Through system analysis of typical explosive trains in various fuses, physical and correspondent mathematical models of typical explosive trains are established, based on mass conservation, momentum conservation, ener...Through system analysis of typical explosive trains in various fuses, physical and correspondent mathematical models of typical explosive trains are established, based on mass conservation, momentum conservation, energy conservation and so on. MAZE and DYNA2D program is used to dispose these models and results of the simulating of elements of explosive trains in a typical fuse are obtained. It is helpful for designing fuses.展开更多
BACKGROUND： Plyometric training has been shown to improve performance in distance running events up to 5-km, but little research has been done on this type of training for marathon （42.195-km） runners. The purpose ...BACKGROUND： Plyometric training has been shown to improve performance in distance running events up to 5-km, but little research has been done on this type of training for marathon （42.195-km） runners. The purpose of this study was to examine the effects of plyometric and explosive speed training （PLYO） on recreational marathoners. METHODS： Twenty-two subjects （ages 18-23）, were randomized to either PLYO or core training （CORE） for a weekly session performed for 12 weeks, in addition to marathon training. Sprint, jump, and distance running performance variables were measured pre- and post-intervention. RESULTS： In the sprint tests, the PLYO group improved in both the 200-m run （P ≤ 0.001） and 60-m run （P = 0.004）, and trended toward improvement in the 30-m fly （P = 0.051）. The difference from CORE was significant only in the 200-m （P = 0.002）. The CORE group did not change in any of the sprint or jump variables. The PLYO group was significantly different from the CORE group in the standing long jump （P = 0.024）. There were no differences between groups in distance running performance. Both improved in 2-mile （3.219-km） time trial （p 〈 0.001）, VO2MAX （P = 0.026 for CORE; P = 0.002 for PLYO）, and running economy （P = 0.01）. CONCLUSION： Weekly PLYO training improves sprint speed and maintains jumping ability in recreational marathoners, but does not augment improvements in distance running performance.展开更多
文摘Through system analysis of typical explosive trains in various fuses, physical and correspondent mathematical models of typical explosive trains are established, based on mass conservation, momentum conservation, energy conservation and so on. MAZE and DYNA2D program is used to dispose these models and results of the simulating of elements of explosive trains in a typical fuse are obtained. It is helpful for designing fuses.
文摘BACKGROUND： Plyometric training has been shown to improve performance in distance running events up to 5-km, but little research has been done on this type of training for marathon （42.195-km） runners. The purpose of this study was to examine the effects of plyometric and explosive speed training （PLYO） on recreational marathoners. METHODS： Twenty-two subjects （ages 18-23）, were randomized to either PLYO or core training （CORE） for a weekly session performed for 12 weeks, in addition to marathon training. Sprint, jump, and distance running performance variables were measured pre- and post-intervention. RESULTS： In the sprint tests, the PLYO group improved in both the 200-m run （P ≤ 0.001） and 60-m run （P = 0.004）, and trended toward improvement in the 30-m fly （P = 0.051）. The difference from CORE was significant only in the 200-m （P = 0.002）. The CORE group did not change in any of the sprint or jump variables. The PLYO group was significantly different from the CORE group in the standing long jump （P = 0.024）. There were no differences between groups in distance running performance. Both improved in 2-mile （3.219-km） time trial （p 〈 0.001）, VO2MAX （P = 0.026 for CORE; P = 0.002 for PLYO）, and running economy （P = 0.01）. CONCLUSION： Weekly PLYO training improves sprint speed and maintains jumping ability in recreational marathoners, but does not augment improvements in distance running performance.
