A kinetic analysis of the judo osoto-gari technique: relationship to sweeping leg velocity.

The present study characterised supporting leg kinetics (sweeping and pivot legs) during osoto-gari and investigated the relationship between kinetic variables and sweeping leg velocity at sweep contact. Fifteen black belt judoka performed osoto-gari. Motion data were recorded using a Mac3D motion analysis system (250 Hz), and ground reaction force (GRF) data were collected using four force plates (1,000 Hz). During the swing phase, the peak anterior (r = -0.535, p = 0.040) and upward (r = -0.693, p = 0.005) GRFs generated by the sweeping leg and the peak plantar flexion moment (r = 0.548, p = 0.034) and power (r = -0.700, p < 0.005) of the sweeping leg ankle joint significantly correlated with the sweeping leg velocity at sweep contact. During the throwing phase, the peak clockwise moment (r = -0.604, p = 0.017) correlated with the peak sweeping leg velocity. The peak knee extension moment (r = 0.602, p = 0.018), hip flexion moment (r = -0.589, p = 0.021) and knee power (r = -0.618, p = 0.016) of the pivot leg also correlated with the sweeping leg velocity at sweep contact. The results indicated that exertion of the sweeping leg ankle plantar flexors positively contributed to the sweeping velocity. Increasing whole-body rotation by contracting the pivot leg knee extensors is a crucial biomechanical factor in accelerating the sweeping leg at sweep contact.

A biomechanics analysis of the judo osoto-gari technique: comparison of black belt and white belt judokas.

The purpose of this study was to determine biomechanical factors for the effective execution of the osoto-gari technique by comparing differences between black belt and white belt judokas. Twenty-two male judokas (12 black belts; 10 white belts) performed osoto-gari, and the motion data were recorded using a Mac3D motion analysis system (250 Hz). The peak angular momentums of the trunk and leg of the uke were larger in the black belts than in the white belts, suggesting that the black belts rotated the uke's body more effectively than the white belts. During the swing phase, the peak angular velocities of the arms and trunk twist in the black belts were larger compared to the white belts. During the throwing phase, the black belts had substantially greater peak angular velocities of the arms, upper torso, and trunk twist. Additionally, the timing of the peak value of the upper torso and trunk twist of the black belts was closer to sweeping leg contact than that of the white belts. The results can provide coaches with suggestions for improving training protocol design when teaching osoto-gari and for helping novices more efficiently master the technique.

Thermographic study on the preservability of heat effects of footbath with salt.

Infrared thermography provides a non-invasive and dynamic measure of heat. The thermal preservability effects of a salt footbath were evaluated by the infrared thermography technique. The subjects were 23 healthy college students. Feet were soaked for 10 min in a 40-42 degrees C normal footbath. Room temperature was set at 26.5-28 degrees C. At the same time on another day within 3 days of the normal footbath experiment, the same feet were soaked for 10 min in a 40-42 degrees C salt footbath. We measured blood pressure, heart rate and temperatures of the feet, second toes, hands and middle fingers, just before and after immersion and at 10-min intervals thereafter. Mean blood pressure changes showed no difference between the normal and the salt footbath. Mean heart rate changes were higher during the normal footbath than at 0, 15 and 20 min during the salt footbath, respectively (p < 0.05). Mean thermal preservability of the feet tended to be lower after the normal footbath than at 20 and 30 min, respectively, after the salt footbath, but these differences did not reach a statistical significance. Mean thermal preservability of the hands and middle fingers was significantly lower after the normal footbath than at 20 and 30 min, respectively, after the salt footbath (p < 0.05). The results suggest that stimulation by a salt footbath affects surface skin temperature, and that stimulation aimed at increasing skin thermal preservability shows a significant difference between normal and salt footbaths.

Changes in bone mineral density and metabolism in women: evaluation of bodily characteristics, bone metabolic markers and bone mineral density.

The relationship of bone mineral density (BMD) and bone metabolic markers in women is an interesting field of research. In this study, we aimed to clarify the relationship of body weight, bone metabolic markers and BMD. The subjects were 72 women. The levels of serum bone-specific alkaline phosphatase (BAP), serum type I collagen-cross-linked peptide (s-NTx) and urinary deoxypyridinoline (u-DPD) were measured. The associations between dependent variables (BMD changes/1 or 4 years in the lumbar spine and femoral neck) and explanatory variables (body weight changes/1 or 4 years, the levels of BAP, s-NTx, u-DPD) were evaluated using multiple regression analysis. Changes in the lumbar spine BMD were significantly correlated with changes in height over a year, and those of the femoral neck were significantly correlated with changes in weight over a year. Changes in the lumbar spine BMD over 4 years were significantly correlated with age, BAP and the changes of weight over 4 years. Changes in the femoral neck BMD over 4 years were significantly correlated with the changes in weight for 4 years. These results suggest that BMD changes of different bones correlate with different explanatory variables and that, to predict BMD changes from bone metabolic markers in women, it is necessary to measure BAP levels.