An analysis of locomotor body movements in pronghorn antelope

1982 ◽  
Vol 60 (8) ◽  
pp. 1871-1880
Author(s):  
Robert E. Bullock
Keyword(s):  
Stride Length ◽  
Slow Motion ◽  
Vertical Movement ◽  
Center Of Gravity ◽  
The Body ◽  
Ground Contact ◽  
Body Movements ◽  
Pronghorn Antelope

Slow-motion film sequences of pronghorn antelope were analyzed to determine movements of the body and various body members during the most frequently employed gaits: walk, trot, canter (lope), and gallop. As speed and gait progress from a walk to a gallop, the angles at which the legs strike and leave the ground become more acute, the body is lower to the ground, and each leg moves through a greater arc during ground contact. Inasmuch as the body levels out somewhat, it is suggested that less energy may be required in raising the center of gravity. This may make more energy available for moving the legs. As speed increases, the feet are lifted progressively higher, the legs travel further, and the feet attain greater backward acceleration before striking the ground. In the gallop, the forelegs are kept fully extended until contacting the ground and the degree of spinal flexure is increased, thus extending stride length to its maximum. Vertical movement of the head increases in the faster gaits and appears to play a larger role in shifting the center of gravity, increasing speed, and maintaining equilibrium.

Shifting of the body center of gravity in low-risk preterm infants: A video-pedoscope study

2018 ◽  
Vol 124 ◽  
pp. 33-37 ◽  
Author(s):  
Natascia Bertoncelli ◽  
Laura Lucaccioni ◽  
Luca Ori ◽  
Christa Einspieler ◽  
Heinz F.R. Prechtl ◽  
...  
Keyword(s):  
Preterm Infants ◽  
Center Of Gravity ◽  
The Body ◽  
Low Risk ◽  
Body Center

Developmental stages in the Digenea

Parasitology ◽  
1964 ◽  
Vol 54 (2) ◽  
pp. 295-312 ◽  
Author(s):  
Elon E. Byrd ◽  
William P. Maples
Keyword(s):  
Body Wall ◽  
Developmental Stages ◽  
Snail Host ◽  
The Body ◽  
Body Movements ◽  
Hatching Enzyme ◽  
Apical Papilla ◽  
Short Time ◽  
Membranous Body ◽  
Egg Capsule

The naturally oviposited egg of Dasymetra conferta is fully embryonated and it hatches only after it is ingested by the snail host, Physa spp.Hatching appears to be in response to some stimulus supplied by the living snail. The stimulus causes the larva to exercise a characteristic series of body movements and to liberate a granular sustance (hatching enzyme) from the larger pair of its cephalic glands. This enzyme reacts with the vitelline fluid to create pressure within the egg capsule, and with the cementum of the operculum, so that it may be lifted away. The larva's escape from the shell, therefore, is due to a combination of pressure and body movements.The hatched larva has a membranous body wall, supporting six epidermal plates, an apical papilla, two penetration glands and a central matrix (the presumptive brood mass).It lives for about an hour within the snail and during this time there is a reorganization of the central matrix which terminates in the formation of an 8-nucleated syncytial brood mass.The miracidial ‘case’, consisting of the body wall and the epidermal plates, ultimately ruptures to liberate the brood mass. Once the brood mass is free it penetrates through the gut wall in an incredibly short time.

Walking Machine Design Based on Certain Aspects of Insect Leg Design

1992 ◽  
Author(s):  
E. F. Fichter ◽  
D. R. Kerr
Keyword(s):  
Control System ◽  
Observational Data ◽  
The Body ◽  
Static Equilibrium ◽  
Machine Design ◽  
Ground Contact ◽  
Careful Attention ◽  
Equilibrium Equations ◽  
Walking Machine ◽  
Leg Design

Abstract A walking machine design originating from observations of insects is presented. The primary concept derived from insects is a leg used to apply force to the body without applying significant moments about the point of body attachment. This is accomplished with legs which have kinematic equivalents to ball-and-socket joints at body attachment and ground contact, with joints in the middle which only change distance between body and ground. Standing and walking with 6 legs of this design requires careful attention to static equilibrium equations but does not necessitate a control system which actively distributes forces to the legs. This paper considers necessary observational data, assumptions on which control is based, mathematical development for control and problems such as foot slip.

scholarly journals Functional Electrical Stimulation Changes Dynamic Resources in Children With Spastic Cerebral Palsy

2006 ◽  
Vol 86 (7) ◽  
pp. 987-1000 ◽  
Author(s):  
Chia-Ling Ho ◽  
Kenneth G Holt ◽  
Elliot Saltzman ◽  
Robert C Wagenaar
Keyword(s):  
Cerebral Palsy ◽  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Stride Length ◽  
The Body ◽  
Stride Frequency ◽  
Spastic Cerebral Palsy ◽  
Significant Difference ◽  
Muscle Complex ◽  
Spring System

