scholarly journals Energetic and physical limitations on the breaching performance of large whales

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Paolo S Segre ◽  
Jean Potvin ◽  
David E Cade ◽  
John Calambokidis ◽  
Jacopo Di Clemente ◽  
...  
Keyword(s):  
The Body ◽  
Muscle Performance ◽  
Energetic Cost ◽  
Honest Signaling ◽  
High Speeds ◽  
Vertebrate Muscle ◽  
Upper Limits ◽  
Physical Limitations ◽  
High Emergence ◽  
Muscle Contractile

The considerable power needed for large whales to leap out of the water may represent the single most expensive burst maneuver found in nature. However, the mechanics and energetic costs associated with the breaching behaviors of large whales remain poorly understood. In this study we deployed whale-borne tags to measure the kinematics of breaching to test the hypothesis that these spectacular aerial displays are metabolically expensive. We found that breaching whales use variable underwater trajectories, and that high-emergence breaches are faster and require more energy than predatory lunges. The most expensive breaches approach the upper limits of vertebrate muscle performance, and the energetic cost of breaching is high enough that repeated breaching events may serve as honest signaling of body condition. Furthermore, the confluence of muscle contractile properties, hydrodynamics, and the high speeds required likely impose an upper limit to the body size and effectiveness of breaching whales.

scholarly journals Serum betaine is inversely associated with low lean mass mainly in men in a Chinese middle-aged and elderly community-dwelling population

2016 ◽  
Vol 115 (12) ◽  
pp. 2181-2188 ◽  
Author(s):  
Bi-xia Huang ◽  
Ying-ying Zhu ◽  
Xu-ying Tan ◽  
Qiu-ye Lan ◽  
Chun-lei Li ◽  
...  
Keyword(s):  
Lean Mass ◽  
Community Dwelling ◽  
The Body ◽  
Muscle Performance ◽  
Whole Body ◽  
Composition Analysis ◽  
Human Beings ◽  
Middle Aged ◽  
Chinese Adults ◽  
Skeletal Muscle Index

AbstractPrevious studies have demonstrated that betaine supplements increase lean body mass in livestock and improve muscle performance in human beings, but evidence for its effect on human lean mass is limited. Our study assessed the association of circulating betaine with lean mass and its composition in Chinese adults. A community-based study was conducted on 1996 Guangzhou residents (weight/mass: 1381/615) aged 50–75 years between 2008 and 2010. An interviewer-administered questionnaire was used to collect general baseline information. Fasting serum betaine was assessed using HPLC-MS. A total of 1590 participants completed the body composition analysis performed using dual-energy X-ray absorptiometry during a mean of 3·2 years of follow-up. After adjustment for age, regression analyses demonstrated a positive association of serum betaine with percentage of lean mass (LM%) of the entire body, trunk and limbs in men (all P<0·05) and LM% of the trunk in women (P=0·016). Each sd increase in serum betaine was associated with increases in LM% of 0·609 (whole body), 0·811 (trunk), 0·422 (limbs), 0·632 (arms) and 0·346 (legs) in men and 0·350 (trunk) in women. Multiple logistic regression analysis revealed that the prevalence of lower LM% decreased by 17 % (whole body) and 14 % (trunk) in women and 23 % (whole body), 28 % (trunk), 22 % (arms) and 26 % (percentage skeletal muscle index) in men with each sd increment in serum betaine. Elevated circulating betaine was associated with a higher LM% and lower prevalence of lower LM% in middle-aged and elderly Chinese adults, particularly men.

scholarly journals Elastic energy savings and active energy cost in a simple model of running

2021 ◽  
Vol 17 (11) ◽  
pp. e1009608
Author(s):  
Ryan T. Schroeder ◽  
Arthur D. Kuo
Keyword(s):  
Elastic Energy ◽  
Energy Cost ◽  
Energy Savings ◽  
Mechanical Energy ◽  
Metabolic Cost ◽  
The Body ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
Mass Model ◽  
Human Running

