The purpose of this study was to identify the control mechanism of changing movement of the body's center of mass (CM) during standing up from a chair. One of the requirements of stand-up motion from a chair is that the movement of the CM must be controlled from forward horizontal direction to upward vertical direction, in order to secure upright balance at the termination of the standing. The CM trajectory and velocity for stand-up motion were computed at three movement speeds (natural, fast, and slow) by a motion analysis system (VICON). Eleven events were identified in each trial. The main events were the time of the peak propulsive power and the peak braking power, the time of the peak horizontal component of the CM velocity occurrnce, and the time from the beginning to the completion the body losing contact with the seat. The timing and sequence of these events were investigated. The results showed that the peak propulsive power in the slow speed group had the earliest timing and in the fast group had the latest at the beginning and at the completion of the body losing contact with the seat. There were statistical significant differences in the sequential times compared with the other group of events. The feature of the timing of events suggests that the control mechanism of changing movement of the CM is produced by the braking power progressively increasing before the time the subject leaves the seat. The timing of these events varied with the conditions of standing up from the chair.
Here, we publish results of a questionnaire which was carried out to aid the development of a clinical measure of balance ability. [Subjects and Methods] We questioned 23 physical therapists who published about balance on journals. The questionnaire consisted of 7 major questions, such as definition of balance, key concepts for measuring balance ability, and requirements for measures of balance ability. [Results] There were some differences among physical therapists in the answers for the definition of balance and key concepts of balance ability. They regarded shorter measurement time, subjectivity of results and clinical usefulness of the results as important. We also recognized there were some issues in the measures of balance ability in practice. [Conclusion] We will develop a new clinically valid measure of balance ability on the basis of these results.
We investigated the trunk muscles, activities for stabilizing the spine against load by arm movement.[Subjects] Eight male subjects participated in this study. [Methods] Subjects performed 1) a pushing forward task (load perpendicular to the trunk) and 2) a pushing downward task (load parallel to the trunk) at different load magnitudes with isometric arm extension. Electromyography (EMG) of rectus abdominis (RA), oblique internus abdominis (OI), oblique externus abdominis (OE), lumbar mutifidus (LM), and longissimus thoracis (LT) were recorded with surface electrodes. [Results] Activity of RA, OE and OI increased with load magnitude in both tasks. RA was influenced by load direction. The activity of RA in the downward pushing task was larger than in the forward pushing task. Activities of LM and LT were influenced by load magnitude, but these muscles activities were low.[Conclusion] The RA muscle is the only muscle influenced by direction of load to the trunk.
[Purpose] The purpose of this study was to identify subjects with post-stroke hemiparesis at the early stage who can be indicated for short-term intervention with Body Weight Supported Treadmill Training (BWSTT).[Subjects] The subjects were 28 post-stroke hemiparesis patients.[Methods] The subjects received BWSTT with 20% of their weight supported for 5 consecutive days. Classification & Regression Trees (CRT) were used to classify the subjects. The dependent variable was change in walking speed across the intervention, and the independent variables were age, type of disease, number of days from onset, Brunnstrom Recovery Stage of lower extremity (BRS), walking speed before intervention, and swing symmetry (symmetry).[Results] The predictive value was 19.6 m/min in the asymmetry group (n=11) with BRS of V and symmetry 0.90; 7.2 m/min in the high walking ability group (n=6) with BRS of V and symmetry 0.91; and 8.1 m/min in the moderate hemiparesis group (n=11) with BRS of IV. The coefficient of determination was 0.60. [Conclusion] Short-term BWSTT intervention for post-stroke hemiparesis at the early stage may be indicated for subjects who maintain higher motor function of the affected lower extremity but show asymmetry in walking pattern. Key words: stroke, body weight supported treadmill training, walking speed
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