GENDER DIFFERENCES OF LOWER EXTREMITY KINEMATICS DURING SINGLE LEG LANDING / 体力科学

The higher anterior cruciate ligament (ACL) injury rate of females is one of the most sever athletic-related problems today. The purpose of this study is to compare the lower extremity kinematics between male and female during single leg landing.Six male and four female healthy subjects participated in this study. They jumped from a 32 cm high box and landed with the dominant leg. The landing action was filmed with three video cameras. The knee flexion, knee valgus/varus, and hip adduction/abduction angle and angle velocity were calculated.In female subjects, the knee flexion angle and hip adduction angle were greater compared to males. Also, the knee valgus velocity and hip adduction velocity were higher in females.Our results suggest that knee valgus kinematics may be related to hip adduction. It is important to evaluate hip kinematics when considering knee kinematics to prevent knee ligament injuries.

THE RELATIONSHIPS BETWEEN SHOULDER'S FUNCTION AND DAMAGE FOR HANDBALL PLAYERS / 体力科学

[Objective] The purpose of this study is to examine the relationships between shoulder's function and damage for handball players. Subjects were nine female handball players with dominant shoulder pain.[Methods] Clinical diagnosis was done from the medical doctor's opinion and MRI. Then, the shoulder joint movement was measured with X rays.[Results] Most of them had admitted a lot the impingement syndrome and the subacromial bursitis. The trunk rotation angle at zero-positions was significantly larger in the symptomatic shoulder (dominant shoulder) than in the asymptomatic shoulder (nondominant shoulder). That is, it was obvious that the damage of the shoulder changed tilting angle of scapula medially.[Conclusion] It is reported that the damage of the shoulder causes abnormality to the “scapulohumeral rhythm” by the previous research. But, these results, suggested to need to understand not only “scapulohumeral rhythm” but also movement to the position of the scapula, when the shoulder joint function was observed for the handball player mainly composed of throwing motion.

EFFECT OF POSITION AND CHANGE OF ANGLE ON ACTIVITY OF SHOULDER MUSCLES DURING SCAPULAR PLANE ABDUCTION / 体力科学

The purpose of this study is to identify the effect of position (full can, empty can) and change of angle on the activity of shoulder muscles during scapular plane abduction ; and also to examine its application to exercises used for rehabilitation of shoulder muscles. Seven healthy subjects (23.4±1.4 yr) with normal shoulder function performed scapular plane abduction with external rotation (full can) and scapular plane abduction with internal rotation (empty can) . An electromyogram was recorded with a fine wire intramuscular electrode at the supraspinatus, deltoid anterior, middle, posterior and trapezius upper with bipolar surface. The EMG activity (RMS) of each muscle was normalized by the highest EMG activity (100%RMS) during a maximum manual muscle test for each muscle (%RMS) . The %RMS of each muscle remarkably increased with a change of the angle for empty can, whereas it showed a slight increase with a change of the angle for full can. This finding suggests that the position of full can and empty can in scapular plane abduction affects the function of shoulder muscles. In addition, full can exercise is recommended in order to improve function of the supraspinatus and the muscular activity balance between the supraspinatus and the deltoid. Empty can exercise is applied to sport-specific exercise for rehabilitation of shoulder muscles.

A GENU VARUM EFFECTS ON EACH LOWER EXTREMITY MUSCLE ACTIVITY DURING LEGPRESS EXERCISE / 体力科学

[Purpose] A leg press generally included in a weight training program to develop the quadriceps. However little is known about the mechanism of the load in lower extremity by the different knee alignment. The purpose of this study is to compare the muscle activity in the different knee align ment during leg press exercise. [Methods] Four normal knee and Five gene varum performed the leg press using three stance of narrow, medium and wide stance with the load of 75%/1 RM. Surface EMG date were collected (1000Hz) from vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), adductor longus (AL), biceps lemons (HF), tibialis anterior (TA), gastrocnemius (GAS), soleus (SQL) . Integrated EMG (iEMG) values were calculated for each muscle during each rep. A video camera recorded the performing form during leg press from the frontal plane. [Results and Discussion] As the leg press was to strengthen of the thigh muscle, VM, VL and RF of both groups worked strongly. However SQL of genu varum worked as strong as the level of activity of the thigh, iEMG of the SQL showed low value significantly by using wide stance. When the genu varum group performed maximal knee flexion using the narrow, their ankle was valuus on the video screen. This result may become cause of SQL higher activity during leg press. From this we can derive the argument that it will be necessary to take that stance into consideration when athletes who are genu varum performs leg press.

