Effect of eccentric exercise on position sense at the human forearm in different postures

2006 ◽  
Vol 100 (4) ◽  
pp. 1109-1116 ◽  
Author(s):  
L. D. Walsh ◽  
T. J. Allen ◽  
S. C. Gandevia ◽  
U. Proske
Keyword(s):  
Eccentric Exercise ◽  
Human Subjects ◽  
Vertical Plane ◽  
Positional Information ◽  
Position Sense ◽  
Matching Task ◽  
Position Errors ◽  
Before And After ◽  
The Relationship ◽  
Minimal Effort

This is a study of the ability of blindfolded human subjects to match the position of their forearms before and after eccentric exercise. The hypothesis tested was that the sense of effort contributed to forearm position sense. The fall in force after the exercise was predicted to alter the relationship between effort and force and thereby induce position errors. In the arms-in-front posture, subjects had their unsupported reference arm set to one of two angles from the horizontal, 30 or 60°, and they matched its position by voluntary placement of their other arm. Matching errors were compared with a task where the arms were counterweighted, so could be moved in the vertical plane with minimal effort, and where the arms were moved in the horizontal plane. In these latter two tasks, the intention was to test whether removal of an effort sensation from holding the arm against gravity influenced matching performance. It was found that, although absolute errors for counterweighted and horizontal matching were no larger than for unsupported matching, their standard deviations, 6.1 and 6.8°, respectively, were significantly greater than for unsupported matching (4.6°), indicating more erratic matching. The eccentric exercise led, the next day, to a fall in maximum voluntary muscle torque of ≥15%. This was accompanied by a significant increase in matching errors for the unsupported matching task from 2.7 ± 0.5 to 0.8 ± 0.7° but not for counterweighted (1.4 ± 0.2 to −0.2°± 1.1°) or horizontal matching (−1.3 ± 0.7° to −1.8 ± 0.7°). This, it is postulated, is because the reduced voluntary torque after exercise was accompanied by a greater effort required to support the arms, leading to larger matching errors. However, effort is only able to provide positional information for unsupported matching where gravity plays a role. In gravity-neutral tasks like counterweighted or horizontal matching, a change in the effort-force relationship after exercise leaves matching accuracy unaffected.

scholarly journals Inter-joint coupling of position sense reflects sensory contributions of biarticular muscles

2021 ◽  
Author(s):  
Troy M. Herter ◽  
Isaac L. Kurtzer ◽  
Lauren M. Granat ◽  
Frédéric Crevecoeur ◽  
Sean P. Dukelow ◽  
...  
Keyword(s):  
Human Subjects ◽  
Sensory Information ◽  
Position Sense ◽  
Matching Task ◽  
Limb Position ◽  
Arm Position ◽  
Joint Coupling ◽  
Position Errors ◽  
Biarticular Muscles ◽  
Joint Coordinates

Perception of limb position and motion combines sensory information from spindles in muscles that span one joint (monoarticulars) and two joints (biarticulars). This anatomical organization should create interactions in estimating limb position. We developed two models, one with only monoarticulars (MO Model) and one with monoarticulars and biarticulars (MB Model), to explore how biarticulars influence estimates of arm position in hand (x,y) and joint (shoulder,elbow) coordinates. In hand coordinates, both models predicted larger medial-lateral than proximal-distal errors, though the MB Model predicted that biarticulars would reduce this bias. In contrast, the two models made significantly different predictions in joint coordinates. The MO Model predicted that errors would be uniformly distributed because estimates of angles at each joint would be independent. In contrast, the MB Model predicted that errors would be coupled between the two joints, resulting in smaller errors for combinations of flexion or extension at both joints and larger errors for combinations of flexion at one joint and extension at the other joint. We also carried out two experiments to examine errors made by human subjects during an arm position matching task in which an robot passively moved one arm to different positions and the subjects moved their other arm to mirror-match each position. Errors in hand coordinates were similar to those predicted by both models. Critically, however, errors in joint coordinates were only similar to those predicted by the MB Model. These results highlight how biarticulars influence perceptual estimates of limb position by helping to minimize medial-lateral errors.

