scholarly journals Locomotion in alligator mississippiensis: kinematic effects of speed and posture and their relevance to the sprawling-to-erect paradigm

1998 ◽  
Vol 201 (18) ◽  
pp. 2559-2574 ◽  
Author(s):  
SM Reilly ◽  
JA Elias
Keyword(s):  
Knee Kinematics ◽  
The Body ◽  
Alligator Mississippiensis ◽  
Vertebrate Evolution ◽  
Evolutionary Transition ◽  
Erect Posture ◽  
Kinematic Data ◽  
Intermediate Model ◽  
Terrestrial Vertebrates ◽  
Sprawling Posture

In terms of locomotory posture, amphibians and lizards are considered to be sprawlers, mammals and dinosaurs are considered to be erect, and extant crocodilians are considered to be intermediate because they use the 'high walk', a semi-erect posture where the body is held half-way between the sprawling and erect grades during locomotion. In addition, crocodilians occasionally use a sprawling posture. Extant crocodilians, therefore, provide an interesting model in which to investigate the sprawling-to-erect transition in vertebrate evolution. This study quantifies the sprawl and high walk kinematics of the alligator Alligator mississippiensis moving at different speeds on a treadmill and compares them with kinematic data available for other vertebrates. These data allow us to examine the effects of speed on crocodilian postures and to examine how crocodilian locomotion relates to the sprawling-to-erect paradigm in vertebrate locomotion. Our results show that the crocodilian sprawl is not functionally equivalent to the primitive sprawling behaviors exhibited by salamanders and lizards. In fact, although the high walks and sprawls of alligators exhibit some kinematic differences, they are actually much more similar than expected and, essentially, the crocodilian sprawl is a lower version of a high walk and could be termed a 'low walk'. In terms of the sprawling-to-erect transition, the high walk has knee kinematics intermediate between those of birds and non-archosaurian tetrapods, but alligators increase speed in a way completely different from other terrestrial vertebrates (distal rather than proximal limb elements are used to increase speed). These kinematic data viewed in the light of the fossil and phylogenetic evidence that modern crocodilians evolved from erect ancestors suggest that modern crocodilians have secondarily evolved a variable semi-erect posture and that they are problematic as an intermediate model for the evolutionary transition from sprawling to erect postures in archosaurs.

scholarly journals How moles walk; it's all thumbs

2019 ◽  
Vol 15 (10) ◽  
pp. 20190503 ◽  
Author(s):  
Yi-Fen Lin ◽  
Nicolai Konow ◽  
Elizabeth R. Dumont
Keyword(s):  
Horizontal Plane ◽  
Stance Phase ◽  
The Body ◽  
Joint Mobility ◽  
Sesamoid Bone ◽  
Erect Posture ◽  
X Ray ◽  
Parasagittal Plane ◽  
Limb Posture ◽  
Sprawling Posture

A recurring theme in the evolution of tetrapods is the shift from sprawling posture with laterally orientated limbs to erect posture with the limbs extending below the body. However, in order to invade particular locomotor niches, some tetrapods secondarily evolved a sprawled posture. This includes moles, some of the most specialized digging tetrapods. Although their forelimb anatomy and posture facilitates burrowing, moles also walk long distances to forage for and transport food. Here, we use X-ray Reconstruction Of Moving Morphology (XROMM) to determine if the mole humerus rotates around its long axis during walking, as it does when moles burrow and echidnas walk, or alternatively protracts and retracts at the shoulder in the horizontal plane as seen in sprawling reptiles. Our results reject both hypotheses and demonstrate that forelimb kinematics during mole walking are unusual among those described for tetrapods. The humerus is retracted and protracted in the parasagittal plane above, rather than below the shoulder joint and the ‘false thumb’, a sesamoid bone (os falciforme), supports body weight during the stance phase, which is relatively short. Our findings broaden our understanding of the diversity of tetrapod limb posture and locomotor evolution, demonstrate the importance of X-ray-based techniques for revealing hidden kinematics and highlight the importance of examining locomotor function at the level of individual joint mobility.

