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The study of muscle growth and muscle length adaptations requires measurement of passive length-tension properties of individual muscles, but until now such measurements have only been made in animal muscles. We describe a new method for measuring passive length-tension properties of human gastrocnemius muscles in vivo. Passive ankle torque and ankle angle(More)
MOST PHYSIOLOGY TEXTS imply that the mechanism by which force is transmitted from sarcomeres to muscle insertions is simple: when skeletal muscles contract, cross-bridge forces are transmitted along myofibrils, through the sarcolemma and extracellular matrix to tendons and, ultimately, bones. At each level of organization, myofibrils, muscle fibers, and(More)
The plantarflexors of the lower limb are often assumed to act as independent actuators, but the validity of this assumption is the subject of considerable debate. This study aims to determine the degree to which passive changes in gastrocnemius muscle length, induced by knee motion, affect the tension in the adjacent soleus muscle. A second aim is to(More)
BACKGROUND Falls are common in people with multiple sclerosis (PwMS). Previous studies have generally included small samples and had varied methods. OBJECTIVES The objectives of this paper are to compile fall rates across a broad range of ages and disease severity and to definitively assess the extent to which MS-associated and demographic factors(More)
INTRODUCTION In this study we compared passive mechanical properties of gastrocnemius muscle-tendon units, muscle fascicles, and tendons in control subjects and people with ankle contractures after spinal cord injury. METHODS Passive gastrocnemius length-tension curves were derived from passive ankle torque-angle data obtained from 20 spinal cord injured(More)
There is urgent need to develop new acceleration techniques capable of exceeding gigaelectron-volt-per-metre (GeV m(-1)) gradients in order to enable future generations of both light sources and high-energy physics experiments. To address this need, short wavelength accelerators based on wakefields, where an intense relativistic electron beam radiates the(More)
BACKGROUND Concern about falling can have devastating physical and psychological consequences in people with multiple sclerosis (MS). However, little is known about physical and cognitive determinants for increased concern about falling inthis group. OBJECTIVE To investigate direct and indirect relationships between MS severity and concern about falling(More)
Several studies have measured the elastic properties of a single human muscle-tendon unit in vivo. However the viscoelastic behavior of single human muscles has not been characterized. In this study, we adapted QLV theory to model the viscoelastic behavior of human gastrocnemius muscle-tendon units in vivo. We also determined the influence of(More)