Taiikugaku kenkyu (Japan Journal of Physical Education, Health and Sport Sciences)
Online ISSN : 1881-7718
Print ISSN : 0484-6710
ISSN-L : 0484-6710
Volume 60, Issue 1
Displaying 1-26 of 26 articles from this issue
Original investigations
  • Shota Sakaguchi, Nobuaki Fujibayashi, Takuya Yoshida, Ryohei Hayashi, ...
    2015 Volume 60 Issue 1 Pages 1-12
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: December 26, 2014
    JOURNAL FREE ACCESS
      This study investigated the process of longitudinal development of rebound jumping (RJ) and running ability in preschool children over a period of one year. The subjects included 24 boys (4 years) and 13 girls (4 years). The measurements used for this purpose were the counter movement jumping (CMJ) height, the consecutive RJ index (jump height and ground contact time), and the velocity during a 20 m run. The main results obtained were as follows:
      1)  The CMJ height, RJ index, RJ jump height, and velocity during the 20 m run were significantly higher in 2013 when compared with the values for 2012. In addition, the RJ contact time was significantly shorter in 2013 than in 2012.
      2)  The rates of change in CMJ ability, RJ ability, and the 20 m run velocity did not correlate significantly with the rate of change in body height. The rate of change in RJ ability was correlated significantly only with the rate of change in the 20 m run velocity.
      These results suggest that RJ ability affects the development of running ability. In addition, exercises similar to RJ can potentially lead to effective longitudinal development of running ability.
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  • Naoyuki Yamashita, Naota Sogo, Tetsuhiro Shiomi, Ryo Ito, Takaaki Mats ...
    2015 Volume 60 Issue 1 Pages 13-26
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: January 20, 2015
    JOURNAL FREE ACCESS
      Purpose: Guidelines for prevention of exertional heat illness issued by academic societies and the Japan Sports Association have been well structured. Although these guidelines have been widely disseminated, the numbers of adolescents suffering heat illness during sports activities is still a concern. Many freshman enrolled in Sports Science-related Departments (SSD) are presumably high-level athletes who engage in high-intensity and/or long-duration exercise during daily practice, and could thus be categorized as a group at high risk of exertional heat illness (EHI). Conversely, the majority of freshman enrolled in non-Sports Science-related Departments (non-SSD) are presumably low-level athletes who might be engaged in comparatively less high-intensity and/or short-duration exercise during daily practice, and could thus be categorized as a group at low risk of EHI. Although sports activities are known to increase the risk of EHI, no evidence is available to suggest whether high-level sports activities increase the risk of EHI. The purpose of the present study was to clarify the prevalence of EHI in SSD and non-SSD freshman.
    Methods: Four hundred eighty students from SSD and 447 students from non-SSD participated in a self-assessed survey designed to clarify the prevalence of EHI experienced by individuals during the period from elementary school to high school age. Chi-squared and post-hoc residual analysis, and odds ratio (OR), were used to compare differences between the groups.
    Results: Completed survey questionnaires were received from 480 SSD students and 447 non-SSD students. The prevalence of heat illness was 31.9% in the SSD group and 16.8% in the non-SSD group [adjusted OR 2.342, 95% confidence interval (CI) 1.712, 3.204]. The number of times individuals had experienced heat illness in the past differed between the SSD and non-SSD groups, but the response ratio was similar. More than 85% of students in both groups who had suffered heat illness in the past had done so during club activities at junior high school and high school. The ratio of students who reported ever suffering from heat illness during sports club activities at junior high school and/or high school (n=860) was 25.6%, whereas 13.4% of students reported that they had never participated in junior high school and/or high school sports club activities during the same period (n=67).
    Conclusion: The present study revealed that high-level athletes (SSD freshman) had experienced EHI twice as often as non-SSD students. In addition, students who had participated in sports club activities at junior high school and/or high school had suffered EHI twice as often as students who had not participated in sports club activities. Coaches and athletes should take more care to prevent EHI during sports and/or physical activities, and when it occurs, steps should be taken to prevent progression to exertional heat stroke.
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  • Jun-ichi Nishida, Kimio Hashimoto, Atsushi Kiuchi, Hideaki Tanimoto, T ...
