...–18:00 h) swimming to examine how self-selected movement strategies are used to modulate energetic efficiency and effort. Overall, self-selected swimming speeds (individual means ranging from 1.0 to 1.96 m s −1 ) tended to minimize cost of transport, and were on the lower range of animal-preferred...

... that the forked tail produces thrust via acceleration reaction forces like the truncate tail during cruising but at increased energetic costs. This reduced efficiency corresponds to differences in the performance of the two tail geometries and body kinematics to maintain similar overall thrust outputs. Our...

...William T. Gough; Hayden J. Smith; Matthew S. Savoca; Max F. Czapanskiy; Frank E. Fish; Jean Potvin; K. C. Bierlich; David E. Cade; Jacopo Di Clemente; John Kennedy; Paolo Segre; Andrew Stanworth; Caroline Weir; Jeremy A. Goldbogen ABSTRACT High efficiency lunate-tail swimming with high-aspect...

...Brad J. Gemmell; Sean P. Colin; John H. Costello ABSTRACT Recently, it has been shown that some medusae are capable of swimming very efficiently, i.e. with a low cost of transport, and that this is in part due to passive energy recapture (PER) which occurs during bell relaxation. We compared...

.../ Summary: Force depression observed after active shortening does not influence the metabolic cost of muscle contraction. Force depression is likely associated with a decrease in the proportion of attached cross-bridges. ATPase activity Force depression Cross-bridge cycling Stiffness Efficiency...

... efficiency, at least at slow speeds and high loads. In conclusion, Nepalese porters accomplish their impressive load carrying without any apparent mechanically determined tricks. Hauling loads roughly equivalent to body mass up 8000 m and down 6300 m in about a week is, by Western standards...

...Giovanni A. Cavagna; Mario A. Legramandi ABSTRACT A long-lasting challenge in comparative physiology is to understand why the efficiency of the mechanical work done to maintain locomotion increases with body mass. It has been suggested that this is due to a more elastic step in larger animals. Here...

.... prepared and edited the manuscript. Competing interests The authors declare no competing financial interests. 6 12 2013 16 6 2014 © 2014. Published by The Company of Biologists Ltd 2014 Achilles tendon strain Muscle fiber Muscle force Human gait Sprinting Efficiency...

... and funnel aperture in a theoretical model of jet propulsion scaled from the smallest (1 mm mantle length) to the largest (3 m) squid. Aperture reduction during mantle contraction increases propulsive efficiency at all squid sizes, although 1 mm squid still suffer from low efficiency (20%) because...

... for prolonged periods at a range of speeds without compromising energetic efficiency. The fascicles of both muscles exhibited rather ‘isometric’ behaviour during the early to mid stance phase of walking, which appears to be independent of walking speed or movement efficiency. However, several functional...

...Frank E. Nelson; Justus D. Ortega; Sharon A. Jubrias; Kevin E. Conley; Martin J. Kushmerick Summary Can human muscle be highly efficient in vivo ? Animal muscles typically show contraction-coupling efficiencies <50% in vitro but a recent study reports that the human first dorsal interosseous...

...Charlotte R. Morris; Frank E. Nelson; Graham N. Askew SUMMARY Little is known about how in vivo muscle efficiency, that is the ratio of mechanical and metabolic power, is affected by changes in locomotory tasks. One of the main problems with determining in vivo muscle efficiency is the large number...

...Graham N. Askew; Richard T. Tregear; Charles P. Ellington SUMMARY For all types of locomotion, the overall efficiency with which chemical energy is converted into mechanical work increases with increasing body size. In order to gain insight into the determinants of the scaling of overall efficiency...

...G. A. Lichtwark; C. J. Barclay SUMMARY Muscle power output and efficiency during cyclical contractions are influenced by the timing and duration of stimulation of the muscle and the interaction of the muscle with its mechanical environment. It has been suggested that tendon compliance may reduce...

...: these corresponded to decreases in the efficiency and changes in coordination. Increases in power were achieved that were not matched by equivalent increases in EMG intensity, but did occur with changes in coordination. It is proposed that the power output from the limb is limited by the coordination pattern...

... consistent with slower, more fatigue-resistant muscles. We hypothesized that these changes may accompany enhanced efficiency of contraction, perhaps in support of the enhanced capacity for endurance running. To assess efficiency, we measured work and associated oxygen consumption from isolated soleus...

... kg –1 at 0.8 L * and–0.70±0.12 W kg –1 at 1.4 L * ). For every 1 J of exoskeleton positive mechanical work subjects saved 0.72 J of metabolic energy (`apparent efficiency'=1.39) at 0.8 L * and 2.6 J of metabolic energy (`apparent efficiency'=0.38) at 1.4 L * . Declining ankle muscle–tendon `apparent...

... <0.0008). The `apparent efficiency' of ankle muscle–tendon mechanical work decreased from 0.53 on level ground to 0.38 on 15% grade. This suggests a decreased contribution from previously stored Achilles' tendon elastic energy and an increased contribution from actively shortening ankle plantar flexor...

...) during unpowered walking. Decreases in total joint positive mechanical power due to powered ankle assistance (∼22%) were not proportional to reductions in net metabolic power (∼10%). The `apparent efficiency' of the ankle joint muscle–tendon system during human walking (∼0.61) was much greater than...

...Z. Jane Wang SUMMARY To seek the simplest efficient flapping wing motions and understand their relation to steady flight, a two-stroke model in the quasi-steady limit was analyzed. It was found that a family of two-stroke flapping motions have aerodynamic efficiency close to, but slightly lower...