The purpose of this study was to investigate the effect of isometric muscle strengthening exercise in gluteus medius on surface EMG power spectrum. Thirty-one healthy volunteers were divided into two groups by content of the exercise (group A ; repeat maximum voluntary contraction (MVC) during 6 sec each 3 times, group B; repeat 50% MVC during 30 sec each 10 times). Each exercise was performed 5 times a week for 8 weeks. Relationship between their muscular strength and computer-aided EMG frequency power spectral analysis during the exercise was studied. The exercise for group A was performed by muscle strengthening, and that for group B was increasing the endurance. Median power frequency of EMG did not show a significant increase after exercise in both groups. However, in group A, the EMG power spectrum shifted to higher frequency band (more than 80 Hz), and in group B, it shifted to lower frequency band (0-45 Hz). As a result, EMG power spectral analysis revealed that the content of muscle strengthening exercise effect upon EMG power spectrum and could become a standard evaluation in clinical practice.

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We evaluated electrically evoked blink reflex (BR) and auditory brain stem response (ABR) from 12 children with cerebral palsy, 7 with spastic diplegia and 5 with athetotic quadriplegia. As a result, patients of spastic type showed the normal pattern in BR and ABR. However, patients of athetotic type showed abnormal pattern in both the reflexes. Delayed latency and absence of late reflex were observed in BR, and absence of response and delayed CCT in ABR. These results suggest that BR and ABR relate to the activity of reflex arc or some cerebral factors, and that BR and ABR may be useful electrically physiological examinations for children with cerebral palsy to evaluate the potential pathogenesis of their brain stem function.

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To clarify the neurophysiological bases of physical therapy, we investigated characteristic changes in long-latency reflexes (LLR) during various grades of voluntary isometric contraction.
Fifteen right-handed healthy subjects (12 males and 3 females) with a mean age of 21.9 (19-30) years participated into the study. LLR were recorded from the opponens pollicis by the electrical stimulation on the right median nerve of the wrist during 25, 50, 75 and 100% of maximal voluntary isometric contraction (MVC).
Amplitude ratio of LLR/M-wave was 13.6±11.4% (M±SD) during 25% MVC, 22.8±13.8% during 50% MVC, 32.5±14.6% during 75% MVC and 46.6±18.5% during 100% MVC. The amplitude ratio of LLR/M-wave gradually increased (p<0.01) as the degree of contraction increased.
Phases (number of peaks) of LLR were 6.8±1.9 during 25% MVC, 5.8±1.6 during 50% MVC, 4.8±1.3 during 75% MVC and 4.0±1.2 during 100% MVC. Phases of LLR gradually decreased (p<0.01) as the degree of contraction increased.
There were no significant differences in latency or duration due to the degree of contraction.
These results suggest that LLR is influenced by the degree of voluntary isometric contraction in healthy subjects.

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Quadriplegic patients use their head to produce a counter-movement against the trunk in their daily living activities such as turning in bed or sitting up bed. It is important to know whether head movement actually affects trunk movement. The purpose of this study is to reveal the influence of dynamic forward head movement of quadriplegic patients.
Fifteen quadriplegic patients underwent motion analyses. They were requested to sit up from a reclining position by only using dynamic head movements. The backrest and the seat were separately mounted on force plates.
Data from the force plates and 3D timehistory data of eight markers attached to the head and the trunk were recorded by “ELETE” gait analysis system.
We confirmed the importance of forward dynamic head movement from the fact that the patients could not sit up by just moving their heads slowly forward from the angle that they could sit up with using dynamic movement.
Data analyses show that the first forward acceleration of the head was supported by the reaction force on the backrest. When the head momentum decreased, the trunk momentum increased. In this way, the head momentum was transferred to the trunk.
We also found a correlation between the maximum backrest angle, from which patients could sit up with using dynamic head movement, and the trunk mobility. The computer link model simulation also shows the importance of dynamic head movement and trunk mobility.

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Responses of heart beat and blood pressure during muscle strengthening exercise for the purpose of minimizing cardiac load are presented. The subjects were seven healthy men, and responses of heart beat and blood pressure to the exercise of knee extensors were determined by tonometry using a CBM 7000. The muscle strengthening exercise consisted of knee extension in a sitting position and Straight Leg Raising (SLR) in the supine position. Cardiac load was elevated with an increase in the intensity of training and the frequency of repetition during the muscle strengthening exercise. This made it possible for cardiac load to be minimized during the exercise, to allow a long time for cessation of the exercise. Blood pressure was significantly higher during SLR in supine position than during knee extension in sitting position. These results suggest that muscle strengthening exercise of knee extensors with minimized cardiac load is possible, under the conditions of lower frequency of repetition, a long cessation period, and appropriate exercise position.

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One of the Proprioceptive Neuromuscular Facilitation (PNF) starting positions increases the amplitude of Hoffman-reflex (H-reflex). This phenomenon is induced by arousal of brain cortex due to the result of EMG reaction time study, muscle tension study and EEG study. According to the previous literature, rotated position stimulates the proprioceptor effectively.
The purpose of this study was to investigate the influence of rotated position of the upper and lower extremity on H-reflex of soleus muscle.
Eleven healthy male subjects participated in this study. Subjects were positioned internal rotated and external rotated on right and left shoulder joint and right hip joint. The H-reflex amplitude at rotated position was compared with at control position.
The amplitude of the H-reflex increased when the right or the left shoulder joint located internal or external rotated position, but not at another position. These results suggest that the excitability level of alpha-motoneuron was increased by the rotated position of the upper extremity. The increase in the H-reflex due to the PNF position indicated that the influential factor was the rotated position of the upper extremity.

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[in Japanese]

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