    2015 Volume 60 Issue 1 Pages 27-39
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: December 26, 2014
    JOURNAL FREE ACCESS
      In Japan, not many people exercise habitually. Physical education (PE) in universities would be expected to contribute to the development of active lifestyles by facilitating lifelong habits of exercise and sports. This study extracted the perceived benefits of PE in universities using text mining. A questionnaire survey was conducted among university freshmen (N=989, men=656, women=331). The questionnaire inquired about basic attributes, including sex, age, and exercise habits, and requested free descriptions about the perceived benefits of PE at universities. The mean age of the participants was 19.1 years. The results indicated that approximately 30% exercised regularly. Words that appeared frequently in free descriptions regarding the perceived benefits of PE in universities were analyzed using morphological analysis, and 18 keywords were identified, including “make or can,” “friends,” and “enjoyable”. Based on these keywords, the following 10 categories of perceived benefits of exercise were extracted: formation and development of friendship, an increase in the frequency of exercise, feeling of enjoyment, increase in physical strength, improvement in communication skills, improvement in life habits, attaining and improving movement skills, understanding exercise methods and rules, understanding the importance of team play, and stress reduction. Furthermore, differences based on sex, as well as sport and exercise habits, were also examined. The results indicated that the frequency of the following categories was higher in women than in men: formation and development of friendship and a feeling of enjoyment. Students without regular exercise habits indicated a higher frequency of “increase in the frequency of taking exercise,” compared to those with exercise habits. The above results suggest the need for planning and enforcing PE programs in universities, as this would seem to promote lifelong exercise habits and participation in sport. Furthermore, perceived benefits of PE in universities should be complemented and increased, according to sex and individual exercise habits. Moreover, students should be taught the importance of exercise and sports. In the future, it will be important to examine the perceived benefits of exercise by matching the benefits with the purpose and contents of PE, and to examine the continuity of the perceived benefits, as well as investigating deep-level perceived benefits.
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  • Kihachiro Fukada, Hidehiko Kushi, Terue Takashina, Naoko Onuma, Akira ...
    2015 Volume 60 Issue 1 Pages 41-51
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: January 10, 2015
    JOURNAL FREE ACCESS
      Introduction: Oxidative stress is one of the causes of lifestyle-related diseases. The aim of this study was to evaluate whether body mass index (BMI), a simple index of the degree of obesity, affects oxidative stress during strenuous exercise.
      Subjects and Methods: 12 young men aged 19–23 years participated in the study. 7 of these men had a BMI of <25, and 5 had a BMI of ≧25. Venous blood samples were collected from the subjects before and after they had performed the Cooper 12-min test (running as far as possible within 12 min), and used for measuring the levels of serum 8-hydroxy-2′-deoxyguanosine (a marker of DNA oxidation, 8-OHdG, ng/ml) and plasma 8-isoprostane (a marker of lipid peroxidation, pg/ml).
      Results: The levels of 8-OHdG before and after exercise were 0.15±0.02 ng/ml and 0.19±0.02 ng/ml in the BMI <25 group and 0.15±0.01 ng/ml and 0.18±0.01 ng/ml in the BMI ≧25 group, respectively, showing a significant increase after exercise in both groups (P<0.01). The corresponding levels of 8-isoprostane were 11.8±0.5 pg/ml and 11.6±0.5 pg/ml in the BMI <25 group and 12.4±0.7 pg/ml and 14.2±0.4 pg/ml in the BMI ≧25 group, respectively, showing a significant increase after exercise in the BMI ≧25 group (P<0.01).
      Conclusions: The present study revealed that the level of 8-isoprostane increases after acute strenuous exercise in young men who are overweight.
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  • Tomohisa Miyanishi, Naoki Sakurai, So Endo
    2015 Volume 60 Issue 1 Pages 53-69
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: December 26, 2014
    JOURNAL FREE ACCESS
      The purpose of the present study was to clarify kinematic differences in the delivery motion of the baseball infielder among various levels of development. A total of 76 delivery motions performed by 22 elementary school (group E), 18 junior high school (group J), 20 high school (group H), and 16 collegiate (group C) baseball infielders were studied using a 3D motion picture analysis. 50 kinematic and 10 temporal variables were measured for the upper trunk, pelvis, throwing shoulder and elbow joint. No significant differences in the anthropometric data were found between infielders in groups H and C. Ball velocity increased significantly with the levels of skill and experience. Significant differences were found in 29 kinematic variables and only one temporal variable among the levels of development. The differences in ball velocity between the younger and older infielders were most likely due to both greater muscle strength and longer segment length, while the differences between infielders in groups H and C were due mainly to higher skill progression. These results are useful for considering the possible reasons for improvements in throwing performance with increased levels of skill and experience.
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  • Takayuki Natsuhara, Masao Nakayama, Takaaki Kato, Tomohisa Nagano, Tak ...
