When human hoppers are surprised by a change in surface stiffness, they adapt almost instantly by changing leg stiffness, implying that neural feedback is not necessary. The goal of this simulation study was first to investigate whether leg stiffness can change without neural control adjustment when landing on an unexpected hard or unexpected compliant (soft) surface, and second to determine wh...

When humans hop or run on different surfaces, they adjust their effective leg stiffness to offset changes in surface stiffness. As a result, the overall stiffness of the leg-surface series combination remains independent of surface stiffness. The purpose of this study was to determine whether humans make a similar adjustment when springs are placed in parallel with the leg via a lower limb orth...

INTRODUCTION: It has been supposed that leg stiffness affect repeated jump performance, such as hopping. Previous study indicated that ankle joint stiffness is important in leg stiffness (Arampatzis et al. 2001). Furthermore, it was demonstrated that Achilles tendon properties could contribute to the total mechanical work during hopping (Lichtwark and Wilson 2005). On the other hand, it is know...

Difference in leg stiffness between females and males is considered to be a cause of higher rates of Anterior Cruciate Ligament injury in female athletes. Females are believed to have lower stiffness and as a consequence different recruitment strategies to adapt functional tasks. The aim of the current study was to evaluate how leg stiffness is tuned to demanding conditions. 22 healthy subjects...

OBJECTIVE To estimate the relation of precisely measured regional body composition with peripheral and central arterial stiffness in the elderly. METHODS We investigated 648 participants (mean age 69.0 +/- 6.0 years) of the Hoorn Study, a population-based cohort study. Trunk fat, leg fat, trunk lean and leg lean mass were distinguished by dual-energy X-ray absorptiometry. We used ultrasound t...

Passively compliant legs have been instrumental in the development of dynamically running legged robots. Having properly tuned leg springs is essential for stable, robust and energetically efficient running at high speeds. Recent simulation studies indicate that having variable stiffness legs, as animals do, can significantly improve the speed and stability of these robots in changing environme...

A running animal coordinates the actions of many muscles, tendons, and ligaments in its leg so that the overall leg behaves like a single mechanical spring during ground contact. Experimental observations have revealed that an animal's leg stiffness is independent of both speed and gravity level, suggesting that it is dictated by inherent musculoskeletal properties. However, if leg stiffness wa...

Leg stiffness between high-arched (HA) and low-arched (LA) runners was compared. It was hypothesized that high-arched runners would exhibit increased leg stiffness, increased sagittal plane support moment, greater vertical loading rates, decreased knee flexion excursion and increased activation of the knee extensor musculature. Twenty high-arched and 20 low-arched subjects were included in this...

During human movement, the leg can be represented as a mechanical spring, with its stiffness potentially contributing to sports performance and injury prevention. Although many individuals perform athletic activities with joint stabilizers, little is known about the effects of prophylactic lower extremity braces on leg stiffness. The objective of this study was to investigate the effect of ankl...

Individual joint deviations are often identified in the analysis of cerebral palsy (CP) gait. However, knowledge is limited as to how these deviations affect the control of the locomotor system as a whole when striving to meet the demands of walking. The current study aimed to bridge the gap by describing the control of the locomotor system in children with diplegic CP in terms of their leg sti...