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Kohei Watanabe Takayuki Sato Takahiro Mukaimoto Wataru Takashima Michio Yamagishi Tetsunari Nishiyama 《Journal of sports sciences》2016,34(15):1413-1422
We aimed to investigate neuromuscular activation of thigh muscles during track cycling at various speeds. Eight male competitive cyclists volunteered to participate in this study. Surface electromyography of the vastus lateralis, biceps femoris and adductor magnus muscles of the bilateral legs was recorded during track cycling on velodromes with a 250-m track. The participants were instructed to maintain three different lap times: 20, 18 and 16 s. The average rectified value (ARV) was calculated from the sampled surface electromyography. Significantly higher ARVs were observed in the right compared to left leg for the biceps femoris muscle during both straight and curved sections at 18- and 16-s lap times (P < 0.05). In the biceps femoris muscle, significant changes in ARVs during the recovery phase with an increase in speed were seen in the right leg only (P < 0.05). There were no significant differences in ARVs between the straight and curved sections for all three muscles (P > 0.05). From our findings, it was suggested that during track cycling on a velodrome the laterality of the biceps femoris muscle activity is a key strategy to regulate the speed, and fixed neuromuscular strategies are adopted between straight and curved sections for thigh muscles. 相似文献
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Increasingly, firms recognize the strategic implications of front-end product design for improving total cost effectiveness. Computer-aided design (CAD) is becoming firms’ competitive weapon beyond its traditional function as a product design tool. Yet, it is unclear how the full potential of IT system, particularly the usage patterns of 3D CAD system, may be realized through organizational capabilities. This paper presents a model of IT system configurations and CAD usage patterns. Next, a typology of IT system configurations is presented based on (1) the degree of CAD integration between assembly makers and suppliers and (2) the structure of product design information (i.e., product architecture). The product architecture of four electronic firms illustrates that information integration through organizational capabilities is more important than IT investment itself. The findings suggest that a Korean firm accomplishes a greater level of IT integration compared to the other two Japanese firms and thus attain better market performance. This study offers valuable insight on effective IT integration strategy for competitive advantage in the global market. 相似文献
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INTRODUCTION On Jan. 17, 1995, the Hyogoken-nanbu earth-quake in Kobe, Japan, caused great destructive and damage to underground structures, such as subway structures, mountain tunnels, multipurpose under-ground ducts and other underground structures, which had previously been considered to be resistant to earthquake effects (JSCE, 1996; ECRHAED, 1998). This earthquake revealed that a number of critical issues should be added in the seismic design and seismic strengthening of undergr… 相似文献
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Masahiro Kawabata Kenta Goto Ken Sasaki Eiji Hihara Takahiro Mizushina 《Journal of sports sciences》2013,31(16):1841-1853
AbstractThe purpose of the present study was to relate 3D acceleration patterns of the lower and upper trunk during running to running gait cycle, assess the validity of stride duration estimated from acceleration patterns, investigate speed-dependent changes in acceleration, and examine the test–retest reliability of these parameters. Thirteen healthy young men performed two running trials each on a treadmill and on land at three speeds (slow, preferred, and fast). The 3D accelerations were measured at the L3 spinous process (lower trunk) and the ensiform process (upper trunk) and synchronised with digital video data. The amplitude and root mean square of acceleration and stride duration were calculated and then analysed by three-way analysis of variance to test effects of running conditions, device location, and running speed. Bland-Altman analysis was used to evaluate the test–retest reliability. Marked changes in acceleration were observed in relation to foot strike during running. Stride durations calculated from the vertical accelerations were nearly equal to those estimated from video data. There were significant speed effects on all parameters, and the low test–retest reliability was confirmed in the anterior–posterior acceleration during treadmill running and the anterior–posterior acceleration at slow speed during treadmill and overground running. 相似文献
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To present three-directional forces at ten human fingertips, we previously developed a bimanual multi-fingered haptic interface consisting of two five-fingered haptic hands and two interface arms. However, there is a risk that the component parts of the haptic interface will collide while an operator is manipulating the interface. A collision could be hazardous for the operator, and thus collision avoidance is essential. To solve this problem, we propose a collision avoidance controller for the bimanual multi-fingered haptic interface. The proposed controller prevents collisions while reducing the collision-induced effects on the haptic display. We carried out several experiments, the results of which show the validity of the proposed collision avoidance controller for the bimanual multi-fingered haptic interface. 相似文献
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Shigetada Kudo Yoshihisa Sakurai Takahiro Miwa Yuji Matsuda 《Journal of sports sciences》2017,35(10):945-952
This study re-evaluated the magnitude of hand propulsion (HP) in the pull and push phases of the front crawl stroke and investigated the association between the angular velocity of shoulder roll (ωSR) and hand propulsive lift (HPL). ωSR was computed in the plane normal to a forward direction for 16 skilled swimmers performing the front crawl stroke at a maximal sprinting pace. HP, hand propulsive drag (HPD) and HPL were determined by a dynamic pressure approach. HP and HPD in the pull phase were greater than in the push phase (P < 0.05) while HPL in the pull phase was similar to that in the push phase. Eleven swimmers out of the 16 swimmers had a significant within-swimmers correlation between ωSR and HPL in the push phase (P < 0.05). That is, HPL increased in the push phase as the ωSR of rolling back to the neutral position became faster. A swimmer should use more drag for hand propulsion in the pull phase and propulsion from drag and lift equally in the push phase. Based on the relationship between ωSR and HPL in the push phase, a possible stroke technique to enhance HPL using ωSR is discussed. 相似文献
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The purpose of this study was to investigate and describe the mentorship experiences of Black student athletes attending undergraduate programs at a Predominantly White Institution in Higher Education (PWI-HE). The research site for this study was a co-educational public research institution (PWI-HE) with an approximate enrollment of 45,000 students. A total of six Black student athletes (five African American and one Jamaican) agreed to participate in this study. Four major interrelated and complex themes emerged from the data analyses. These themes were: (a) mentoring study habits and routines, (b) mentoring academic schedule and time management, (c) personal development within an isolated environment, and (d) family members’ support and encouragements. To better support Black student athletes at PWI-HEs, athletic department administrators, coaches, faculty, and all students should be encouraged to respect, value, and embrace the racial identities, origins, languages, and cultures of the student athletes that are being mentored. 相似文献
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The University of the Air of Japan (UAJ) was established to provide all people access to university level education. The purpose of this paper is to evaluate from several different perspectives the cost-effectiveness of UAJ and its nationwide expansion.Even when considering only direct cost, the per student cost of UAJ is lower than that of any conventional campus-based university program. When indirect cost such as opportunity cost and study expenses are also considered, the economic advantage of UAJ is especially apparent. Much of UAJ's economic advantage is the result of the very low opportunity cost to UAJ students.The economic advantage of UAJ as indicated by cost per graduate and cost per credit is smaller than that indicated by cost per student. When both direct and indirect cost are considered, the cost per credit of UAJ is 0.51 and 0.53 of that at national and public universities; 0.65, 0.86 and 2.8 of that of day programs, evening programs and correspondence programs respectively at private universities.Simulations of a nationwide expansion demonstrate that UAJ will be more economical if a satellite broadcasting system is used. Although it will require high initial and fixed costs, the cost per credit will decrease with an increase in the number of students. The most economical method of expansion may be to send video tapes to study centers and students until the number of students reaches economical levels, and to increase cooperation with conventional universities in the cooperative use of classrooms for study centers and credit transfer. 相似文献
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