scholarly journals Elastic energy storage across speeds during steady-state hopping of desert kangaroo rats (Dipodomys deserti)

2022 ◽  
Author(s):  
Brooke A. Christensen ◽  
David C. Lin ◽  
M. Janneke Schwaner ◽  
Craig P. McGowan
Keyword(s):  
Energy Storage ◽  
Elastic Energy ◽  
Kangaroo Rats ◽  
Storage Mechanism ◽  
Extensor Tendons ◽  
Tendon Thickness ◽  
Recent Species ◽  
Specific Material ◽  
Species Specific

Small bipedal hoppers, including kangaroo rats, are thought to not benefit from substantial elastic energy storage and return during hopping. However, recent species-specific material properties research suggests that, despite relative thickness, the ankle extensor tendons of these small hoppers are considerably more compliant than had been assumed. With faster locomotor speeds demanding higher forces, a lower tendon stiffness suggests greater tendon deformation and thus a greater potential for elastic energy storage and return with increasing speed. Using the elastic modulus values specific to kangaroo rat tendons, we sought to determine how much elastic energy is stored and returned during hopping across a range of speeds. In vivo techniques were used to record tendon force in the ankle extensors during steady-speed hopping. Our data support the hypothesis that the ankle extensor tendons of kangaroo rats store and return elastic energy in relation to hopping speed, storing more at faster speeds. Despite storing comparatively less elastic energy than larger hoppers, this relationship between speed and energy storage offer novel evidence of a functionally similar energy storage mechanism, operating irrespective of body size or tendon thickness, across the distal muscle-tendon units of both small and large bipedal hoppers.

Elastic energy storage in tendons: mechanical differences related to function and age

1990 ◽  
Vol 68 (3) ◽  
pp. 1033-1040 ◽  
Author(s):  
R. E. Shadwick
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Energy Storage ◽  
Elastic Energy ◽  
Storage Element ◽  
Extensor Tendons ◽  
Growth And Aging ◽  
And Function

We investigated the possibility that tendons that normally experience relatively high stresses and function as springs during locomotion, such as digital flexors, might develop different mechanical properties from those that experience only relatively low stresses, such as digital extensors. At birth the digital flexor and extensor tendons of pigs have identical mechanical properties, exhibiting higher extensibility and mechanical hysteresis and lower elastic modulus, tensile strength, and elastic energy storage capability than adult tendons. With growth and aging these tendons become much stronger, stiffer, less extensible, and more resilient than at birth. Furthermore, these alterations in elastic properties occur to a significantly greater degree in the high-load-bearing flexors than in the low-stress extensors. At maturity the pig digital flexor tendons have twice the tensile strength and elastic modulus but only half the strain energy dissipation of the corresponding extensor tendons. A morphometric analysis of the digital muscles provides an estimate of maximal in vivo tendon stresses and suggests that the muscle-tendon unit of the digital flexor is designed to function as an elastic energy storage element whereas that of the digital extensor is not. Thus the differences in material properties between mature flexor and extensor tendons are correlated with their physiological functions, i.e., the flexor is much better suited to act as an effective biological spring than is the extensor.

Deactivation rate and shortening velocity as determinants of contractile frequency

1990 ◽  
Vol 259 (2) ◽  
pp. R223-R230 ◽  
Author(s):  
R. L. Marsh
Keyword(s):  
Energy Storage ◽  
Elastic Energy ◽  
High Speed ◽  
Adductor Muscle ◽  
Stride Frequency ◽  
Kinetic Properties ◽  
Shortening Velocity ◽  
Thermal Dependence ◽  
Jet Propulsion