Electromyographic Activity of Shoulder Muscle at Different Positions During External Rotation / 体力科学

Electromyographic activity of the shoulder muscle at 20 and 90°abduction (20 Abd, 90 Abd) during external rotation was investigated in seven healthy men with no history of injury or instability of the shoulder joint.<BR>Electromyography (EMG) was recorded using intramuscular fine-wire electrodes inserted into the M. Supraspinatus, M. Infraspinatus and M. Teres minor, and with bipolar surface electrodes on the middle and posterior parts of M. Deltoid anti the upper and middle parts of M. Trapezius. To compare activity in different muscles, the integrated EMG (iEMG ) activity of each muscle was normalized.<BR>M. Infraspinatus and M. Teres minor showed significantly higher activity at both the 20 Abd and 90Abd compared with the middle and posterior parts of M. Deltoid and upper parts of M. Trapezius. M. Supraspinatus, the middle and posterior parts of M. Deltoid, and upper and middle parts of M. Trapezius all showed a difference in activity level between the two positions.<BR>These findings suggest that when M. Infraspinatus and M. Teres minor contribute to external rotation as a stabilizer and prime mover, consecutively, M. Supraspinatus, the middle and posterior parts of M. Deltoid, and upper and middle parts of M. Trapezius function according to the positions. Moreover, the activity of the upper and middle parts of M. Trapezius in 90Abd should influence stabilization, adduction and upward rotation of the scapula. Therefore, we conclude that the external rotation position is closely related to shoulder muscle activity and coordination.

EFFECT OF ACUPUNCTURE STIMULATION ON DELAYED ONSET MUSCLE SORENESS PRODUCED BY ECCENTRIC EXERCISE / 体力科学

Delayed Onset Muscle Soreness (DOMS) is characterized by a sensation of discomfort that usually develops 24-48 hours after unaccustomed exercise, with muscle swelling and stiffness that usually results in a reduced range of movement. Muscle weakness is often seen. It may be surmised that DOMS is a problem that affects all athletes.<BR>We examined six male subjects to determine the effect of acupuncture stimulation on DOMS, which was induced experimentally in both legs using a heel raising exercise. Acupuncture stimulation has long been used in the treatment of pain, but there is insufficient proof of its efficacy. A problem acupuncture research has had to face is the concept of a control group. To deal with this, we used non-invasive acupuncture stimulation, which would allow the simulation of the acupuncture procedure without penetrating the skin. The leg that would receive actual acupuncture stimulation and the leg that would receive non-invasive stimulation after the induction of DOMS were determined by randomization.<BR>The muscle stiffness, ankle range of movement, maximal voluntary contraction, one-legged vertical jump, muscle tenderness, pain on muscle stretching, pain on muscle contraction, ankle mobility and subjective muscle strain were measured as indices of stimulation efficacy. Pain on muscle stretching was significantly less (p<0.05) at 48 hours after exercise for the side stimulated by acupuncture as compared with the side stimulated non-invasively. The other indices did not differ significantly between the side stimulated using acupuncture stimulation and the side stimulated non invasively. These results suggest that the early relief of DOMS can be achieved by acupuncture stimulation.

Electromyographic analysis of shoulder muscles during shoulder external rotation with reference to load magnitude / 体力科学

Electromyographic muscle activities of the shoulder muscles during shoulder external rotation with reference to load magnitude were studied in 8 healthy male subjects without history of shoulder injuries. In addition, we discussed the relationship between rotator cuff muscles and superficial muscles. The subjects performed shoulder external rotation from 60°internal rotation to 45° external rotation at 20° of shoulder abduction and 20° of flexion. A Cybex dynamometer used to prescribe angle and velocity of the shoulder movement. At the same time, intramuscular wire electrodes were inserted into the supraspinous, infraspinous and teres minor muscles, and then surface electrodes were placed over the posterior deltoid and middle trapezius muscles. The load magnitude ranged 2-18 Nm and the angle velocity was set at 15 deg/sec. The rotator cuff muscles became significantly to be activated from 2 Nm (the supraspinous and infraspinous m.) and from 4-5 Nm (the teres minor m.) compared with the muscle activity during non-load. The superficial muscles became significantly to be activated from 4-7 Nm (the posterior deltoid m.) and from 3-6 Nm (the middle trapezius m.) compared with the muscle activity during non-load. Within the load range (18 Nm 46.8% MVC), %iEMG of the rotator cuff muscles was always larger than that of the superficial muscles. Therefore, we concluded that the contribution of the rotator cuff muscles was larger than that of the superficial muscles up to 3-4 Nm, and activities of the superficial muscles increased gradually from 3-4 Nm during shoulder external rotation.

