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1.
Miyamoto N Wakahara T Sugisaki N Murata K Kanehisa H Fukunaga T Kawakami Y 《Journal of sports sciences》2010,28(14):1535-1542
The aim of the present study was to examine elbow joint extension power-load characteristics with and without a countermovement. Eight male participants performed maximal elbow extensions with and without a countermovement against different loads (0, 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0 kg). Electromyographic activity of the lateral and long heads of the triceps brachii and the biceps brachii muscles was recorded. The average joint power in the concentric phase was significantly enhanced in the countermovement condition at all loads except for 0 kg. The optimal load for the maximal joint power was greater in the countermovement (7.5 kg) than in the no countermovement condition (5.0 kg). Electromyographic activity was unchanged over the intensities and conditions. Our results suggest that the optimal load for the maximal joint power depends on the type of action (i.e. with or without a counter-movement), and that the enhanced joint power in the countermovement condition is due primarily to the storage and utilization of elastic energy. 相似文献
2.
Hiroaki Katsutani 《Community College Journal of Research & Practice》2013,37(5-6):369-372
The author has developed a learning system for students to independently practice the fundamentals of mathematics. This system consists of material from the World Wide Web (WWW). The learner uses a Web browser on client computers connected with a Local Area Network (LAN). The system generates problems of the type that the learner selects. When a learner inputs the answer to a given problem, the system judges whether it is correct or incorrect and then makes an appropriate response according to the result. The system presents four to six problems in each session. After the learner has finished solving all problems in one session, the system shows the score of the session and records this score in the learner s personal file in the server computer. 相似文献
3.
Leg amputation side determines performance in curve sprinting: a case study on a Paralympic medalist
Johannes Funken Kai Heinrich Steffen Willwacher Ralf Müller Jonas Böcker Hiroaki Hobara 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(1):75-87
The lower limb kinetics of curve sprinting in amputees are not well described in the literature, particularly with respect to the effect of the side of amputation. This is an issue due to the importance of the knowledge for prosthetic design and classification of athletes. Thus, the aim of this study was to investigate the influence of side of amputation on curve sprinting performance in athletes with a unilateral leg amputation. A three-dimensional motion analysis system (Vicon), four force plates (Kistler) and a modified mathematical human model (ALASKA) were used to compare clockwise and counter clockwise curve sprinting lower limb kinematics and kinetics of a Paralympic medalist with a left-sided knee exarticular amputation. Results reveal that vertical ground reaction force application and total vertical impulse were lower when the affected limb was at the inside of the curve. The unaffected limb showed joint mechanics different to those established for non-amputee athletes and might contribute better to propulsion when being the inside limb. Curve sprinting biomechanics and the ability to attain high radial velocities are directly dependent on the side of amputation relative to the curve direction in a unilateral amputee athlete of highest performance level. 相似文献
4.
Satoru Hashizume Hiroaki Hobara Yoshiyuki Kobayashi 《European Journal of Sport Science》2019,19(6):757-764
Negative work, which is mainly generated by eccentric muscle contraction, has an important influence on the associated muscle damage. Generally, mechanical parameters are determined for one side of a lower extremity on the assumption of negligible between-limb differences. However, between-limb differences in the negative work of lower extremity joints during running remain unclear. This study examines between-limb differences in negative work and associated mechanical parameters during the contact phase of running. Twenty-five young adult males voluntarily participated in this study. Each participant was asked to run on a straight runway at a speed of 3.0?m?s?1. Negative work, amplitude, duration of negative power, moment, and angular velocity were computed for both sides of the lower extremities. Significant differences were found in negative work between limbs for the hip (18.9?±?11.7%), knee (13.6?±?10.4%), and ankle (11.8?±?8.5%) joints. For the hip joint, asymmetric negative work was attributable to the between-limb difference in the amplitude of negative power owing to a corresponding difference in the moment. The between-limb differences concerning the duration and amplitude of negative power could explain the asymmetric negative work in the knee joint. The asymmetric negative work of the ankle joint was attributable to the between-limb difference in the amplitude and duration of the negative power and the moment. These results indicate that asymmetric negative work was generated in each lower extremity joint; however, the major mechanical parameters corresponding to the negative work are not the same across the joints. 相似文献
5.
The aim of the present study was to examine the effects of viscoelastic properties of human tendon structures during stretch?–?shortening cycle exercise. The elongation of tendon and aponeurosis of the medial gastrocnemius muscle of 26 participants was measured by ultrasonography while they performed ramp isometric plantar flexion up to the voluntary maximum, followed by a ramp relaxation. The relationship between estimated muscle force and tendon elongation during the ascending phase was fitted to a linear regression, the slope of which was defined as stiffness. The percentage of the area within the muscle force?–?tendon elongation loop relative to the area beneath the curve during the ascending phase was defined as hysteresis. In addition, maximal voluntary concentric contractions at 2.09 and 3.14 rad?·?s?1 with and without prior eccentric contractions were performed. The difference in the concentric torque at equivalent joint angles with and without prior eccentric contractions (i.e. pre-stretch augmentation) was negatively correlated with stiffness (P <?0.05) and hysteresis (P <?0.05). Furthermore, there was a higher correlation between the pre-stretch augmentation and the viscoelastic properties index – that is, the sum of normalized score values of stiffness and hysteresis (P <?0.01) – than with either stiffness or hysteresis alone. The results of this study suggest that performance during stretch?–?shortening cycle exercise is significantly affected by the viscoelastic properties of the tendon structures. 相似文献
6.