The kinetic properties of muscle that could influence locomotor frequency include rate of activation, rate of cross-bridge "attachment", intrinsic shortening velocity, and rate of deactivation. The latter two mechanisms are examined using examples from high-speed running in lizards and escape swimming in scallops. During running, inertial loading and elastic energy storage probably mitigate the effects of thermal alterations in intrinsic muscle shortening velocity. The result is a rather low thermal dependence of stride frequency over a 15-20 degree C temperature range. However, at lower temperatures, the longer times required for deactivation cause the thermal dependence of frequency to increase greatly. Scallops use a single muscle to swim by jet propulsion. In vivo shortening velocity in these animals also shows a low thermal dependence. As with high-speed running, the mechanics of jet propulsion may limit the effects of thermally induced changes in intrinsic shortening velocity. The largest thermal effect during swimming is on the initial phase of valve opening. The effects of temperature on the rate of deactivation of the adductor muscle could play an important role in limiting reextension of the muscle, which is dependent on elastic energy storage in the hinge ligament. These examples illustrate that the relative importance of various intrinsic contractile properties in controlling locomotor performance depends on the mechanics of the movements.

scholarly journals Evidence of a tunable biological spring: elastic energy storage in aponeuroses varies with transverse strain in vivo

2019 ◽  
Vol 286 (1900) ◽  
pp. 20182764 ◽  
Author(s):  
Christopher J. Arellano ◽  
Nicolai Konow ◽  
Nicholas J. Gidmark ◽  
Thomas J. Roberts
Keyword(s):  
Energy Storage ◽  
Mechanical Behaviour ◽  
Elastic Energy ◽  
Biaxial Loading ◽  
Longitudinal Direction ◽  
General Assumption ◽  
Transverse Strain ◽  
Longitudinal Stiffness

Tendinous structures are generally thought of as biological springs that operate with a fixed stiffness, yet recent observations on the mechanical behaviour of aponeuroses (broad, sheet-like tendons) have challenged this general assumption. During in situ contractions, aponeuroses undergo changes in both length and width and changes in aponeuroses width can drive changes in longitudinal stiffness. Here, we explore if changes in aponeuroses width can modulate elastic energy (EE) storage in the longitudinal direction. We tested this idea in vivo by quantifying muscle and aponeuroses mechanical behaviour in the turkey lateral gastrocnemius during landing and jumping, activities that require rapid rates of energy dissipation and generation, respectively. We discovered that when aponeurosis width increased (as opposed to decreased), apparent longitudinal stiffness was 34% higher and the capacity of aponeuroses to store EE when stretched in the longitudinal direction was 15% lower. These data reveal that biaxial loading of aponeuroses allows for variation in tendon stiffness and energy storage for different locomotor behaviours.

Allometry of muscle, tendon, and elastic energy storage capacity in mammals

1994 ◽  
Vol 266 (3) ◽  
pp. R1022-R1031 ◽  
Author(s):  
C. M. Pollock ◽  
R. E. Shadwick
Keyword(s):  
Energy Storage ◽  
Body Mass ◽  
Elastic Energy ◽  
Strain Energy ◽  
Elastic Strain Energy ◽  
Large Mammals ◽  
Cross Sectional ◽  
Positive Allometry ◽  
Mass Exponents

This paper considers the structural properties of muscle-tendon units in the hindlimbs of mammals as a function of body mass. Morphometric analysis of the ankle extensors, digital flexors, and digital extensors from 35 quadrupedal species, ranging in body mass from 0.04 to 545 kg, was carried out. Tendon dimensions scale nearly isometrically, as does muscle mass. The negative allometry of muscle fiber length results in positive allometric scaling of muscle cross-sectional areas in all but digital extensors. Maximum muscle forces are predicted to increase allometrically, with mass exponents as high as 0.91 in the plantaris, but nearly isometrically (0.69) in the digital extensors. Thus the maximum amount of stress a tendon may experience in vivo, as indicated by the ratio of muscle and tendon cross-sectional areas, increases with body mass in digital flexors and ankle extensors. Consequently, the capacity for elastic energy storage scales with positive allometry in these tendons but is isometric in the digital extensors, which probably do not function as springs in normal locomotion. These results suggest that the springlike tendons of large mammals can potentially store more elastic strain energy than those of smaller mammals because their disproportionately stronger muscles can impose higher tendon stresses.

scholarly journals Scaling of elastic energy storage in mammalian limb tendons: do small mammals really lose out?

