During quiet standing the human "inverted pendulum" sways irregularly. In previous work where subjects balanced a real inverted pendulum, we investigated what contribution the intrinsic mechanical ankle stiffness makes to achieve stability. Using the results of a plausible model, we suggested that intrinsic ankle stiffness is inadequate for providing stability. Here, using a piezo-electric tran...

BACKGROUND YKL-40, a proposed marker of inflammation and endothelial dysfunction, is associated with atherosclerosis and an increased cardiovascular mortality in the general population. However, the relationship between YKL-40 and arterial stiffness in hypertensive patients has not been adequately assessed. METHODS The relationship between serum levels of YKL-40 and arterial stiffness was eva...

BACKGROUND AND OBJECTIVES Increased central arterial stiffness is an emerging risk factor for cardiovascular disease. Acute aerobic exercise reduces arterial stiffness, while acute resistance exercise may increase arterial stiffness, but this is not a universal finding. We tested whether an acute resistance exercise program was associated with an increase in arterial stiffness in healthy young ...

Arterial stiffness increases with ageing and hypertension. Regular physical activity has been recommended as an important management component of hypertension. The purpose of this study was to examine the acute impact of maximal dynamic exercise and the effect of 20 weeks of aerobic exercise on arterial stiffness of the carotid and brachial arteries in older hypertensives. Nine previously seden...

Assessment of spinal stiffness is widely used by manual therapy practitioners as a part of clinical diagnosis and treatment selection. Although studies have commonly found poor reliability of such procedures, conflicting evidence suggests that assessment of spinal stiffness may help predict response to specific treatments. The current study evaluated the criterion validity of manual assessments...

Information on the stiffness of the actin and myosin filaments is a key parameter in the study of muscle contraction. For example, the number of motors attached to actin in each half-sarcomere of a muscle fibre can be obtained from measurements of the half-sarcomere stiffness, provided that the compliances of the actin and myosin filaments are known (Piazzesi et al., 2007). The stress–strain re...

AIM To investigate the diagnostic performance of liver stiffness measurement (LSM) by elastography point quantification (ElastPQ) in animal models and determine the longitudinal changes in liver stiffness by ElastPQ after splenectomy at different stages of fibrosis. METHODS Liver stiffness was measured in sixty-eight rabbits with CCl4-induced liver fibrosis at different stages and eight healt...

Wrist stiffness has been shown to have a greater effect on wrist dynamics than inertia and damping for all but the fastest wrist rotations [1]. Therefore, making coordinated wrist rotations requires that humans predict and compensate for the effects of wrist stiffness. Because wrist stiffness is anisotropic (with greater stiffness in radial-ulnar deviation than flexion-extension), some movement...

We consider the problem of estimating on line the nonlinear stiffness of flexible transmissions in robots with variable stiffness actuation in agonistic-antagonistic configuration. Stiffness estimation is obtained using a dynamic residual that provides a filtered version of the unmeasured flexibility torques, combining it with a recursive least squares algorithm that fits a polynomial model to ...

Purpose: Myocardial stiffness has been a significant biomarker for various cardiovascular disease processes, such as myocardial infarction, hypertension, diastolic dysfunction and tissue rejection in heart transplant patients [1-4]. Many factors contribute to stiffening of the myocardium, but it is important to understand its correlation to age. Pressure/volume based techniques are commonly use...