Firm Floor Research Articles

Influences of visual and supporting surface conditions on standing postural control and correlation with walking ability in patients with post-stroke hemiplegia.

[Purpose] To quantify the influence of visual and under-foot-surface conditions on standing balance in patients with post stroke hemiplegia and examine associations of this ordinal score with somatosensory disturbance and walking ability. [Subjects] Sixty-six patients with post-stroke hemiplegia. [Methods] Standing balance was tested in 4 conditions (firm floor or foam rubber surface with eyes open or eyes closed) for 30 s per condition and scored using a 5-category ordinal scale. The accuracy of the standing balance score to distinguish patients above/below cut-offs for the timed up-and-go test (14 s) and functional ambulation category (4) was determined. [Results] Standing balance score was correlated with sensory impairments (tactile and vibration perception) and walking ability (up-and-go and functional ambulation category). The standing balance score distinguished patients with up-and-go times ≤14 and >14 s with moderate sensitivity and specificity, and distinguished patients with functional ambulation category <4 and ≥4 with high sensitivity and specificity. [Conclusion] Patients with post-stroke hemiplegia may be unable to adapt to changing visual or surface conditions. Therapists should perform comprehensive balance tests. The standing balance ordinal scale score was moderately correlate with walking ability, distinguishing patients according to walking ability. This scale’s validity and reliability must be assessed in clinical settings.

A Test of the Metabolic Cost of Cushioning Hypothesis during Unshod and Shod Running

This study aimed to investigate the effects of surface and shoe cushioning on the metabolic cost of running. In running, the leg muscles generate force to cushion the impact with the ground. External cushioning (surfaces or shoes) may reduce the muscular effort needed for cushioning and thus reduce metabolic cost. Our primary hypothesis was that the metabolic cost of unshod running would decrease with a more cushioned running surface. We also hypothesized that because of the counteracting effects of shoe cushioning and mass, unshod running on a hard surface would have approximately the same metabolic cost as running in lightweight, cushioned shoes. To test these hypotheses, we attached 10- and 20-mm-thick slats of the same foam cushioning used in running shoe midsoles to the belt of a treadmill that had a rigid deck. Twelve subjects who preferred a midfoot strike pattern and had substantial barefoot/minimalist running experience ran without shoes on the normal treadmill belt and on each thickness of foam. They also ran with lightweight, cushioned shoes on the normal belt. We collected V˙O2 and V˙CO2 to calculate the metabolic power demand and used a repeated-measures ANOVA to compare between conditions. Compared to running unshod on the normal belt, running unshod on the 10-mm-thick foam required 1.63% ± 0.67% (mean ± SD) less metabolic power (P = 0.034) but running on the 20-mm-thick foam had no significant metabolic effect. Running with and without shoes on the normal belt had similar metabolic power demands, likely because the beneficial energetic effects of cushioning counterbalanced the detrimental effects of shoe mass. On average, surface and shoe cushioning reduce the metabolic power required for submaximal running.

La muerte, redención artística de la vida Bernhard y el fracaso de la ética individualista

The author's intention is to show the peculiar perspective that has about the death one of the most polemic and brilliant writers in German language of the last century: Thomas Bernhard. For it, he will be centered it in the study of one of his works summit, Correction. The essay is structured around four topics: (1) the social, political and cultural context of the Austria Feliz, context that is at the time obsessive mark of a merciless work and firm floor that sustains it. (2) The problem of the authenticity in the Bernhard’s writings, in short, two topics: the liberating function of the work of art and the necessity of the lie for the preservation of the life. (3) The characterization of the death, not like mal, terrifying for unbeatable; but like redeemer place in which the artist's lucid vision finds the rest of itself and of a miserable and corrupt reality. (4) The opposition between the socio-political analysis of the scandal of the death, characteristic in the Correction and the metaphysical approximation to that problem, characteristic of three perspectives about the particularly consistent death: the epicurean, the Christian and the schopenhauariana.

Comparison of Different Structural Foot Types for Measures of Standing Postural Control

Matched group comparison of 3 subject groups with 3 different foot structures for force plate and clinical measures of postural control. To determine if subjects with different weight-bearing foot structure would demonstrate differences in static standing postural control, and to determine the reliability of study procedures. Weight-bearing foot structure may influence postural control either because of a decreased base of support (supinated foot structure) or because of passive instability of the joints of the foot (pronated foot structure). Young adults were categorized based on weight-bearing foot structure into neutral, pronated, or supinated groups (15 subjects per group). Postural control in single-limb stance with eyes closed was assessed using force plate measures and by measuring duration of single-limb stance on a firm floor and on a balance pad. Force plate measures were normalized center-of-pressure average speed; and standard deviation and maximum displacement in the anterior-posterior and medial-lateral directions. Individuals in the supinated group had significantly greater center-of-pressure average speed, greater maximum displacement in the anterior-posterior direction, and greater SD and maximum displacement in the medial-lateral direction than individuals in the neutral group. The individuals in the pronated group had significantly greater SD and maximum displacement in the anterior-posterior direction, used more trials to complete force plate testing, and had shorter single-limb stance duration than those in the neutral group. Individuals with pronated feet or supinated feet have poorer postural control than individuals with neutral feet, but perhaps through different mechanisms.

Contrôle attentionnel de la stabilité posturale chez la personne âgée institutionnalisée : effets d'un programme d'activité physique

Objective 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. Method 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. Results 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. Conclusion 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.

