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11.
Masayuki Konishi Masaki Takahashi Naoya Endo Shigeharu Numao Shun Takagi Masashi Miyashita 《Journal of sports sciences》2013,31(3):248-255
Abstract The aim of this study was to investigate the effects of sleep deprivation on autonomic and endocrine functions during the day and on exercise tolerance in the evening. Ten healthy young males completed two, 2-day control and sleep deprivation trials. For the control trial, participants were allowed normal sleep from 23:00 to 07:00 h. For the sleep deprivation trial, participants did not sleep for 34 h. Autonomic activity was measured from 19:00 h on day 1 to 16:00 h on day 2 by frequency-domain measures of heart rate variability. Endocrine function was examined by measuring adrenocorticotropic hormone and cortisol from venous blood samples collected on day 2 at 09:00, 13:00, and 17:00 h and immediately after an exercise tolerance testing. Autonomic regulation, particularly parasympathetic regulation estimated from the high-frequency component of heart rate variability analysis, was significantly higher in the sleep deprivation trial than in the control trial in the morning and afternoon of day 2. Plasma adrenocorticotropic hormone concentrations were significantly higher at 09:00 and 13:00 h of day 2 under sleep deprivation. Heart rate during exercise was significantly lower following sleep deprivation. Therefore, the effects of sleep deprivation on autonomic regulation depend on the time of the day. 相似文献
12.
Differences in stroke phases, arm-leg coordination and velocity fluctuation due to event, gender and performance level in breaststroke 总被引：3，自引：0，他引：3
Takagi H Sugimoto S Nishijima N Wilson B 《Sports biomechanics / International Society of Biomechanics in Sports》2004,3(1):15-27
The purpose of this study was to analyse stroke phases, arm-leg coordination and trunk motion fluctuation during breaststroke in elite male and female 50, 100 and 200 m events at the 9th FINA World Swimming Championships, Fukuoka 2001. Four phases of the arm stroke and three phases of the leg kick as well as phases of simultaneous arm and leg propulsion and recovery were identified from video of swimmers' motions below the surface. The duration of each phase was expressed as a proportion of the whole stroke cycle. Three measures of the arm-leg coordination, percent simultaneous arm-leg recovery time (%SRT), percent arm lag time (%ALT) and percent simultaneous arm-leg propulsion time (%SPT) were calculated. Mean mid-pool swimming hip velocity (V), stroke rate (SR) and stroke length (SL) were also calculated. In addition, the intra-cycle hip velocity of the swimmers was obtained by cinematographic analysis. The SR decreased and SL increased significantly as the event distance increased. For the arm-leg coordination the %ALT, %SPT and %SRT indicated significant differences between event, gender and performance level. In particular, for increasing event distance and for the higher performing swimmer the lower the %SPT and the higher the %SRT. In addition, the range of the intra-cycle hip velocity fluctuation in the lower performing group was greater than the higher performing group. The non-propulsive phase seems to be a key factor for better performance. The breaststroke swimmers must avoid rapid deceleration during the non-propulsive phase by adopting a low resistance posture and stroking technique. 相似文献
13.
This paper presents the construction of a pneumatic active suspension system for a one-wheel car model using fuzzy reasoning and a disturbance observer. The one-wheel car model can be approximately described as a nonlinear two degrees of freedom system subject to excitation from a road profile. The active control is composed of fuzzy and disturbance controls, and the active control force is constructed by actuating a pneumatic actuator. A phase lead-lag compensator is inserted to counter the performance degradation due to the delay of the pneumatic actuator. The experimental result indicates that the proposed active suspension improves much the vibration suppression of the car model. 相似文献
14.
Toshihiko?HayamizuEmail author Kazuyo?Kino Kuniko?Takagi Eng-Hai?Tan 《Asia Pacific Education Review》2004,5(2):127-135
The purpose of this study is to examine whether a new construct “Assumed-Competence based on undervaluing others (AC)” could
be a determinant of anger and sadness for contemporary Japanese adolescents. A set of questionnaires was administered to 584
high school students, who rated ACS-2 (Assumed-Competence Scale, second version), Rosenberg’s self-esteem scale, in relation
to their perceived emotional reactions toward certain negative personal and social events, and other scales. The results indicated
that the students who got angry at personal events were likely to have high AC. However, those who felt neither anger nor
sadness in relation to such social events were likely to have high AC. The role of AC in emotional reactions and suggestions
for future research was also discussed. 相似文献
15.
Kohei Takagi 《Frontiers of Education in China》2015,10(4):578-607
In the changing higher education environment, universities increasingly engage in areas outside the traditional teaching and research missions. The new missions extend over wide yet specialized areas, such as technological advancement, internationalization, entrepreneurship, and enhancement of teaching and learning. To effectively handle these areas, universities require specific talents that may not be found in conventional academic and administrative cadres. The transformation highlights blurred boundaries between academic and non-academic spheres of the university. Situated in the University of Hong Kong (HKU), this paper explores how the university utilizes new professionals and administrative staff in new missions. Qualitative interviews with university staff reveal their profiles and perceptions in evolving organizational structures. By examining understudied subjects in Hong Kong, it discusses implications of changing university staff and how universities may optimize their new talent. 相似文献
16.
Taishu Nakamura Tasuku Miyoshi Shota Sato Motoki Takagi Yasuhisa Kamada Yoshiyuki Kobayashi 《Sports Engineering》2018,21(3):149-159
Soccer kicks are characterized by segmental and joint rotations in multiple planes, where large discrepancies between two- and three-dimensional analyses for angular measurements of soccer kicks exist. The aim of this study was to clarify the differences in motions of the lower limbs and the pelvis required to achieve a shot without rotations as compared with an instep kick. Kinematic parameters obtained from non-rotational shots and instep kicks were analyzed using principal component analysis (PCA). The results clearly demonstrated that the PCA identified the differences in the instep kick and the non-rotational shot relative to the kinematic motions of the lower limbs and the pelvis. These findings suggest that the key issue for executing the NR shot is achieving a straight-line foot trajectory in the impact phase. 相似文献
17.
Tsuyoshi Takeda Hideki Takagi Shozo Tsubakimoto 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):370-381
This study investigated the effects of both anterior–posterior position and inclination of a back plate positioned on a starting platform on swimming start performance. Ten male college swimmers performed eight starts with varying combinations of take-off angle (normal and lower), inclination angle (10°, 25°, 45°, and 65°) and position (0.29, 0.44, and 0.59 m from the front edge of the starting block). Two-way repeated measures analysis of variance (ANOVA; take-off angle × back plate) for four conditions with take-off angles (normal and lower) and inclinations (10° and 45°), and one-way ANOVA for comparisons between four inclinations and three positions were carried out. Multiple comparisons were made using Bonferroni's method. The main effects of the take-off angle were on the vertical and resultant take-off velocities [F(1,18) = 36.72, p < 0.001 and F(1,18) = 9.58, p = 0.013, respectively]. Comparisons between the plate positions showed that the 5 m time of the 0.29 m condition was significantly longer, the take-off angle and vertical take-off velocity of the 0.59 m condition were significantly lower, and horizontal and resultant take-off velocities of the 0.29 m condition were significantly less. Rear foot take-off times were significantly longer in the ascending order: 0.29, 0.44, and 0.59 m. 相似文献