排序方式： 共有4条查询结果，搜索用时 125 毫秒
1
1.
2.
Innovation studies and sustainability transitions: The allure of the multi-level perspective and its challenges 总被引：4，自引：0，他引：4
Sustainable development is prompting a re-assessment of innovation and technological change. This review paper contributes three things towards this re-assessment activity. First, it considers how the history of innovation studies for sustainable development can be explained as a process of linking broader analytical frameworks to successively larger problem framings. Second it introduces an emerging framework whose allure rests in its ability to capture the bigger picture: the multi-level perspective on socio-technical transitions (MLP). Whilst burgeoning researcher networks and literature suggests this policy-relevant theory is attractive, it is not without its challenges. The third purpose of this paper is to elaborate these challenges as areas for further research and development. We do this by drawing upon contributions to this special section and the wider literature. 相似文献
3.
Jan-Peter Goldmann Maximilian Sanno Steffen Willwacher Kai Heinrich Gert-Peter Brüggemann 《Journal of sports sciences》2013,31(4):424-433
Abstract The metatarsal phalangeal joint (MPJ) and its crossing toe flexor muscles (TFM) represent the link between the large energy generating leg extensor muscles and the ground. The purpose of this study was to examine the functional adaptability of TFM to increased mechanical stimuli and the effects on walking, running and jumping performance. Fifteen men performed a heavy resistance TFM strength training with 90% of the maximal voluntary isometric contraction (MVIC) for 7 weeks (560 contractions) for the left and right foot. Maximal MPJ and ankle plantar flexion moments during MVICs were measured in dynamometers before and after the intervention. Motion analyses (inverse dynamics) were performed during barefoot walking, running, and vertical and horizontal jumping. Athletic performance was determined by measuring jump height and distance. Left (0.21 to 0.38 Nm · kg?1; P < 0.001) and right (0.24 to 0.40 Nm · kg?1; P < 0.001) MPJ plantar flexion moments in the dynamometer, external MPJ dorsiflexion moments (0.69 to 0.75 Nm · kg?1; P = 0.012) and jump distance (2.25 to 2.31 m; P = 0.006) in horizontal jumping increased significantly. TFM responded highly to increased loading within a few weeks. The increased force potential made a contribution to an athlete's performance enhancement. 相似文献
4.
Mitsuo Otsuka Wolfgang Potthast Steffen Willwacher Jan-Peter Goldmann Toshiyuki Kurihara Tadao Isaka 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(3):229-244
The purpose of this study was to validate the calculation of reaction time (RT) and normalised power in block starts without considering arm ground reaction forces (GRFs) or using two kinematics-only methods. The RT and normalised power in the action phase were calculated using four different methods: using GRFs of arms and legs by force plates (whole F-based method), which can be regarded as the most valid method, using GRFs of legs captured by force plates (legs F-based method), using position of the centre of mass of the entire body captured by high-speed cameras (whole P-based method), and using only a partial subset of segment position (partial P-based method). Bland–Altman plots demonstrated that the RT of the legs F-based method was not similar to that of the whole F-based method: the mean difference was 7.4 ms and the 95% limits of agreement was?45.1 to 59.8 ms, and it was the least valid method for the calculation among the four methods. In contrast, the normalised power was more valid in the legs F-based method, followed by whole and partial P-based methods. This information will help researchers and practitioners to decide upon their analysis methods when analysing block start performance. 相似文献
1