The role of hind limb flexor muscles during swimming in the toad, Bufo marinus

Gillis, Gary B.

doi:10.1016/j.zool.2006.08.002

Cited by 42 publications

(65 citation statements)

References 21 publications

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“…This relatively large magnitude of shortening is consistent with some previous studies (Olson & Marsh 1998;Roberts & Marsh 2003). However, other studies have shown strains to be lower in the plantaris of Bufo marinus (Gillis & Biewener 2000) and the semimembranosus of Rana pipiens (Lutz & Rome 1994. These differences may, in part, be due to variation in the jump distance in different experiments, as shorter jumps will require less mechanical work, which may be produced with less muscle shortening.…”

Section: Discussion (A) Operating Lengths Of the Frog Plantarissupporting

confidence: 91%

Muscle performance during frog jumping: influence of elasticity on muscle operating lengths

2010

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A fundamental feature of vertebrate muscle is that maximal force can be generated only over a limited range of lengths. It has been proposed that locomotor muscles operate over this range of lengths in order to maximize force production during movement. However, locomotor behaviours like jumping may require muscles to shorten substantially in order to generate the mechanical work necessary to propel the body. Thus, the muscles that power jumping may need to shorten to lengths where force production is submaximal. Here we use direct measurements of muscle length in vivo and muscle force-length relationships in vitro to determine the operating lengths of the plantaris muscle in bullfrogs (Rana catesbeiana) during jumping. We find that the plantaris muscle operates primarily on the descending limb of the force-length curve, resting at long initial lengths (1.3 + 0.06 L o ) before shortening to muscle's optimal length (1.03 + 0.05 L o ). We also compare passive force-length curves from frogs with literature values for mammalian muscle, and demonstrate that frog muscles must be stretched to much longer lengths before generating passive force. The relatively compliant passive properties of frog muscles may be a critical feature of the system, because it allows muscles to operate at long lengths and improves muscles' capacity for force production during a jump.

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Section: Discussion (A) Operating Lengths Of the Frog Plantarissupporting

confidence: 91%

Muscle performance during frog jumping: influence of elasticity on muscle operating lengths

2010

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“…These findings accord to the conclusions drawn from earlier studies which compare jumping and swimming in other anurans (Kamel et al, 1996;Gillis and Biewener, 2000;Gillis and Blob, 2001; but see Emerson and De Jongh, 1980). Thus, the divergence between jumping and swimming impulses must seemingly be attributed to differences in the neuronal hind limb control, an assumption that is likely reinforced by the fact that no correlations could be detected between individual maximal jumping and swimming performance (Nauwelaerts et al, 2007;Nauwelaerts et al, 2005a).…”

Section: Introductionsupporting

confidence: 88%

“…Intensity and timing of the muscle activation should be based on the quantitative analysis of EMG-recordings (e.g. Kamel et al, 1996;Gillis and Biewener, 2000) and identical activation patterns should be applied in a terrestrial and aquatic environment (the later probably requiring intricate CFD application). Obviously, when combined with function analysis of actual jumping and swimming, such a challenging modelling approach may unravel much of the neuromechanics of real frog locomotion and provide better insight into the way the neuromotoric system copes with the changing physical properties of the environment.…”

Section: Discussionmentioning

confidence: 99%

Environmentally induced mechanical feedback in locomotion: Frog performance as a model

Aerts

Nauwelaerts

2009

Journal of Theoretical Biology

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A c c e p t e d m a n u s c r i p t 2 AbstractAt first glance, the strategy for generating propulsive impulses for both jumping and swimming in frogs is quite similar. Both modes rely on powerful extension of the hind limbs.However, in Rana esculenta (the semi-aquatic green frog), propulsive impulses for jumping were found to be much larger than those generated during swimming (Nauwelaerts and Aerts, 2003). The hypothesis that differences in propulsive impulse between swimming and jumping are largely caused by specific environmental constraints rather than being due to changes in motor control is tested in the present study. To assess this question, the actuator of a simple mathematical model, mimicking a frog with symmetrically kicking hind limbs, is first tuned to perform frog-like jumps. Next, the same actuator activation is applied to drive the model in an 'aquatic environment'. Despite the entirely identical activation, the resulting in silico propulsive swimming impulse was less than half that produced during jumping, just as observed in vivo. Although duration of limb extension is similar for both locomotor modes (both in vivo and in silico), this conspicuous difference in model behaviour is entirely explained by the actuator working at different positions along its force-velocity curve. These findings suggest that the same environmentally induced effects are also involved in real swimming and jumping as well, thus explaining the apparent difference in performance level.

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“…Bilateral implants were used to increase the likelihood of getting extensor and flexor data from the same limb. Bipolar electrodes were made and implanted as described in detail in previous work [11]. EMG signals were amplified 1000Â with Grass P511 preamplifiers using a notch filter at 60 Hz.…”

Section: Materials and Methods (A) Animalsmentioning

confidence: 99%

“…Unlike in many anuran jumpers, toad hindlimbs rapidly flex back towards the body immediately after take-off. In addition, toad hindlimbs maintain a relatively flexed configuration in a relaxed state [9] in which the femur and tibiofibula are nearly perpendicular to one another, and extension beyond this develops passive tension in the limb, as underlying tissues including major flexor muscle-tendon units are stretched (electronic supplementary material, figure S1). We propose a model in which limb extension during take-off stretches such elastic tissues, effectively loading a tension-spring, which can then recoil and help pull the limb back into a flexed position during recovery (figure 1a).…”

Section: Introductionmentioning

confidence: 99%

Indirect evidence for elastic energy playing a role in limb recovery during toad hopping

et al. 2014

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Elastic energy is critical for amplifying muscle power during the propulsive phase of anuran jumping. In this study, we use toads (Bufo marinus) to address whether elastic recoil is also involved after take-off to help flex the limbs before landing. The potential for such spring-like behaviour stems from the unusually flexed configuration of a toad's hindlimbs in a relaxed state. Manual extension of the knee beyond approximately 908 leads to the rapid development of passive tension in the limb as underlying elastic tissues become stretched. We hypothesized that during take-off, the knee regularly extends beyond this, allowing passive recoil to help drive limb flexion in mid-air. To test this, we used high-speed video and electromyography to record hindlimb kinematics and electrical activity in a hindlimb extensor (semimembranosus) and flexor (iliofibularis). We predicted that hops in which the knees extended further during take-off would require less knee flexor recruitment during recovery. Knees extended beyond 908 in over 80% of hops, and longer hops involved greater degrees of knee extension during take-off and more intense semimembranosus activity. However, knee flexion velocities during recovery were maintained despite a significant decrease in iliofibularis intensity in longer hops, results consistent with elastic recoil playing a role.

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The role of hind limb flexor muscles during swimming in the toad, Bufo marinus

Cited by 42 publications

References 21 publications

Muscle performance during frog jumping: influence of elasticity on muscle operating lengths

Muscle performance during frog jumping: influence of elasticity on muscle operating lengths

Environmentally induced mechanical feedback in locomotion: Frog performance as a model

Indirect evidence for elastic energy playing a role in limb recovery during toad hopping

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