There have been an apparent trend in the decline of back-lift strength of young people during recent years. The purpose of this study was to investigate the cause-effect relationship of such a trend using young peoples and university students. In order to examine the characteristics of activities in the lumber back muscles during various physical activities, the surface electromyography (EMG) was obtained from the trapezius, latissimus dorsi, and elector spinae muscles for individuals with poor back-lift strength (5 male children and 4 university male students) and individuals with relatively strong back-lift strength (5 male children and 2 male university students) . The children with poor back-lift strength had significantly less EMG activities in both the trapezius and elector spinae muscles during the measurement of back-lift strength using a dynamometer than the strong back-lift strength children. The former children also had a less EMG activities in elector spinae muscle and a greater EMG activities in trapezius muscle during cycling the bicycle elgometer. Such a trend became more distinct when the load was increased. The university students with poor back-lift strength had a less EMG activity in the elector spinae muscle during the measurement of back-lift strength than those with strong back-lift strength. During running, there was not a distinct difference in the EMG activities of the muscles in the back between the poor and strong strength students. However, as the running speed increased, a greater EMG activity in the trapezius muscle or the latissimus dorsi muscle were observed for the poor back-lift strength students than the stronger back-lift strength students.
These results indicated that the individuals with poor back-lift strength relied more on the upper portion of the back muscle group than the lower portion of the back muscle group during both static and dynamic activities, suggesting that the trend in the decline of back-lift strength of children and students was due to a lack of opportunity to use the lower back muscles in the daily physical activities.

A study was conducted to examine the feasibility and validity of using integrated electromyographic signals (IEMG) for determination of anaerobic threshold (AT) in the elderly. Twentynine healthy elderly subjects (aged 67.6±7.7 yr) and twelve young males (aged 23.2±7.9 yr) performed ramp cycle exercise to exhaustion, increasing at a rate of 12.5 W/min for the elderly group and 25.0 W/min for the young group, following 3 min of exercise at zero work load. Myoelectrical signals were measured continuously from the vastus lateralis muscle, and values in terms of IEMG were computed every 10s throughout the test with AID conversion at 500 Hz. For the criterion of IEMG threshold, the breakpoint in the relationship between power output and IEMG was determined by two-segmental linear regression. VT was defined as the VO₂ at the onset of a nonlinear increase in VE and/or a sustained rise in VE/VO₂ without a rise in VE/VCO₂. It was found that the value of VO₂ in terms of IEMGT was similar to VT in both groups, 16.3 and 18.1 ml/kg/min for the elderly group and 33.5 and 36.3 ml/kg/min for the young group, respectively. Furthermore, IEMGT was correlated significantly (p<0.001) with VT in both groups (r=0.871 for the elderly group and r=0.925 for the young group) . It is concluded that the IEMGT method for determination of AT in the elderly is simple and useful.

The electromyographic (EMG) activities of the back and thigh muscles while pedaling a bicycle ergometer at different load levels (300, 450, 600 and 750 kpm/min) and during walking and running at top speed up and down a staircase were investigated in children classified as physically less and more active than average. Each child underwent a battery of physical fitness tests to determine his physical fitness level relative to the national standard. Although the physiques of the inactive and active children did not differ, there were considerable differences between their back-lift, grip and knee-extension strengths, and the maximum anaerobic power, and 50-m dash performances of the two groups. The EMG data for each of the different tasks over selected periods (bicycle pedaling: 5 complete revolutions, staircase task: 5 stepping cycles) under different workload conditions were full-wave rectified and integrated (IEMG) . Under low workload conditions (ergometer tasks at 300 and 450 kpm/min and walking up and down stairs), the mean IEMG values (mIEMG) of all the muscles tested did not differ significantly in the inactive and active children. However, for all the higher workload tasks (pedaling at 600 kpm/min and running up and down stairs), the mIEMG values of the erector spinae muscles in the inactive children were significantly lower than those of the active children, and the difference increased gradually as the workload increased. This trend was even more marked when normalized mIEMG values were used. When the children ran up and down stairs at top speed, the inactive group had lower thigh, gluteus maximus and erector spinae muscle mIEMG values than the active group, and the difference between the normalized mIEMGs of the erector spinae muscles of the two groups showed a particularly strong statistical significance (P<0.01) when running both up and down stairs. As a similar trend was observed when the workload was maintained at a high level for the bicycle pedaling task, we concluded that at least part of the difference between the muscular activities of the two groups of children demonstrated when they carried out the running task was attributable to differences in the development of the muscle fibers and neuronal mechanisms of the erector spinae muscles.