The evolution of the terrestrial vertebrates: environmental and physiological considerations

1985 ◽  
Vol 309 (1138) ◽  
pp. 289-322 ◽  
Keyword(s):  
Fresh Water ◽  
Osmotic Dehydration ◽  
The Body ◽  
Geological Evidence ◽  
Air Breathing ◽  
Marine Origin ◽  
Terrestrial Vertebrates ◽  
Terrestrial Life ◽  
Tetrapod Evolution

Physiological evidence has long been used to suggest that the gnathostomous vertebrates (those possessing jaws) were primitively fresh water. The same was also the case for the Osteichthyes (bony fish) and the Tetrapoda (Amphibia, Reptilia, Aves, Mammalia). However, the geological evidence favours a marine origin for the vertebrates as a whole, and, for the gnathostomes and the osteichthyans in particular. Some of the earliest amphibian remains may be associated with tidally influenced sediments. Furthermore, during the early part of the Devonian, fresh water chemistry may well have been different from that of today, lessening the divide between marine and non-marine environments. Urea formation via the ornithine cycle, and urea retention in the body fluids, are useful adaptations for terrestrial life. They prevent excessive water loss associated with the elimination of nitrogenous waste. These abilities may have been primitive for the gnathostomes, and were developed in the marine environment to reduce osmotic dehydration. In the .aqueous medium, gaseous exchange is effected by the gills. These organs are, on the whole, useless in air. For vertebrates, air-breathing is effected by an inflatable sac, with moist linings, and an internal location. Some form of air-breathing sac was primitive for the osteichthyans, and may have been primitive for the gnathostomes. Again, this adaptation for terrestrial life developed in response to conditions experienced in the marine, aquatic environment. A new model of tetrapod evolution is proposed in the light of the basic marine origin and character of the ancestors of the tetrapods.

scholarly journals AN AYURVEDIC MANAGEMENT OF SPINAL MUSCULAR ATROPHY (SMA) – A CASE STUDY

2021 ◽  
Vol 9 (11) ◽  
pp. 2897-2902
Author(s):  
Raheena B ◽  
Shaila Borannavar ◽  
Ananta S Desai
Keyword(s):  
Spinal Muscular Atrophy ◽  
Motor Neurons ◽  
Autosomal Recessive ◽  
Muscular Atrophy ◽  
Genetic Disorder ◽  
The Body ◽  
Erect Posture ◽  
Smn1 Gene ◽  
Autosomal Recessive Pattern

Spinal Muscular Atrophy (SMA) is the second leading genetic disorder inherited in the autosomal recessive pattern due to the absence of the SMN1 gene characterized by loss of motor neurons and progressive muscle wasting, often leading to dependent life and decreased life span. In Ayurveda, this condition can be considered as Kulaja Vyadhi wherein the patient’s Mamsa and Snayu is affected by Vata. This can be regarded as Mamsa-Snayugata Sarvanga Vata. It is said that Prakruta Vata dosha is the life, it is the strength, it is the sustainer of the body, it holds the body and life together. If it is Vikruta it produces Sankocha, Khanja, Kubjatva, Pangutva, Khalli and Soshana of Anga. So, in this disease aggravated Vata does the vitiation of Mamsa and Snayu thus leading to Soshana of both, resulting in Stambha, Nischalikarana of Avayava. A 21years female patient was admitted to our I.P.D with c/o of reduced strength in all four limbs leading to the inability to walk and to maintain erect posture during standing and sitting positions. Based on Ayurvedic principles the patient was initially subjected to Avaranahara Chikitsa followed by Brimhana line of management. Keywords: Mamsagata vata, Snayugata vata, Sarvanga vata, Spinal muscular atrophy (SMA)

Studies on Temperature Regulation

1946 ◽  
Vol 22 (3-4) ◽  
pp. 213-220
Author(s):  
R. L. KIRK ◽  
LANCELOT HOGBEN
Keyword(s):  
Body Temperature ◽  
Rana Temporaria ◽  
Large Body ◽  
Bufo Bufo ◽  
Thermal Capacity ◽  
The Body ◽  
External Temperature ◽  
Terrestrial Vertebrates ◽  
Temperature And Humidity ◽  
Frog Rana Temporaria

1. The upper thermal death-point of the slow worm (Anguis fragilis) is significantly above that of either the toad (Bufo bufo) or the frog (Rana temporaria). That of the toad differs only slightly from that of the frog. 2. In response to external variation with respect to temperature and humidity, the body temperature of the toad behaves in a manner similar to that of the frog, being considerably below that of the air at low humidities, though appreciably above that of the wet-bulb thermometer. It is concluded that the toad loses water as freely as the frog. 3. The body temperature of the slow worm and that of the alligator (A. mississippiensis) differs only slightly from that of the air under all conditions of sustained air temperature and humidity. 4. The body temperature reaction of the alligator is more sluggish than that of the slow worm, presumably owing to the higher thermal capacity of the animal. 5. The significance of these results in relation to the evolution of the terrestrial vertebrates is discussed. It is suggested that homoeothermic stocks could arise only from reptiles of relatively small size, and that large body size would militate against survival during periods of low mean external temperature.

