Lumbar braces are often used for acute and chronic low back pain and for its prevention in work environments. However, the mechanism underlying the clinical efficacy of corsets is not well understood. The purpose of this study was to investigate the effects of lumbar corset on forward bending, that often triggers low back pain, with respect to lumbar and pelvic motion and electromyographic (EMG) activities of erectores spinae and rectus abdominis muscles. An electromagnetic tracking device was used in combination with surface EMG. Eighteen healthy young adults volunteered in the study. The forward bending was divided into flexion (from standing position to maximum bending) and extension (from maximum bending to standing position) phases for analysis. The results showed that flexion without brace began with predominance of lumbar over pelvic motion and ended with predominance of pelvic over lumbar motion and that extension was the reverse, as reported previously by others. The brace inhibited the initial lumbar motion in flexion, but had no apparent effects on lumbar and pelvic motion in extension. The EMG activities of erector spinae decreased in the terminal phase of flexion without corset (so called relaxation phenomenon usually seen), but with corset, they did not appear. In contrast to flexion, the EMG activities of erector spinae were not inhibited by brace in extension. We conclude that the primary effect of lumbar braces is restriction of lumbar motion particularly in the initial phase of flexion and that they do not have beneficial effects on the electrical activities of that muscle in the terminal phase of maximum flexion.

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5-fluorouracil (5-FU) is known to cause multifocal cerebral demyelination. To date, cases of peripheral neuropathy have rarely been described after the administration of 5-FU alone. We describe one patient who had peripheral neuropathy diagnosed by electrophysiologic testing and sural nerve biopsy. A 42-year-old man was diagnosed as having early gastric carcinoma (IIc). After gastrectomy, he received chemotherapy (5-FU, 2.46mg/kg/day) from June 19, 1996 to November 5, 1998. The patient complained of weakness and sensory disturbance in the lower limbs starting from October 1998. On neurologic examination, he had distal hypesthesia to touch, distal pain, and paresthesia. Cobalamin (vitamin B₁₂) was slightly decreased, but anemia was not present. Electrophysiologic studies demonstrated slightly slowed conduction velocity of the lower limbs. Needle electromyography showed fibrillation potentials and positive sharp waves in the upper and lower limb muscles. Pathologic changes in sural nerve biopsy indicated drug poisoning.

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Several authors have reported that disuse might not be a major factor of muscle wasting in hemiplegic patients with stroke. A number of published investigations have shown that pathological spontaneous activity can occur in electromyographic studies in upper motor neuron lesions. There have been some reports that the decrease of hemiplegic side M-potential reflects the drop of motor unit numbers. Most of them have estimated that pathological spontaneous activity in hemiplegic muscles might due to transsynaptic degeneration. The submaximal stimuli can evoke a sample of motor unit action potentials of S-MUAPs in the F-response entirely representative of the relative numbers of surface detected S-MUAPs of different sizes. The motor unit number estimation (MUNE) was investigated among the bilateral abductor pollicis brevis (APB) muscles in seven healthy normal controls and fifteen stroke patients with moderate-to-severe hemiplegia. The needle EMG was examined in hemiplegic side APB. The average S-MUAP on each APB muscle was calculated from a selected population of F-wave responses. The MUNE was calculated by dividing the negative peak amplitude measured from the average S-MUAP waveform into corresponding values measured from a maximum M-potential. There was no statistically difference between the both sides motor units number among normal subjects and this MUNE method also revealed the good reproducibility in them. The needle EMG revealed the spontaneous activity in hemiplegic APB muscles at 3-4 months after the onset. The motor unit number on the hemiplegic side was significantly lower than on the unaffected side (p<0.05, Mann-Whitney test) among stroke patients. About one year later, most stroke patients revealed no spontaneous activity by needle EMG but the motor unit decrement in hemiplegic side was also recognized by the MUNE method among them. The motor unit could decrease in the moderate-to-severe hemiplegic muscle due to the trans-synaptic degeneration secondary to the upper motor neuron lesion. Some investigations, however, reported that there was no significant difference in morphometrical anterior horn cell number between the affected and unaffected sides in strokes. The transsectional areas of anterior horn cells associated with the hemispheric lesional side were reported to be significantly decreased compared with those of the unaffected sides in patients and normal subjects. The motor units may remain morphometrically unchanged in their number but the functional motor units number in the hemiplegic side might decrease because the loss of trophic effect from the upper motor neurons could alter the functional state of anterior horn cell in the affected side. The investigation and therapy for the muscle wasting should be proceeded more for the rehabilitation in upper motor neuron lesions.

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There are many studies about the relationship between physical activity and health, physical fitness, and chronic disease. The measurement of daily physical activity is important for patients with several major chronic diseases and with physical disabilities, such as coronary heart disease, osteoporosis, and diabetes. In the clinical practice, the assessment of daily physical activity is useful for advising patients about their life style and designing a rehabilitation program to maintain their physical fitness and optimal physical function. Oxygen consumption is the best parameter to show the intensity of different activities; however, it is almost impossible to measure oxygen consumption without inhibiting the subject's daily routine. Many methods instead of measuring oxygen consumption for measurement of physical activity have been studied and reported. The most generally used and well-known methods for this purpose are (a) self-administered quantitative histories or physical activity recall surveys, (b) time study method included in self-report diaries and observation, (c) doubly-labeled water method, and (d) mechanical and electronic monitor. The first two methods have been used many epidemiological studies. However both of these are subjective and influenced by subject inaccuracies or unwillingness to record every activity. The third method involves the administration of isotopes of hydrogen and oxygen and the determination of the washout kinetics of both isotopes as their concentrations fall back down to the pre-administration level. Although the technique is feasible and non-invasive, it has not been widely used because of the cost and scarcity of isotopes. The fourth method can be classified into two types. One type of devices that makes use of biological signals from electromyography (EMG) and electrocardiograph (ECG). The other type of devices that assess the quantity of body movement by using mercury-switch transducer and accelerometer technology. The mechanical and electronic monitors have been improved for overcoming the technical problems in accuracy and confidence by using three-dimensional accelerometer and computer technology. This review demonstrated these methods for measuring physical activity and the recently progress.

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