Three-dimensional dynamics of elbow and shoulder joint throwing motion in relation to throwing arm movement and injury in baseball / 体力科学

This study was designed to clarify the causes of throwing injuries of the elbow and shoulder joints in baseball. Five varsity-skilled baseball players without pain in the elbow and shoulder joints were subjects for this study. They were fixed to a chair and asked to throw a baseball using three different throwing arm movements (T<SUB>0</SUB>, T<SUB>45</SUB>, and T<SUB>90</SUB>) . These movements were filmed using three-dimensional DLT videography. Linked rigid-body segment inverse dynamics were then employed to determine resultant joint force and torque at the elbow and shoulder joints. Peak varus torque at the elbow joint for T<SUB>90</SUB> was less than for the other movements during the acceleration phase. In the follow-through phase, however, a large anterior shear force (70 N) at the elbow, for elbow extension, was present for T<SUB>90</SUB>. These results indicate that T<SUB>90</SUB> was a high risk movement which leads to extension injuries rather than medial tension injuries. After the ball release, a large superior shear force (118 N) at the shoulder joint was present in all movements. This superior force may result from the subacromial impingement syndrome, except for critical zones of impingement caused by the different throwing arm movements. These findings suggest that the mechanisms of throwing arm injuries are closely related to differences in throwing arm movements.

CHANGES IN BONE METABOLISM MARKERS ASSOCIATED WITH LONG-DISTANCE RUNNING / 体力科学

To investigate the influence of long-distance running on bone metabolism, we measured bone metabolism markers in eight healthy young men before and 4 months after the start of training program of 10 km running. Measurements were then taken the day before a marathon race, immediately after, and 1 day, 2 days and 5 days after.<BR>As a result of exercise, the levels of serum osteocalcin (OC), a bone formation marker, and urinary deoxypyridinolin (D-Pyr), a bone resorption marker, decreased significantly. After the marathon race, the OC level decreased further corresponding to an increase of hydrocortisone right after the race. However, from the day following the race, the OC level showed a slight increase. D-Pyr showed an increasing tendency immediately after the race, and the levels of OC and D-Pyr increased significantly 5 days after the race.<BR>Bone formation and resorption decreased as a result of light, low-frequency endurance exercise. However, both of them increased after intense physical stress. From this result, it is suggested that the intensity and frequency of exercise affect bone metabolism differently, even though the type of exercise load is similar.

Quantitative measurement of quadriceps femoris with MRI. Morphological change of contraction phase and relaxation phase / 体力科学

The purpose of this study was to investigate the mechanism of the dynamic morphological change of the femoral extensor evoked by contraction.<BR>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.<BR>The results were as follows:<BR>1. The shift of the center of gravity of each component was very characteristic.<BR>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.<BR>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.

MENISCAL ALLOGRAFT / 体力科学

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.<BR>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.<BR>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.<BR>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.<BR>There were no differences between the blood matching group and the non-matching group macroscopicaly, histologicaly and biochemicaly.

Meniscal allograft. An experimental study in the dogs / 体力科学

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.<BR>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.<BR>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.<BR>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.<BR>There were no differences between the blood matching group and the non-matching group macroscopicaly, histologicaly and biochemicaly.

The effect of water polo training on bone mineral content / 体力科学

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.<BR>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) .<BR>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.<BR>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.<BR>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) .

Shoulder injuries caused by throwing during water polo / 体力科学

A study was conducted to investigate the influence on the shoulder joint of throwing during water polo. One hundred sixty-seven water polo players were interviewed about injuries caused by water polo, and 70 players claimed to have had shoulder pain.<BR>In 21 players, clinical examinations were performed, and in 31 players, assessment of external rotation stability was made. Then three-dimensional analysis of hand-to-hand shoot motion was performed in 7 players.<BR>The results were as follows;<BR>1. The painful phases of the throwing motion were the take-back phase and the acceleration phase, the pain being present at the anterior and lateral portions of the shoulder joint, <BR>2. Assessment of stability revealed that the external rotation displacement on the affected side was significantly larger than that on the control side in the injured players.<BR>3. Analysis of hand-to-hand shoot motion revealed that the external rotation angle in the acceleration phase was significantly larger in non-injured subjects than in the injured.<BR>4. The external rotation angle after ball contact was increased in the injured, but decreased in the non-injured.<BR>5. To prevent injury, it appears important to catch and throw the ball using the upper extremity and rotation of the trunk in a high body position in the water, and to strengthen the muscles of the shoulder.