    2015 Volume 60 Issue 1 Pages 71-85
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: February 04, 2015
    JOURNAL FREE ACCESS
      Some of the mechanisms underlying superior performance in sports may be clarified by investigating the role of visual information in the execution of particular responses by expert athletes. The aim of this study was to examine how soccer players process visual information when executing a tactical pass in a 4 vs. 4 attacking play scenario. To identify the cognitive processes operating during task execution, we measured eye movement and correlated it with verbal reports from players. The subjects comprised 30 soccer players with differing proficiencies (15 “experts” and 15 “sub-experts”). 2 tests were carried out: a test to evaluate the level of passing skill, and a decision-making test to evaluate the reproducibility of tactical passing and the accuracy of passes aimed to specific locations. Eye movements were measured during the decision-making test. Furthermore, in each trial of the decision-making test, verbal reports were collected. These related to how and why participants decided to pass the ball to any particular player among the 4 attackers on screen and, in order to determine their best judgment, how they captured the play situation and what they paid attention to. The results revealed that for execution of the pass, the experts were significantly more proficient at passing accurately to the aimed location, and their passing judgment was more reproducible in comparison to the sub-experts, although both groups had a uniform level of passing skill in terms of pass execution. In addition, eye movement data obtained during pass execution confirmed that in the play observation phase, while experts maintained their line of sight on other objects, they also maintained a longer gaze on defensive players to identify gaps between them. Also in the ball approach phase, the experts maintained a longer gaze on the player who was judged to be the best choice for receiving an accurate pass. These observations suggest that the superior passing performance of expert soccer players is attributable to accurate and efficient extraction of visual information and utilizing it in the context of their accumulated knowledge base.
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  • Masahiro Kageyama, Chiharu Suzuki, Takashi Sugiyama, Tomohito Wada, Ak ...
    2015 Volume 60 Issue 1 Pages 87-102
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: March 17, 2015
    JOURNAL FREE ACCESS
      The purpose of this study was to clarify the relationship between ball velocity and the mechanical power of the lower limbs during pitching motion in 30 collegiate baseball pitchers. 3-dimensional positions of 37 reflective markers attached to the subject were tracked by an optical motion capture system (Mac3D System) with 12 cameras. The ground-reaction forces (GRF) of the pivot and stride legs during pitching were determined using 2 multicomponent force plates. Pitching motion was assessed in terms of the joint torques, joint torque powers and work done by each of joint in the lower limbs using a three-dimensional motion system. The joint torques of the hip, knee, and ankle were calculated using inverse-dynamics computation of a musculoskeletal human model (nMotion musculous 1.51). Pitching motion was divided into 2 phases: phase 1 was defined as the time taken from the knee of the stride leg reaching maximal height (MKH, 0%time) to the stride foot making contact with the ground (SFC, 100%time), and phase 2 was defined as the time taken from SFC to the ball being released (REL, 200%time).
      These studies revealed that the positive work resulting from hip abduction (r=0.401) and knee extension (r=0.355) of the pivot leg (Phase 1) was positively correlated with ball velocity (p<0.05). The positive work resulting from hip adduction (r=0.359) and knee extension (r=0.409) of the stride leg (Phase 2) was positively correlated with ball velocity (p<0.05). In addition, the pitched ball velocity was positively correlated with pivot hip abduction torque at 74–94%time, pivot hip internal rotation torque at 76–89%time, stride hip adduction torque at 96–114%time, stride hip adduction torque power at 108–114%time, stride knee extension torque at 101–131%time, stride knee extension angular velocities at 158–189%time, and stride knee extension torque power at 156–174%time (p<0.05).
      These results indicate that a pitcher with high pitched ball velocity can generate hip abduction and knee extension power of the pivot leg, and that these are increased by hip abduction and hip internal rotation torque when moving the body forward before stride foot contact. In addition, it is suggested that high-ball-velocity pitchers can generate hip abduction and knee extension torque in order to stabilize the body just after stride foot contact, and that these are increased by the knee extension power for increasing trunk rotation and trunk twisting from the first half to the middle of the second phase.
      Therefore, the present results indicate that pitchers with a higher ball velocity can generate greater mechanical power of the lower limbs for increasing the energy of trunk rotation and the arm.
