Neuromechanical simulation of the locust jump

Cofer, David W.; Cymbalyuk, Gennady; Heitler, W. J.; Edwards, Donald H.

doi:10.1242/jeb.034678

Cited by 36 publications

(37 citation statements)

References 26 publications

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“…We have demonstrated experimentally that passive joint forces can act in ranges of joint angles where neither active nor passive muscle forces would be effective in generating joint torque. The contributions of passive joint forces, and in particular the consequences of this decoupling from muscle moment arms, have been overlooked in most models of limb joint function, with the exception of [36]. Passive joint forces are likely to be unaffected by the patterns or history of limb muscle activation, or by neuromodulators.…”

Section: Discussionmentioning

confidence: 99%

Passive Joint Forces Are Tuned to Limb Use in Insects and Drive Movements without Motor Activity

Ache

Matheson

2013

Current Biology

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SummaryBackgroundLimb movements are generally driven by active muscular contractions working with and against passive forces arising in muscles and other structures. In relatively heavy limbs, the effects of gravity and inertia predominate, whereas in lighter limbs, passive forces intrinsic to the limb are of greater consequence. The roles of passive forces generated by muscles and tendons are well understood, but there has been little recognition that forces originating within joints themselves may also be important, and less still that these joint forces may be adapted through evolution to complement active muscle forces acting at the same joint.ResultsWe examined the roles of passive joint forces in insect legs with different arrangements of antagonist muscles. We first show that passive forces modify actively generated movements of a joint across its working range, and that they can be sufficiently strong to generate completely passive movements that are faster than active movements observed in natural behaviors. We further demonstrate that some of these forces originate within the joint itself. In legs of different species adapted to different uses (walking, jumping), these passive joint forces complement the balance of strength of the antagonist muscles acting on the joint. We show that passive joint forces are stronger where they assist the weaker of two antagonist muscles.ConclusionsIn limbs where the dictates of a key behavior produce asymmetry in muscle forces, passive joint forces can be coadapted to provide the balance needed for the effective generation of other behaviors.

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Section: Discussionmentioning

confidence: 99%

Passive Joint Forces Are Tuned to Limb Use in Insects and Drive Movements without Motor Activity

Ache

Matheson

2013

Current Biology

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“…From the data presented here it is not possible to differentiate between the hypotheses stated by Bennet-Clark and by Rothschild about the locking mechanisms for the leg joints. Bennet-Clark hypothesized that the joints were locked by the moment arm of the trochanteral depressor muscle going 'over centre', and thus the resilin 'spring' would act initially as a trochanteral levator [a similar mechanism has been proposed for the claw snap of an alpheid shrimp (Ritzmann, 1974) and for the femoro-tibial joint of the locust hindleg (Cofer et al, 2010)]. Subsequently, activation of another muscle pulls the apodeme over so that the spring acts as a depressor, thus triggering the jump (Bennet-Clark and Lucey, 1967).…”

Section: Discussionmentioning

confidence: 99%

Biomechanics of jumping in the flea

Sutton

Burrows

2011

Journal of Experimental Biology

114

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SUMMARYIt has long been established that fleas jump by storing and releasing energy in a cuticular spring, but it is not known how forces from that spring are transmitted to the ground. One hypothesis is that the recoil of the spring pushes the trochanter onto the ground, thereby generating the jump. A second hypothesis is that the recoil of the spring acts through a lever system to push the tibia and tarsus onto the ground. To decide which of these two hypotheses is correct, we built a kinetic model to simulate the different possible velocities and accelerations produced by each proposed process and compared those simulations with the kinematics measured from high-speed images of natural jumping. The in vivo velocity and acceleration kinematics are consistent with the model that directs ground forces through the tibia and tarsus. Moreover, in some natural jumps there was no contact between the trochanter and the ground. There were also no observable differences between the kinematics of jumps that began with the trochanter on the ground and jumps that did not. Scanning electron microscopy showed that the tibia and tarsus have spines appropriate for applying forces to the ground, whereas no such structures were seen on the trochanter. Based on these observations, we discount the hypothesis that fleas use their trochantera to apply forces to the ground and conclude that fleas jump by applying forces to the ground through the end of the tibiae. Supplementary material available online at

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“…This delay may have been caused by relaxation of an internal spring, such as an apodeme. Alternatively, a snap transition in the spring, torque reversal or shifting lever lengths may delay the spring release (Burrows and Morris, 2003;Cofer et al, 2010;Forterre et al, 2005;Holmes and Crosby, 2007;Noh et al, 2012;Ritzmann, 1974). This delay likely provides the necessary time for the flexor muscle to relax and not tear during the rapid outward rotation of the appendage.…”

Section: Control Of Strike Releasementioning

confidence: 99%

Feed-forward motor control of ultrafast, ballistic movements

Kagaya

Patek

2015

Journal of Experimental Biology

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To circumvent the limits of muscle, ultrafast movements achieve high power through the use of springs and latches. The time scale of these movements is too short for control through typical neuromuscular mechanisms, thus ultrafast movements are either invariant or controlled prior to movement. We tested whether mantis shrimp (Stomatopoda: Neogonodactylus bredini) vary their ultrafast smashing strikes and, if so, how this control is achieved prior to movement. We collected high-speed images of strike mechanics and electromyograms of the extensor and flexor muscles that control spring compression and latch release. During spring compression, lateral extensor and flexor units were co-activated. The strike initiated several milliseconds after the flexor units ceased, suggesting that flexor activity prevents spring release and determines the timing of strike initiation. We used linear mixed models and Akaike's information criterion to serially evaluate multiple hypotheses for control mechanisms. We found that variation in spring compression and strike angular velocity were statistically explained by spike activity of the extensor muscle. The results show that mantis shrimp can generate kinematically variable strikes and that their kinematics can be changed through adjustments to motor activity prior to the movement, thus supporting an upstream, central-nervous-systembased control of ultrafast movement. Based on these and other findings, we present a shishiodoshi model that illustrates alternative models of control in biological ballistic systems. The discovery of feed-forward control in mantis shrimp sets the stage for the assessment of targets, strategic variation in kinematics and the role of learning in ultrafast animals.

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Neuromechanical simulation of the locust jump

Cited by 36 publications

References 26 publications

Passive Joint Forces Are Tuned to Limb Use in Insects and Drive Movements without Motor Activity

Passive Joint Forces Are Tuned to Limb Use in Insects and Drive Movements without Motor Activity

Biomechanics of jumping in the flea

Feed-forward motor control of ultrafast, ballistic movements

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