scholarly journals Adaptation to Coriolis perturbations of voluntary body sway transfers to preprogrammed fall-recovery behavior

2014 ◽  
Vol 111 (5) ◽  
pp. 977-983 ◽  
Author(s):  
Avijit Bakshi ◽  
Joel Ventura ◽  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Postural Sway ◽  
Body Sway ◽  
Forward Motion ◽  
Coriolis Forces ◽  
Adaptation Mechanisms ◽  
Before And After ◽  
Postural Correction ◽  
Fall Recovery ◽  
Voluntary Sway ◽  
Postural Recovery

In a rotating environment, goal-oriented voluntary movements are initially disrupted in trajectory and endpoint, due to movement-contingent Coriolis forces, but accuracy is regained with additional movements. We studied whether adaptation acquired in a voluntary, goal-oriented postural swaying task performed during constant-velocity counterclockwise rotation (10 RPM) carries over to recovery from falling induced using a hold and release (H&R) paradigm. In H&R, standing subjects actively resist a force applied to their chest, which when suddenly released results in a forward fall and activation of an automatic postural correction. We tested H&R postural recovery in subjects ( n = 11) before and after they made voluntary fore-aft swaying movements during 20 trials of 25 s each, in a counterclockwise rotating room. Their voluntary sway about their ankles generated Coriolis forces that initially induced clockwise deviations of the intended body sway paths, but fore-aft sway was gradually restored over successive per-rotation trials, and a counterclockwise aftereffect occurred during postrotation attempts to sway fore-aft. In H&R trials, we examined the initial 10- to 150-ms periods of movement after release from the hold force, when voluntary corrections of movement path are not possible. Prerotation subjects fell directly forward, whereas postrotation their forward motion was deviated significantly counterclockwise. The postrotation deviations were in a direction consistent with an aftereffect reflecting persistence of a compensation acquired per-rotation for voluntary swaying movements. These findings show that control and adaptation mechanisms adjusting voluntary postural sway to the demands of a new force environment also influence the automatic recovery of posture.

scholarly journals Rapid adaptation to Coriolis force perturbations of voluntary body sway

2019 ◽  
Vol 121 (6) ◽  
pp. 2028-2041 ◽  
Author(s):  
Avijit Bakshi ◽  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Postural Control ◽  
Coriolis Force ◽  
Sagittal Plane ◽  
Postural Sway ◽  
Force Plate ◽  
Arm Movement ◽  
Mirror Image ◽  
Body Sway ◽  
Coriolis Forces ◽  
Voluntary Sway

Studying adaptation to Coriolis perturbations of arm movements has advanced our understanding of motor control and learning. We have now applied this paradigm to two-dimensional postural sway. We measured how subjects ( n = 8) standing at the center of a fully enclosed rotating room who made voluntary anterior-posterior swaying movements adapted to the Coriolis perturbations generated by their sway. Subjects underwent four voluntary sway trials prerotation, 20 per-rotation at 10 rpm counterclockwise, and 10 postrotation. Each trial lasted 20 s, and subjects were permitted normal vision. Their voluntary sway during rotation generated Coriolis forces that initially induced rightward deviations of their forward sway paths and leftward deviations of their backward sway. Sagittal plane sway was gradually restored over per-rotation trials, and a mirror image aftereffect occurred in postrotation trials. Dual force plate data analysis showed that subjects learned to counter the Coriolis accelerations during rotation by executing a bimodal torque pattern that was asymmetric across legs and contingent on forward vs. backward movement. The experience-dependent acquisition and washout of this compensation indicate that an internal, feedforward model underlies the leg-asymmetric bimodal torque compensation, contingent on forward vs. backward movement. The learned torque asymmetry we observed for forward vs. backward sway is not consistent with parallel two-leg models of postural control. NEW & NOTEWORTHY This paper describes adaptation to Coriolis force perturbations of voluntary sway in a rotating environment. During counterclockwise rotation, sway paths are deviated clockwise, but full restoration of fore-aft sway is regained in minutes. Negative aftereffects are briefly present postrotation. Current parallel leg models of postural control cannot account for these findings, which show that postural control, like arm movement control, can adapt rapidly and completely to the Coriolis forces generated in artificial gravity environments.