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  • Shuji Kidokoro, Toshimasa Yanai
    2015 Volume 60 Issue 1 Pages 103-115
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: March 10, 2015
    JOURNAL FREE ACCESS
      In baseball, batters occasionally aim to hit the ball toward the opposite field. Players and coaches generally believe that the impact surface of the bat needs to face toward the opposite field at the instant of ball impact, so that the ball makes an oblique impact with the bat and bounces off toward the opposite field. Photograms and video recordings of opposite-field hitting, however, often give an impression that the impacting surface of the bat does not necessarily face toward the opposite field. Therefore, there may be an overlooked mechanism for opposite-field hitting. The purpose of this study was to examine the kinematic parameters of ball impact that determine the direction of the struck ball in opposite-field hitting. Sixteen collegiate baseball players performed 10 trials of opposite-field hitting, and the movements of the ball and bat before, at, and after impact were recorded with 3 high-speed cameras (1000 fps) for three-dimensional analysis. The projection angles of the bat on the horizontal plane (horizontal bat angle), the vertical plane (vertical bat angle) and the angle from horizontal of the line of impact (line of impact angle) were determined at the instant of ball impact. The struck ball travelled toward the opposite field at 23.0±7.5° from the center line of the field. Whereas the mean value of the horizontal bat angle was 6.7° toward the opposite field, the bat was facing towards the center and the same field in 16.4% of all trials. These results indicate that the batter can hit the ball toward the opposite field even if the impact surface of the bat is facing toward the center or the same field at the instant of ball impact. In this paper, we reveal an additional mechanism for hitting the ball toward the opposite field.
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  • Yosuke Hayashi
    2015 Volume 60 Issue 1 Pages 117-136
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: April 10, 2015
    JOURNAL FREE ACCESS
      In the present study, an attempt was made to clarify the whole structure and originality of Taiiku-gaku (Science of PE, Health and Sport Sciences), centering on the ‘tree of sciences’ theory of René Descartes (1596-1650). In the study of physical education philosophy, some attempts have been made to reveal the whole structure and originality of Taiiku-gaku. It seems more appropriate to discuss and address this issue by defining certain principles at the outset. For this purpose, it would informative to examine this issue from the philosophical perspective of Descartes' ‘tree of sciences’ philosophy.
      In the history of discussion to clarify the whole structure and originality of Taiiku-gaku among researchers, three essential characteristics become evident: (1) Science should be aimed at being practical and useful, (2) it should contribute to our well-being, and (3) it should aid the search for wisdom. Up to now, it appears that Taiiku-gaku as a science has advanced in line with these characteristics. However, Descartes revealed his vision of the purpose of science through the “tree of sciences” in his Principia Philosophiae (Principles of Philosophy). He analogized the whole structure of science (philosophy) to a tree with its roots, trunk, branches and fruit. The present paper therefore utilizes this concept of Descartes to answer the question. In conclusion, the whole structure of Taiiku-gaku could be understood as being analogous to a tree, and the originality of Taiiku-gaku does not depend on humans themselves or human movement as a fundamental research object. The originality of Taiiku-gaku can be analogized with the achievement of Generosity, which is the goal of the “tree of sciences”. Thus, on the basis of output diversity analogous to fruit taken from branches of the tree, the originality can be characterized as a science that tries to achieve the highest performance of human movement imaginable. More enlightened discussion can ensue by reconsidering the concept of taiiku (which is different from Physical Education) and the identity of Taiiku-gaku researchers.
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  • Yasushi Kariyama, Koji Zushi
    2015 Volume 60 Issue 1 Pages 137-150
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: March 13, 2015
    JOURNAL FREE ACCESS
      The present study attempted to develop a training model using the rebound jump (RJ) for improving stiffness during bounding (BD), focusing on joint kinetics. 17 male track and field athletes (sprinters, jumpers, and decathletes) performed the BD and RJ. Video images of their jumping motions in the sagittal plane (300 Hz) and their ground reaction force data (1,000 Hz) were recorded. Stiffness was calculated using the spring-mass model, and the joint extension and plantar flexion torques during the first half of the take-off phase and negative torque power of the 3 lower joints (ankle, knee, hip) were calculated. The foot angle at the moment of touchdown during BD was also calculated. The results were as follows:
    1.  During BD and RJ, stiffness was correlated with the ankle joint torque during the first half of the take-off phase and the negative torque power about the ankle joint.
    2.  The foot angle at the moment of touchdown during BD was correlated with stiffness, contact time, ankle joint torque during the first half of the take-off phase, and negative torque power of the ankle joint.
    3.  Ankle joint torque and negative torque power about the ankle joint during the first half of the take-off phase in BD were correlated with those during RJ.
      These results suggest that stiffness during BD and RJ are affected by ankle joint kinetics. On the basis of these results, previous studies and sports training principles, plyometric training using the RJ may be useful for improving the stiffness in BD via ankle joint kinetics.
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  • Takashi Sugiyama, Mai Kameda, Masahiro Kageyama, Kazufusa Kiba, Hiroak ...
