Effect of stretching on the elastic characteristics and the contractile component of frog striated muscle

Cavagna, G; Citterio, G.

doi:10.1113/jphysiol.1974.sp010552

Cited by 148 publications

(74 citation statements)

References 6 publications

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“…The enhancement in mechanical performance has been known to occur by stretching an active muscle despite a decrease in the amount of overlap between the filaments; stretched active muscles can generate isometric tension higher than the normal tension at the same muscle length (Fenn, 1924;Abbot & Aubert, 1952;Deleze, 1961;Sugi, 1972) and can shorten for some distance against a load above PO (Cavagna & Citterio, 1974;Cavagna, Citterio & Jacini, 1975). Using single fibres, Edman, Elizinga & Noble (1978) showed a shift of the force-velocity curve towards higher force values with no significant change in Vmax in fibres stretched during isometric tetanus.…”

Section: Discussionmentioning

confidence: 99%

Enhancement of mechanical performance in frog muscle fibres after quick increases in load.

Sugi¹,

Tsuchiya²

1981

The Journal of Physiology

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SUMMARY1. The change in the ability of frog skeletal muscle fibres to sustain a load was studied during the course of oscillatory length changes or continuous isotonic lengthening following quick increases in load, by applying 'test' load steps and measuring the initial velocity of resulting isotonic motion.2. When quick decreases in load were applied during oscillatory length changes or continuous isotonic lengthening, the fibres were found to shorten against a load above the maximum tension (P0), indicating an increase in load-sustaining ability after quick increases in load.3. If quick increases in load were applied at various times after preceding quick increase in load, the initial velocity of resulting isotonic lengthening decreased with time, also indicating an increase in load-sustaining ability.4. An increase in load-sustaining ability was also observed during the course of rapid isotonic lengthening under a load of 1-6-1-7 P0, in which the fibres lengthened with increasing velocity.5. The increase in load-sustaining ability after quick increases in load was associated with a shift of the force-velocity curve towards higher force values, while no significant change was observed in the maximum shortening velocity at zero load.6. The stiffness of muscle fibres was estimated by measuring quick length changes coincident with load steps. It decreased with decreasing isotonic load below P0, approaching a certain finite value as the load tended to zero. For isotonic loads above P0, the stiffness increased with increasing isotonic load up to 1-6-1'7 P0, when step decreases in load were used for stiffness measurements.7. The mechanism of enhancement of mechanical performance of the fibres after quick increases in load is discussed in relation to the sliding filament/cross bridge hypotheses of muscle contraction.

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Section: Discussionmentioning

confidence: 99%

Enhancement of mechanical performance in frog muscle fibres after quick increases in load.

Sugi¹,

Tsuchiya²

1981

The Journal of Physiology

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“…Maximum isometric stresses of reptilian limb muscle are generally over 200·kPa (John-Alder and Bennett, 1987;Marsh, 1988), though muscle stresses can be as much as 80% greater than maximum isometric stress during lengthening contractions (Cavagna and Citterio, 1974;Flitney and Hirst, 1978). Because the knee flexes in the first half of the contact interval (Fig.·2), eccentric contraction of the knee extensors is likely.…”

Section: Appendixmentioning

confidence: 99%

Mechanics of limb bone loading during terrestrial locomotion in river cooter turtles (Pseudemys concinna)

Butcher

Blob

2008

Journal of Experimental Biology

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SUMMARY Studies of limb bone loading during terrestrial locomotion have focused primarily on birds and mammals. However, data from a broader functional and phylogenetic range of species are critical for understanding the evolution of limb bone function and design. Turtles are an interesting lineage in this context. Although their slow walking speeds and robust limb bones might lead to low locomotor forces and limb bone stresses similar to other non-avian reptiles, their highly sprawled posture could produce high bending loads,leading to high limb bone stresses similar to those of avian and mammalian species, as well as high torsion. To test between these possibilities, we evaluated stresses experienced by the femur of river cooter turtles(Pseudemys concinna) during terrestrial walking by synchronizing measurements of three-dimensional joint kinematics and ground reaction forces(GRFs) during isolated hindlimb footfalls. Further, we evaluated femoral safety factors for this species by comparing our locomotor stress calculations with the results of mechanical property tests. The net GRF magnitude at peak tensile bone stress averaged 0.35 BW (body weight) and was directed nearly vertically for the middle 40–65% of the contact interval, essentially orthogonal to the femur. Peak bending stresses experienced by the femur were low (tensile: 24.9±9.0 MPa; compressive: –31.1±9.1 MPa)and comparable to those in other reptiles, yet peak shear stresses were higher than those in other reptiles, averaging 13.7±4.2 MPa. Such high torsion is present despite cooters lacking a large tail, a feature that has been hypothesized to contribute to torsion in other reptiles in which the tail is dragged along the ground. Comparison of femoral stresses to measurements of limb bone mechanical properties in cooters indicates safety factors to yield of 13.9 in bending and 6.3 in torsion, considerably higher than values typical for birds and mammals, and closer to the elevated values calculated for other reptile species. Thus, not only do turtle limb bones seem considerably`over-designed' for resisting the loads that they encounter, but comparisons of bone loading across tetrapod lineages are consistent with the hypothesis that low limb bone loads, elevated torsion and high safety factors may be primitive features of limb bone design.

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“…Evidence of an enhancement of positive work production induced by previous stretching of muscletendon units was found both on human running [19], on living animals during running, hopping and trotting [20][21][22] and on man's forearm flexors and isolated specimens in controlled laboratory conditions [23][24][25][26][27] (Figure 5). Figure 5.…”

Section: The Stretch-shorten Cycle Of Muscle-tendon Unitsmentioning

confidence: 99%

Symmetry and Asymmetry in Bouncing Gaits

Cavagna

2010

Symmetry

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Abstract:In running, hopping and trotting gaits, the center of mass of the body oscillates each step below and above an equilibrium position where the vertical force on the ground equals body weight. In trotting and low speed human running, the average vertical acceleration of the center of mass during the lower part of the oscillation equals that of the upper part, the duration of the lower part equals that of the upper part and the step frequency equals the resonant frequency of the bouncing system: we define this as on-offground symmetric rebound. In hopping and high speed human running, the average vertical acceleration of the center of mass during the lower part of the oscillation exceeds that of the upper part, the duration of the upper part exceeds that of the lower part and the step frequency is lower than the resonant frequency of the bouncing system: we define this as on-off-ground asymmetric rebound. Here we examine the physical and physiological constraints resulting in this on-off-ground symmetry and asymmetry of the rebound. Furthermore, the average force exerted during the brake when the body decelerates downwards and forwards is greater than that exerted during the push when the body is reaccelerated upwards and forwards. This landing-takeoff asymmetry, which would be nil in the elastic rebound of the symmetric spring-mass model for running and hopping, suggests a less efficient elastic energy storage and recovery during the bouncing step. During hopping, running and trotting the landing-takeoff asymmetry and the mass-specific vertical stiffness are smaller in larger animals than in the smaller animals suggesting a more efficient rebound in larger animals.

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Effect of stretching on the elastic characteristics and the contractile component of frog striated muscle

Cited by 148 publications

References 6 publications

Enhancement of mechanical performance in frog muscle fibres after quick increases in load.

Enhancement of mechanical performance in frog muscle fibres after quick increases in load.

Mechanics of limb bone loading during terrestrial locomotion in river cooter turtles (Pseudemys concinna)

Symmetry and Asymmetry in Bouncing Gaits

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