Human running at low and intermediate speeds is characterized by a greater average force exerted after 'landing', when muscle-tendon units are stretched ('hard landing'), and a lower average force exerted before 'takeoff', when muscle-tendon units shorten ('soft takeoff'). This landing-takeoff asymmetry is consistent with the force-velocity relation of the 'motor' (i.e. with the basic property ...

A promising class of devices for ocean wave energy conversion is called the oscillating water column in which power transferred to an airflow that rotates a turbine. closed cycle takeoff (CCPTO), air forced through two valves and turbine, has main benefits such system: it allows unidirectional smooths large variations pressure due irregular (i.e., polychromatic) seas. This paper presents design...

Subjects performed maximum vertical jumps on a force platform to reveal whether resulting force-time curves could identify characteristics of good performances. Instantaneous power-time curves were also derived from the force-time curves. Eighteen temporal and kinetic variables were calculated from the forceand power-time curves and were compared with the takeoff velocities and maximum heights ...

UNLABELLED The aim of this study was to determine the validity and reliability of a microelectromechanicals (MEMs) based system (Keimove™) in measuring flight time and takeoff velocity during a counter-movement jump (CMJ). As criterion reference, data of a high- speed camera (HSC) and a force-platform (FP) synchronized with a linear position transducer (LPT) was used. Thirty professional soccer...

This study explored the muscle strain and activation patterns of several key flight muscles of the pigeon (Columba livia) during takeoff and landing flight. Using electromyography (EMG) to measure muscle activation, and sonomicrometry to quantify muscle strain, we evaluated the muscle function patterns of the pectoralis, biceps, humerotriceps and scapulotriceps as pigeons flew between two perch...

We study robust hovering control of vertical/short takeoff and landing (V/STOL) aircraft. For hovering control, we can model a V/STOL aircraft as a planar vertical takeoff and landing (PVTOL) aircraft. We use a recently developed optimal control approach to design a robust hovering control. The resulting control is a nonlinear state feedback whose robustness is demonstrated by numerical simulat...

The triple jump is an athletic event involving three ground contact phases during which athletes must trade off the maintenance of horizontal velocity against the generation of vertical velocity. Previous studies have indicated that individual athletes have a linear relationship between the loss in horizontal velocity and the gain in vertical velocity during each phase. This study used computer...

We reviewed the growth characteristics of American boys and girls from published studies, including age at takeoff, age at peak height velocity, peak height velocity, duration of puberty, and the magnitude of the pubertal contribution to adult height. Age at takeoff is highly variable and sex-dependent. The mean takeoff age in children growing at an average rate is approximately 11 years in boy...