    2015 Volume 60 Issue 1 Pages 151-163
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: April 06, 2015
    JOURNAL FREE ACCESS
      The present study aimed to clarify the relationships between running and functional single leg jumps in jumping variables and kinematics of the lower extremities in collegiate male basketball players, with specific emphasis on the differences between the two jumping legs. Twelve basketball players performed maximal single leg jumps with a running approach (RSJ) as well as functional jumps (FJs), including drop and bound jumps from a height of 30 cm (DJ), five repeated rebound jumps, vertical countermovement jumps, and squat jumps from a knee angle of 120° (SQJ) using the dominant leg (D-leg) and non-dominant leg (ND-leg). Three-dimensional kinematics data during each jump were collected using a 12 Raptor camera infrared motion analysis system (MAC 3D system) at a sampling frequency of 500 Hz. Jump height, jump index, running velocity, change in horizontal velocity at takeoff phase (ΔHV), reactive strength (%SQJ) and kinematics of the lower extremities were calculated. The symmetry indices of the jumping and kinematics variables were calculated as {2×(D-leg−ND-leg)/(D-leg+ND-leg)}×100. Jump heights, jump indices, and %SQJs in the RSJ and DJ, and ΔHV in the RSJ were significantly higher for the D-leg than for the ND-leg. During the takeoff phase in the two jumps, the joint angles and angular velocities of the ankle were significantly larger for the D-leg than for the ND-leg. Moreover, the symmetry indices of jump height in DJ, ΔHV in RSJ, %SQJ, and kinematics of the ankle joint in the RSJ and DJ were positively correlated with the symmetry index of jump height in the RSJ. These findings indicate that 1) the asymmetry of jump ability in the RSJ is attributable to the asymmetry of ankle behavior in the touchdown and takeoff phases, and 2) among FJs, the DJ may be useful for assessing and improving the asymmetry of the RSJ.
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  • Takaaki Tsunokawa, Yasuo Sengoku, Shozo Tsubakimoto, Hideki Takagi
    2015 Volume 60 Issue 1 Pages 165-175
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: March 17, 2015
    JOURNAL FREE ACCESS
      The purpose of this study was to identify the characteristics of the pressure distribution around the foot during breaststroke kicking and the relationship between the fluid force and the pressure distribution by comparison among different swimmers. Eight male elite swimmers, whose specialties were breaststroke and individual medley, participated in this study. In trials conducted in a water channel, swimmers performed breaststroke kicking for 10 seconds at individually controlled flow velocity determined in prior time trials without upper limb motion. During the trials, 8 pressure sensors were attached to the left foot to measure the pressure distribution around the foot, and the fluid forces were estimated using the procedure reported by Tsunokawa et al. (2012). To identify the relationship between the fluid force and the pressure distribution around the foot, raw pressure values and the pressure differences between the plantar side and the dorsal side were indicated. This revealed significant differences in the absolute values of pressure between the plantar and dorsal sides (p<0.01), except for the area around the fifth toe. The dorsal side pressure for high-level swimmers decreased to about −25 kN/m2, and that for slightly low-level swimmers decreased to about −12 kN/m2. These results suggest that a decrease of dorsal side pressure is closely related to an increase in the fluid force acting on the foot, and that the kicking motions of high-level swimmers create a rapid decrease of dorsal side pressure. Furthermore, unsteady vortex-like flow is closely related to an increase in the fluid force acting on the foot. Therefore, swimmers and coaches should be aware of these influences of unsteady fluid forces.
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  • Munenori Murata, Norihisa Fujii, Yuta Suzuki
    2015 Volume 60 Issue 1 Pages 177-195
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: May 11, 2015
    JOURNAL FREE ACCESS
      Mechanical energy is known to be transferred between a body segment and a joint. However, the transformation of this energy has not been classified. By focusing on the racquet-holding arm during a tennis serve, the present study examined the transformation between translational and rotational energies due to the joint force, and investigated the kinetic chain from the viewpoint of energetics. Twenty-two tennis players were asked to perform flat services to the deuce side (i.e., the receiver's right side), and the three-dimensional coordinates of reflective markers attached to each player and racquet were collected with a motion capture system. The mechanical power acting on each segment and the mechanical energy generated/absorbed by each joint were divided into the following components: (1) STP=the time rate of change in the rotational energy of a segment due to the joint torque, (2) JTP=the generation/absorption of rotational energy due to the joint torque, (3) JFPt=the time rate of change in the translational energy of a segment due to the joint force, and (4) JFPr=the time rate of change in the rotational energy of a segment due to the moment of the joint force. The findings are summarized below.
    1.  The proposed method can divide the power acting on the segment due to joint force into the translational component (JFPt) and the rotational component (JFPr).
    2.  The racquet-holding arm mainly acquires mechanical energy as translational energy with decreasing rotational energy of the upper trunk (around right-leftward rotation).
    3.  The main role of the shoulder joint is not to generate rotational energy but to change the energy form (from translational energy to rotational energy).
    4.  The main role of the phase before most of the shoulder external rotation is to store the translational energy in the racquet-holding arm.