scholarly journals Temporal profiles of cortisol accumulation and clearance support scale cortisol content as an indicator of chronic stress in fish

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Frédéric Laberge ◽  
Irene Yin-Liao ◽  
Nicholas J Bernier
Keyword(s):  
Chronic Stress ◽  
The Body ◽  
High Dose ◽  
Stress Hormone ◽  
Stress Indicators ◽  
Stress Indicator ◽  
Terrestrial Vertebrates ◽  
Non Invasive ◽  
Goldfish Carassius Auratus ◽  
Temporal Profiles

Abstract The development of chronic stress indicators for fish is of great interest, but appropriate non-invasive methods are lagging those used in terrestrial vertebrates. Here, we explore the possibility that levels of the stress hormone cortisol in scales could be used as a chronic stress indicator. Three experiments were conducted to assess the temporal profiles of cortisol rise and fall in plasma and scales of goldfish (Carassius auratus) in response to stressors of varying intensity and duration. Results show that a single acute air emersion stressor does not influence scale cortisol content. In contrast, relative to plasma levels, the fall in scale cortisol content following a high-dose cortisol implant is delayed by at least 8 days, and the rise and fall in scale cortisol content in response to unpredictable chronic stress are delayed by at least 7 days. Also, scale cortisol content is spatially heterogeneous across the body surface of goldfish. Overall, since high and sustained circulating cortisol levels are needed to influence scale cortisol content and the rates of cortisol accumulation and clearance are much slower in scales than in plasma, our results show that scales can provide an integrated measure of cortisol production and serve as a chronic stress indicator.

Extrapolating body masses in large terrestrial vertebrates

Paleobiology ◽  
2017 ◽  
Vol 43 (4) ◽  
pp. 693-699 ◽  
Author(s):  
Nicolás E. Campione
Keyword(s):  
Body Mass ◽  
Model Fitting ◽  
The Body ◽  
Linear Functions ◽  
Quadratic Functions ◽  
Quadratic Model ◽  
Implicit Assumption ◽  
Terrestrial Vertebrates ◽  
Scaling Models ◽  
Degree Term

AbstractDespite more than a century of interest, body-mass estimation in the fossil record remains contentious, particularly when estimating the body mass of taxa outside the size scope of living animals. One estimation approach uses humeral and femoral (stylopodial) circumferences collected from extant (living) terrestrial vertebrates to infer the body masses of extinct tetrapods through scaling models. When applied to very large extinct taxa, extant-based scaling approaches incur obvious methodological extrapolations leading some to suggest that they may overestimate the body masses of large terrestrial vertebrates. Here, I test the implicit assumption of such assertions: that a quadratic model provides a better fit to the combined humeral and femoral circumferences-to-body mass relationship. I then examine the extrapolation potential of these models through a series of subsetting exercises in which lower body-mass sets are used to estimate larger sets. Model fitting recovered greater support for the original linear model, and a nonsignificant second-degree term indicates that the quadratic relationship is statistically linear. Nevertheless, some statistical support was obtained for the quadratic model, and application of the quadratic model to a series of dinosaurs provides lower mass estimates at larger sizes that are more consistent with recent estimates using a minimum convex-hull (MCH) approach. Given this consistency, a quadratic model may be preferred at this time. Still, caution is advised; extrapolations of quadratic functions are unpredictable compared with linear functions. Further research testing the MCH approach (e.g., the use of a universal upscaling factor) may shed light on the linear versus quadratic nature of the relationship between the combined femoral and humeral circumferences and body mass.

scholarly journals Impact of Engaging the Nonthrowing Arm on Maximal Ball Velocity From an Overhand Throw With Both the Dominant and Nondominant Arms: A Pilot Study

2021 ◽  
pp. 1-18
Author(s):  
Alanna Weisberg ◽  
Hyun Suk Lee ◽  
Tak Fung ◽  
Larry Katz
Keyword(s):  
The Body ◽  
Whole Body ◽  
Camera Motion ◽  
Ball Speed ◽  
Kinematic Data ◽  
Overhand Throw ◽  
Ball Velocity ◽  
Analysis System ◽  
The Impact ◽  
Camera Motion Analysis