Yusuke Mori Hiroaki Yamane Yoshitaka Ushiku Tatsuya Harada 《Information processing & management》2019,56(5):1865-1879
Creativity is considered a human characteristic; creative endeavors, including automatic story generation, have been a major challenge for artificial intelligences. To understand how humans create and evaluate stories, we (1) construct a story dataset and (2) analyze the relationship between emotions and story interestingness. Given that understanding how to move readers emotionally is a crucial creative technique, we focus on the role of emotions in evaluating reader satisfaction. Although conventional research has highlighted emotions read from a text, we hypothesize that readers’ emotions do not necessarily coincide with those of the characters. The story dataset created for this study describes situations surrounding two characters. Crowdsourced volunteers label stories with the emotions of the two characters and those of readers; we then empirically analyze the relationship between emotions and interestingness. The results show that a story’s score has a stronger relationship to the readers’ emotions than the characters’ emotions. 相似文献
7.
The aim of the present study was to examine the effects of viscoelastic properties of human tendon structures during stretch - shortening cycle exercise. The elongation of tendon and aponeurosis of the medial gastrocnemius muscle of 26 participants was measured by ultrasonography while they performed ramp isometric plantar flexion up to the voluntary maximum, followed by a ramp relaxation. The relationship between estimated muscle force and tendon elongation during the ascending phase was fitted to a linear regression, the slope of which was defined as stiffness. The percentage of the area within the muscle force-tendon elongation loop relative to the area beneath the curve during the ascending phase was defined as hysteresis. In addition, maximal voluntary concentric contractions at 2.09 and 3.14 rad x s(-1) with and without prior eccentric contractions were performed. The difference in the concentric torque at equivalent joint angles with and without prior eccentric contractions (i.e. pre-stretch augmentation) was negatively correlated with stiffness (P < 0.05) and hysteresis (P < 0.05). Furthermore, there was a higher correlation between the pre-stretch augmentation and the viscoelastic properties index--that is, the sum of normalized score values of stiffness and hysteresis (P < 0.01)--than with either stiffness or hysteresis alone. The results of this study suggest that performance during stretch-shortening cycle exercise is significantly affected by the viscoelastic properties of the tendon structures. 相似文献
8.
Masahiro Niitsuma Masaki Matsubara Masaki Oono Hiroaki Saito 《Information processing & management》2011
The purpose of this study is to develop an automatic basso continuo playing system. In order to find a musically appropriate sequence of chords, we propose the principle of “harmony cost”, which is defined as the sum of two different costs: one is the “local cost” which indicates the unlikelihood of a certain chord allocation and the other is the “transition cost”, which indicates the unlikelihood of a certain connection between two chords. Automatic basso continuo playing is realised by searching for the optimal chord sequence, which minimises the accumulated harmony cost. The proposed method is evaluated by three experiments. Each experiment verifies the effectiveness of the proposed method. 相似文献
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10.
The purpose of this study was to evaluate the efficacy of multi-capillary electrophoresis instrument in clinical laboratory.
An automated clinical capillary electrophoresis system was evaluated for performing serum proteins electrophoresis and immuno-fixation
electrophoresis by subtraction. In this study the performance of capillary electrophoresis was compared with the cellulose
acetate membrane electrophoresis and agarose gel immunofixation electrophoresis for serum proteins. The results of capillary
electrophoresis and cellulose acetate membrane electrophoresis were good (r=0.89∼0.97) for protein fractions and A/G ratio
except for β-gobulin fraction (r=0.60). Both within-run and day to day precisions (CVs) of assay results for 5 main fractions
and A/G ratio (n=10) were between 0.3∼6.3%. The reference ranges of serum protein fractions obtained from 200 healthy individuals
by cellulose acetate membrane electrophoresis were almost equal to that of capillary electrophoresis except for α-1 globulin
fraction. No significant difference of electropherograms between cellulose acetate electrophoresis and capillary electrophoresis
was observed in the abnormal serum such as presence of bilirubin (<20mg/dl), hemoglobin (<300 mg/dl), lipid (Intralipos <1%)
and samples from patients with acute phase response, liver injury, polyclonal hyper gammaglobulinemia or M-proteinemia. The
method of capillary immuno-fixation electrophoresis by subtraction showed good agreement with agarose gel immunofixation electrophoresis
by subtraction identifying 30 monoclonal gammmopathy patient samples. 相似文献