Adaptation of B and A cell function during prolonged glucose infusion in human subjects

1984 ◽  
Vol 246 (5) ◽  
pp. E405-E411 ◽  
Author(s):  
W. K. Ward ◽  
J. B. Halter ◽  
J. C. Beard ◽  
D. Porte
Keyword(s):  
Cell Function ◽  
Human Subjects ◽  
Glucose Infusion ◽  
Healthy Men ◽  
Before And After ◽  
Mild Hyperglycemia ◽  
A Cell ◽  
Per Se ◽  
Insulin Responses ◽  
The Relationship

States of insulin resistance are characterized by hyperinsulinemia that often appears to be out of proportion to the minimal degree of hyperglycemia. One possible explanation for these findings is that mild hyperglycemia per se can cause an adaptive increase in islet sensitivity to glucose, leading to increased insulin output at a given glucose level. To test this hypothesis, we compared acute insulin responses (AIR) and acute glucagon responses (AGR) to 5-g arginine injections before and after 20-h glucose infusions (200 mg X m-2 X min-1) in 11 healthy men of varying age and degree of adiposity. The 20-h glucose infusion caused an increase in fasting plasma glucose (PG) in all subjects (95 +/- 2 vs. 130 +/- 3 mg/dl). PG was clamped at three levels (approximately 95, 165, and 235 mg/dl) before and after the 20-h glucose infusion. Despite matching of PG levels, consistent increases of AIR were observed after the 20-h glucose infusion: 86 +/- 10 vs. 57 +/- 8 at PG = 95 (P = 0.002); 241 +/- 20 vs. 192 +/- 22 at PG = 165 (P = 0.02); and 508 +/- 59 vs. 380 +/- 50 microU/ml at PG = 235 mg/dl (P = 0.009). In addition, the slope of the relationship between AIR and PG level (potentiation slope), a measure of B cell sensitivity to glucose, increased consistently from 2.28 +/- 0.35 (control) to 3.07 +/- 0.45 (P = 0.004) after the 20-h infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Effects of side-dominance on knee joint proprioceptive target-matching asymmetries

2018 ◽  
Vol 105 (3) ◽  
pp. 257-265 ◽  
Author(s):  
K Galamb ◽  
B Szilágyi ◽  
OM Magyar ◽  
T Hortobágyi ◽  
R Nagatomi ◽  
...  
Keyword(s):  
Knee Joint ◽  
Right Hemisphere ◽  
Position Sense ◽  
Matching Task ◽  
Isokinetic Dynamometer ◽  
Absolute Position ◽  
Position Errors ◽  
Side Dominance ◽  
Target Matching ◽  
Hemisphere Specialization

Aims Right- and left-side-dominant individuals reveal target-matching asymmetries between joints of the dominant and non-dominant upper limbs. However, it is unclear if such asymmetries are also present in lower limb’s joints. We hypothesized that right-side-dominant participants perform knee joint target-matching tasks more accurately with their non-dominant leg compared to left-side-dominant participants. Methods Participants performed position sense tasks using each leg by moving each limb separately and passively on an isokinetic dynamometer. Results Side-dominance affected (p < 0.05) knee joint absolute position errors only in the non-dominant leg but not in the dominant leg: right-side-dominant participants produced less absolute position errors (2.82° ± 0.72°) with the non-dominant leg compared to left-side-dominant young participants (3.54° ± 0.33°). Conclusions In conclusion, right-side-dominant participants tend to perform a target-matching task more accurately with the non-dominant leg compared to left-side-dominant participants. Our results extend the literature by showing that right-hemisphere specialization under proprioceptive target-matching tasks may be not evident at the lower limb joints.

scholarly journals Assessing Proprioceptive Function: Evaluating Joint Position Matching Methods Against Psychophysical Thresholds

2014 ◽  
Vol 94 (4) ◽  
pp. 553-561 ◽  
Author(s):  
Naveen Elangovan ◽  
Amanda Herrmann ◽  
Jürgen Konczak
Keyword(s):  
Position Sense ◽  
Matching Task ◽  
Joint Position ◽  
Active Motion ◽  
Matching Methods ◽  
Position Errors ◽  
Orthopedic Injury ◽  
Threshold Testing ◽  
Opposite Limb ◽  
Proprioceptive Function

Background The importance of assessing proprioceptive function for rehabilitation after neurological or orthopedic injury has long been recognized. Yet, neither the validity nor the accuracy of the available tests is firmly established. Testing typically involves repeated matching of a given joint position with the same or opposite limb where the difference between the 2 positions indicates proprioceptive acuity. Objectives The aim of this study was to compare position sense acuity between ipsilateral and contralateral matching methods against a psychophysical threshold method to establish the accuracy and relationships between these models. Design A repeated-measures design was used. Method Assessment of forearm position sense for a 10-degree reference position in 27 young adults who were healthy. Results Psychophysical thresholds were revealed to be the most precise and least variable acuity measure. The mean (±SD) threshold (1.05°±0.47°) was significantly lower than mean position errors obtained by both joint position matching tasks (ipsilateral: 1.51°±0.64°; contralateral: 1.84°±0.73°)—a 44% to 75% difference in measurement accuracy. Individual participant position errors correlated poorly with respective thresholds, indicating a lack of concurrent validity. Position errors for both matching methods correlated only mildly with each other. Limitations The data represent performance of a healthy, young adult cohort. Differences between methods will likely be more pronounced in aging and clinical populations. Conclusions Threshold testing and joint position matching methods examine different physiological aspects of proprioceptive function. Because threshold testing is based on passive motion, it most closely reflects afferent sensory feedback processing (ie, proprioception). Matching methods require active motion and are consequently influenced by additional sensorimotor processes. Factors such as working memory and transmission between brain hemispheres also influence joint matching task outcomes.

