The purpose of this study was to clarify the differences in reaction time, stepping frequency and stepping endurance estimated by chronological age compared to skeletal age. The participants were 76 well-trained soccer players aged from 9.7 to 14.8 years old. Height and weight were measured before training. Their skeletal ages were evaluated by RUS score of TW II method. RUS score was calculated for skeletal age by Murata's method. Reaction time, stepping frequency and endurance were measured by Talent-Diagnose-System (Werthner Sports Consulting, KEG, Co, Ltd.) . For chronological age, height increased linearly from 9 to 14. Height estimated by skeletal age increased slowly from 8 to 10, then increased drastically between the ages of 10 to 15. Significant change was shown between the ages of 12 and 13 (p<0.01) . Complex reaction time (CRT) estimated from chronological age developed linearly from 9 to 14 years of age. However for skeletal age, CRT at 10 was slower than at 8 and 9 years of age. Then it developed significantly between the ages of 10 and 11 (p<0.05) . On the other hand, stepping frequency and endurance did not show as remarkable a change with increasing age as reaction time. The results of this present study indicate that in adolescent soccer players, there are some differences between skeletal age and chronological age in cross-sectional change of reaction time. Moreover, skeletal age did not affect the development of stepping frequency and endurance.

In this study, we have investigated the use of cryopreserved menisci to orthotopically replace the medial menisci in adult beagle dogs. Red cell group typing and white blood cell group typing were determined and beagles were divided into the blood-matching group and the non-matching group. The medial meniscus was replaced with an allograft meniscus that had been preserved at -70 degrees for 7-21 days. As a control, the medial meniscus was removed and reattached after cryopreservation. Replaced menisci were examined macroscopicaly, histologicaly and biochemicaly at an interval of 2 weeks, 1, 3, 6, 12 months postoperatively.
After 6 months, the transplanted menisci had completely healed macroscopicaly. However, chondral erosions of the medial tibial plateau were seen in about one-half of the transplanted knees, and were thought to be caused by improper fixation of the anterior or posterior meniscal horns.
At 12 weeks, an infiltration of fibroblasts and capillaries from the synovial fringe into the meniscus were seen histoloigicaly. The central core of the menisci remained acellular. At 12 months, regenerated chondrocytes in the deep layer and fibrocartilage were seen in the macroscopical good allografted group. In the macroscopical poor group, the extracellular matrix of the meniscus was destroyed and the empty lacunae were presented.
The water content of the macroscopical poor group was significantly greater than that of the control group. In the good group the collagen content was siginificantly greater than that of the poor group.
There were no differences between the blood matching group and the non-matching group macroscopicaly, histologicaly and biochemicaly.

Despite their wide clinical application and success, our understanding of the effects of insoles is relatively limited. The purpose of this study was to assess the biomechanical effects of wearing lateral/medial wedged insoles on subtalar and knee joints during normal walking. Motion analysis was conducted with a 3D motion-analysis system and a ground reaction force analysis using force plate when subjects walked with three different insole conditions : 5-degree medial wedge, no wedge, and 5-degree lateral wedge. Significant differences were found in subtalar or ankle joint motion in coronal and sagittal planes compared with the no-wedge condition. No differences were found in knee joint motion in the coronal and axial planes. The lateral-wedge insole reduced the knee varus moment and increased subtalar pronation moment in mid-stance during walking. At footstrike, however, the lateral wedge increased the knee varus moment and reduced the subtalar supination moment. The medial-wedge insole increased the knee varus moment and decreased subtalar pronation moment during the mid-stance phase. However, the medial wedge reduced the knee varus moment and increased subtalar supination moment at footstrike. The results of this study indicate that the influence of the insoles varied during the stance phase. Therefore, it is requested to select the shape of insole based on the injury mechanism, the location of the pain and the injury prevention.

[Objective]Skeletal Muscle atrophy is induced in response to unloading by Hindlimb Suspension (HS). Numerous studies have been performed to prevent Skeletal Muscle atrophy. However, the molecular mechanisms underlying Electro-acupuncture (EA) on skeletal muscle have not been identified, and the effect of EA to prevent skeletal muscle atrophy is unknown. Therefore, we aimed to determine the effect of EA and Chishin (where the needles are kept in muscle for thirty minutes) on skeletal muscle atrophy in an animal experiment.
[Methods]Twenty mice (8 week, C57BL6) were randomly grouped into 4 groups;Normal group (N group), Hindlimb Suspension Group (HS group), HS +Chishin group (Chishin group), and HS +EA 1Hz group (1Hz group) (n = 5/group, respectively). Acupuncture interventions were conducted on the gastrocnemius of the Chishin and 1Hz groups. We measured the muscle mass, the cross sectional area, the percentage of Antrogin-1 and MuRF1 (Atrophy related E3ubiquitin ligases) expressions of the soleus 0f each mouse at 2 weeks after acupuncture interventions.
[Result]The weight and Cross sectional area of the soleus of the 1Hz group were significantly greater than the HS group (P<0.01, P<0.01, respectively). On the contrary, the percentage of Atrogin-1 and MuRF1 expressions of the 1Hz group was significantly less than the HS groups (P<0.01, P<0.05, respectively).
[Conclusion]These results suggest that EA and Chishin may influence the activity of Atrogin-1 &MuRF1 expression.

