The height of a maximum Vertical Squat Jump (VSJ) reflects the useful power produced by a jumper during the push-off phase. In turn this partly depends on the coordination of the jumper's segmental rotations at each instant. The physical system constituted by the jumper has been shown to be very sensitive to perturbations and furthermore the movement is realized in a very short time (ca. 300 ms...

During bipedal walking, modern humans dorsiflex their forefoot at the metatarsophalangeal joints (MTPJs) prior to push off, which tightens the plantar soft tissues to convert the foot into a stiff propulsive lever. Particular features of metatarsal head morphology such as "dorsal doming" are thought to facilitate this stiffening mechanism. In contrast, chimpanzees are believed to possess MTPJ m...

The contribution of muscle in-series compliance on maximum performance of the muscle tendon complex was investigated using a forward dynamic computer simulation. The model of the human body contains 8 Hill-type muscles of the lower extremities. Muscle activation is optimized as a function of time, so that maximum drop jump height is achieved by the model. It is shown that the muscle series elas...

In these days, the world experiences an unprecedented demand for data and data services, driven mainly by the popularity of the Web services and by the evolution of the Internet towards an information super-highway. We introduce a hybrid scheduling that effectively combines broadcasting for very popular data (push data) and dissemination upon-request for less popular data (pull data) in asymmet...

In this paper we experimentally investigate how the allocation of inventory risk in a two-stage supply chain affects channel efficiency. We first evaluate two common wholesale price contracts that differ in which party incurs the risk associated with unsold inventory; a push contract in which the retailer incurs the risk, and a pull contract in which the supplier incurs the risk. Our experiment...

Steady state human locomotion at level ground needs compensatory energy input against impulsive energy loss during heel strike. Ground push-off by the stance leg right before the onset of double support phase appeared to be four times energy efficient than the an active hip torque generation during the swing phase [1]. However, if there is biomechanical constraint applied to the maximum allowab...

This study examined whether the elasticity of the tendinous tissues plays an important role in human locomotion by improving the power output and efficiency of skeletal muscle. Ten subjects performed one-leg drop jumps (DJ) from different dropping heights with a constant rebound height. The fascicle length of the vastus lateralis muscle was measured by using real-time ultrasonography during DJ....