Shin Murata

Lumbar lordosis angle (LLA) and leg strength predict walking ability in elderly males

There is an association between gait performance and spinal alignment in elderly females but it is unclear if this association is gender-dependent and postural changes would also predict gait performance in healthy elderly males. We measured thoracic kyphosis angle (TKA), LLA as indices of spinal alignment and maximal walking speed (WS), timed up and go test (TUG), 10-m obstacle walking time, and 6-min walk distance as indices of gait performance in healthy old males (n=124, age 73.0 ± 7.2 years). Knee extensor strength and one-leg standing time with eyes open were measures of physical function. The LLA but not TKA correlated with performance in each of the 4 gait test. Multiple-regression analyses showed that only the combination of knee extensor strength and LLA accounted for significant variation in gait performance. While previous studies showed that spinal alignment is associated with gait performance in elderly women, in healthy elderly males both functional (leg strength) and structural (spinal alignment) factors contribute to gait performance.

The Activities of the Muscles around the Ankle Joint during Foot-gripping are Affected by the Angle of the Ankle

[Purpose] The purpose of this study was to determine the activities of the muscles around the ankle joint during foot gripping. [Subjects] The subjects of this study were 17 healthy females. [Methods] We measured the maximum voluntary contraction (MVC) activities of the soleus muscle, the medial head of the gastrocnemius muscle, and the tibialis anterior muscle, and calculated %IEMG during foot gripping in 3 different ankle joint positions: 10° of plantar flexion, 0°, and 10° of dorsiflexion. [Results] The maximal force of foot gripping achived by the crural muscles in any ankle position was 30–50% IMEG of the MVC. Repeated analysis of variance showed that the %IEMG was significantly lower in 10°of dorsiflexion than in the other 2 positions for all muscles. [Conclusion] These results suggested that the crural muscles help the ankle joint by co-contracting during foot gripping.

An Examination of Limb Position for Measuring Toe-grip Strength.

[Purpose] The purpose of the present study was to investigate the limb position at which the maximum toe-grip strength could be exerted as well as measurement reproducibility. [Subjects] Twenty healthy young women were selected. [Methods] We measured toe-grip strength under three conditions: 90° hip and knee flexion while sitting, 90° hip flexion and knee extension while sitting, and a standing position. [Results] We found that toe-grip strength was significantly lower in the 90° hip flexion and knee extension sitting position than in the 90° hip and knee flexion sitting position and standing position. Moreover, the 90° hip and knee flexion sitting position produced the best intraclass correlation coefficient (r = 0.813). [Conclusion] The results suggest that 90° hip and knee flexion while sitting is the most suitable limb position for measuring toe-grip strength, as this position allows maximum strength to be exerted and allows measurements to be repeated.

Verification of the correlation between cognitive function and lower limb muscle strength for the community-dwelling elderly

[Purpose] The purpose of this study was to evaluate the lower limb muscle strength of the community-dwelling elderly, with or without cognitive decline, using isometric knee extension strength (IKES) and the 30-second chair stand test (CS-30). [Subjects] A total of 306 community-dwelling elderly participated in this study. Assessment items were the CS-30, IKES, Mini-Mental State Examination (MMSE), and Trail-Making Test Part A (TMT-A). [Methods] Participants were divided into three groups according to their MMSE score: cognitive impairment (MMSE ≤ 24), cognitive decline (MMSE 25 to 27), and normal (MMSE ≥ 28). We compared IKES and CS-30 among the three groups. [Results] IKES was not significantly different among the three groups. However, the CS-30 was significantly different among the three groups. Upon further analysis the CS-30 score of each group, when adjusted for age and TMT-A, did not indicate a significant difference. [Conclusion] These results suggest that the lower limb muscle strength of the elderly does not differ with cognitive decline. Moreover, we suggest that when using the CS-30 score as an indicator of lower limb muscle strength attentional function should be taken into account.

Activity of the Femoral Muscles during Toe-gripping Action.

[Purpose] In the present study, we investigated femoral muscle activity during toe-gripping, and the role of the femoral muscles in toe-gripping strength. [Subjects] Fourteen healthy young women were selected. [Methods] We measured the maximum voluntary contraction of the rectus femoris and long head of the biceps femoris muscles. We then calculated the percent integrated EMG (%IEMG) during the toe-gripping action. [Results] We found that the %IEMG of the biceps femoris was significantly higher than that of the rectus femoris. Moreover, a significant positive correlation was found between the %IEMG of the rectus femoris and that of the biceps femoris. [Conclusion] These results suggest that femoral muscles co-contract during the toe-gripping action, and thus possibly contribute to knee joint stability.

