background: in this experimental study, the radiographic and biomechanical characteristics of osteoperforated rabbit tibia during bone repair period were investigated. materials and methods: using dental drills, 2 mm holes were drilled at the mid-shaft of right tibia in 12 new zealand white rabbits. the left tibia was intact and selected as the control. x-rays of the left and right tibias were ...

Humans and animals adapt their leg impedance during running for both internal (e.g. loading) and external (e.g. surface) changes. To date the mechanical complexities of designing usefully robust tunable passive compliance into legs has precluded their implementation on practical running robots. This work describes the design of novel, structure-controlled stiffness legs for a hexapedal running ...

We describe a technique for measuring the stiffness of regenerate bone after leg lengthening. This allows early identification of slow healing by reference to normal patterns. We determined the time of removal of the fixator from clinical and radiological information independent of the stiffness result. In a series of 30 leg lengthenings there were no refractures when the tibial stiffness had r...

Beerse, Matthew, "Effects of frequency on single leg hopping in typically developing preadolescents. Abstract Hopping is considered a mass-spring model movement in which the leg supports the center of mass. There is a preferred hopping frequency and hopping outside of that frequency is more difficult and requires more energy. Leg stiffness has been shown to be an important factor when hopping a...

Previous research has resulted in increasing insight into neuro-mechanical control strategies during perturbed locomotion. In contrast, more general analyses on simple model (template)-related parameters during avian terrestrial locomotion are still rare. Quail kinematic data obtained using X-ray videography combined with ground reaction force measurements were used as a basis to investigate ho...

Serving to improve stability and energy efficiency during locomotion, in nature, animals modulate their leg stiffness to adapt to their terrain. Now incorporated into many locomotive robot designs, such compliance control can enable disturbance rejection and improved transition between changing ground conditions. This paper presents a novel design of a variable stiffness leg utilizing a magneto...

When mammals run, the overall musculoskeletal system behaves as a single linear "leg spring". We used force platform and kinematic measurements to determine whether leg spring stiffness (k(leg)) is adjusted to accommodate changes in surface stiffness (ksurf) when humans hoop in place, a good experimental model for examining adjustments to k(leg) in bouncing gaits. We found that k(leg) was great...

In this paper, we present the concept of adapting to changes in ground conditions like stiffness, damping and friction, using a novel two degree of freedom reconfigurable leg length hopping robot with a fixed passive compliance. In such a robot, the change in the dynamics of the single legged hopper can be induced by the change in coupled stiffness and damping of the system, i.e., stiffness and...

The purpose of this study was to understand how humans regulate their 'leg stiffness' in hopping, and to determine whether this regulation is intended to minimize energy expenditure. 'Leg stiffness' is the slope of the relationship between ground reaction force and displacement of the centre of mass (CM). Variations in leg stiffness were achieved in six subjects by having them hop at maximum an...

Recent developments in legged robotics have found that constant stiffness passive compliant legs are an effective mechanism for enabling dynamic locomotion. In spite of its success, one of the limitations of this approach is reduced adaptability. The final leg mechanism usually performs optimally for a small range of conditions such as the desired speed, payload, and terrain. For many situation...