2005 ◽  
Vol 1 (1) ◽  
pp. 57-59 ◽  
Author(s):  
Sharon R Bullimore ◽  
Jeremy F Burn
Keyword(s):  
Energy Storage ◽  
Body Mass ◽  
Elastic Energy ◽  
Storage Capacity ◽  
Mechanical Work ◽  
Kangaroo Rats ◽  
Percentage Contribution ◽  
Scaling Relationships ◽  
Kangaroo Rat ◽  
Energy Storage Capacity

It is widely believed that elastic energy storage is more important in the locomotion of larger mammals. This is based on: (a) comparison of kangaroos with the smaller kangaroo rat; and (b) calculations that predict that the capacity for elastic energy storage relative to body mass increases with size. Here we argue that: (i) data from kangaroos and kangaroo rats cannot be generalized to other mammals; (ii) the elastic energy storage capacity relative to body mass is not indicative of the importance of elastic energy to an animal; and (iii) the contribution of elastic energy to the mechanical work of locomotion will not increase as rapidly with size as the mass-specific energy storage capacity, because larger mammals must do relatively more mechanical work per stride. We predict how the ratio of elastic energy storage to mechanical work will change with size in quadrupedal mammals by combining empirical scaling relationships from the literature. The results suggest that the percentage contribution of elastic energy to the mechanical work of locomotion decreases with size, so that elastic energy is more important in the locomotion of smaller mammals. This now needs to be tested experimentally.

Elastic energy storage in the hopping of kangaroo rats (Dipodomys spectabilis)

2009 ◽  
Vol 195 (3) ◽  
pp. 369-383 ◽  
Author(s):  
A. Biewener ◽  
R. McN. Alexander ◽  
N. C. Heglund
Keyword(s):  
Energy Storage ◽  
Elastic Energy ◽  
Kangaroo Rats ◽  
Dipodomys Spectabilis

Elastic energy storage in rigored skeletal muscle cells under physiological loading conditions

1986 ◽  
Vol 250 (1) ◽  
pp. R56-R64 ◽  
Author(s):  
J. G. Tidball ◽  
T. L. Daniel
Keyword(s):  
Skeletal Muscle ◽  
Energy Storage ◽  
Elastic Energy ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Electron Microscopic ◽  
Physiological Range ◽  
Parallel Structures ◽  
Oriented Parallel

The capability of heavy meromyosin (HMM) to store energy in reversible deformations has been investigated previously; yet, whether HMM is the site of most elastic energy storage in skeletal muscle cells has not been established. We conducted dynamic loading tests on single rigored muscle cells over the physiological range of sarcomere lengths. These tests enabled us to calculate the energy stored in reversible deformations or dissipated in the cell during each cycle of oscillation. Our findings show that these cells are capable of storing approximately 0.5 J . kg-1 of elastic energy during the last 50 ms of passive extension in vivo by agonists and before their own active contraction. Possible sites of this energy storage are HMM subunit 2, the proximal portion of HMM subunit 1, and parallel structures. However, energy storage increases monotonically as myofilament overlap decreases in the physiological range. This negative correlation suggests that HMM subunits are not the primary sites of elastic energy storage. Our electron-microscopic observations show that collagen fibrils at the cell's surface become oriented parallel to the cell's long axis over the range of sarcomere lengths where energy storage increases. This provides a mechanism for the observed increases in elastic energy storage.

scholarly journals In vivo muscle force and elastic energy storage during steady-speed hopping of tammar wallabies (Macropus eugenii)

1995 ◽  
Vol 198 (9) ◽  
pp. 1829-1841 ◽  
Author(s):  
A Biewener ◽  
R Baudinette
Keyword(s):  
Energy Storage ◽  
Elastic Energy ◽  
Energy Recovery ◽  
High Speed ◽  
Muscle Activation ◽  
Metabolic Energy ◽  
Flexor Digitorum Longus ◽  
Foot Placement ◽  
Flexor Digitorum