scholarly journals Adaptation to Coriolis force perturbations of postural sway requires an asymmetric two-leg model

2019 ◽  
Vol 121 (6) ◽  
pp. 2042-2060 ◽  
Author(s):  
Avijit Bakshi ◽  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Coriolis Force ◽  
Postural Sway ◽  
Balance Control ◽  
Force Plate ◽  
Companion Paper ◽  
Two Dimensions ◽  
Body Sway ◽  
Coriolis Forces ◽  
Movement Trajectories ◽  
Parameterized Model

In the companion paper (Bakshi A, DiZio P, Lackner JR. J Neurophysiol. In press, 2019), we reported how voluntary forward-backward sway in a rotating room generated medial-lateral Coriolis forces that initially deviated intended body sway paths. Pure fore-aft sway was gradually restored over per-rotation trials, and a negative aftereffect occurred during postrotation sway. Force plate recordings showed that subjects learned to compensate for the Coriolis forces by executing a bimodal torque, the distribution of which was asymmetric across the two legs and of opposite sign for forward vs. backward sway. To explain these results, we have developed an asymmetric, nonparallel-leg, inverted pendulum model to characterize upright balance control in two dimensions. Fore-aft and medial-lateral sway amplitudes can be biomechanically coupled or independent. Biomechanical coupling occurs when Coriolis forces orthogonal to the direction of movement perturb sway about the ankles. The model includes a mechanism for alternating engagement/disengagement of each leg and for asymmetric drive to the ankles to achieve adaptation to Coriolis force-induced two-dimensional sway. The model predicts the adaptive control underlying the adaptation of voluntary postural sway to Coriolis forces. A stability analysis of the model generates parameter values that match those measured experimentally, and the parameterized model simulations reproduce the experimentally observed sway trajectories. NEW & NOTEWORTHY This paper presents a novel nonparallel leg model of postural control that correctly predicts the perturbations of voluntary sway that occur in a rotating environment and the adaptive changes that occur to restore faithful movement trajectories. This engaged leg model (ELM) predicts the asymmetries in force distribution and their patterns between the two legs to restore accurate movement trajectories. ELM has clinical relevance for pathologies that generate postural asymmetries and for altered gravitoinertial force conditions.

scholarly journals Gender Differences in Postural Stability among 13-Year-Old Alpine Skiers

2020 ◽  
Vol 17 (11) ◽  
pp. 3859 ◽  
Author(s):  
Agnieszka D. Jastrzębska
Keyword(s):  
Gender Differences ◽  
Postural Balance ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Body Sway ◽  
Foot Pressure ◽  
Eyes Closed ◽  
Before And After ◽  
Eyes Open ◽  
Alpine Skiers

This experiment examined changes in body sway after Wingate test (WAnT) in 19 adolescents practicing alpine skiing, subjected to the same type of training load for 4–5 years (10 girls and nine boys). The postural examinations were performed with eyes open (EO), eyes closed (EC), and sway reverenced vision (SRV) in the medial-lateral (ML) and anterior-posterior (AP) planes. The displacement of center of foot pressure (CoP), range of sway (RS), mean sway velocity (MV), way length, and surface area were measured in bipedal upright stance before and after the WAnT to assess the influence of fatigue on postural balance. There were no significant differences in WAnT parameters between girls and boys. Relative peak power (RPP), relative total work (RWtot) were (girls vs. boys) 8.89 ± 0.70 vs. 9.57 ± 1.22 W/kg, p < 0.05 and 227.91 ± 14.98 vs. 243.22 ± 30.24 W/kg, p < 0.05 respectively. The fatigue index (FI) was also on similar level in both genders; however, blood lactate concentration (BLa) was significantly higher in boys (10.35 ± 1.16 mM) than in girls (8.67 ± 1.35 mM) p = 0.007. In the EO examination, statistically significant differences between resting and fatigue conditions in the whole group and after the division into girls and boys were found. In fatigue conditions, significant gender differences were noted for measurements in the ML plane (sway path and RS) and RS in the AP plane. Comparison of the three conditions shows differences between EO vs. EC and SRV in AP plane measured parameters, and for RS in ML plane in rest condition in girls. The strong correlations between FI and CoP parameters mainly in ML plane in the whole group for all examination conditions were noted. By genders, mainly RS in ML plane strongly correlates with FI (r > 0.7). No correlation was found between BLa and CoP parameters (p > 0.06). The presented results indicate that subjecting adolescents of both genders to the same training may reduce gender differences in the postural balance ability at rest but not in fatigue conditions and that girls are significantly superior in postural balance in the ML plane than boys. It was also shown that too little or too much information may be destructive to postural balance in young adolescents.

