1. The normalized force or power developed during each of a series of repeated contractions was averaged over the entire cycle of activity and rest to provide a measure of performance referred to as sustained force or sustained power. We tested the hypotheses that compared with slow soleus muscles, fast extensor digitorum longus (EDL) muscles would attain lower maximum values of sustained force...

Mechanical properties of spontaneously contracting isolated nonpregnant human myometrium (NPHM) were investigated throughout the whole continuum of load from zero load up to isometry. This made it possible to assess the three-dimensional tension-velocity-length (T-V-L) relationship characterizing the level of contractility and to determine crossbridge (CB) kinetics of myosin molecular motors. S...

Introduction: Muscles can adapt to altered length change by increasing or decreasing serial sarcomere number [1]. The functional result of this adaptation is for the muscle to work on or around optimal sarcomere length. If this finding applies to muscles after tendon transfer surgery, this would be desirable, as intraoperative measurements reveal that transferred muscles may be overstretched to...

We examined the relationship between mantle muscle structure and mantle kinematics in an ontogenetic series (5-85 mm dorsal mantle length) of oval squid, Sepioteuthis lessoniana. Thick filament length increased during growth in the mantle muscle fibres that power jet locomotion (i.e. the circular muscles). The thick filament length of both the superficial mitochondria-rich (SMR; analogous to ve...

KAPOPORT, STANLEY I., AND JEANNETTE M. BIDINGER. Eject of stretch on contractility and ionic contents of the sartorius muscle of Rana pipiens. Am. J. Physiol. 226(Z) : 452-457’ 1974.-When sartorius muscles of frogs are soaked in Ringer at room temperature, they gain Na, lose K, and lose contractility with time. These changes are retarded by stretching the muscles to ZO-30Y0 of their rest length...

Many locomotor activities require muscles to actively lengthen, dissipate energy and decelerate the body. These eccentric contractions can disrupt cytoskeletal structures within myofibrils and reduce force output. We examined how architectural features of pennate muscles can provide a protective mechanism against eccentric muscle damage by limiting fascicle lengthening. It has been previously s...

KAPOPORT, STANLEY I., AND JEANNETTE M. BIDINGER. Eject of stretch on contractility and ionic contents of the sartorius muscle of Rana pipiens. Am. J. Physiol. 226(Z) : 452-457’ 1974.-When sartorius muscles of frogs are soaked in Ringer at room temperature, they gain Na, lose K, and lose contractility with time. These changes are retarded by stretching the muscles to ZO-30Y0 of their rest length...

Extraocular muscles are characterized by their faster rates of contraction and their higher resistance to fatigue relative to limb skeletal muscles. Another often reported characteristic of extraocular muscles is that they generate lower specific forces (sP(o), force per muscle cross-sectional area, kN/m(2)) than limb skeletal muscles. To investigate this perplexing issue, the isometric contrac...