    5.  The main role of the phase after most of the shoulder external rotation is to transfer the translational and rotational energies to the racquet.
    6.  The proposed method can quantify not only the generation/absorption and transmission of mechanical energy but also the transformation of the energy form. Therefore, this method may produce new findings that have not yet been clarified.
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  • Ryoji Toyoshima, Kenji Tauchi, Toshinori Endo, Shigeo Iso, Shinji Saku ...
    2015 Volume 60 Issue 1 Pages 197-208
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: April 30, 2015
    JOURNAL FREE ACCESS
      The purpose of this study was to clarify the biomechanical factors that influence intra-individual variations in step frequency (SF) and length (SL) during sprint running. One male sprinter participated as a study subject, and performed a 60-m sprint at maximal effort. Experiments were conducted 5 times, with a total number of 14 trials. The ground reaction force and positions of markers attached to the joints were recorded using force plates and a motion capture system. Trials were divided into SF type and SL type depending on the SF/SL ratio, and the kinematic variables and ground reaction force were compared. The main results were as follows.
      1)  There were no significant differences in sprint velocity and stance time between the SF type and the SL type.
      2)  The flight time of the SL type was longer than that of the SF type.
      3)  Vertical components of the ground reaction force and impulse during the stance phase were larger for the SL type than for the SF type.
      4)  The thigh angle of the swing leg was larger for the SL type than for the SF type during almost all phases.
      5)  The hip joint of the swing leg was flexed to a greater degree during the stance phase and first half of the flight phase for the SL type than for the SF type.
      6)  There were no marked differences in the segment and joint angular velocities between the SF type and the SL type.
      These results indicate that changes in step frequency and step length with flight time are due to an increase or decrease of vertical impulse. Moreover, it was revealed that vertical impulse is influenced by the thigh angle of the swing leg during the stance phase, rather than by the angular velocity of the swing leg.
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  • Hitomi Okubo, Hideaki Takai, Takamasa Sakabe, Yasuhisa Kusumoto
    2015 Volume 60 Issue 1 Pages 209-221
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: May 12, 2015
    JOURNAL FREE ACCESS
      The purpose of this study was to examine the effects of time pressure (TP) on the speed of stimulus evaluation and processing resources, and speed and accuracy of the behavioral response, using P300. The participants were 13 physical education students (mean age 18.85 years, SD 0.95), who were presented with a flanker task involving spacing between letters. Under non-TP conditions, there was no feedback sound even if there was no reaction before the stimulus was replaced by a new stimulus. The TP condition was a feedback sound that was triggered if no reaction occurred within 350 ms. The results showed that in terms of behavioral parameters, the reaction time became shorter with increasing TP. In addition, response accuracy decreased with increasing TP. Among physiological indices, P300 latency at Pz was shorter and P300 amplitude at Pz was larger under TP conditions than under non-TP conditions. Our results suggest that TP shortens the process of stimulus evaluation, and that more processing resources are required under TP conditions.
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  • Ryoji Shimotake
    2015 Volume 60 Issue 1 Pages 223-238
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: April 27, 2015
    JOURNAL FREE ACCESS
      Prior research on extracurricular sports in Japan has focused on the survival of such activities as an apparatus of discipline after postwar reform of democratic education. This situation has been criticized, whereas a philosophy of “childhood autonomy” has been idealized as an intrinsic value; research in this field has advocated “student freedom” through release from the apparatus of discipline. However, the current situation is paradoxical, as repeated discussions about “childhood autonomy” have not yet led to realization of their goals. Therefore, it is necessary to reconsider the strategy employed in previous research, and the present study attempted to do this by focusing on the activities of students in a high school track and field club based on Foucault's theory of power.
      An important component of Foucault's theory is not to aim for release from power, but to describe the function of power in relation to knowledge. However, prior research has tended to overlook how “childhood autonomy” can be recognized in relation to the function of power. Therefore, the present study attempted to clarify the function of power within the context of extracurricular sports activities, while capturing the process whereby students recognize the philosophy of “childhood autonomy”.
      Unexpectedly, it was found that free practice allows students to gain affinity for discipline within the context of extracurricular sports activities as an apparatus of discipline, but it is not for becoming “docile bodies”, and that it is possible to find potential avenues of freedom, as defined by Foucault, in such activities. Foucault's freedom requires individuals to experience the functions of power rather than being released from them. Therefore, extracurricular sports activities as an apparatus of discipline provides a milieu that enables students to engage in free practice, rather than inhibiting their freedom. Our findings highlight the possibilities and limitations of freedom that students can experience within the context of extracurricular sports activities.
