...Roger W. P. Kissane; Graham N. Askew ABSTRACT The work loop technique was developed to assess muscle performance during cyclical length changes with phasic activation, simulating the in vivo conditions of many muscles, particularly during locomotion. To estimate muscle function in vivo...

...Kathryn L. Hurley; Jordan R. Bassett; Jenna A. Monroy ABSTRACT Evidence suggests that the giant muscle protein titin functions as a tunable spring in active muscle. However, the mechanisms for increasing titin stiffness with activation are not well understood. Previous studies have suggested...

...Anthony L. Hessel; Brent J. Raiteri; Michael J. Marsh; Daniel Hahn ABSTRACT Much of our understanding of in vivo skeletal muscle properties is based on studies performed under maximal activation, which is problematic because muscles are rarely activated maximally during movements such as walking...

...Vladimir A. Vityazev; Jan E. Azarov ABSTRACT The activation sequence of the ventricular myocardium in ectotherms is a matter of debate. We studied the correlation between the ventricular activation sequence and the pattern of local stretches in 13 toads ( Bufo bufo ). Epicardial potential mapping...

... the nature of the relationship between the distribution of activation and the distribution of force-generating capacity among the three heads of the triceps surae [soleus (SOL), gastrocnemius medialis (GM) and gastrocnemius lateralis (GL)]. Twenty volunteers performed isometric plantarflexions, during which...

...Ollie M. Blake; James M. Wakeling Animals produce rapid movements using fast cyclical muscle contractions. These types of movements are better suited to faster muscle fibres within muscles of mixed fibre types as they can shorten at faster velocities and achieve higher activation–deactivation rates...

... be recruited. Faster motor units have faster activation–deactivation rates than slower motor units, and they contract at higher strain rates; therefore, recruitment of faster motor units may be advantageous for tasks that involve rapid movements or high rates of work. This study identified motor unit...

...M. Rockwell Parker; Robert T. Mason SUMMARY Vertebrates indicate their genetic sex to conspecifics using secondary sexual signals, and signal expression is often activated by sex hormones. Among vertebrate signaling modalities, the least is known about how hormones influence chemical signaling. Our...

... (V/V max ) of skeletal muscle during cyclical contractions: length–force effects and velocity-dependent activation and deactivation . J. Exp. Biol. 201 , 1527 - 1540 . Askew G. N. , Marsh R. L. ( 2001 ). The mechanical power output of the pectoralis muscle of the blue-breasted...

... contributed equally to this work 3 11 2008 2009 muscle parvalbumin isometric force activation relaxation proteomics swimming Muscles power a huge diversity of activities requiring a wide range of mechanical properties; however, our understanding of the molecular mechanisms...

... in adaptation by domains of cytoplasm along a myofibre; serve researchers, through a marker role, as `clues' to various activities of muscle; are `connectors' that physically, and through signalling and cell-fibre communications, bridge myofibres to the intra- and extra-muscular environment; and are equipped...

... (0.5 mmol l –1 ), but not affected by internal GDPβS (1 mmol l -1 ). The voltage of half-maximum ( V 1/2 )activation was –46 mV in both perforated and conventional modes. V 1/2 of inactivation was –80 mV in perforated mode and –86 mV in conventional mode. Internal GTPγS (0.5 mmol l –1 ) shifted the V 1...

... in the half-inactivation and a negative shift in the half-activation potentials for the sodium current, accompanied by a slowing of the rate of inactivation to half of the experimentally observed values. This suggests that once-only spiking can be attributed to the steady-state values of activation...

... was predicted. Subsequent experiments revealed that bass rostral white muscle showed faster rates of activation and relaxation than more caudal muscle, as has been observed in white muscle of other fish species. Rostral–caudal variations in white muscle protein composition and contractile properties...

... of the body in the internal red (aerobic) muscle. Additionally, a buckle force transducer was fitted around the deep caudal tendons on the same side of the peduncle as the electrodes. Recordings of muscle activity and caudal tendon forces were made while the fish swam over a range of steady, sustainable...

... charges in this segment. Despite their charge differences, both these jellyfish channels produce currents with activation and inactivation curves shifted by approximately +40 mV relative to other Shaker currents. Adding charge without changing segment length by mutating the N-terminal side of jShak1 S4...

...F. Lou; N. A. Curtin; R. C. Woledge ABSTRACT The energetic cost of activation was measured during an isometric tetanus of white muscle fibres from the dogfish Scyliorhinus canicula . The total heat production by the fibres was taken as a measure of the total energetic cost. This energy consists...

...Alberto Salleo; Giovanni Musci; Paolo F. A. Barra; Lilia Calabrese ABSTRACT The events which trigger the activation of nematocytes are still poorly understood, and no evidence has been presented so far on either the nature of the activatory signal for the nematocyte or the transduction mechanism...