A study was conducted to observe the relationship between the architecture and function of the muscle-tendon complex in human movements. Using real time ultrasonography, we were able to observe clearly and noninvasively the movement of the fascicle and aponeurosis in human muscle in vivo, and measure directly the changes in pennation angle and fascicle length during muscle contraction. During dorsal and plantar flexion without additional load, the movement of tendinous tissue in the tibialis anterior muscle (TA) appeared to synchronize with the displacement of the ankle joint. On the other hand, when the ankle joint was fixed and the TA contracted "statically or isometrically", the ultrasonic echo from the deep aponeurosis in the TA was observed to move proximately, indicating that the elastic component (i.e. mainly tendinous tissue) was stretched significantly by the muscle contraction force. When the knee extensors contracted "isometrically", the fascicle length decreased at every joint angles and its magnitude was greater (30%) when the knee was closer to full extension than at flexed positions (5%). During "isokinetic" knee extension, the fascicle shortening velocity changed significantly due to the joint angle, i.e. the highest shortening velocity was observed at a knee joint angle of 60 degree. This indicates that the assumption of a constant muscle shortening velocity in isokinetic testing is not valid. In vertical jumping, the fascicle length of the gastrocnemius medialis muscle (GM) decreased by 27% in the first half of the push-off phase, when the whole length of the muscle-tendon complex (MTC) of the GM remained constant. On the other hand, before take-off the GM muscle contracted isometrically while the MTC length decreased. This means that in the first half of jumping, the elastic component is lengthened by the contraction force of the muscle fibers (elastic energy stored), and that in the following take-off phase MTC shortening is causked by the elastic energy stored previously when the muscle fibers contract isometrically. The present results clearly show that the architecture of actively contracting muscle fibers differs considerably from that which occurs when movement is passively induced. Therefore, the use of cadaver data in studies of the architecture and modeling of muscle functions would result in inaccurate, and in some cases even erroneous results.

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A study was conducted to explore the utilization of effective social support to prevent athlete burnout. First, 76 varsity-athlete freshmen who belonged to 4 different clubs answered a questionnaire composed of the Athletic Social Support Scale (ASSS; Tsuchiya &amp Nakagomi, 1994), Athletic Burnout Inventory (ABI; Kishi et al., 1989) and Network Map, which is a modification of the Psychological Distance Map (Wapner, 1978), and they also described their perceived stress by the free description method. We carried out 4 measurements after the subjects had started club activities; one week later (1W), two months late (2M), four months later (4M) and six months later (6M). Secondly, eight of the study freshmen were interviewed during the investigation (60 min×4 lessions). The main results obtained were as follows; 1) The freshmen encountered 3 different types of stress, which were characterized by their transition period. The first type of stress, termed "confusion about athletic life" was experienced more frequently in 1W, the second type, termed "unease about performance enhancement", occurred in 4M, and the third type, termed "complicated relationships with others", occured in 6M. 2) The althletes' perceived stress and burnout tendencies were significantly correlated, and both uncreased throughout the study period. However, the burnout tendency of freshmen with good social support was arrested, whereas that of freshmen with poor social support increased significantly after 2M. Furthermore, path analysis of a longitudinal model for social support and athlete burnout showed that a supportive environment for freshmen at the beginning of their activities was critical for mitigating the stress-burnout relationship. 3) Effective social support for these three types of stress were observed throughout the case study, and identified by multiple regressio n analysis. It is suggested that instrumental support from seniors in 1W, esteem and companionship support from teammates and new friends in 2M, instructive support from coaches and trainers in 4M, and esteem support from seniors and teammates in 6M could buffer the negative effect of stress. Future work should expand these findings into an educational intervention program for freshmen.

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Magnetic resonance imaging (MRI) was performed on 89 female athletes (26 handball players and 63 track and field athletes) to investigate the association between lumbago, degenerative disks (DD) and herniated intervertebral disks (HID). Longitudinal scans of the lumbar vertebrae were obtained with a slice thickness of 7.5 or 10 mm in the sagittal plane. DD were diagnosed by their low signal intensity, and HID by protrusion of the intervertebral disk at the level of L1/2 to L5/S1. In all subjects, the prevalence rate of DD was 31.5%. The subjects with lumbago had a higher prevalence of DD than those without lumbago (P&lt0.05). The subjects with DD had a higher prevalence of HID than those without DD (P&lt0.01). The phenomenon was prominent specifically in L4/5 and L5/S1. None of the subjects had HID without DD.

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A study was conducted to investigate the influence of maximal running speed, aerobic and anaerobic components and muscular endurance of the lower limbs on the decrease in running speed during 400 m running. Fifteen track and field athletes (400 m sprinters, decathletes and middle-distance runners) participated. The subjects were used to obtain data on changes in running speed during 80 m and 400 m running, maximal O_2 intake, O_2 debt and isokinetic muscular endurance. The time taken to cover 400 m was negatively correlated with maximum O_2 (r=-0.558; p&lt0.05) and muscular endurance of hip flexion (r=-0.521; p&lt0.05). Running speed over a distance of 400 m began to decrease after 80 m, and kept decreasing until the finish. The change in running speed after 80 m was expressed as a linear regression equation, and the regression gradient was interpreted to be an index of the decrease in running speed. There were significant correlations between the muscular endurance of hip flexion and extension respectively (r=-0.666; p&lt0.01, r=-0.517, p&lt0.05). These results suggest that the muscular endurance of hip flexion affects the decrease in running speed during 400 m running, and also performance.

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