Postural Sway

Gymnasts are known to practice and compete although suffering from injuries and pain. Pain may change strategies for postural control. The primary aim of the present study was to investigate how center of pressure (COP) measurements are influenced by low back pain and lower extremity injury in top-level female gymnasts. A secondary aim was to study the reliability of these measurements using a test-retest design, and how this depends on the duration of the test. Fifty-seven top-level gymnasts were included in four groups: non-injured (NI, n=18), low back pain (LBP, n=11), lower extremity injury (LEI, n=17) and a multiple injury group (MI, n=11). COP excursion during quiet stance was measured on a force platform, during 120s: (1) hard surface/eyes open, (2) hard surface/eyes closed, (3) foam surface/eyes open and (4) foam surface/eyes closed. The COP excursion increased, for all groups, during the foam surface/eyes closed measurement compared to the other three tests. Furthermore, the LBP group showed a 49% (p=0.01) larger COP area compared to the LEI group in the foam surface/eyes closed condition. Measurements on foam surface were in general more reliable than tests on hard surface and tests with eyes closed were more reliable than tests with eyes open. Tests during 120s were in most cases more reliable than tests during 60s. In conclusion the COP excursion is influenced by injury location. Quiet stance measurements on foam surface with eyes closed seems to be reliable and sensitive in young female gymnasts.

Le but de cette étude était d'examiner l'effet d'un programme d'activités physiques sur la stabilité et le contrôle attentionnel de la posture lors de la réalisation concomitante d'une tâche cognitive attentionnelle chez des personnes âgées en perte d'autonomie.Douze personnes âgées (M = 81,4 ± 9 ans), institutionnalisées en structure gériatrique ont participé à un programme d'activités physiques de type posture–équilibration–motricité (PEM) pendant 12 semaines à raison de deux séances d'une heure par semaine. Les paramètres stabilométriques de surface et de longueur du trajet parcouru par le centre de pression plantaire (CPP), les yeux ouverts (YO) et les yeux fermés (YF), en condition simple-tâche et en condition double-tâche sur sol dur ont été analysés avant et après le programme d'entraînement. En condition double-tâche, les sujets effectuaient, lors de l'évaluation stabilométrique, une tâche cognitive attentionnelle de génération de chiffres aléatoires.Les principaux résultats ont révélé que seule la longueur du trajet parcouru par le CPP était plus importante en condition double-tâche qu'en condition simple-tâche (p = 0,05). Lors de l'évaluation initiale, la performance à la tâche cognitive était significativement moins bonne en condition double-tâche (debout) qu'en condition simple-tâche (assis), seulement dans la modalité YF mais pas dans la modalité YO (p < 0,05). Toutefois, à l'issue du programme d'entraînement, les performances à la tâche cognitive ne se différenciaient plus (n.s.) pour les deux conditions assis YF et debout YF.L'entraînement a permis d'améliorer la capacité des sujets à réaliser une tâche mentale attentionnelle tout en maintenant un équilibre correct, notamment les yeux fermés. Bien que les performances stabilométriques semblaient moins bonnes en condition double-tâche qu'en condition simple-tâche, ces résultats pourraient être interprétés comme une amélioration, suite au programme d'entraînement, du contrôle attentionnel du maintien de la posture. Les limites méthodologiques de cette étude sont ensuite discutées.We aimed to examine the effect of a physical activity program on postural sway and on the attentional control of postural abilities in elderly frail adults.Twelve older adults (age 81.4 ± 9 years) institutionalised in a geriatric care institution participated in the physical activity program posture–balance–mobility (PBM) twice a week (1 hour per session) for 12 weeks. We analysed stabilometric data for surface and length of the center of pressure (COP) sway, with eyes open and eyes closed, under single-task and dual-task conditions on a firm floor before and after the training program. During the static postural evaluation and under the dual-task condition, subjects performed an attention-demanding cognitive task, the random number generation task.Only the length of COP sway was more important under the dual-task condition than under the single-task condition (p = 0.05). At baseline, cognitive performance was significantly weaker under the dual-task condition (standing) than under the single-task condition (seated), with eyes closed but not eyes open (p < 0.05). However, after the training program, the performance of the cognitive task did not significantly differ between the dual-task condition with eyes closed and the single-task condition with eyes closed.The training program allowed elderly subjects to improve their ability to perform an attention-demanding cognitive task while standing still, in particular with their eyes closed. Although balance seemed to be less stable under the dual-task condition than under the single-task condition, these results could be interpreted as an improvement of the attentional control of postural stability.

A literature review examining conventional proprioceptive interventions (i.e. unstable surface training) and novel proprioceptive interventions (i.e. tactile and vibratory stimulation) of the ankle and foot on measures of proprioception (i.e. joint position sense, joint movement perception threshold) and balance/postural sway (i.e. center-of-pressure) in young healthy adults and those with FAI or acute ankle injury. Directives for ankle/foot rehabilitation protocols and propositions for future research are included.