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Practical investigation
  • Yuki Mitsumoto, Masaaki Oba
    2015 Volume 60 Issue 1 Pages 239-248
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: January 10, 2015
    JOURNAL FREE ACCESS
      The purpose of this study was to examine the influence of creating two Free-Shoot Zones (FSZ) at freely chosen spots on acquisition of tactics in the setting of 4-on-3 basketball games in upper-elementary physical education classes. Tactics learning was incorporated as an important part of basketball classes, and implemented at two different upper-elementary grade levels during physical education classes. Because the purpose of creating the FSZ is to ensure opportunities to take a shot, it prevents defenders from interfering, thus maximizing the shooter's chances of a successful shot. During the study, 25 1-m2 squares were placed in restricted areas, and then the students chose two preferred areas before the game. In order to analyze the influence of the FSZ, students' conversations were recorded during tactical timeouts in every class using a digital voice recorder. At those times, students discussed where to place the FSZ. They recorded the offensive strategies of their team on their learning cards. Furthermore, the teacher categorized the students' strategic ideas into patterns A, B, or C. Later, for every physical education class, the number of occurrences of each predetermined strategy was recorded on the basis of the three patterns. The data were then displayed on a line graph to illustrate how the tactical patterns differed among the classes. The main findings were as follows:
      1.  Many teams modified their strategies intentionally or made gradual tactical transformations depending on the defense's positions and movements when the FSZ was both guarded and unguarded.
      2.  After determining spots where it was possible to create unmarked spaces, many teams devised strategies to attract the defense to create free spaces for shooting, and also collaborated in creating shooting opportunities.
      The present findings demonstrate the effectiveness of incorporating a FSZ into tactical learning in elementary school basketball classes.
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Case studies
  • Jun Murai
    2015 Volume 60 Issue 1 Pages 249-265
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: February 20, 2015
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      This case study aimed to clarify the contents of comments made by student teachers at conferences on physical education lessons during practical teacher training at elementary school level.
      For this research, first, the investigator acted as an observer at conferences concerning physical education lessons, and took shorthand notes of the student teachers' comments. Secondly, the analyst classified these shorthand notes by the inductive method to clarify the contents of the student teachers' reflections. Thirdly, the analyst compared the classified result with the theoretical framework of structures for physical education classes. Finally, the analyst examined differences between the practitioners' comments and the observers' comments.
      The following results were obtained: 1. Student teachers' comments were classified into 11 types: “impression of the lesson”, “teaching plan”, “teaching goals”, “tools for the lesson”, “setting of instruments”, “teacher”, “teaching materials”, “children”, “being a student teacher”, “being a teacher” and “reconsideration of common sense”. Student teachers made many comments about “teaching”, but only made a few comments about “evaluation”. 2. Student teachers' comments were focused on “teacher”, especially with regard to “teaching”. 3. Student teachers' comments showed differences from those of practitioners and observers; in particular, “teacher” was commented on more often by practitioners than by observers, and “tools for the lesson” was commented on more often by observers than by practitioners.
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  • Kenryu Aoyagi, Kaori Ishii, Ai Shibata, Hirokazu Arai, Hanako Fukamach ...
    2015 Volume 60 Issue 1 Pages 267-282
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: January 14, 2015
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      Use of external coaches for school-based extracurricular sports activities has been promoted because of the lack of teachers who can coach expertly and the large burden placed on teachers when coaching and managing such activities. However, it has been reported that securing external coaches through human resources is difficult. To promote the use of external coaches, previous studies have suggested some possible strategies: 1) clarifying the role and status of external coaches, and promoting cooperative coaching with external coaches and teachers; 2) interactive collection and provision of information about external coaches and schools, and improving recognition of the mediation system; 3) improving the way external coaches are recruited, and setting a suitable trial period; 4) moderating institutional limitations for coaching frequency and number of coaches; and 5) holding workshops for external coaches. However, these suggestions were made from only an individual viewpoint (i.e. that of teachers, external coaches, and potential external coaches), and did not consider organizational perspectives. In Japan, there are some organizations that help recruitment of external coaches for school-based extracurricular sports activities. It is necessary to consider the opinions of these organizations to develop more realistic and concrete promotion strategies. Therefore, the present study explored in detail the trials, problems, challenges, and strategies of organizations in order to promote the recruitment of external coaches for school-based extracurricular sports activities. Face to face semi-structured interviews were conducted involving 15 individuals in 11 organizations (2 national and 4 prefectural organizations, 3 schools, 1 university, and 1 company) supporting the recruitment of external coaches for school-based extracurricular sports activities. The interviews contained questions asking details of the recruitment system, problems, challenges and management strategies. All interviews were audio-recorded with agreement from the participants. The transcript data were integrated into 7 trials and their details, problems, challenges, and strategies were described. The results indicated that in order to promote the engagement of external coaches, a number of factors were important, including building human relationships between external coaches and teachers led by teachers that could share information, interactive collection and provision of information through mediator and cooperation with other organizations, collecting information about external coaches and interviewing them before formal acceptance, keeping the coaching non-compensatory, holding workshops and creating feedback to promote communication and learning of external coaches, and considering the continuity of the trial. Knowledge of the various problems, challenges, and strategies from an organizational perspective would contribute to improvement of recruitment strategy. The results of the present study could also provide information that is beneficial for other organizations wishing to conduct similar trials.