The purpose of this study was to examine the relationship between balancing ability during abrupt acceleration and the habitual physical activity level of elderly females. Thirty-one elderly females, aged 65-75 years, volunteered for this study. Changes in the center of foot pressure (CFP) were measured during postural sway following platform acceleration, and the response time and CFP displacement were evaluated. The scores of their daily physical activities (TS) -consisting of house-hold activities (HS), leisure time activities (LS) and sports activities (SS) -were estimated by the modified Voorrips's questionaire method. Response time and CFP displacement correlated significantly with age (p<0.001) . Response time also correlated significantly with the SS, LS and TS scores (p<0.05) . CFP displacement also correlated significantly with the SS and TS scores (p<0.05) . These results suggest that postural balancing ability during abrupt acceleration correlates signifi-cantly with the habitual physical activity levels, especially sports activities in elderly females.

A 34-year-old male patient was admitted to our hospital with sudden onset of severe chest pain. A diagnosis of acute aortic dissection (Stanford type A) was made based on the results of examinations such as CT-scan and angiography. An emergency surgical replacemant of the ascending aorta was carried out. Multiple malperfusion phenomena such as cerebral, renal, right upper extremity and visceral Ischemia appeared postoperatively. With strict conservative therapy and laparotomy (descending colectomy), he survived and was rehabilitated. Acute aortic dissection associated with malperfusion phenomena are frequent and potentially extremely poor complication. Therefore, prognosis is determined by accurate and rapid diagnosis and salvage of the ischemic organs. In treatment of the acute aortic dissection, the control of the blood pressure is important, but also close attention should be paid to sufficient perfusion of the major organs.

 The purpose of this study was to systemically review cohort studies of the preventive effects on locomotorium diseases in order to collectively evaluate the evidence.
 We searched the databases of PubMed, CINAHL, and lchushi-Web for papers published from1990 to September 17, 2009. The search was not limited by the language in which the paper was written.
 We found only one article (in Japanese) that fulfilled the eligibility criteria. Results in this article showed that bone fractures were significantly lower in the group with two times or more utilization of the hot spa bathing per year compared to the group with one time or less utilization per year, even after adjusting for the confounding effects of exercise habits and WHO-QOL. However, a metaanalysis could not be applied.
 We propose that it is necessary to conduct more cohort studies in which researchers choose suitable outcome measurements that assess long term effects.

Upper ministernotomy is frequently selected in aortic valve replacement by minimary invasive cardiac surgery. However, retrograde cardioplegia cannulae cannot be inserted to some sites. CT examinations in our department revealed that lower ministernotomy can be used for surgery of the aortic valve in many Japanese cases. The usefulness of 2 approaches was examined in 68 cases with aortic valve disease who received aortic valve replacement by minimary invasive cardiac surgery from January 1997 to March 2002: Those who received upper ministernotomy (U group) and those who received lower ministernotomy (L group). Retrograde cardioplegia is frequently used in aortic valve replacement for myocardial protection. Those in the L group showed effectiveness in myocardial protection and in securing the operation field except in cases who were switched to full sternotomy. In the L group, the MAZE operation was performed and no significant differences were observed in aortic cross-clamping time, artificial cardiorespiratory time, operation time, bleeding amount and other factors. Lower ministernotomy was more effective than upper ministernotomy in myocardial protection by retrograde cardioplegia and securing the operation field in aortic valve replacement by minimally invasive cardiac surgery.

Minimally invasive cardiac surgery (MICS) for treating valvular disease was introduced in our division in July 1997, and we have treated a total of 236 cases by July 2002. Among the various types of surgical treatment, there were 21 cases (M-group) of double valve replacement (DVR) to treat combined valvular disease. There had been 8 cases (F-group) of DVR by means of conventional full sternotomy during the period from January 1990 to June 1997, before the introduction of MICS. A comparison of the results of these surgical treatments yielded the following results. There were no differences in operation time and blood loss during the operations between the 2 groups, whereas the aortic cross clamp time and cardiopulmonary bypass time were significantly longer in the M-group than the F-group (M-group: 189±6 and 228±7min; F-group: 132±18 and 183±16min, respectively). There were significantly more cases of concomitant maze operation in the M-group than in the F-group. There were no differences in the durations of postoperative intubation or ICU stay. The days required from operation to starting walking were significantly shorter in the M-group compared to in the F-group (M-group: 2.4±0.2 days; F-group: 3.3±0.2 days), while there were no differences in the postoperative hospitalization periods. There were no major postoperative complications, and 1 case each there was 1 death in each group during the hospitalization period. Although the aortic cross clamp time and cardiopulmonary bypass time were longer in the M-group than in the F-group, the postoperative course and surgical outcome were good. So MICS for DVR was considered acceptable. In addition, MICS was thought to provide high patient satisfaction with regard to cosmesis or thoracic fixation, although early discharge from the hospital, which was possible in cases of single valve MICS, was not obtained.