In order to evaluate the role of elastic energy recovery in the hopping of macropodids, in vivo measurements of muscle­tendon forces using buckle force transducers attached to the tendons of the gastrocnemius (G), plantaris (PL) and flexor digitorum longus (FDL) of tammar wallabies were made as the animals hopped on a treadmill at speeds ranging from 2.1 to 6.3 m s-1. These muscles and tendons constitute the main structures that are most important in energy storage and recovery. Electromyographic recordings from the lateral gastrocnemius and plantaris muscles, together with high-speed films (200 frames s-1) and video (60 fields s-1), were also used to correlate muscle activation and kinematic patterns of limb movement with force development. On the basis of in situ calibrations of the buckle transducers, we found that muscle forces and elastic energy storage increased with increased hopping speed in all three muscle­tendon units. Elastic energy recovery reached a maximum of 25 % of metabolic energy expenditure at 6.3 m s-1 and is probably greater than this at higher speeds. Force sharing among the three muscles was consistently maintained over this range of speeds in terms of recruitment. Although forces and stresses were generally comparable within the gastrocnemius and plantaris muscles, maximal tendon stresses were considerably greater in the gastrocnemius, because of its smaller cross-sectional area (peak muscle stress: 227 versus 262 kPa; peak tendon stress: 36 versus 32 MPa, G versus PL). As a result, energy storage was greatest in the gastrocnemius tendon despite its much shorter length, which limits its volume and, hence, energy storage capacity, compared with PL and FDL tendons. Forces and stresses (17 MPa maximum) developed within the FDL tendon were consistently much lower than those for the other two tendons. Peak stresses in these three tendons indicated safety factors of 3.0 for G, 3.3 for PL and 6.0 for FDL. The lower stresses developed within the tendons of the plantaris and, especially, the flexor digitorum longus may indicate the need to maintain sufficient stiffness for phalangeal control of foot placement, at the expense of reduced strain energy recovery.

Jumping, Climbing and Suspensory Locomotion

2018 ◽  
Keyword(s):  
Energy Storage ◽  
Elastic Energy ◽  
The Core ◽  
Power Amplification ◽  
Core Concepts

Jumping, climbing and suspensory locomotion are specialized locomotor mechanisms used on land and in the air. Jumping is used for rapid launches from substrates. Climbing and suspensory movements enable locomotion up, under and through vertically-structured habitats, such as forests. Elastic energy storage is particularly important for jumping and catapult systems and we address the core concepts of power amplification that are exemplified in nature’s extreme jumpers. We examine the diverse mechanisms of attachment that characterize animals that can grasp and adhere to a diversity of structures. We conclude the chapter by examining the integration of biological capabilities with engineering innovations in these systems.

scholarly journals Sequence Comparison of Vaginolysin from Different Gardnerella Species

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 86
Author(s):  
Erin M. Garcia ◽  
Myrna G. Serrano ◽  
Laahirie Edupuganti ◽  
David J. Edwards ◽  
Gregory A. Buck ◽  
...  
Keyword(s):  
Amino Acid ◽  
Human Microbiome ◽  
Human Microbiome Project ◽  
Distinct Species ◽  
Vaginal Swab ◽  
Metagenomic Data ◽  
Gardnerella Vaginalis ◽  
Vaginal Epithelial Cells ◽  
Species Specific

Gardnerella vaginalis has recently been split into 13 distinct species. In this study, we tested the hypotheses that species-specific variations in the vaginolysin (VLY) amino acid sequence could influence the interaction between the toxin and vaginal epithelial cells and that VLY variation may be one factor that distinguishes less virulent or commensal strains from more virulent strains. This was assessed by bioinformatic analyses of publicly available Gardnerella spp. sequences and quantification of cytotoxicity and cytokine production from purified, recombinantly produced versions of VLY. After identifying conserved differences that could distinguish distinct VLY types, we analyzed metagenomic data from a cohort of female subjects from the Vaginal Human Microbiome Project to investigate whether these different VLY types exhibited any significant associations with symptoms or Gardnerella spp.-relative abundance in vaginal swab samples. While Type 1 VLY was most prevalent among the subjects and may be associated with increased reports of symptoms, subjects with Type 2 VLY dominant profiles exhibited increased relative Gardnerella spp. abundance. Our findings suggest that amino acid differences alter the interaction of VLY with vaginal keratinocytes, which may potentiate differences in bacterial vaginosis (BV) immunopathology in vivo.

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