In this study, we have investigated the use of cryopreserved menisci to orthotopically replace the medial menisci in adult beagle dogs. Red cell group typing and white blood cell group typing were determined and beagles were divided into the blood-matching group and the non-matching group. The medial meniscus was replaced with an allograft meniscus that had been preserved at -70 degrees for 7-21 days. As a control, the medial meniscus was removed and reattached after cryopreservation. Replaced menisci were examined macroscopicaly, histologicaly and biochemicaly at an interval of 2 weeks, 1, 3, 6, 12 months postoperatively.
After 6 months, the transplanted menisci had completely healed macroscopicaly. However, chondral erosions of the medial tibial plateau were seen in about one-half of the transplanted knees, and were thought to be caused by improper fixation of the anterior or posterior meniscal horns.
At 12 weeks, an infiltration of fibroblasts and capillaries from the synovial fringe into the meniscus were seen histoloigicaly. The central core of the menisci remained acellular. At 12 months, regenerated chondrocytes in the deep layer and fibrocartilage were seen in the macroscopical good allografted group. In the macroscopical poor group, the extracellular matrix of the meniscus was destroyed and the empty lacunae were presented.
The water content of the macroscopical poor group was significantly greater than that of the control group. In the good group the collagen content was siginificantly greater than that of the poor group.
There were no differences between the blood matching group and the non-matching group macroscopicaly, histologicaly and biochemicaly.

The purpose of this prospective study was to examine the injury characteristics in collegiate women’s lacrosse players. Injury data were collected from the Division I collegiate women’s lacrosse team for a 2-year. The total athlete-hours and athlete-exposures over the 2-year period were 27,621 and 13,437, respectively. The total number of injury was 309 injuries, and the total incidence rate was 11.19 injuries (95% confidence interval, 9.94 — 12.43) per 1000 athlete-hours and 23.00 injuries (20.43 — 25.56) per 1000 athlete-exposures, respectively. The most frequent location of injury was the ankle, followed by the knee and the thigh (20.1%, 14.6%, and 10.7% of all injuries). The proportion of lower extremity injuries accounted for 73.5% of all injuries. The most common types of injury was sprains and muscle cramps/spasms (24.9% and 24.6%, respectively). Overuse, contact (e.g., other players, the cross, and the ball), and non-contact injury was the 3 most common cause of injury (39.1%, 24.9%, and 17.2%, respectively). The primary injury characteristics of collegiate women’s lacrosse players were non-contact ankle sprain. Injury recurrence accounted for 26.1% of all injuries, and the most common period required for the player to return to practice and/or games was between 3 and 7 days. Midfield position player suffered the most number of injuries compared to other position player. An understanding of the injury characteristics of women’s lacrosse players may facilitate the development of the comprehensive strategy for injury prevention which is recommended by the sports medicine community.

The laxity of shoulder is one of main factors affecting shoulder lesions in athletes.
To measure the anterior-posterior laxity of shoulder, a stress machine was arranged because the ordinary rentogenographic measurement is not suitable. The measurement of the anterior-posterior laxity was done with athletes in several kinds of sports in which shoulder joints are mainly used. The result was compared with those from clinical examinations and stress rentogenography. Conclusions :
1. The anterior-posterior displacements of the affected side in baseball, volleyball and javelin players were significantly larger than that of the control side.
2. For the anterior-posterior displacement of the shoulder joint, baseball, volleyball and javelin players showed significantly larger values than truck runners as the control whereas significantly smaller values were found in water polo players.
3. There was no correlation between the anterior-posterior laxity and the inferior laxity.

An investigation was conducted to clarify both the effect of water polo training on bone mass and the effect of training-induced menstrual disorders on bone. The subjects were 12 female college water polo players and 7 age-matched sedentary college women as a control group.
Menstrual condition was evaluated by 12 montes of basal body temperature measurement. Seven of the water polo players were eumenorrheic, and five had training-dependent (reversible) menstrual disorders (two with amenorrhea and three with cycle disturbances) .
Bone mineral measurement revealed differences between the water polo players and the sedentary women. The eumenorrheic water polo players had a higher bone mineral density (BMD) in the lumbar spine and total body skeleton than the sedentary control group, being 11.2% and 11.3% higher, respectively.
Effects of menstrual disorders (including cycle disturbance) were clear in the water polo players. The BMD of water polo players with menstrual disorders was 9.8% and 9.6% lower in the total body and lumbar spine that of eumenorrheic water polo players.
Hormonal examinations revealed a lower serum estradiol level in water polo players with menstrual disordsers in comparison with eumenorrheic water polo playes. Serum estradiol level showed a positive correlation with both total body BMD (r=0, 78, p<0.01) and lumbar spine BMD (r=0.71, p<0.01) .

The purpose of this study was to investigate the mechanism of the dynamic morphological change of the femoral extensor evoked by contraction.
In this study, the morphological changes during contraction and relaxation of the femoral extensor were analysed using MRI, and, the centers of gravity of the entire extensor group and of each extensor component were calculated using a pattern analyzer. The subjects were 10 female college basketball players, aged 18 to 22 years, with no history of knee injuries.
The results were as follows:
1. The shift of the center of gravity of each component was very characteristic.
2. The greatest dynamic morphological change was observed in the middle of the femoral extensors when the most muscle volume was involved, and the muscles were at their maximal volume.
3. During muscle contraction, obvious anterior protrusion of the muscle belly of each component of the quadriceps femoris was observed. The muscular force may be transferred effectively into the patellar tendon insertion.