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Materials
  • Kenji Yomoda, Riki Sukou, Yoshinori Okade
    2015 Volume 60 Issue 1 Pages 283-301
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: December 23, 2014
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      The purpose of this study was to examine trends in the methods documented in the international English literature on teacher education in physical education focusing on journals specializing in the pedagogy of physical education.
      The data sources were 102 articles appearing in 5 international journals of physical education pedagogy over a 10-year period from 2002 to 2011. The research methods described in the methods section of each article were categorized according to the research approach, the attributes of the participants, data collection techniques, data analysis methods, and techniques for establishing validity and reliability. The ratios of these categories and the numbers of types of qualitative data collection techniques used in each article were then compared between the first and the latest 5-year periods.
      The results revealed that qualitative research had been the major research approach in the entire decade. It was also found that the techniques used for qualitative data collection in each article had diversified from 2007, and that articles employing data triangulation techniques had also increased. The proportion of articles describing approaches for establishing reliability and validity relative to that of articles employing qualitative data had also increased significantly from 2007. It was also suggested that articles focusing on elementary school classroom teachers and preservice teachers in general education courses had been relatively limited.
      Such shifts in research trends might have resulted from developments in theoretical frameworks of methodology. It is suggested that critical future issues in our research field in Japan will include accumulation of exploratory qualitative studies, appropriate application and description of approaches for establishment of reliability and validity, such as triangulation of data, investigators, and methods, and selection of appropriate research methods for specific research themes.
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  • Daiki Nasu, Tomoyuki Matsuo
    2015 Volume 60 Issue 1 Pages 303-313
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: January 20, 2015
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      The aim of the present study was to investigate the differences in kinematics between 2 types of motor strategy for expert dart throwing. We divided 8 experts into 2 groups based on the motor strategies they had demonstrated in a previous study (Nasu et al., 2014): group A were experts who had a longer time window in which a release could result in hitting the bull's eye, and group B were experts who had a shorter time window but greatly reduced their timing error. Each subject performed 60 dart throws, aiming at the center of the dart board (bull's eye). The movement of the dart, index finger, and joint motion of the upper extremity were captured using a motion capture system with 7 cameras (480 Hz, Oqus300, Qualysis Inc.). We compared the shape of the hand trajectory and joint kinematics between the groups. We found that experts in group A demonstrated a smaller shoulder angle (lower elbow height) and a larger angle of elbow flexion through forward swing than those in group B. These differences affected the time window that led to a successful throw, i.e. the time for which the mutually complementary relationship among the release parameters (especially the relationship between velocity and direction of motion) was maintained. These results may be useful as basic data to help clarify how throwing accuracy can be improved in several sports.
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  • Eishin Teraoka, Tsuyoshi Matsumoto
    2015 Volume 60 Issue 1 Pages 315-325
    Published: 2015
    Released on J-STAGE: June 13, 2015
    Advance online publication: February 20, 2015
    JOURNAL FREE ACCESS
      This study was conducted to clarify the status of coaching within club activities at Japanese junior high schools. To obtain relevant data, a questionnaire was administered to 202 teachers working at 50 public schools in I prefecture. At the time of the survey, the teachers were coaching students in soccer, basketball, table tennis, tennis, and baseball. The questionnaires were filled out anonymously, and then distributed and collected by post. The questionnaire included information on coaching methods (24 items on a 5-point scale) based on the Teaching Games for Understanding theory. The results were as follows. (1) About 70% of the teachers had not received special education in coaching. (2) About 10% of the teachers “had not received special education,” “had no personal experience of playing,” and “had less than 3 years experience in coaching”. (3) The teachers differentiated between team sports and individual sports. (4) More than half of the teachers felt a degree of uneasiness about coaching. (5) The self-rating scores were influenced more by the teachers' playing experience than by coaching experience. (6) To improve coaching competence, teachers need to acquire skills such as fostering players' problem-solving capability using appropriate questions to prompt students' awareness and ensuring that the aims of practice are met. Future studies should focus on identifying the most crucial aspects of coaching and on analyzing teachers' behavior in greater detail.
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