The energetic economy of running benefits from tendon and other tissues that store and return elastic energy, thus saving muscles from costly mechanical work. The classic “Spring-mass” computational model successfully explains the forces, displacements and mechanical power of running, as the outcome of dynamical interactions between the body center of mass and a purely elastic spring for the leg. However, the Spring-mass model does not include active muscles and cannot explain the metabolic energy cost of running, whether on level ground or on a slope. Here we add explicit actuation and dissipation to the Spring-mass model, and show how they explain substantial active (and thus costly) work during human running, and much of the associated energetic cost. Dissipation is modeled as modest energy losses (5% of total mechanical energy for running at 3 m s-1) from hysteresis and foot-ground collisions, that must be restored by active work each step. Even with substantial elastic energy return (59% of positive work, comparable to empirical observations), the active work could account for most of the metabolic cost of human running (about 68%, assuming human-like muscle efficiency). We also introduce a previously unappreciated energetic cost for rapid production of force, that helps explain the relatively smooth ground reaction forces of running, and why muscles might also actively perform negative work. With both work and rapid force costs, the model reproduces the energetics of human running at a range of speeds on level ground and on slopes. Although elastic return is key to energy savings, there are still losses that require restorative muscle work, which can cost substantial energy during running.

Locomotion in Burrowing and Vagrant Wolf Spiders (Lycosidae)

1981 ◽  
Vol 92 (1) ◽  
pp. 305-321 ◽  
Author(s):  
T. M. WARD ◽  
W. F. HUMPHREYS
Keyword(s):  
Wolf Spider ◽  
The Body ◽  
Power Stroke ◽  
Phase Lag ◽  
Running Speed ◽  
Wolf Spiders ◽  
High Speeds ◽  
Phase Lags ◽  
The Relationship

Locomotion in the vagrant wolf spider Trochosa ruricola is compared to that in the burrow dwelling wolf spider Lycosa tarentula (Araneae: Lycosidae). L. tarentula takes relatively shorter steps than T. ruricola. At high speeds T. ruricola approximates an alternating tetrapod gait but this does not occur in L. tarentula. Phase lag differs between species and varies marginally with speed except for ipsilateral phase lags in L. tarentula which are erratic if they include leg 1. In both species the protraction/retraction ratio is directly related to both running speed and stepping frequency, but the relationship is more marked in L. tarentula. The protraction/retraction ratio is more variable in leg 1 and varies between legs along the body but by a greater amount in L. tarentula. In these spiders, in contrast to the situation in many insects, both the duration of protraction and retraction show marked inverse relationships to stepping frequency. The power stroke (retraction) occupies a variable proportion of the stepping cycle, which is not the case in other spiders, and this proportion is lower than for other spiders. It is suggested that the first pair of legs is used more for sensory than for locomotory purpose and that this is more marked in the burrow dwelling species, L. tarentula.

Fairy-Tale Bodies: Prostheses and Narrative Perspective in Dinah Mulock Craik’s The Little Lame Prince

2019 ◽  
pp. 139-160
Author(s):  
Kylee-Anne Hingston
Keyword(s):  
Fairy Tale ◽  
Physical Development ◽  
The Body ◽  
Physical Difference ◽  
Narrative Perspective ◽  
The Disabled ◽  
Physical Limitations ◽  
Infinite Variety

As a literary fairy tale, Dinah Mulock Craik’s The Little Lame Prince and His Travelling Cloak: A Parable for Young and Old (1874) employs a fantasy setting and magical circumstances to depict the moral, psychological, and physical development of its hero, Prince Dolor. The hybrid story combines fairy tale, Bildungsroman, and parable, defies conventional narrative closure, and produces incongruous understandings of disability. The story’s narrative trajectory moves towards closure, first reinforcing Dolor’s physical deviance and the eradicating it through magical prosthetic gifts; as such, the outer structure creates a story of disability as abnormal, restricting, and in need of compensation if not cure. However, by making readers aware first of the narrator’s physical limitations and of their own roles as spectators, and then by focalizing through the disabled hero while he is a spectator, The Little Lame Prince undermines its earlier use of Dolor as a sentimental spectacle. Moreover, moments in which readers focalize with Dolor through his magical prostheses reveal the limitations of all bodies and speculate on the beauty and infinite variety of physical difference. These colliding views of disability in The Little Lame Prince exhibit the complex, shifting role of the body in Victorian thought.

