Precocious Locomotor Behavior Begins in the Egg: Development of Leg Muscle Patterns for Stepping in the Chick

2016 ◽  
pp. 181-201
1997 ◽  
Vol 36 (04/05) ◽  
pp. 372-375 ◽  
Author(s):  
J. R. Sutton ◽  
A. J. Thomas ◽  
G. M. Davis

Abstract:Electrical stimulation-induced leg muscle contractions provide a useful model for examining the role of leg muscle neural afferents during low-intensity exercise in persons with spinal cord-injury and their able-bodied cohorts. Eight persons with paraplegia (SCI) and 8 non-disabled subjects (CONTROL) performed passive knee flexion/extension (PAS), electrical stimulation-induced knee flexion/extension (ES) and voluntary knee flexion/extension (VOL) on an isokinetic dynamometer. In CONTROLS, exercise heart rate was significantly increased during ES (94 ± 6 bpm) and VOL (85 ± 4 bpm) over PAS (69 ± 4 bpm), but no changes were observed in SCI individuals. Stroke volume was significantly augmented in SCI during ES (59 ± 5 ml) compared to PAS (46 ± 4 ml). The results of this study suggest that, in able-bodied humans, Group III and IV leg muscle afferents contribute to increased cardiac output during exercise primarily via augmented heart rate. In contrast, SCI achieve raised cardiac output during ES leg exercise via increased venous return in the absence of any change in heart rate.


2015 ◽  
Vol 2 (2) ◽  
pp. 72
Author(s):  
Slamet ' ◽  
Ali Mandan ◽  
Ardiah Juita ◽  
Ridwan Sinurat

This study is correlational research that aims to find the contribution of leg muscleexplosive power to yield long jump squat style. The student sample was the son of varsity sportscoaching education Riau semester totaling 42 people. As the independent variable is theexplosive power leg muscle while dependent variable is the result of the long jump jongok style.Data (x) obtained from the test results without the leading long jump (standing board jump) toassess leg muscle explosive power while data (y) obtained from testing the long jump squat styleusing the prefix. Data were analyzed with statistical normality test is a test last lilifors alsoanalyzed the data to look for the correlation coefficient, and then proceed to test "t" after itsought the contribution. From the results of data processing for the normal distribution of dataobtained for the provision of data (x) and abnormally distributed in terms of data (y). r = 0.32,then through the test "t", t_ (count>) ttabel then there is a significant relationship between theexplosive muscle power with the outcome long jump squat style, via analysis of leg muscleexplosive power of determination have contributed 10.24% and 89 , 76% was contributed byother factors.


2020 ◽  
Vol 54 (5) ◽  
pp. 23-28
Author(s):  
E.V. Fomina ◽  
◽  
T.B. Kukoba ◽  

Testing of 25 cosmonauts showed that the amount of resistance training weight loading in long-term space mission influences dynamics of the leg-muscle strength and velocity recovery. On Earth, the loads equal from 70 to 130 % of the body mass is sufficient for keeping up endurance and maximum strength moments of shin and thigh muscles. In the group of cosmonauts who had not used the strength training device or chosen loads less than 30 % of the body mass the leg-muscle maximum strength and thigh endurance were decreased substantially on day 4 of return and all the more by day 15 back on Earth.


2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Chelsea A. Weitekamp ◽  
Allison Kvasnicka ◽  
Scott P. Keely ◽  
Nichole E. Brinkman ◽  
Xia Meng Howey ◽  
...  

Abstract Background Across taxa, animals with depleted intestinal microbiomes show disrupted behavioral phenotypes. Axenic (i.e., microbe-free) mice, zebrafish, and fruit flies exhibit increased locomotor behavior, or hyperactivity. The mechanism through which bacteria interact with host cells to trigger normal neurobehavioral development in larval zebrafish is not well understood. Here, we monoassociated zebrafish with either one of six different zebrafish-associated bacteria, mixtures of these host-associates, or with an environmental bacterial isolate. Results As predicted, the axenic cohort was hyperactive. Monoassociation with three different host-associated bacterial species, as well as with the mixtures, resulted in control-like locomotor behavior. Monoassociation with one host-associate and the environmental isolate resulted in the hyperactive phenotype characteristic of axenic larvae, while monoassociation with two other host-associated bacteria partially blocked this phenotype. Furthermore, we found an inverse relationship between the total concentration of bacteria per larvae and locomotor behavior. Lastly, in the axenic and associated cohorts, but not in the larvae with complex communities, we detected unexpected bacteria, some of which may be present as facultative predators. Conclusions These data support a growing body of evidence that individual species of bacteria can have different effects on host behavior, potentially related to their success at intestinal colonization. Specific to the zebrafish model, our results suggest that differences in the composition of microbes in fish facilities could affect the results of behavioral assays within pharmacological and toxicological studies.


Sign in / Sign up

Export Citation Format

Share Document