The relationship between body fat growth and physical fitness and motor ability development in school age children is not well understood. We determined the similarities and differences in body fat growth and physical fitness and motor ability development curves by applying cross correlation functions, and attempted to show the structure of growth and development between these attributes. The subjects were 647 boys aged 7 to 15 years. The measurements were height, weight, body mass index and body fat percentage as physical characters; and 20-m sprint, Pro Agility test, side steps, standing long jump, vertical jump, and rebound jump (RJ) index as physical fitness and motor ability. The wavelet interpolation method was applied to growth and distance values for physique, body fat and physical fitness and motor ability, and growth and development curves were derived. Cross correlation functions were then applied to the respective pairs of the compared velocity curves. There were large changes in the behavior of the growth velocity curve around the take off age for height, and so the relationship between body fat percentage and physical fitness and motor ability was investigated using the respective cross correlation functions around the take off age. Before the take off age, positive correlations were seen between body fat percentage and physical fitness and physical fitness and motor ability except for the RJ index. After the take off age, in contrast, there were negative correlations between body fat percentage and physical fitness and motor ability except for the RJ index. These results show the new finding that after the take off age in boys, there are contrary similarity between body fat and speed, agility, and instantaneous force.

In food science, natural ingredients that can inhibit dipeptidyl peptidase IV ( DPP IV ) may be useful for preventing diabetes mellitus. This study aimed to evaluate the effectiveness of bonito dashi having a high DPP IV inhibitory activity (IC50 ; 3049 µg/ ml) on the postprandial increase in blood glucose levels in 14 subjects. Bonito dashi (5 g) was subsequently subjected to oral glucose tolerance tests. Blood glucose levels of all subjects were measured at fasting and at 30 min after ingesting of bonito dashi or of warmed tap water as a control, and were also measured at 30, 45, 60, 75, 90, 120, and 150 min after ingestion of cooked rice. The maximum blood glucose level between 0 and 150 min after ingesting of bonito dashi was for 30 min, of warmed tap water for 45 min ). The blood glucose levels after ingestion of bonito dashi and warmed tap water were 135.6 ± 8.7 mg/ dl and 140.3 mg/ dl, respectively at 30 min ( p = 0.602 ); 135.6 ± 8.7 mg/ dl and 144.1 ± 10.7 mg/ dl, respectively at 45 min ( p = 0.057 ); 120.0 ± 4.9 mg/ dl and 136.8 ± 7.8 mg/ dl, respectively at 60 min ( p = 0.063 ); 110.0 ± 5.9 mg/ dl and 134.9 ± 6.9 mg/ dl, respectively at 75 min ( p = 0.006 ); 110.3 ± 6.8 mg/ dl and 129.3 ± 6.6 mg/ dl, respectively, at 90 min ( p = 0.036 ); 103.4 ± 4.1 mg/ dl and 118.7 ± 8.0 mg/ dl, respectively, at 120 min ( p = 0.091 ); 91.5 ± 3.8 mg/ dl and 102.3 ± 5.9 mg/ dl, respectively, at 150 min ( p = 0.232 ). The area under the curve for blood glucose levels after ingestion of bonito dashi and warmed tap water was 4753.1 ± 439.7 mg/ dl ×min and 6879.4 ± 728.1 mg/ dl ×min, respectively ( p = 0.005 ). Postprandial increase in blood glucose levels was lower in subjects ingestion of bonito dashi than in those ingestion of the warmed tap water. No serious adverse events related to ingestion of bonito dashi were observed. Our findings suggested that the ingestion of bonito dashi (5 g) suppressed postprandial increase in blood glucose levels in our subjects.