The purposes of this study were to select useful questionnaire items when measuring mental toughness in water polo players through an examination of item analysis, and to determine the reliability of reselected items based on Cronbach's α-coefficient. It was assumed that a hypothetical structure of mental toughness consists of 17 sub-domains. A survey composed of 102 items representing each sub-domain (6 items) was administered to competitive water polo players.
In the examination results of internal consistency and good-poor analyses, 3 items were eliminated and 99 items were reselected as useful items. Inter-consistency (factor validity) by component analysis and reliability by Cronbach's α-coefficient were examined according to each domain. Although all domains had high reliability coefficients of 0.70 or over, items with a low validity were also confirmed. Next, considering practicability, four items with higher validity were selected from each domain, factor validity and reliability were examined again. It was confirmed that all items have high validity and reliability. Sixty-eight items finally selected are considered to be useful questionnaire items to measure mental toughness of water polo players. From now, it will be necessary to select useful items considering an examination of factorial structure of mental toughness.
There are very few reports on the changes with age in BMI and Rohrer index, and little discussion on the relationship between the age-related changes in these two indices and the age at menarche. In the present study, we applied the wavelet interpolation method (WIM) to changes with age in BMI and the Rohrer index between the first year of elementary school and the third year of high school. We then analyzed the age-distance curve of BMI and the Rohrer index. From the results we identified the age at maximum peak velocity of BMI and the lowest point on the trough of the Rohrer index. By verifying the relationship with age at menarche, we investigated whether the MPV of BMI and the lowest trough point of the Rohrer index were valid as biological parameters. The subjects were 102 university students at a women's university in the Tokai region of Japan, who completed a questionnaire regarding age at menarche and level of exercise. Longitudinal growth information for height and weight were obtained from school health check records from the first year of elementary school until the third year of high school (from 1987 to 1998). BMI and the Rohrer index were calculated from height and weight values for these years, and the WIM was applied to the distances of the BMI and Rohrer index in these school years. Curves showing the changes with age in BMI and the Rohrer index were drawn with the WIM, and the age at MPV of BMI was identified from the peak velocity curve, which for BMI is the differential curve. With regard to the Rohrer index, the lowest trough point was identified from the age-distance curve. It was seen that the age at menarche and the age at MPV of BMI were nearly the same. It was also indicated that the interval between the age at MPV of BMI and the age at menarche was nearly 0. The mean difference between the lowest trough point of the Rohrer index and the age at menarche was 0.7 ± 1.00, with menarche occurring at about 0.7 years before the lowest trough point of the Rohrer index. Therefore, we conjecture that these two indices are valid biological parameters, with age at MPV of BMI indicating the critical period for age of menarche, and the lowest trough point of the Rohrer index the inflection point of internal body density.
In this study, we determined the effects of voluntary running exercise on resident peritoneal macrophage functions in middle aged mice by measuring glucose consumption, lysosomal enzymes（acid phosphates: APH and β-glucuronidase : GLU）, cytoplasmic enzyme（lactate dehydrogenase: LDH）, and production of nitric oxide（NO）and interleukin1β（IL-1β）to stimulation by lipopolysaccharide（LPS）. Male BALB/c mice（12 months old）were divided into two groups: a group given voluntary running exercise（exercise group）and a non-exercise group（control group）. The applied exercise consisted of spontaneous running in wheels for 3 days per week over 8 weeks. Glucose consumption of peritoneal macrophages in the exercise group was significantly higher than that in the control group. Also, activities of GLU and LDH in the peritoneal macrophages in the exercise group were significantly increased. Compared with the control group, the exercise group had a significant increase in macrophage production of NO stimulated by LPS. A significant increase in macrophage production of IL-1β stimulated by LPS was noticed in the exercise group. We concluded that voluntary running exercise enhanced macrophage functions in the middle aged mice.
Effects of chronic exercises were investigated on the persons with physical disabilities. The three subjects have been suffered from osteogenesis imperfecta, cerebral palsy, or spinal cord injury. They have performed the prescribed exercises every 7 to 10 days for three years which were tailored for each personal health condition. All subjects showed the correlation between the heart rate, the intake of oxygen, and the subjective physical exercise strength after three years. These and other results indicate that the three years exercises improved the respiro-circulatory functions of those persons with physical disabilities.
The purpose of this study was to examine relationships between the subjective muscle-fatigue sensation (SMS) and blood lactate concentration (La) during intermittent repeated grips (IRG) using various target values based on MVC (50%, 75%, and 100% maximal voluntary contraction: MVC) and the recovery phase after gripping. Ten young males performed IRG with three target forces for 6 min. La and maximal grip strength were measured before, just after and 4 min and 7 min after each grip test. SMS of the forearm was measured every 30 s during and after each grip test. The average grip forces were lower at 50% MVC than 75% MVC until 150 s after the grip onset, but were higher at 50% MVC than 100% MVC at 270-300 s. The cross-correlations between average forces and SMS for every 30 s were significant and very high at -0.89 or over in all conditions. The La value after IRG tests with 75% and 100% MVCs tended to be higher than that at 50% MVC. There was no significant difference in recovery rates of maximal grip strength and La after each grip test. In conclusion, the decreasing property and SMS during IRG differ in intensity (target forces). The force output with 50% MVC during IRG decreased little because the target force came near the force output during a steady state. IRG at lower than 50% MVC (2 s interval) is considered not to be useful as a muscle endurance test.