Enhancing Spatial Ability Through Sport Practice

2012 ◽  
Vol 33 (2) ◽  
pp. 83-88 ◽  
Author(s):  
David Moreau ◽  
Jérome Clerc ◽  
Annie Mansy-Dannay ◽  
Alain Guerrien
Keyword(s):  
Mental Rotation ◽  
Spatial Representations ◽  
Mental Rotation Test ◽  
Sport Training ◽  
Sport Practice ◽  
Undergraduate University Students ◽  
Before And After ◽  
Cognitive Plasticity ◽  
Reported Data ◽  
The Relationship

This experiment investigated the relationship between mental rotation and sport training. Undergraduate university students (n = 62) completed the Mental Rotation Test ( Vandenberg & Kuse, 1978 ), before and after a 10-month training in two different sports, which either involved extensive mental rotation ability (wrestling group) or did not (running group). Both groups showed comparable results in the pretest, but the wrestling group outperformed the running group in the posttest. As expected from previous studies, males outperformed women in the pretest and the posttest. Besides, self-reported data gathered after both sessions indicated an increase in adaptive strategies following training in wrestling, but not subsequent to training in running. These findings demonstrate the significant effect of training in particular sports on mental rotation performance, thus showing consistency with the notion of cognitive plasticity induced from motor training involving manipulation of spatial representations. They are discussed within an embodied cognition framework.

Klein with Lacan: A Study on the Reception of Lacanian Ideas in Uruguay and Its Effects on Clinical Practices (1955–82)

2020 ◽  
Vol 22 (3) ◽  
pp. 341-361
Author(s):  
Gonzalo Grau-Pérez ◽  
J. Guillermo Milán
Keyword(s):  
Clinical Practice ◽  
Clinical Material ◽  
Clinical Practices ◽  
Before And After ◽  
The Difference ◽  
The 1960S ◽  
The Relationship ◽  
Discursive Approach ◽  
The Way ◽  
Clinical Cases

In Uruguay, Lacanian ideas arrived in the 1960s, into a context of Kleinian hegemony. Adopting a discursive approach, this study researched the initial reception of these ideas and its effects on clinical practices. We gathered a corpus of discursive data from clinical cases and theoretical-doctrinal articles (from the 1960s, 1970s and 1980s). In order to examine the effects of Lacanian ideas, we analysed the difference in the way of interpreting the clinical material before and after Lacan's reception. The results of this research illuminate some epistemological problems of psychoanalysis, especially the relationship between theory and clinical practice.

STUDY ON THE RELATIONSHIP BETWEEN PARASITIC INFECTION AND KNOWLEDGE, HYGIENIC PRACTICAL MEASURES OF PARASITIC INFECTIOUS PREVENTION IN VINH THAI COMMUNITY

2017 ◽  
pp. 119-124
Author(s):  
Keyword(s):  
Health Education ◽  
Risk Behaviors ◽  
Ascaris Lumbricoides ◽  
Intestinal Parasite ◽  
Parasitic Infection ◽  
Parasite Infection ◽  
Intestinal Parasite Infection ◽  
Before And After ◽  
Parasite Infections ◽  
The Relationship

Introduction: Intestinal parasite infections werecommonintropical country such as Vietnam. Having good knowledge of parasitic infectious prevention and changing risk behaviors can decrease the infection rate. Objective: To evaluate the parasitic infectious rate in Vinh Thai community before and after being health education and the changing of knowledge of parasitic infectious prevention and risk behaviors. Materials and methods: 60 households in Vinh Thai commune were interviewed their knowledge of parasitic infectious prevention and examined intestinal parasite infection by Kato technique and then trained the knowledge of parasitic infectious prevention. The interview and examination parasite infectiousrate were carried out after 6 months to evaluating their knowledge. Result: Before health education, the rate of intestinal parasite infection was 17.4% with the prevalence of Ascaris lumbricoides, hookworm, whipworm, pinworm, small fluke worm and co-infection with A. lumbricoides - whipworm, hookworm-whipworm were 0.1%; 8.0%; 5.8%; 0.6%; 0.3%; 1.2% and 3.0% respectively. Six months later the rate of intestinal parasite infection was decreased in 12.6% even though not statistical significantly. However, there were no case of small fluke worm and co-infection with hookworm-whipworm. Receiving health education, their knowledge of parasitic infectious prevention was higher significantly but their risk behaviors were not changed so much. Conclusion: Health education can change the rate of parasite infection with higher knowledge of parasitic infectious prevention but it was necessary continuous study to change the risk behaviors. Key words: intestinal parasite, health education

