The effects of chronic overload by synergist ablation (SA) on fiber type, myosin heavy chain (MyoHC) isoforms, and contractile properties in the rat plantaris muscle were studied. Plantaris muscle was overloaded by bilateral removal of its synergist of gastrocnemius muscle in Fischer 344 female rats (aged 8 weeks) . Muscles of sham-operated legs served as controls.
The overloaded plantaris was 20% heavier than control 3 weeks after SA. Overload by SA resulted in remarkable increases in cross-sectional areas of muscle fibers of all types ; however, the percentage increase was less in type II b fibers. Twitch contraction and half-relaxation time before and after tetanus did not change, but fatigue resistance increased significantly with overload. The percentage of area occupied by type II b fibers, which have lower oxidative capacity, decreased while the percentage of area occupied by other type II fibers, but not type I fibers, increased. Analysis of MyoHC isoforms with gradient sodium dodecylsulfate polyacrylamide gel electrophoresis revealed a decrease in II b isoforms and an increase in II d isoforms.
These results suggest that chronic overload produces changes in muscle fiber type and MyoHC isoform compositions which partly account for increased fatigue resistance in overloaded muscles.

To examine personal space perception, a method of identifying joint position was determined by having the subject equally bisect the joint angle, by producing a minimum increment in change of position and by selecting a threshold for two-point discrimination using the metacarpophalangeal joint of digits 2-5.
Eight healthy adults (6 males and 2 females) were used as subjects. The subjects' eyes were covered at all times to prevent any visual feedback.
Each metacarpophalangeal joint of digits 2-5 was extended, flexed and pointed to the bisection position in 6 sec (about 2 sec in each position) . The difference in the bisection position selected using the index finger with the shoulder, elbow and hand in variety of positions was determined. The deviation from the mid-bisection point and the standard deviation were less when the hand was positioned most comfortably and near the face (“natural and near”) than when the hand was positioned in the more uncomfortable position and further from the face (“unnatural and further”) .
In a second test, the index finger was moved from full extension to the full flexion in increments as small as possible at a rate of one change in position per second. Again, the effect of arm position was determined.
In case of“the natural and near”position, each increment in joint position was smaller than in“the unnatural and further”position.
In“the natural and near”position, the two point threshold was smallest of all. It was measured at the thumb side of right palm in the proximo-distal direction.
These results suggest that personal space perception of metacarpophalangeal joint is affected by the position of adjoining limb segments.

To examine personal space perception, a method of identifying joint position was determined by having the subject equally bisect the joint angle, by producing a minimum increment in change of position and by selecting a threshold for two-point discrimination using the metacarpophalangeal joint of digits 2-5.
Eight healthy adults (6 males and 2 females) were used as subjects. The subjects' eyes were covered at all times to prevent any visual feedback.
Each metacarpophalangeal joint of digits 2-5 was extended, flexed and pointed to the bisection position in 6 sec (about 2 sec in each position) . The difference in the bisection position selected using the index finger with the shoulder, elbow and hand in variety of positions was determined. The deviation from the mid-bisection point and the standard deviation were less when the hand was positioned most comfortably and near the face (“natural and near”) than when the hand was positioned in the more uncomfortable position and further from the face (“unnatural and further”) .
In a second test, the index finger was moved from full extension to the full flexion in increments as small as possible at a rate of one change in position per second. Again, the effect of arm position was determined.
In case of“the natural and near”position, each increment in joint position was smaller than in“the unnatural and further”position.
In“the natural and near”position, the two point threshold was smallest of all. It was measured at the thumb side of right palm in the proximo-distal direction.
These results suggest that personal space perception of metacarpophalangeal joint is affected by the position of adjoining limb segments.