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.

Postural sway with earth-fixed and body-referenced finger contact in young and older adults

1999 ◽  
Vol 9 (2) ◽  
pp. 103-109
Author(s):  
Reginald L. Reginella ◽  
Mark S. Redfern ◽  
Joseph M. Furman
Keyword(s):  
Older Adults ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Sensory Information ◽  
Body Sway ◽  
Support Surface ◽  
Proprioceptive Information ◽  
Postural Control System ◽  
Fixed Reference ◽  
Older Subjects

Sensory information from lightly touching a reference with the hand is known to influence postural sway in young adults. The primary aim of this study was to compare the influence of finger contact (FC) with an earth-fixed reference to the influence of FC with a body-fixed reference. A second goal of this study was to determine if FC is used differently by older adults compared to younger adults. Using a force plate, center of pressure at the feet was recorded from blindfolded young and older subjects during several conditions. Subjects either did or did not lightly touch a force-sensitive plate that was either earth-fixed or moved forward and backward in synchrony with body sway (that is, sway-referenced). In addition, support surface conditions were also varied, including a fixed floor and a sway-referenced floor using an EquitestTM. Results showed that the type of FC, floor condition, and age each had an effect on postural sway. Touching an earth-fixed plate decreased postural sway as compared to no touching, while touching a sway-referenced plate incresased sway. This influence of FC was enhanced when the floor was sway-referenced. Although older subjects swayed more than young subjects overall, no age-FC interactions occurred, indicating that FC was not utilized differently between the age groups. This study suggests that FC cannot be disregarded as erroneous, especially when proprioceptive information from the legs is distorted. Further, FC is integrated with other sensory information by the postural control system similarly in young and older persons.

Musicians body sway embodies musical structure and expression: A recurrence-based approach

2017 ◽  
Vol 22 (2) ◽  
pp. 244-263 ◽  
Author(s):  
Alexander P. Demos ◽  
Roger Chaffin ◽  
Topher Logan
Keyword(s):  
Serial Position ◽  
Linear Models ◽  
Postural Sway ◽  
Statistical Tests ◽  
Body Sway ◽  
Musical Structure ◽  
Mixed Linear Models ◽  
Self Similarity ◽  
Performance Style ◽  
The Relationship

Musicians’ sway during performance seems to be related to musical structure. However, it has yet to be shown that examples of the relationship are not simply due to chance. Progress has been impeded by three problems: the assumption that musical structure is constant across performances; the complexity of the movements; and the inability of traditional statistical tests to accurately model the multilevel temporal hierarchies involved. We solved these problems in a study of the side-to-side postural sway of two trombonists as they each recorded two performances of each of two solo pieces in each of three different performance styles (normal, expressive, non-expressive). The musicians reported their phrasing immediately after each performance by marking copies of the score. We measured the rate and stability (mean line) of recurrence (self-similarity) and assessed the effect of serial position within a phrase, using mixed linear models to model the nesting of phrases within pieces, within performances, across expressive styles and musicians. Recurrence and stability of recurrence changed systematically across the course of a phrase, producing sinusoidal-like and arch-shaped phrasing contours that differed with the performance style and length of phrase. As long suspected, musicians’ expressive movements reflect musical structure.

Contribution of Somatosensory and Parietal Association Areas in Improving Standing Postural Stability Through Standing Plantar Perception Training in Community-Dwelling Older Adults

2020 ◽  
pp. 1-10
Author(s):  
Satoshi Matsuno ◽  
Takuya Yoshiike ◽  
Atsushi Yoshimura ◽  
Sachiyo Morita ◽  
Yusuke Fujii ◽  
...  
Keyword(s):  
Older Adults ◽  
Postural Stability ◽  
Near Infrared ◽  
Postural Sway ◽  
Cortical Activity ◽  
Community Dwelling ◽  
Training Outcomes ◽  
Before And After ◽  
Association Area ◽  
Perception Training

