... ultrasound imaging with joint-level perturbations to quantify ankle, muscle and tendon impedance simultaneously across activation levels from 0% to 30% of maximum voluntary contraction. We found that muscle and tendon stiffness, the static component of impedance, increased with voluntary plantarflexion...

... of these interactions and how they give rise to fish swimming was carried out more than 20 years ago. In this Review, we summarize work on passive and active body mechanics in fish, physical models of fish and bioinspired robots. We also revisit some of the first studies to explore flexural stiffness and discuss...

... , Tribolonotus novaeguineae , Heloderma horridum and Heloderma suspectum ). Based on the strain recorded in situ and from isolated osteoderms, the skin of the species investigated can be ranked along a marked stiffness gradient that mostly reflects the features of the osteoderms. Some species such as T. rugosa...

...Eman Y. Merza; Stephen J. Pearson; Glen A. Lichtwark; Peter Malliaras ABSTRACT The Achilles tendon (AT) exhibits volume changes related to fluid flow under acute load which may be linked to changes in stiffness. Fluid flow provides a mechanical signal for cellular activity and may be one mechanism...

... of the current range bone strength and elasticity properties for vertebrates. Bending Bradypus Choloepus Compression Elasticity Strength Stiffness National Science Foundation http://dx.doi.org/10.13039/100000001 MRI-0959438 Long bones in limbs of vertebrates are composed...

... is crucial in kinetic spring–mass analyses of running, where approximation of a runner's impact angle and calculation of leg stiffness require that input. Here, a new method is presented to approximate a runner's stance velocity via measurement of contact and flight times with the runner's average speed, leg...

... derived and validated a time-dependent vGRF function characterized by four spring–mass parameters – stiffness, touchdown angle, leg length and contact time – using a sinusoidal approximation. Next, we compared the NLR-estimated spring–mass parameters with traditional calculations in runners. The mixed...

..., we analysed the structure, mineral content and compressive stiffness of secondary bone from the cranial and caudal cortices of the white-tailed deer proximal humerus. We found significantly larger Haversian systems and canals in the cranial cortex but no significant difference in mineral content...

... the spines of P. volitans to determine mechanical properties (Young's modulus, elastic energy storage and flexural stiffness). The short and recurved anal and pelvic spines are stiffer and resist bending more effectively than the long dorsal spines. In addition, mechanical properties differ along the length...

...-radiographed to measure double cone proportion and apex angles, and were mechanically tested at three displacement rates to 4% strain. We determined the variation in toughness and stiffness of vertebral centra among shark species and ontogenetic stages, testing strain rates, and compared anterior and posterior...

... fringes, and low stiffness and high elasticity when wet; it likely bends in the closed mouth when not used for filtration. Calculation of flexural modulus from stress/strain experiments shows that the balaenid baleen is slightly more flexible where it emerges from the gums and at its ventral terminus...

... in response to hydrodynamic forces during swimming. Here, we developed an experimental setup to measure the elastic properties of caudal fins in vivo by applying micro-Newton forces to obtain bending stiffness and a tensional modulus. We detected overall bending moments of 1.5×10 −9 –4×10 −9 N m 2 along...

... the result of a compromise between the increasing slenderness of the tibia and its increasing material stiffness. The use of an optimal radius to thickness ratio, a soft resilin-dominated core, and chitin fibres oriented in both longitudinal and circumferential directions are presumably additional strategies...

... of the Achilles at all contraction levels (10%, 20% and 30% of MVC; P <0.01). Calculations showed that force on the proximal tendon portion was ∼60% lower, stress ∼70% lower, stiffness ∼30% lower and Poisson's ratio 6-fold higher compared with those for the distal portion of the Achilles tendon. These marked...

..., the ATP cost was measured during the last 30 s of isometric contractions using an enzyme-coupled assay. Stiffness was calculated during a quick stretch–release cycle of 0.2% fibre length performed once the steady state had been reached after active shortening and during the purely isometric reference...

...Deeksha Seth; Brooke E. Flammang; George V. Lauder; James L. Tangorra ABSTRACT Knowledge about the stiffness of fish fins, and whether stiffness is modulated during swimming, is important for understanding the mechanics of a fin's force production. However, the mechanical properties of fins have...

... variable power transmission. Elastic modulus Viscous modulus Stiffness Viscoelastic Mineralized cartilage Intervertebral joint capsule Among vertebrates, the vertebral column of sharks functions in a novel way: during swimming, both intervertebral joints and vertebral centra undergo...

... but crucial deletion in the titin protein. Myofibrils from normal and mdm mice were stretched from sarcomere lengths of 2.5 to 6.0 μm. Actively stretched myofibrils from normal mice were stiffer and generated more force than passively stretched myofibrils at all sarcomere lengths. No increase in stiffness...

...Alex M. Wilks; Sarah R. Rabice; Holland S. Garbacz; Cailin C. Harro; Andrew M. Smith ABSTRACT The terrestrial slug Arion subfuscus produces a defensive secretion that is sticky and tough, despite being a dilute gel. It is unusual in having high stiffness for a gel, yet retaining the high...

.... Oscillatory frequency is proportional to the square root of stiffness, and we observed that mutants had lower active muscle stiffness in vitro . The lower tremor frequencies in mutants are consistent with reduced active muscle stiffness and suggest that titin affects the tuning of shivering frequency. Much...