The purpose of this study is to evaluate physical characteristics of boxing players with/without low back pain (LBP). Materials and methods : 18 college boxing players were divided into two groups ; The first group consisted of eight subjects with LBP (LBP group), the other one consisted of ten subjects without LBP (no LBP group). The evaluation items were as follows : muscular strength of trunk extension/ flexion/ rotation, cross-sectional areas of the muscles of the lumber region, X ray photograph of lumber spine, MRI, general joint laxity test, muscle tightness test, muscle hardness, tenderness and moiré topography. Results : 9 out of 18 subjects showed lumber region abnormalities in their X ray photograph and MRI. The following evaluation items of LBP group read significant differences compared to those of no LBP group ; The trunk rotator peak torque was weaker at the angular velocity of 120 deg/sec, the laterality of SLR was significantly larger, while the finger floor distance value indicated significantly lower. Discussion : In LBP group, it is suggested that the decline of trunk flexion muscle strength possibly preceded the fall of trunk extension muscle strength which, however, was not observed.

Purpose : This study was to investigate the patterns of electromyography (EMG) amplitude responses during maximal, eccentric muscle action with shoulder adduction and diagonal movement, at 6 different positions on the dynamometer.Methods : The participants for this investigation were 9 males and 5 females. Testing consisted of each subject performing eccentric muscle exercise of the dominant shoulder muscle at a velocity of 60°/sec and 180°/sec. Muscle activity values was recorded individually from six different muscles and peak torque values were extracted for each test from torque curves once. EMG data were normalized to the highest root mean square (RMS), and were expressed as a % maximum voluntary isometric contraction (%MVIC).Results : The posterior parts of upper extremity muscle complex generate overall high muscle activity (> 40%MVIC) during all testing for eccentric muscle activity with diagonal shoulder movement. Posterior deltoid (PD), upper trapezius (UT), and middle trapezius (MT) muscles show differences between eccentric muscle action with shoulder adduction and eccentric muscle action with diagonal shoulder movement.Conclusion : The present results show that an improved understanding of muscle activity patterns during different movement may benefit many fields of athletic trainers, coaches, and athletes, in addition to assisting in injury prevention for throwers, and even rehabilitation after injury.

The purpose of this study is to identify the risk factors which affect the consecutive onset of throwing shoulder injury of a collegiate baseball team, and to calculate regression formula which could predict the future onset.Prospective study. The subjects are 69 asymptomatic collegiate baseball players. We executed medical checkups and investigated who got throwing shoulder injury during this year. We did logistic regression analysis with the medical checkup findings and the data of the onset and found out the factors which significantly affected the onset. We also calculated Odds ratio of these factors and regression formula which predict the probability of the onset of throwing shoulder injury and evaluated the validity of regression model.52%(36/69 cases) of the players suffered throwing shoulder injury during this year. Among the medical checkup findings of asymptomatic phase, pitcher and catcher, past history of throwing shoulder injury, abnormality of scapula-humeral rhythm, heel-buttock distance were thought to be the risk factors which were near-related to the onset of throwing shoulder injury. We calculated regression formula using the medical checkup findings of asymptomatic phase and we could predict the onset of throwing shoulder injury with 82.5% accuracy.In order to prevent this injury, the method used in this study could be useful for field players to predict the onset of throwing shoulder injury.

The purpose of this study was to increase knowledge about the landing posture that induces anterior cruciate ligament (ACL) injury. Analysis was done to determine the knee abduction moment during single limb landing using our previously proposed mathematical model. Our model has proven that the criterion of knee abduction occurring is when the acting line of the ground reaction force is directed laterally to the lower leg segment. Based on this, we predicted a medial shift of the knee joint and a lateral leaning of the trunk segment to induce the knee abduction moment. To verify the results of our model prediction, we conducted a motion analysis experiment with a single limb-landing task. Three male and four female subjects participated in the experiment. Subjects were instructed to fall from a 30 cm high box and land on a target which was assigned by PC-controlled laser pointers. Since the landing target was unexpectedly moved during landing, the subjects were perturbed and exhibited various landing postures. The results of the landing experiment showed that trunk leaning laterally towards the landing limb and medially shifted knee alignment induced the knee abduction moment. These results are consistent with the results predicted by our model. In conclusion, appropriate control of both lower limb alignment and trunk motion in the frontal plane in essential for reducing the risk of ACL injury.

The purpose of this study was to examine the effects of knee flexion angles during maximum isometric hip extension. Ten healthy men performed maximum isometric hip extension in prone position at 15° and 90° knee flexion. Then, the hip extension torque was measured, and electromyographic (EMG) data were obtained from the biceps femoris long head, semitendinosus, semimembranosus, adductor magnus, and gluteus maximus muscles. The EMG data were full-wave rectified and integrated (IEMG). The IEMG values obtained during the measurement of isometric hip extension were normalized with the values collected at 90° knee flexion (normalized IEMG [NIEMG]). The hip extension torque at 15° knee flexion was significantly greater than that at 90° knee flexion. The NIEMG values from the hamstrings at 15° knee flexion significantly increased compared with those at 90° knee flexion. Meanwhile, the NIEMG values from the gluteus maximus at 90° knee flexion were significantly greater than those at 15° knee flexion. However, the NIEMG values from the adductor magnus did not significantly differ between 15° and 90° knee flexion. These results indicate that the hamstrings effectively generate contracting force during isometric hip extension and at knee extended position because its fiber length was close to the optimal length.