Abstract Background and Purpose. Children with cerebral palsy (CP) often are faced with difficulty in walking. The purpose of this experiment was to determine the effects of functional electrical stimulation (FES) applied to the gastrocnemius-soleus muscle complex on the ability to produce appropriately timed force and reduce stiffness (elastic property of the body) and on stride length and stride frequency during walking. Subjects and Methods. Thirteen children with spastic CP (including 4 children who were dropped from the study due to their inability to cooperate) and 6 children who were developing typically participated in the study. A crossover study design was implemented. The children with spastic CP were randomly assigned to either a group that received FES for 15 trials followed by no FES for 15 trials or a group that received no FES for 15 trials followed by FES for 15 trials. The children who were having typical development walked without FES. Kinematic data were collected for the children with CP in each walking condition and for the children who were developing typically. Impulse (force-producing ability) and stiffness were estimated from an escapement-driven pendulum and spring system model of human walking. Stride length and stride frequency also were measured. To compare between walking conditions and between the children with CP and the children who were developing typically, dimensional analysis and speed normalization procedures were used. Results. Nonparametric statistics showed that there was no significant difference between the children with CP in the no-FES condition and the children who were developing typically on speed-normalized dimensionless impulse. In contrast, the children with CP in the FES condition had a significantly higher median value than the children who were developing typically. The FES significantly increased speed-normalized dimensionless impulse from 10.02 to 16.32 when comparing walking conditions for the children with CP. No significant differences were found between walking conditions for stiffness, stride length, and stride frequency. Discussion and Conclusion. The results suggest that FES is effective in increasing impulse during walking but not in decreasing stiffness. The effect on increasing impulse does not result in more typical spatiotemporal gait parameters. [Ho CL, Holt KG, Saltzman E, Wagenaar RC. Functional electrical stimulation changes dynamic resources in children with spastic cerebral palsy. Phys Ther. 2006;86:987–1000.]

Muscle strain histories in swimming milkfish in steady and sprinting gaits

1999 ◽  
Vol 202 (5) ◽  
pp. 529-541 ◽  
Author(s):  
S.L. Katz ◽  
R.E. Shadwick ◽  
H.S. Rapoport
Keyword(s):  
White Muscle ◽  
Beat Frequency ◽  
The Body ◽  
Body Volume ◽  
Implicit Assumption ◽  
Muscle Strain ◽  
Body Movements ◽  
Wide Range ◽  
Speed Range ◽  
Local Body

Adult milkfish (Chanos chanos) swam in a water-tunnel flume over a wide range of speeds. Fish were instrumented with sonomicrometers to measure shortening of red and white myotomal muscle. Muscle strain was also calculated from simultaneous overhead views of the swimming fish. This allowed us to test the hypothesis that the muscle shortens in phase with local body bending. The fish swam at slow speeds [U<2.6 fork lengths s-1 (=FL s-1)] where only peripheral red muscle was powering body movements, and also at higher speeds (2. 6>U>4.6 FL s-1) where they adopted a sprinting gait in which the white muscle is believed to power the body movements. For all combinations of speeds and body locations where we had simultaneous measurements of muscle strain and body bending (0.5 and 0.7FL), both techniques were equivalent predictors of muscle strain histories. Cross-correlation coefficients for comparisons between these techniques exceeded 0.95 in all cases and had temporal separations of less than 7 ms on average. Muscle strain measured using sonomicrometry within the speed range 0.9-2.6 FL s-1 showed that muscle strain did not increase substantially over that speed range, while tail-beat frequency increased by 140 %. While using a sprinting gait, muscle strains became bimodal, with strains within bursts being approximately double those between bursts. Muscle strain calculated from local body bending for a range of locations on the body indicated that muscle strain increases rostrally to caudally, but only by less than 4 %. These results suggest that swimming muscle, which forms a large fraction of the body volume in a fish, undergoes a history of strain that is similar to that expected for a homogeneous, continuous beam. This has been an implicit assumption for many studies of muscle function in many fish, but has not been tested explicitly until now. This result is achieved in spite of the presence of complex and inhomogeneous geometry in the folding of myotomes, collagenous myosepta and tendon, and the anatomical distinction between red and white muscle fibers.