Influence d'une activité physique sur les capacités posturales de personnes âgées : effets du temps de pratique

Objective. – The aim of this work was to define the influence of physical activity on static postural control of two groups of elderly people qualified as “non-active” for the first one and “active” as far as the second group is concerned. The first group practised a physical activity during 3 months whereas the second group practised during 9 months. Subjects and method. – The two groups were composed of 21 subjects of 73 years-old and 10 subjects of 74 years-old. They were characterised by stabilometric data of surface, lengths and spontaneous sway in the lateral ( X) and antero-posterior ( Y) axis. The evaluations were separated by a period of 12 months and realised with open eyes and closed eyes on firm floor. Results. – The statistical analysis showed a significant difference of both groups on surface data in closed eyes condition ( P < 0.04). Conclusion. – The methodological conditions of the study and the heterogeneity of this kind of population could explain the lack of significant effect of the protocol. Data showed different postural adaptations between the two groups after training for a part of stabilometric parameters. Those data focused on the interest of the individualisation of training for elderly people. This approach may well favour the well-being and functional autonomy of this population.

Prolonged optokinetic stimulation generates podokinetic after rotation.

Previous studies showed that after prolonged stepping in place on the center of a rotating platform blindfolded subjects could no longer step in place on a firm floor. Instead, they invariably rotated themselves relative to space without perceiving their rotation, a phenomenon termed podokinetic after-rotation (PKAR). We speculated that prolonged optokinetic stimulation (OK) alone may generate similar PKAR. The purpose of this study was to evaluate the effects of prolonged OK on podokinetic (PK) responses. Ten healthy subjects participated in the study. After a control stepping test, they were seated in a circular closed cage and randomly (right or left) exposed to an OK (45 degrees /s) covering the whole visual field for 30 min. After this procedure, blindfolded subjects attempted to step in place on the stationary floor for 30 min. When trying to do so, all subjects turned relative to space without any perception of rotation. The direction of this optokinetically after-rotation (oPKAR) was opposite of that of the direction of OK. Mean peak velocity of oPKAR was 7.8 +/- 4.1 degrees /s, and it was reached after approximately 6 min of stepping. After that, there was a progressive velocity decay, which exhibited a discharging time constant on the order of 42 min toward a final positive asymptote of 3.1 degrees /s. We conclude that OK alone causes oPKAR. Long-term OK probably charges a storage element for podomotor activity with a relatively prolonged time constant. This novel form of neural interaction and adaptive plasticity may have significant implications for the treatment of vestibular and parietal lobe disorders.

Effets de l’obésité sur la régulation posturale d’adolescentes. Étude préliminaire

Objective. – The purpose of this work was to define the influence of obesity on static postural control of teenagers. Subjects and method. – Nine obese subjects and seven non-obese subjects were charactezised with stabilometric data of Surface, of Lenghts and spontaneous sway in the lateral (X) and antero-posterior (Y) axis with open eyes and closed eyes in two conditions on firm floor and foam floor condition. Results. – For length data, significative differences were observed between the two groups for the opened eyes condition ( p < 0.02) and eyes closed ( p < 0.03) during foam floor condition. Conclusion. – During experimental sollicitations, obesity influences significatively the postural control of teenagers. Instead of systematic statistic differences, we observed a decrease in balance capacities of obese subjects. The effects of fat tissue distributions were not verified.

Comparison of leg muscle responses to transcranial magnetic stimulation during standing on stable and unstable supports

The role of supraspinal structures in postural adjustment upon standing on stable and unstable supports was studied in healthy individuals. For this purpose, transcranial magnetic stimulation (TMS) of the motor cortex was used in the region of leg representation. The subject stood with the eyes closed on a firm floor or on an unstable support in the form of a paperweight (20 cm in height, with a base radius of 32 cm) with mobility in the sagittal direction. Electric responses of four muscles—the soleus muscle, the anterior tibial muscle, the femoral biceps muscle, and the femoral rectus muscle—were recorded. It was shown that, in all the muscles, the response to TMS upon standing on an unstable support increased by 1.8–2.7 times as compared with the response upon standing on a firm floor. Since the increase in the tonic activity of the muscles studied was statistically insignificant upon switching over from standing on a firm floor to standing on an unstable support, it is hypothesized that the increase in the amplitude of muscle responses is connected with an increased activity of the supraspinal structures or with an increase in the effectiveness of corticospinal connections. The results are discussed from the point of view of the role of the motor cortex in maintaining balance on an unstable support.

Influence d’une pratique motrice de type « posture-équilibration-motricité » sur les capacités posturales du sujet âgé

Objective: The object of this work was to observe the influence of the “Posture-Balance-Motivity” (PBM) activity on the total motivity in older adults. Subjects and method: After 12 weeks of practice, to observe the effects on the control of static postural sway by the intermediary of a force platform of 15 subjects (mean age 75.5, SD = 6.6). Results: Scores on “Posture”, “Balance” and “Motivity” show respectively and significantly improvements. All scores of a clinical balance assessment scale, the POMA, have also improved. On the platform, parameters of spontaneous postural sway in the lateral (X) and antero-posterior (Y) axis have been evaluated with eyes open, eyes closed, on firm floor and foam floor condition. Values on the lateral axis did not show any significant decrease. But values on the antero-posterior axis showed a significant decrease for all modalities translating a better postural stability in this plan. Conclusion: These first results show the advantages of a typical “PBM” activity.