eyes of Hong Kong youth swimmers and to understand the prevalence of sport harassment sustained by them. Given that some forms of sport harassment are more offensive than others, the study also aims to identify those forms which youth swimmers find more offensive.
This study examined an alternative approach to the acquisition of a complex motor skill, using constraints. To determine the efficacy of two alternative methods of learning tennis strokes, forehand and backhand strokes were practiced over five successive days using two contrasting training methods. The novel, multiple movement method required alternate forehand and backhand strokes, whereas the traditional, simple movement method required repeated forehand or backhand strokes as separate series of events. Five subjects were randomly assigned to each of the two conditions. Their strokes were recorded and analyzed kinematically before and after the training sessions. The simple movement method resulted in no changes in the range of trunk rotation perse, but the center of the range shifted unfavorably, in the direction opposite to that in which the ball was struck, for both forehand and backhand strokes. By contrast, the multiple movement method increased the range of trunk rotation, and the center of the range shifted favorably in the direction toward which the ball was struck, for both strokes. These differences were confirmed by the trajectories observed in hyper-cylindrical phase space as dynamical systems. In the multiple movement group, the forehand and backhand clusters converged after training, whereas in the simple movement group the two clusters diverged after training. From a dynamical systems perspective, we argue that the multiple movement method achieves its superiority by exploiting the inertia of the trunk rotation movement as a constraint that is produced by the preceding striking action, whether it be forehand or backhand.
The purpose of this study is to investigate behavioral differences among windsurfer specialization subgroups through the use of conjoint analysis. Recreation specialization is a concept that explains the developmental process of behavior patterns whereby recreation participants acquire knowledge and skills and progress to higher stages of involvement in a particular leisure activity over time. This conceptual framework has been employed in understanding leisure and sport behaviors through a segmentation approach. In this research, conjoint analysis was used to examine windsurfers' preferences. Three attributes -- wind velocity, season and crowding -- were considered in the research design. The data were collected through interviewing windsurfers in Sumiyoshihama Resort Park, Japan. Participant observation was also conducted simultaneously. Windsurfing participants were segmented in terms of skill, frequency of participation and types of activity. Four types of leisure and sport participants could be identified: occasional windsurfers, social windsurfers, competitive windsurfers and pleasure windsurfers. On the one hand, occasional windsurfers and social windsurfers were types of social participants, on the other hand, competitive windsurfers and pleasure windsurfers were types of serious participants. The findings of the conjoint analysis include the following: season was the most influential factor in participant preferences for occasional and social windsurfers, while season and wind velocity were more influential factors for competitive windsurfers.
The purpose of this study was to examine the feasibility of constructing a new test by analyzing the item characteristic of motor function and physical independence ADL tests based on the item response theory (IRT). Subjects were 137 males and 198 females, aged over 65 years old. The average of age was 69.2±5.4 years old (male 70.4±5.5, female 68.7±5.2). The physical independence and the motor function ADL test were consisted of 15 items with 2 options. Unidimesionality of physical independence and motor function ADL tests were satisfied for item characteristic analysis. Item difficulty and item discrimination were calculated by using two-parameter logistic model. Item characteristic curves, item information functions, test characteristic curves, and test information functions were obtained from the item difficulty and the item discrimination. In the new test, 70% of the whole subjects were able to achieve 80% or more based on the item characteristic. The item difficulty, the item discrimination, and the amount of item information of each item were confirmed. Eighty % of the whole subjects were able to achieve 80% or more in physical independence ADL test. Fifty % of the whole subjects were able to achieve 80% or more in motor function ADL test. It was concluded that the new test satisfied target test characteristics could be composed from previous test items applying IRT techniques.