Although standing plantar perception training (SPPT) may improve standing postural stability, the underlying neural mechanisms remain unclear. The authors investigated the relationship between regional cortical responses to SPPT using a balance pad and training outcomes in 32 older participants (mean ± SD:72.2 ± 6.0, range:60–87). Regional cortical activity was measured in the bilateral supplementary motor area, primary sensorimotor area, and parietal association area using near-infrared spectroscopy. Postural sway changes were compared before and after SPPT. Changes in two-point plantar discrimination and regional cortical activity during SPPT, associated with standing postural stability improvements, were examined using multiple regression and indicated improved standing postural stability after SPPT (p < .0001). Changes in right parietal association area activity were associated with standing postural stability improvements while barefoot. Overall, the results suggest that right parietal association area activation during SPPT plays a crucial role in regulating standing postural stability and may help develop strategies to prevent older adults from falling.

Reliability of Force-Platform Measures of Postural Sway and Expertise-Related Differences

2011 ◽  
Vol 20 (4) ◽  
pp. 442-456 ◽  
Author(s):  
Zohreh Meshkati ◽  
Mehdi Namazizadeh ◽  
Mahyar Salavati ◽  
Masood Mazaheri
Keyword(s):  
Outcome Measures ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Intraclass Correlation ◽  
Specific Property ◽  
Force Platform ◽  
Quiet Standing ◽  
Eyes Closed ◽  
Before And After ◽  
Eyes Open

Context:Although reliability is a population-specific property, few studies have investigated the measurement error associated with force-platform parameters in athletic populations.Objective:To investigate the skill-related differences between athletes and nonathletes in reliability of center-of-pressure (COP) summary measures under eyes-open (EO) and eyes-closed (EC) conditions.Design:Test–retest reliability study.Setting:COP was recorded during double-leg quiet standing on a Kistler force platform before and after a fatiguing treadmill exercise, with EO and EC.Participants:31 male participants including 15 athletes practiced in karate and 16 nonathletes.Main Outcome Measures:Standard deviation (SD) of amplitude, phase-plane portrait, SD of velocity, mean total velocity, and area were calculated from 30-s COP data. Intraclass correlation coefficient (ICC), standard error of measurement, and coefficient of variation (CV) were used as estimates of reliability and precision.Results:Higher ICCs were found for COP measures in the athlete (compared with the nonathlete) group, postfatigued (compared with prefatigued) condition, and EC (compared with EO) tests. CVs smaller than 15% were obtained for most of the COP measures. SD of velocity in the anteroposterior direction showed the highest reliability in most conditions.Conclusions:Tests with EC and to a lesser extent tests performed in the athlete group and in the postfatigued condition showed better reliability.

Effect of Plantar Flexor and Dorsiflexor Fatigue on Unilateral Postural Control

1993 ◽  
Vol 9 (3) ◽  
pp. 191-201 ◽  
Author(s):  
Thomas M. Lundin ◽  
Jon W. Feuerbach ◽  
Mark D. Grabiner
Keyword(s):  
Ankle Joint ◽  
Postural Sway ◽  
Plantar Flexor ◽  
Plantar Flexors ◽  
Joint Injury ◽  
Balance System ◽  
Fatigue Protocol ◽  
Before And After ◽  
Ankle Muscle ◽  
Male Subjects

The purpose of this study was to determine the effect of plantar flexor and dorsiflexor fatigue on postural sway amplitude during unilateral, or one-legged, stance. It was hypothesized that plantar flexor and dorsiflexor fatigue would increase unilateral postural sway amplitude. Eight uninjured male subjects participated in pre- and postfatigue unilateral stability tests. Selected parameters describing medial-lateral (ML) and anterior-posterior (AP) postural sway were measured on a Chattecx Balance System before and after an isokinetic fatigue protocol. The fatigue protocol resulted in a significant increase in ML postural sway amplitude (p< 0.05) and an increase in AP sway amplitude (p= 0.065). Previously, links have been established between increased postural sway amplitude and ankle joint injury. Thus, fatigue of the plantar flexors and dorsiflexors, which increased postural sway amplitude, may render the ankle joint susceptible to injury. Induced ankle muscle fatigue may represent a valid paradigm to study the causes of traumatic ankle joint injury.

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