Water skating in the larvae of dixella aestivalis (Diptera) and hydrobius fuscipes (Coleoptera)

1999 ◽  
Vol 202 (7) ◽  
pp. 845-853
Author(s):  
J. Brackenbury
Keyword(s):  
High Speed ◽  
The Body ◽  
Water Interface ◽  
Body Movements ◽  
Chironomid Larvae ◽  
High Speed Video ◽  
Adhesive Organ ◽  
Video Recordings ◽  
Air Water Interface

The kinematics of locomotion was investigated in the aquatic larvae of Dixella aestivalis and Hydrobius fuscipes with the aid of high-speed video recordings. Both insects are able to skate on the surface of the water using the dorso-apical tracheal gill as an adhesive organ or ‘foot’. Progress relies on the variable adhesion of the foot between ‘slide’ and ‘hold’ periods of the locomotory cycle. The flexural body movements underlying skating in D. aestivalis can be derived directly from the figure-of-eight swimming mechanism used in underwater swimming. The latter is shown to be similar to figure-of-eight swimming in chironomid larvae. This study shows how the deployment of a ‘foot’ enables simple side-to-side flexural movements of the body to be converted into effective locomotion at the air-water interface.

Light Dance

Leonardo ◽  
2020 ◽  
Vol 53 (1) ◽  
pp. 90-91
Author(s):  
Seth Riskin
Keyword(s):  
Simple Approach ◽  
The Body ◽  
Speed Of Light ◽  
Body Movements ◽  
Room Light ◽  
Shared Space ◽  
Surrounding Space ◽  
The Individual ◽  
Individual Body ◽  
Movement Expression

The author discusses the origin and meaning of his Light Dance artwork. The simple approach—placing a source of light on the body and thereby manipulating the illumination of the surrounding space through body movements—alters the viewer’s perception of space and time. Architecture appears malleable as the performer affects the size, shape and speed of light forms that reach from the body to the boundaries of the room. Light, in this perceptual environment, is not a mere transmitter of information between the invariant material surroundings and the eye of the viewer; light is a space-defining extension of the performer’s body that transposes movement expression from the individual body to the shared space. An inversion of subjective and objective “spaces” is realized in the experience of Light Dance wherein the prevailing conceptual hierarchy of light and vision is overcome.

Consolidation Effects in a Full-Body Diving Task

2017 ◽  
Vol 5 (2) ◽  
pp. 291-303
Author(s):  
Maxime Trempe ◽  
Jean-Luc Gohier ◽  
Mathieu Charbonneau ◽  
Jonathan Tremblay
Keyword(s):  
Skill Acquisition ◽  
Training Session ◽  
Video Camera ◽  
The Body ◽  
Initial Training ◽  
Body Movements ◽  
Training Tool ◽  
Significant Performance ◽  
The Moment ◽  
Full Body

In recent years, it has been shown that spacing training sessions by several hours allows the consolidation of motor skills in the brain, a process leading to the stabilization of the skills and, sometimes, further improvement without additional practice. At the moment, it is unknown whether consolidation can lead to an improvement in performance when the learner performs complex full-body movements. To explore this question, we recruited 10 divers and had them practice a challenging diving maneuver. Divers first performed an initial training session, consisting of 12 dives during which visual feedback was provided immediately after each dive through video replay. Two retention tests without feedback were performed 30 min and 24 hr after the initial training session. All dives were recorded using a video camera and the participants’ performance was assessed by measuring the verticality of the body segments at water entry. Significant performance gains were observed in the 24-hr retention test (p < .05). These results suggest that the learning of complex full-body movements can benefit from consolidation and that splitting practice sessions can be used as a training tool to facilitate skill acquisition.

A shape memory alloy–actuated soft crawling robot based on adaptive differential friction and enhanced antagonistic configuration

2020 ◽  
Vol 31 (16) ◽  
pp. 1920-1934 ◽  
Author(s):  
Chen Liang ◽  
Yongquan Wang ◽  
Tao Yao ◽  
Botao Zhu
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Stride Length ◽  
Parametric Design ◽  
Thermoplastic Polyurethane ◽  
Interaction Mechanism ◽  
Experimental Tests ◽  
The Body ◽  
3D Printed ◽  
Miniature Robot

This article presents a soft crawling robot prototype with a simple architecture inspired by inchworms. The robot functionally integrates the torso (body) and feet in a monolithic curved structure that only needs a single shape memory alloy coil and differential friction to actuate it. A novel foot configuration is proposed, which makes the two feet, with an anti-symmetrical friction layout, can be alternately anchored, to match the contraction–recovery sequence of the body adaptively. Based on the antagonistic configuration between the shape memory alloy actuator and the elastic body, a vertically auxiliary spring was adopted to enhance the interaction mechanism. Force and kinematic analysis was undertaken, focusing on the parametric design of the special foot configuration. A miniature robot prototype was then 3D-printed (54 mm in length and 9.77 g in weight), using tailored thermoplastic polyurethane elastomer as the body material. A series of experimental tests and evaluations were carried out to assess its performance under different conditions. The results demonstrated that under appropriate actuation conditions, the compact robot prototype could accomplish a relative speed of 0.024 BL/s (with a stride length equivalent to 27% of its body length) and bear a load over five times to its own weight.

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