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OBJECTIVES: The objective of this study was to investigate the effect of attentional focus instructions on gait stability during level-ground walking among older adults. METHODS: We recruited 140 community-dwelling older adults (mean age = 70.3 years, SD = 4.7 years) from elderly community centers in Hong Kong. The experiment included assessments on participant's characteristics and walking trials. During walking trials, each participant was invited to walk at a self-selected pace along a 6-m walkway. Internal focus instructions (Internal condition), external focus instructions (External condition), or no instruction (Control condition) were given in a randomized order for three trials per condition, giving a total of nine walking trials. Spatial and temporal gait parameters were measured. RESULTS: Results showed significantly higher body sway and variability of swing and stance time under Internal condition relative to External and Control conditions. Moreover, reduced velocity and shorter steps were demonstrated under Internal condition relative to External and Control conditions. DISCUSSION: External focus instructions did not improve gait stability in older adults when compared to Control condition. Internal focus instructions appear to compromise gait stability. Future research should investigate if walking instructions that refer to body movements explicitly compromise gait rehabilitation for older adults in clinical settings.
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Atención , Marcha , Caminata/psicología , Anciano , Femenino , Humanos , Masculino , Equilibrio PosturalRESUMEN
Background/Study Context: Adjustments of posture in response to balance challenges may lead to subsequent increases in conscious posture processing. If cognitive resources are stretched by conscious processing of postural responses fewer resources will be available to attend to environmental trip or fall hazards. The objective of the study was to explore brain activity related to conscious processing of posture as a function of movement specific reinvestment and fear of falling. Method: Forty-three older adults (M = 71.4, SD = 4.1) stood with a wide or narrow stance on a force-plate while neural coherence between verbal-analytical (T3) and motor planning (Fz) regions of the brain was assessed using electroencephalography. The propensity for movement specific reinvestment was assessed using the Chinese version Movement Specific Reinvestment Scale (MSRS-C) and fear of falling was assessed using the Chinese version Fall Efficacy Scale International (FES-I[CH]). Results: Scores from the MSRS-C were negatively correlated with changes in T3-Fz coherence that occurred when participants shifted from wide to narrow stance. Together, MSRS-C and FES-I(CH) uniquely predicted the percentage change in T3-Fz coherence between the two stance conditions. Conclusion: Presented with two postural tasks of different complexities, participants with a lower propensity for conscious control of their movements (movement specific reinvestment) exhibited larger changes in real-time brain activity (neural coherence) associated with conscious postural processing.
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Envejecimiento/fisiología , Encéfalo/fisiología , Postura/fisiología , Accidentes por Caídas , Anciano , Electroencefalografía , Miedo/fisiología , Femenino , Humanos , Masculino , Movimiento/fisiología , Equilibrio Postural/fisiologíaRESUMEN
Visual illusions caused by varied orientations of visual patterns may influence the perception of space and size, possibly affecting body stability during locomotion. This study examined the effect of variations in shoe top visual patterns on perception and biomechanical stability while walking and running. Twenty healthy adults performed five walking and running trials along an instrumented walkway when wearing shoes with five different striped patterns (plain, vertical, outward, horizontal, and inward). Before these locomotion trials, participants ranked their perceptions of shoe width. We used synchronized force platform and motion capturing systems to measure ground reaction force, mediolateral center of position displacement, ankle inversion and eversion, ankle excursion, and maximum eversion velocity. We rated stability perception on a 150-mm visual analog scale immediately after each shoe condition. Data analyses indicated that participants perceived plain and horizontal striped shoes as significantly wider than inward and vertical patterned shoes. During walking, participants wearing shoes with plain and horizontal striped patterns demonstrated smaller mediolateral center of position displacement, maximum eversion velocity, and ankle range of motion when compared with walking when wearing outward and vertical striped patterns; when running, we observed a similar effect for maximum eversion velocity. Thus, certain visual patterns on the tops of shoes influence the wearers' width perception and locomotion in ways that affect ankle stability during walking and running, with implications for risk of injury.