Fast Cars and Vital Exhaustion

2020 ◽  
pp. 171-214
Author(s):  
Sarah Waters
Keyword(s):  
Knowledge Economy ◽  
The Body ◽  
Research Centre ◽  
Vital Exhaustion ◽  
Physical Limitations ◽  
Art Research ◽  
Material Conditions ◽  
The Individual ◽  
The Mind ◽  
Conditions Of Work

Chapter five examines a series of suicides at car manufacturer Renault, situating them in the transition from an industrial model to a knowledge economy, in which value is expropriated from the resources of the mind. Suicides did not take place in the emblematic spaces of the factory, where cars were once mass produced, but in a state-of-the art research centre, where cognitive workers conceptualised and designed cutting-edge cars of the future. In the knowledge economy, the mind is treated as an endlessly productive resource that reproduces itself continuously and is unencumbered by the physical limitations of the body. I argue that suicides were the end point of a form of vital exhaustion that transcends the corporeal defences of the physical body and depletes the mental and emotional resources of the self. Suicides do not reflect a deterioration in formal or material conditions of work, but rather a transformation in forms of constraint, as the individual worker internalises modes of discipline and becomes his or her own boss. Suicides affected workers who experienced a phase of chronic overwork in which the quest to achieve productivity targets pushed them to work continuously and obsessively.

scholarly journals Sustained elevation of MG53 in the bloodstream increases tissue regenerative capacity without compromising metabolic function

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Zehua Bian ◽  
Qiang Wang ◽  
Xinyu Zhou ◽  
Tao Tan ◽  
Ki Ho Park ◽  
...  
Keyword(s):  
Blood Circulation ◽  
Tissue Injury ◽  
Eccentric Contraction ◽  
The Body ◽  
Muscle Performance ◽  
Membrane Repair ◽  
Injury Repair ◽  
Family Protein ◽  
Normal Glucose ◽  
Dermal Wound

Abstract MG53 is a muscle-specific TRIM-family protein that presides over the cell membrane repair response. Here, we show that MG53 present in blood circulation acts as a myokine to facilitate tissue injury-repair and regeneration. Transgenic mice with sustained elevation of MG53 in the bloodstream (tPA-MG53) have a healthier and longer life-span when compared with littermate wild type mice. The tPA-MG53 mice show normal glucose handling and insulin signaling in skeletal muscle, and sustained elevation of MG53 in the bloodstream does not have a deleterious impact on db/db mice. More importantly, the tPA-MG53 mice display remarkable dermal wound healing capacity, enhanced muscle performance, and improved injury-repair and regeneration. Recombinant human MG53 protein protects against eccentric contraction-induced acute and chronic muscle injury in mice. Our findings highlight the myokine function of MG53 in tissue protection and present MG53 as an attractive biological reagent for regenerative medicine without interference with glucose handling in the body.

scholarly journals The rising cost of warming waters: effects of temperature on the cost of swimming in fishes

2011 ◽  
Vol 8 (2) ◽  
pp. 266-269 ◽  
Author(s):  
Andrew M. Hein ◽  
Katrina J. Keirsted
Keyword(s):  
Water Temperature ◽  
Fish Species ◽  
Global Climate ◽  
Swimming Performance ◽  
Metabolic Cost ◽  
Quantitative Model ◽  
The Body ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
The Cost

Understanding the effects of water temperature on the swimming performance of fishes is central in understanding how fish species will respond to global climate change. Metabolic cost of transport (COT)—a measure of the energy required to swim a given distance—is a key performance parameter linked to many aspects of fish life history. We develop a quantitative model to predict the effect of water temperature on COT. The model facilitates comparisons among species that differ in body size by incorporating the body mass-dependence of COT. Data from 22 fish species support the temperature and mass dependencies of COT predicted by our model, and demonstrate that modest differences in water temperature can result in substantial differences in the energetic cost of swimming.