This study asked whether individual differences in the influence of vision on postural stability could be used to predict the strength of subsequently induced visual illusions of self-motion (vection). In the experiment, we first measured spontaneous postural sway while subjects stood erect for 60 s with their eyes both open and both closed. We then showed our subjects two types of self-motion display: radially expanding optic flow (simulating constant velocity forwards self-motion) and vertically oscillating radially expanding optic flow (simulating constant velocity forwards self-motion combined with vertical head oscillation). As expected, subjects swayed more with their eyes closed (compared to open) and experienced more compelling illusions of self-motion with vertically oscillating (as opposed to smooth) radial flow. The extent to which participants relied on vision for postural stability – measured as the ratio of sway with eyes closed compared to open – was found to predict vection strength. However, this was only the case for displays representing smooth self-motion. It seems that for oscillating displays, other factors, such as visual-vestibular interactions, may be more important.

This pilot study aimed to show that information-free stimulation of the tongue can improve behavioral measures and induce sustained neuromodulation of the balance-processing network in individuals with balance dysfunction. Twelve balance-impaired subjects received one week of cranial nerve non-invasive neuromodulation (CN-NINM). Before and after the week of stimulation, postural sway and fMRI activation were measured to monitor susceptibility to optic flow. Nine normal controls also underwent the postural sway and fMRI tests but did not receive CN-NINM. Results showed that before CN-NINM balance-impaired subjects swayed more than normal controls as expected (p ≤ 0.05), and that overall sway and susceptibility to optic flow decreased after CN-NINM (p ≤ 0.005 & p ≤ 0.05). fMRI showed upregulation of visual sensitivity to optic flow in balance-impaired subjects that decreased after CN-NINM. A region of interest analysis indicated that CN-NINM may induce neuromodulation by increasing activity within the dorsal pons (p ≤ 0.01).

The aim of the central nervous system in upright stance is to control an intrinsically unstable plant. Internal disturbances, such as hæmodynamics and respiration, constitute an endogenous threat to equilibrium. The way CNS reacts to those perturbations was studied in this work, through the analysis of summary scores taken from posturographic and pneumographic data. Signals were recorded simultaneously during trials administered on a sample population of healthy young adults, while sitting and standing and at paced and spontaneous uncontrolled breathing. The extraction of posturographic and pneumographic parameters was accompanied by the utilization of techniques for the detection of phase synchronization in bivariate data, and the extraction of an interaction index, the mutual information MI. The effects of the biomechanical condition and respiratory amplitude on MI and summary measures were tested with a two-way ANOVA. Summary scores clearly depend on posture condition. Synchronization between breath and postural sway is always present, depends on both biomechanical condition and respiratory threat, and cannot be reduced to a simple linear relation.

The aim of this study is to examine the effect of eight-week core and balance training on single-leg sway parameters and well-directed kick of male soccer players. 24 male players of an amateur soccer club aged 14 to 15 participated in the study. The participants were randomized into an experimental group (EG, n=12) performing core and balance trainings with soccer training and a control group (CG, n=12) performing only their routine soccer training programs for 8 weeks. Biodex Balance SD (Biodex Inc., Shirley, NY) device was used to measure single-leg sway parameters and Mor–Christian general aptitude soccer test was used to evaluate well-directed kick. EG athletes showed statistically better results in well-direct kick and dominant-leg-sway parameters than CG athletes (p < 0.05) while there was not seen any changes on non-dominant leg sway parameters (p > 0.05). When classical soccer practice supported by core and unstable surface exercises, possible developments in balance affects dominant and non-dominant legs of athletes to achieve in soccer the necessary skills more easily so it can be concluded that regular soccer training with core and balance exercises would be particularly effective in improving balance parameters and soccer skills.

Objectives: To determine whether an individualized falls prevention program comprising exercise, visual, and counseling interventions can reduce physiological falls risk and falls in older people.Design: Randomized, controlled trial of 12 months' duration.Setting: Falls Clinic, Royal North Shore Hospital, Sydney, Australia.Participants: Six hundred twenty people aged 75 and older recruited from a health insurance company membership database.Interventions: Participants in the extensive intervention group (EIG) received individualized interventions comprising exercise and strategies for maximizing vision and sensation; the minimal intervention group (MIG) received brief advice; and the control group (CG) received no intervention.Measurements: Accidental falls, vision, postural sway, coordinated stability, reaction time, lower limb muscle strength, sit-to-stand performance, and physiological profile assessment (PPA) falls risk scores.Results: At the 6-month follow-up, PPA falls risk scores were significantly lower in the EIG than in the CG. EIG subjects assigned to the extensive exercise intervention group showed significant improvements in tests of knee flexion strength and sit-to-stand times but no improvements in balance. EIG subjects assigned to the extensive visual intervention group showed significant improvements in tests of visual acuity and contrast sensitivity. The rate of falls and injurious falls within the trial period were similar in the three groups.Conclusion: The individualized intervention program reduced some falls risk factors but did not prevent falls. The lack of an effect on falls may reflect insufficient targeting of the intervention to an at-risk group.