The overhand throw is a complex whole-body motor skill that is fundamental to many sports and activities. When throwing properly, the momentum generated to complete the movement begins in the lower body and transfers through the trunk to the throwing arm. This proof-of-concept study’s primary purpose was to evaluate the impact of the nonthrowing arm on the ball speed during an overhand throw with both the dominant and nondominant arms. Eighteen participants (age: 20.20 ± 2.90 years, nine women) were divided into two intervention groups: a pulling group taught to engage the nonthrowing arm through a pull toward the body and a nonpulling group taught the overhand throw using a component-based physical education curriculum. Each participant completed 12 total throws, six for each side (dominant and nondominant arm). Ball speed and kinematic data were collected using an eight-camera motion analysis system and were assessed using a pre–post study design. The two groups showed significant improvements pre–post when throwing with both the dominant and nondominant arms. Based on effect size comparisons, engaging the nonthrowing arm makes a meaningful difference in maximal ball velocity.

scholarly journals Postural characterization in visually impaired young adults: preliminary study.

2014 ◽  
Vol 12 ◽  
pp. 205
Author(s):  
Graziela Morgana Silva Tavares ◽  
Caroline Cunha do Espírito Santo ◽  
Cristina Maria Santos Calmon ◽  
Paula Martins Nunes ◽  
Thiele De Cássia Libardoni ◽  
...  
Keyword(s):  
Young Adults ◽  
Visual System ◽  
Low Cost ◽  
The Body ◽  
Erect Posture ◽  
Postural Control System ◽  
Postural Changes ◽  
Anterior Pelvic Tilt ◽  
Microsoft Office ◽  
Postural Analysis

Introduction: The postural control system, responsible for maintaining the erect posture, it is strongly influenced by the visual system. Posture is the state of balance between muscles and bones, capable of protecting other structures of the human body from possible injuries. The visual system plays an important role in stabilizing the posture by continuously provide, with respect to the current position and the segments of the body in relation to themselves and the environment information nervous system. Objective: Characterize postural profile of young adults with visual impairment using computerized photogrammetry. Method: A postural analysis was performed in thirteen subjects 8 female and 5 male (30.85 ± 6.85 years), by recording images of the anterior, posterior and lateral views. All data were analyzed using the SAPO postural assessment software and the results tabulated in Microsoft Office Excel 2007 program. Descriptive statistics were performed. Results: It was shown that the subjects in this study had the following changes in postural profile: forward head, torso leaning back, pelvic anteversion and valgus hindfoot. Conclusion: The findings of this study showed that the attitude of these individuals is characterized by forward head, posterior tilt of the trunk, anterior pelvic tilt, knees flexed and valgus hindfoot. Additionally, it appears that this quantitative and qualitative method, low cost, can easily be incorporated into the clinical setting, it is useful to health professionals in the identification of postural changes and consequently the most appropriate treatment for these individuals.

scholarly journals THE EFFECTS OF ANALOGY INSTRUCTIONS ON SPRINT PERFORMANCE AND KINEMATICS

2021 ◽  
Vol 17 (1) ◽  
pp. 35
Author(s):  
Hanisah Abdullah ◽  
Jeffrey Low Fook Lee
Keyword(s):  
Sprint Performance ◽  
The Body ◽  
Control Group ◽  
Kinematic Data ◽  
Significant Difference ◽  
Post Test ◽  
Timing Gate ◽  
Post Hoc ◽  
And Control ◽  
Running Mechanics

The purpose of this study was to examine the effects of analogy and explicit instructions on 50-m sprint performance and their running kinematics. Forty-five male Physical Education undergraduates participated in this study and were randomly divided into three groups, (i.e. analogy, explicit and control). Their sprint performances were assessed using wireless timing gate while the kinematic data was assessed by Kinovea software. The analogy group received three analogies which were “run tall”, “chin to pocket” and “claw the track” throughout the intervention sessions whereas the explicit group received “keep the body posture in an upright position and aligned, head and butt not tilting outward”, “arms should maintain a 90-degree angle at the elbow throughout the upswing as well as backswing” and “the foot landing should always be on the balls of the feet”. The control group did not receive any instruction throughout the intervention period. All participants were tested again after three weeks for the post test and retention test a week after. A 3 group x 3 tests mixed design ANOVA was used to analyze the sprinting performance whereas the kinematic data was analyzed by using one way MANOVA test. Results displayed that there was no significant difference in sprint performance among the groups. However, the post hoc test showed that the analogy group improved significantly in the post test. The kinematic data showed that both intervention groups were significantly better than the control group. This study concluded that both analogy and explicit instructions resulted in better running mechanics but only the analogy group elicited better in performance. Thus, analogy instructions are suggested to be an effective method to coach sprinters.

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