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Marcha/fisiología , Equilibrio Postural/fisiología , Carrera/fisiología , Zapatos , Caminata/fisiología , Adulto , Articulación del Tobillo/fisiología , Fenómenos Biomecánicos/fisiología , Humanos , Masculino , Rango del Movimiento Articular/fisiología , Adulto JovenRESUMEN
The objective of the study was to compare in vivo estimates of Cd bioavailability in two diet materials (lettuce and durum wheat grain) with bioaccessibility estimates from three in vitro methods. For both dietary materials, the Cd was either incorporated during growth or applied topically as a soluble salt just prior to experimentation. Simulated gastric/intestinal digestion using a physiologically based extraction technique (PBET) solubilized less than 56% (lettuce) or 13% (grain) of the Cd that was either incorporated into the plant tissues during growth, or added to the plant tissues before experimentation, as Cd(NO3)2.H2O. Amended diets could not be distinguished from incorporated diets. More of the Cd solubilized from amended lettuce than from incorporated lettuce moved to the outside of MWCO 10 kD and 25 kD dialysis sacs; no difference between the amended and incorporated diets was observed for grain. The percentage of lettuce-Cd solubilized by the PBET and sorbed by Caco-2 cells was greater for incorporated than for amended lettuce; for Cd in grain, the reverse occurred. As expected, none of the in vitro estimates of bioaccessibility were the same percentage of Cd in the lettuce or grain as was measured as bioavailable in vivo. The in vitro assays all predicted that substantially less than 100% of the Cd in the foods would be bioavailable, as was identified in vivo, and simulating intestinal selectivity improved the comparison to in vivo. Some of the in vitro assays identified subtle differences between the diets (i.e., amended vs. incorporated) that were consistent with in vivo studies, and with speculated differences in Cd speciation; this suggests their potential usefulness for the study of modifiers to dietary Cd bioavailability.
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Cadmio/farmacocinética , Contaminación de Alimentos/análisis , Mucosa Intestinal/metabolismo , Modelos Biológicos , Contaminantes del Suelo/farmacocinética , Animales , Disponibilidad Biológica , Células CACO-2 , Digestión , Cadena Alimentaria , Humanos , Lactuca/crecimiento & desarrollo , Conejos , Triticum/crecimiento & desarrolloRESUMEN
OBJECTIVE: The purpose of this study was to use a novel method that was based on the application of chaperonin-60 sequencing to describe the vaginal microflora of 16 healthy women. STUDY DESIGN: Asymptomatic women consented for vaginal swabs to be collected at the time of a clinical pelvic examination. Total genomic DNA was isolated from the vaginal swabs. Degenerate, universal polymerase chain reaction primers were used to amplify an approximately 555 base pair region of the universal chaperonin-60 gene, which is found in all eubacteria and eukaryotes, from the total genomic DNA and libraries of cloned polymerase chain reaction products were constructed. Library clones were sequenced, and the resulting sequences were assigned to taxonomic groups on the basis of similarity to reference sequence data. Presence of Chlamydophila psittaci sequences in the samples was confirmed by species-specific polymerase chain reaction. RESULTS: Sixteen of the 23 women who were enrolled had normal flora by Nugent's score of <4 and had adequate polymerase chain reaction product for assessment. Vaginal flora libraries were dominated by a variety of sequences with similarity to Lactobacillus spp L. crispatus, L. iners, L. gasseri, L. jensenii, and L. buchneri. Other sequences that were identified included representatives of Gardnerella spp, sequences with similarity to Porphyromonas spp and Megasphaera spp and sequences identical to C psittaci. CONCLUSION: Culture-independent, chaperonin-60 sequence-based molecular methods can lead to the identification of greater diversity within defined taxa compared with those that are identified by standard culture-based methods and to the identification of novel organisms that were not previously associated with vaginal flora.