Effects of vibratory stimulation-induced kinesthetic illusions on the neural activities of patients with stroke

[Purpose] This study evaluated the influence of vibratory stimulation-induced kinesthetic illusion on brain function after stroke. [Subjects] Twelve healthy individuals and 13 stroke patients without motor or sensory loss participated. [Methods] Electroencephalograms were taken at rest and during vibratory stimulation. As a neurophysiological index of brain function, we measured the μ-rhythm, which is present mainly in the kinesthetic cortex and is attenuated by movement or motor imagery and compared the data using source localization analyses in the Standardized Low Resolution Brain Electromagnetic Tomography (sLORETA) program. [Results] At rest, μ-rhythms appeared in the sensorimotor and supplementary motor cortices in both healthy controls and stroke patients. Under vibratory stimulation, no μ-rhythm appeared in the sensorimotor cortex of either group. Moreover, in the supplementary motor area, which stores the motor imagery required for kinesthetic illusions, the μ-rhythms of patients were significantly stronger than those of the controls, although the μ-rhythms of both groups were reduced. Thus, differences in neural activity in the supplementary motor area were apparent between the subject groups. [Conclusion] Kinesthetic illusions do occur in patients with motor deficits due to stroke. The neural basis of the supplementary motor area in stroke patients may be functionally different from that found in healthy controls.

Kinematic analysis during toe-gripping strength exertion: angular changes in the ankle joint and leg muscle activities.

[Purposes] To investigate angular changes in the ankle joint and leg muscle activities during toe-gripping, and to examine the relationship between these changes and toe-gripping strength. [Subjects] Eleven healthy young women were selected. [Methods] We measured the toe-gripping strength, angular changes in the ankle joint, and leg muscle activities of all patients during toe-gripping. [Results] The mean change in the ankle angle in dorsiflexion from a neutral position was 3°, and a positive correlation was observed between this angle and toe-gripping strength (r = 0.61). Thus, toe-gripping strength increased with the angle of dorsiflexion. Regarding the leg muscle activities, activities of the tibialis anterior muscle and medial head of the gastrocnemius muscle demonstrated positive correlations with toe-gripping strength (r = 0.75 and r = 0.72, respectively). [Conclusion] These findings suggest that the ankle dorsiflexes in order to exert great toe-gripping strength, and the crural muscles contract simultaneously because of ankle fixation.

Reproducibility and validity of the 50-meter walking test in community-dwelling elderly

[Purpose] This study aimed to investigate the reproducibility and validity of the 50-m walking test. [Subjects] Reproducibility was investigated in 19 community-dwelling elderly women (mean age, 76.3 years), and validity was investigated in 31 community-dwelling elderly individuals (12 men and 19 women; mean age, 75.7 years). [Methods] The time taken to walk 50 m, the time taken to walk each 10-m section (laps 1–5), the time taken to walk 10 m, and grip strength were measured. In addition, the functional reach test (FRT), one-leg standing test, and timed up and go (TUG) test were performed. [Results] In a reproducibility analysis, the interclass correlation coefficient (1,1) was 0.97. In a Bland-Altman analysis, no systematic error was found. The measured values from the 50-m walking test included a measurement error of 1.5 s, and the acceptable margin of error was confirmed to be 3.1 s. In a validity analysis, the 50-m walking test score was significantly correlated with the 10-m walking and TUG test scores. [Conclusion] Our results suggest that the 50-m walking test score may be a useful index of the walking ability of community-dwelling elderly.

Relationships between the Occlusal Force and Physical/Cognitive Functions of Elderly Females Living in the Community

[Purpose] The present study, was conducted to examine the occlusal force and physical, cognitive, and attentional functions of elderly females living in the community to evaluate the significance of measuring the occlusal force. [Subjects and Methods] The number of subjects was 104. The Occlusal Force Meter GM10 was used to measure their occlusal force. Their physical functions were assessed using eight examinations, including the 30-second Chair Stand Test, and the cognitive functions of the Mini-Mental State Examination and attention functions of the Trail Making Test. [Results] Significant correlations were noted between the occlusal force and all measurements, except for the results of forward bending in a sitting position. Multiple regression analysis was conducted with the occlusal force as an objective variable, and significant partial correlations were noted with the 30-second Chair Stand Test. [Conclusion] These results suggest that it is necessary to provide the elderly with comprehensive support focusing on maintaining their occlusal force, as a nursing care-prevention measure, to help them continue to live a healthy, independent life.

Usefulness of a 50-meter round walking test for fall prediction in the elderly requiring long-term care

[Purpose] This study aimed to verify the usefulness of a 50-m round walking test developed as an assessment method for walking ability in the elderly. [Subjects] The subjects were 166 elderly requiring long-term care individuals (mean age, 80.5 years). [Methods] In order to evaluate the factors that had affected falls in the subjects in the previous year, we performed the 50-m round walking test, functional reach test, one-leg standing test, and 5-m walking test and measured grip strength and quadriceps strength. [Results] The 50-m round walking test was selected as a variable indicating fall risk based on the results of multiple logistic regression analysis. The cutoff value of the 50-m round walking test for determining fall risk was 0.66 m/sec. The area under the receiver operating characteristic curve was 0.64. The sensitivity of the cutoff value was 65.7%, the specificity was 63.6%, the positive predictive value was 55.0%, the negative predictive value was 73.3%, and the accuracy was 64.5%. [Conclusion] These results suggest that the 50-m round walking test is a potentially useful parameter for the determination of fall risk in the elderly requiring long-term care.