ABSTRACT
The purpose of this study was to compare effects of different amounts of carbohydrate (CHO) in beverage on plasma glucose (GLU) concentration during exercise after feeding breakfast. Seven healthy Japanese male subjects performed 30-min cycling at an intensity on the 75% of maximal load at 3-h after feeding breakfast under 3 types of CHO (0 g, 30 g and 150 g) beverage conditions. The subjects ingested 500 mL of beverage dissolved each amount of glucose at 30-min before the exercise. The GLU concentrations were measured at 35- and 10-min before the exercise and every 5-min during the exercise. The minimum GLU concentrations under the 30 g condition for all subjects were lower than a criterion for hypoglycemic (72 mg / dL). The mean value also fell below the criterion at from 10- to 20-min during exercise. The minimum GLU concentration under the 150 g condition of only one subject was lower than the criterion, but the mean value did not fall below the criterion. Significant negative correlations were found between the subjects’ maximum oxygen uptake (VO2max) and the decreases in GLU concentration from maximum to minimum under both the 30 g (r = -0.947, p < 0.01) and 150 g conditions (r = -0.884, p < 0.01). This study clarified that feeding breakfast at 3-h before the exercise followed by the 30 g CHO beverage ingestion at 30 min before the exercise induced exercise-induced hypoglycemia, and that the subjects with higher VO2max had the greater decreases in GLU concentration.
ABSTRACT
We performed exercise intervention for 12 weeks in young females (22.3±2.5 yrs ; mean±SD) with a %fat value of 30% or more (dual energy X-ray absorptiometry : DXA) despite a body mass index (BMI) of less than 25 kg/m<sup>2</sup>, which indicates hidden obesity, and the following results were obtained.The intensity of exercise was established as the double product break point calculated from heart rate and systolic blood pressure, and the subjects were instructed to exercise for 30 minutes or more for 3 or more times a week. Six weeks after exercise intervention, the BMI, body fat level, and plasma glucose level were lower than those before exercise intervention, and the %fat value was lower 12 weeks after intervention. Furthermore, cardiac autonomic function (CAF) was negatively correlated with changes in Total power and changes in fat (kg), suggesting that exercise-related improvement in CAF is involved in a decrease in %fat.
ABSTRACT
PURPOSE : The purpose of the present study was to clarify the effect of static stretching on muscular performance with concentric isotonic muscle actions under various loads.METHODS : Concentric isotonic leg extension power outputs were assessed in 12 healthy male subjects after two types of pre-treatment. The pre-treatments included 1) static stretching (SS) treatment performing static stretching of leg extensors, and 2) non-stretching (NS) treatment by resting in a sitting position. Loads during the assessment of the power output were set to 5%, 30% and 60% of the maximum voluntary contractile (MVC) torque with isometric leg extension in each subject.RESULTS : The peak power output following the SS treatment was significantly (P<0.05) lower than that following the NS treatment under each load.CONCLUSION : The present study demonstrated that static stretching significantly reduces power output with concentric isotonic muscle actions under various loads. This result suggests that static stretching decreases power performance.