External work in walking

1963 ◽  
Vol 18 (1) ◽  
pp. 1-9 ◽  
Author(s):  
G. A. Cavagna ◽  
F. P. Saibene ◽  
R. Margaria
Keyword(s):  
Inertial Force ◽  
Center Of Gravity ◽  
The Body ◽  
External Work ◽  
High Speeds ◽  
Moving Body ◽  
Vertical Displacements ◽  
Lateral Displacements ◽  
Work Done ◽  
Static Contractions

From records obtained from a triple accelerometer applied to the trunk of a subject the displacements of the trunk in vertical, forward, and lateral directions have been calculated. With motion pictures taken simultaneously, displacements of the center of gravity within the body were measured. From these data the external mechanical work of walking was calculated. The sum of work for vertical and for forward displacements of the center of gravity of the body gives the total external work; energy for the lateral displacements was negligible. Total external work appears to be lower than that calculated from the vertical displacements alone, because work done in lifting is partly sustained by the inertial force of the forward-moving body. Total external work reaches a highest value (0.1 kcal/km kg) at the most economical speed of walking, 4 km/hr, which corresponds to an energy consumption of 0.48 kcal/km kg. At this speed the internal work appears negligible; it amounts to appreciable entities at very low speeds because of the static contractions of the muscles, and at high speeds because of considerable stiffening of the limbs and movements not involving a displacement of the center of gravity. Submitted on May 25, 1962

scholarly journals Sarcolipin overexpression improves muscle energetics and reduces fatigue

2015 ◽  
Vol 118 (8) ◽  
pp. 1050-1058 ◽  
Author(s):  
Danesh H. Sopariwala ◽  
Meghna Pant ◽  
Sana A. Shaikh ◽  
Sanjeewa A. Goonasekera ◽  
Jeffery D. Molkentin ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Performance ◽  
Force Frequency ◽  
Frequency Curve ◽  
Muscle Energetics ◽  
Store Operated Calcium Entry ◽  
Flexor Digitorum Brevis ◽  
Flexor Digitorum ◽  
Muscle Contractile ◽  
Frequency Curves

Sarcolipin (SLN) is a regulator of sarcoendoplasmic reticulum calcium ATPase in skeletal muscle. Recent studies using SLN-null mice have identified SLN as a key player in muscle thermogenesis and metabolism. In this study, we exploited a SLN overexpression ( Sln OE) mouse model to determine whether increased SLN level affected muscle contractile properties, exercise capacity/fatigue, and metabolic rate in whole animals and isolated muscle. We found that Sln OE mice are more resistant to fatigue and can run significantly longer distances than wild-type (WT). Studies with isolated extensor digitorum longus (EDL) muscles showed that Sln OE EDL produced higher twitch force than WT. The force-frequency curves were not different between WT and Sln OE EDLs, but at lower frequencies the pyruvate-induced potentiation of force was significantly higher in Sln OE EDL. SLN overexpression did not alter the twitch and force-frequency curve in isolated soleus muscle. However, during a 10-min fatigue protocol, both EDL and soleus from Sln OE mice fatigued significantly less than WT muscles. Interestingly, Sln OE muscles showed higher carnitine palmitoyl transferase-1 protein expression, which could enhance fatty acid metabolism. In addition, lactate dehydrogenase expression was higher in Sln OE EDL, suggesting increased glycolytic capacity. We also found an increase in store-operated calcium entry (SOCE) in isolated flexor digitorum brevis fibers of Sln OE compared with WT mice. These data allow us to conclude that increased SLN expression improves skeletal muscle performance during prolonged muscle activity by increasing SOCE and muscle energetics.

scholarly journals Muscular anatomy of the tail of the western grey kangaroo, Macropus fuliginosus

2014 ◽  
Vol 62 (2) ◽  
pp. 166 ◽  
Author(s):  
Rebekah Dawson ◽  
Nick Milne ◽  
Natalie M. Warburton
Keyword(s):  
Body Weight ◽  
The Body ◽  
Functional Roles ◽  
High Speeds ◽  
Hind Limbs ◽  
Grey Kangaroo ◽  
Western Grey Kangaroo ◽  
Low Speeds ◽  
Fifth Limb

The western grey kangaroo, Macropus fuliginosus, is a large-bodied kangaroo that engages in pentapedal locomotion at low speeds and bipedal hopping at high speeds. The tail is thought to have functional roles in both of these modes of locomotion. In pentapedal locomotion the tail acts as a ‘fifth limb’ to support the body weight together with the forelimbs while the hind limbs are drawn forward. The tail has also been suggested to have a role as a counterbalance during bipedal hopping. On the basis of these functional roles for the tail in locomotion, the caudal musculature of the western grey kangaroo was dissected and described in this study. The arrangement of the caudal musculature showed particular adaptations for the role of the tail in both pentapedal locomotion and bipedal hopping.

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