Sunlight exposure: the effects on the performance of paragliding fabric

2018 ◽  
Vol 69 (05) ◽  
pp. 381-389
Author(s):  
MENGÜÇ GAMZE SÜPÜREN ◽  
TEMEL EMRAH ◽  
BOZDOĞAN FARUK
Keyword(s):  
Mechanical Properties ◽  
Aging Process ◽  
Air Permeability ◽  
Sunlight Exposure ◽  
Test Results ◽  
Coating Materials ◽  
Strength Tests ◽  
Before And After ◽  
The Relationship ◽  
Dark Blue

This study was designed to explore the relationship between sunlight exposure and the mechanical properties of paragliding fabrics which have different colors, densities, yarn counts, and coating materials. This study exposed 5 different colors of paragliding fabrics (red, turquoise, dark blue, orange, and white) to intense sunlight for 150 hours during the summer from 9:00 a.m. to 3:00 p.m. for 5 days a week for 5 weeks. Before and after the UV radiation aging process, the air permeability, tensile strength, tear strength, and bursting strength tests were performed. Test results were also evaluated using statistical methods. According to the results, the fading of the turquoise fabric was found to be the highest among the studied fabrics. It was determined that there is a significant decrease in the mechanical properties of the fabrics after sunlight exposure. After aging, the fabrics become considerably weaker in the case of mechanical properties due to the degradation in both the dyestuff and macromolecular structure of the fiber

APPLICATION OF THE ATP-BIOLUMINESCENCE METHOD TO ASSESS THE QUALITY OF SANITATION OF MILKING EQUIPMENT

2020 ◽  
Vol 1 (4) ◽  
pp. 468-472
Author(s):  
P.A. Popov ◽  
◽  
D.V. Gruznov ◽  
S.V. Tokarev ◽  
◽  
...  
Keyword(s):  
Dairy Farms ◽  
Laboratory Studies ◽  
Before And After ◽  
Atp Bioluminescence ◽  
Microbial Number ◽  
Proportional Relationship ◽  
The Relationship ◽  
Number Of Bacteria ◽  
Bioluminescence Method

The article presents the results of determining the relationship between the total microbial number and microbial ATP on the surface of milking equipment before and after treatment with neutral anolyte ANK-SUPER. The possibility of using the ATP-bioluminescence method to control the quality of sanitation of milking equipment on dairy farms is shown. Laboratory studies revealed a proportional relationship between the level of bacterial ATP and the number of bacteria on the surface of milking equipment before and after sanitation.

scholarly journals Post-Drive Standing Balance of Vehicle Passengers Using Wearable Sensors: The Effect of On-Road Driving and Task Performance

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 4997
Author(s):  
Victor C. Le ◽  
Monica L. H. Jones ◽  
Kathleen H. Sienko
Keyword(s):  
Task Performance ◽  
Postural Sway ◽  
Wearable Sensors ◽  
Standing Balance ◽  
Balance Performance ◽  
Real Time Traffic ◽  
Balance Exercises ◽  
Before And After ◽  
The Relationship ◽  
And Task

Postural sway has been demonstrated to increase following exposure to different types of motion. However, limited prior studies have investigated the relationship between exposure to normative on-road driving conditions and standing balance following the exposure. The purpose of this on-road study was to quantify the effect of vehicle motion and task performance on passengers’ post-drive standing balance performance. In this study, trunk-based kinematic data were captured while participants performed a series of balance exercises before and after an on-road driving session in real-time traffic. Postural sway for all balance exercises increased following the driving session. Performing a series of ecologically relevant visual-based tasks led to increases in most post-drive balance metrics such as sway position and velocity. However, the post-drive changes following the driving session with a task were not significantly different compared to changes observed following the driving session without a task. The post-drive standing balance performance changes observed in this study may increase vulnerable users’ risk of falling. Wearable sensors offer an opportunity to monitor postural sway following in-vehicle exposures.

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