... at three sinusoidal frequencies. Flight kinematics were recorded, together with landing forces and pitch torque via a perch-mounted sensor. In support of our hypothesis for stable landings, lovebirds timed half their landings (51.3%) when the perch was approaching either extreme of motion near zero...

... understanding of the relative contributions of these different structures remains incomplete. We aimed to determine the distinct toe-flexion torque–angle relationships of the plantar intrinsic muscles (PIMs), extrinsic muscles and passive structures, therefore offering insight into their force-generating...

...Sharn P. Shelley; Rob S. James; Jason Tallis ABSTRACT Force–length relationships derived from isometric activations may not directly apply to muscle force production during dynamic contractions. As such, different muscle starting lengths between isometric and dynamic conditions could be required...

... reorganization, there is a lack of data on the force profiles of human climbers. This study utilized high-speed videography and force plate analysis to assess single limb forces during climbing from 44 human participants of varying climbing experience and compared these data with climbing data from eight species...

... in response to long-term temperature changes; other anthropogenic environmental changes, including pollutants, might also alter animal tissue mechanics, locomotor performance and behaviour. Climate Force Muscle Pollution Power Temperature Global temperatures are forecast to continue...

...Sharn P. Shelley; Rob S. James; Steven J. Eustace; Emma Eyre; Jason Tallis ABSTRACT This study examined the effect of stimulation frequency (140, 200, 230 and 260 Hz) on isometric force, work loop (WL) power and the fatigue resistance of extensor digitorum longus (EDL) muscle ( n =32), isolated...

... muscle. Four-week-old female CD-1 mice were randomly selected to consume either a standard laboratory diet or a standard laboratory diet in conjunction with a HFD for 20 weeks. Peripheral soleus and core diaphragm were isolated from each animal and maximal isometric force and work loop power were...

... by the force at the onset of the perturbation. This relationship holds across different frequencies and timings of stimulation. This history dependence behaves like a viscoelastic memory producing perturbation responses that vary with the frequency of the underlying movement. Fig. 7. A three-parameter...

... of measuring kinetics and kinematics of animals moving within a medium. We describe a new system for measuring 3D reaction forces during burrowing, called a ‘tunnel-tube’, which is composed of two, separately instrumented plastic tubes: an ‘entry tube’ with no medium, in series with a ‘digging tube’ filled...

...Zoe T. Self Davies; Andrew J. Spence; Alan M. Wilson ABSTRACT The horse has evolved to gallop economically at high speed. Limb force increases with speed but direct measures of limb ground reaction forces (GRFs) at gallop are sparse. This study reports GRFs for multiple limbs, using force plates...

... that drive variation in self-righting performance. To evaluate the mechanical factors that contribute to success versus failure when animals attempt to self-right, we compared force production and kinematic behavior in the rigid-bodied, pleurodire turtle Emydura subglobosa between successful and unsuccessful...

... force and power produced by increasing the demand on weight-supporting muscle. However, when normalised to body mass, muscle performance of obese individuals is reduced. Isolated muscle preparations show that obesity often leads to a decrease in force produced per muscle cross-sectional area, and power...

... pressure during vertical locomotion and PTI during suspension were significantly higher for the palm compared with those for the fingers. When considering differences in contact area between the palm and fingers ( Figs 3 and 6 ), this result suggests comparatively greater normal force being exerted...

...Anne K. Gutmann; John E. A. Bertram ABSTRACT To interpret the movement strategies employed in locomotion, it is necessary to understand the source of metabolic cost. Muscles must consume metabolic energy to do work, but also must consume energy to generate force. The energy lost during steady...

... predators on other constrictors remain unknown. To begin addressing these mechanisms, we studied the scaling of muscle cross-sectional area, pulling force and constriction pressure across the ontogeny of six species of snakes ( Lampropeltis californiae , L. getula , L. holbrooki , Pantherophis...

... but not sprint performance in carp ( Cyprinus carpio ). We accept our hypothesis that hypothyroidism reduces force production in isolated skeletal muscle, when compared with the thyroid hormone T 2 , but we reject the hypothesis that this effect is mediated by influencing SERCA activity. Blocking SERCA activity...

... (force per muscle cross-sectional area) and maximal work loop power output (normalised to muscle mass) all significantly increased with greater SVL. In contrast, fatigue resistance during repeated work loops significantly decreased with SVL and there was no effect of size on tetanus activation time. When...

... well the contractile properties of skinned fibres reflect the properties of the muscle fibres in vivo . Here, we compare the mechanical performance of intact fibre bundles and skinned fibres from muscle of the same animals. This is the first such direct comparison. Maximum power and isometric force...

...Joseph E. Rupert; Jacob A. Rose; Jason M. Organ; Michael T. Butcher Scratch-digging mammals are commonly described as having large, powerful forelimb muscles for applying high force to excavate earth, yet studies quantifying the architectural properties of the musculature are largely unavailable...

... avoiding the cyclic absorption and regeneration of mechanical energy by active muscle, offers some metabolic energy savings during running. However, this assumption has not been tested directly. We used muscle ergometry and myothermic measurements to determine the cost of force production in muscles acting...