The objective of this study was to investigate whether isometric resistance exercise (IRE) can attenuate musculoskeletal atrophy during unloading and accelerate its recovery during reloading. Twenty-six female Fischer 344 rats, aged 16 weeks, had their hindlimbs suspended for 3 weeks (unloading) ; 12 of these rats were allowed subsequent cage activity (reloading) for 3 weeks with or without IRE. IRE (stationary support on a cylindrical grid inclined 60 or 80 degrees) was done for 30 min/day, 6 days/week, with an additional load of 30% or 50% body mass attached to the tail during the unloading and reloading periods. The tibial bone and hindlimb skeletal muscles from four experimental and two age-matched control groups were evaluated with dual-energy X-ray absorptiometry, mechanical testing, and muscle mass measurement. Bone mineral density (BMD) was measured in the whole tibia and in 7 regions divided equally along the long axis of the epiphysis from proximal (R1) to distal (R7) . After unloading, fat-free dry mass (FFDM), bone mineral content (BMC), and BMD of the whole tibia decreased by 8%, 10%, and 6%, respectively. FFDM and BMC, but not BMD, returned to the levels of age-matched controls during reloading. Unloading-induced decreases in BMD were observed in the regions from the proximal epiphysis to the diaphysis (R1 to R4) and the distal epiphysis (R7) . The rate of decrease in BMD was regionally specific and was particularly pronounced (12%) in the most proximal region (R1) . These findings indicate regional variations in responses of BMD to skeletal unloading. The BMD in R2 to R4 remained less than that in age-matched control after reloading. No significant changes were observed in maximum breaking load, energy, and deformation after unloading and reloading. Hindlimb-unloading induced loss of mass in the soleus (38%), plantaris (14%), gastrocnemius (25%), tibialis anterior (8%), extensor digitorum longus ( 8%), and rectos lemons (17%) muscles, but the mass of muscles, except for the soleus muscle, recovered during reloading. IRE ameliorated the loss of mass in the soleus and gastrocnemius muscles during unloading but did not promote the recovery of mass in any muscles during reloading. Moreover, IRE showed no effect on bone responses after unloading and reloading. This lack of beneficial effects of IRE on osteopenia may be due, in part, to insufficient exerciseinduced load. We concluded that 1) regional analysis of BMD can be used to assess local bone metabolism, 2) the response of BMD to altered loading conditions does not necessarily depend on the response of muscle mass, 3) recovery from osteopenia progresses more slowly than that from sarcopenia, and a longer time than the unloading period is required to restore BMD. Further studies are needed to develop more effective countermeasures against osteopenia and sarcopenia.

Objective : We conducted a fact-finding survey for the consecutive past 3 years to establish whether inpatients with brain injury who had wished to resume driving after discharge from our hospital had in fact resumed driving after discharge. The survey included both driving status and information about collisions. Methods : Patients who had been evaluated for resumption of driving and were discharged more than 1 year ago were sent a fact-finding survey questionnaire aimed at establishing whether they were currently driving. The patients who had resumed driving (resumers) were compared with those who had not resumed driving (non-resumers). From the questionnaire results we investigated driving status and whether collisions had occurred. Results : We obtained effective responses from 40 of the 54 people (48 males, 6 females) who were sent the questionnaire ; the collection rate was 74.1%. Of these, twenty-nine people had resumed driving, all were male. There were no significant differences between the resumers and non-resumers in higher brain function tests. In regard to driving ability, hemiparesis impairments were significantly milder in the resumers than in the non-resumers. Two respondents had hit posts or walls within the year. All these collisions occurred when parking. One respondent had a collision while driving along a road. Conclusion : We hope to provide patients with useful and appropriate information on resuming driving so that we can support them in a safe return to the driving environment.

To examine the variation in the knee extension force and the integrated electromyogram from rectus femoris, medial vastus and lateral vastus muscles with the knee joint angle in growing children, measurements were conducted in 61 school boys aged from 7 to 12 years old. Anthropometric measurements were also done on the body height, the lower limb length, and so on. Results obtained were as follows.
1) Ratio of the lower limb length comparing with the body height increased with the grade.
2) Maximal force at each joint angle in each grade was shifted peak from 70°to 90°with the grade.
3) The pattern of the integrated surface electromyogram from rectus femoris, medial vastus or lateral vastus muscle at each joint angle was the same in all of the grade. The integrated electromyogram at the maximal voluntary contraction was maximal at 45°of the knee joint angle in the rectus femoris muscle, at 110°in the medial vastus and at 90°in the lateral vastus muscle.

Objective：An actual-condition survey was conducted to verify the validity of reference values of higher brain function necessary for patients with brain injury to resume automobile driving.　Subjects：Of the 74 patients admitted to the Tokyo Metropolitan Rehabilitation Hospital between November 1, 2008 and November 30, 2012, who underwent evaluation using the hospital's automobile driving resumption system at the time of discharge, 71 patients with brain injury who were judged capable of resuming driving were included in this study. Methods：Questionnaires were sent at least 1 year after discharge, to determine whether the subjects had actually resumed automobile driving. Subjects were classified by admission date into two groups：1）A provisional reference group that included patients admitted between November 2008 and November 2011 who had resumed driving；and 2) verification group that included patients who had been admitted between December 2011 and November 2012 and had resumed driving. The relationship between results on the higher brain function test for the verification group and provisional reference values was investigated. Results：The provisional reference value group included 29 patients, and the verification group included 13 patients. In the verification group, the results of 9 patients with brain injury on the higher brain function test were within provisional reference values. Conclusion：The results of the paper-based test are a reliable predictor of whether a patient is capable of resuming driving, but do not represent an absolute standard. Therefore, the safety of resuming driving should be investigated on a case-by-case basis.