Non-contact anterior cruciate ligament (ACL) injury is one of the most severe knee problems for female athletes. Several studies have reported that the decreased lower limb control of women such as decrease of hip abductions muscle strength increase the risk of ACL injury. Also ACL Injury often occurs as a result of knee valgus collapse during single leg landing or pivoting in sports activities like basketball. Female basketball players often show an excessive knee valgus and hip adduction during the play. The purpose of this study was to analyze the effect of hip abductions muscle strength on knee alignment during a single leg landing. Thirty healthy female basketball players participated in this study. Mean age, height, body weight and plyer career were 17.3 years old±3.7, 162.7cm±17.2, 56.2kg±10.9, 8.9 years±3.8 respectively. All subjects were obtained written consent from after explanation of the procedure. Significant negative correlations showed that greater hip abductor peak torque (hip flexion 0 and 30degrees) exhibited less motion toward the knee valgus direction during single leg landing. And also, dynamic Trendelenburg test showed that all positive reactions cause knee valgus direction. These results suggest keeping proper knee position safety during single leg landing; female basketball player should improve the hip abductions muscle strength. Hip joint control will be a major issue for prevention of the non-contact ACL injury.

The purpose of this study was to evaluate the change of the hardness of the gastrocnemius muscle (GM) and the Achilles tendon (AT) using Real-time Tissue Elastography (RTE) before and after acute exercise. Nine healthy young male without any exercising custom performed a total of 100 reps. of one-leg heel-rise exercise and the hardness of the gastrocnemius muscle and the Achilles tendon before and after the exercise was examined in comparison. The strain ratio (SR) was even measured in comparison to a reference material. The result indicated that the SR of the GM significantly increased immediately, 15min, 30min and 24h after the exercise, whereas the SR of the AT significantly increased just immediately and 15min after the exercise. In summary, the hardness of GM and AT increased after exercise. These findings suggest that RTE is a useful technique for assessing specific hardness of muscles and tendon, More RTE measurements of various parts of the body and the examination of the relationship between injury and RTE are required for the conditioning of muscles and tendons.

Strenuous and consecutive exercise results in fatigue symptoms accompanied decrease in salivary secretory immunoglobulin A (sIgA) in athletes. On the other hand, it has been reported that plasma taurine concentration was increased after the high intensity exercise. However, change in salivary taurine concentration after strenuous and consecutive exercise is unknown. The purpose of this study was to investigate the relationship between fatigue symptoms and changes in salivary taurine concentration in collegiate male soccer players. Thirty seven collegiate male soccer players participated in three consecutive days of match program. To detect of fatigued players, we measured awakening heart rate and body weight. As the results of these two measurements, we divided subjects to two groups (non-fatigue group, n=15; fatigue group, n=22). We also measured salivary sIgA and taurine concentrations before and after program. Before the program, there were no significant differences in any parameters between two groups. Salivary flow rate and sIgA secretion rate were significantly decreased after the program in the fatigue group. Furthermore, salivary taurine concentration was significantly increased after the program in the fatigue group. In the non-fatigue group, there were no significant differences in any parameters during program. Our results indicated that salivary taurine concentration increased after consecutive high-intense exercise in the collegiate male soccer players.

To determine the effect of taurine on blood glucose concentration during prolonged exercise, fifteen male university students cycled for 120 min at 50%VO₂max after 7 days with or without taurine supplementation. Exercise tended to reduce the blood glucose concentration, whereas taurine significantly prevented this decline. Exercise significantly increased plasma glucagon concentrations in both groups to a similar degree. Serum insulin concentrations did not differ during exercise under both conditions. Taurine supplementation respectively significantly inhibited and tended to inhibit the plasma noradrenaline and adrenaline concentrations increased by exercise. These results suggest that taurine supplementation can maintain the blood glucose concentration during prolonged exercise through enhanced catecholamine sensitivity.

The aim of this study is to examine the potential of the two-dimensional posture evaluation method as a screening tool for detecting the high-risk population for anterior cruciate ligament injury.Eleven healthy adults participated in this study. They jumped from a 31 cm-high box and landed on their dominant leg. Three-dimensional knee flexion/extension, knee valgus/varus and hip adduction/abduction angle during single-legged landing were calculated. At the same time, the Frontal-plane Knee Displacement index (FKD)-the knee joint position relative to the line between the hip and ankle joint-was measured.FKD reflects the time variation of three-dimensional knee valgus and hip adduction angle very well.Our results suggest that FKD has potential as a screening tool particularly for movement occurring primarily in the frontal-plane.