Contribution of acceleration by location tracking system to energy expenditure during Soccer -based intermittent exercise / 体力科学

The purpose of this study was to examine the contribution of the location-tracking information to the energy expenditure during the soccer-based intermittent sprint run. Twenty-four young healthy men participated in the present investigation (1st experiment: 14 men, 2nd experiment 10 men). In the 1st experiment, the sprint runs were 12 times of the 10 m (SS10), or 6 times of the 20 m (SS20), or td 3 times of the 40 m (SS40). In the 2nd experiment, the sprint runs 15 times of the 10 m (SS), or 15 times of the 10 m of the sprint run with change of direction for 90, 135, 180 degrees (CD90, CD135 and CD180). All course of the experiment, the expired gas was analyzed using the portable gas analyzer. The running index including speed, acceleration, distance, were calculated at 15 Hz interval based on the location-tracking information using the portable global positioning system. The intermittent run with the straight sprint run expended significantly larger calorie compared with that without the straight sprint (p < 0.001). The intermittent run with the changes of direction expended significantly larger calorie compared with that without the changes of direction (p < 0.05). A multiple stepwise regression analysis revealed that body weight, the acceleration and the change of direction were significant determinants of the energy expenditure and accounted for 75% of the total variance. These results indicate that the magnitude of the acceleration is significant predictor for the energy expenditure of the intermittent exercise.

Relationship between the exercise history from early childhood through adulthood and bone health determined using dual energy X-ray absorptiometry in young Japanese premenopousal females / 体力科学

The purpose of the present investigation was to examine the relationships between the exercise history and the bone mineral density (BMD) and bone mineral content (BMC) in female Japanese young adults using dual X-ray absorptiometry (DXA). One-hundred twenty females, aged between 18 to 28 years, participated in the present investigation. The BMD at the lumbar spine (L-BMD), whole body BMD and BMC (WB-BMD and WB-BMC), lean body mass (LBM) and fat mass (FM) were measured by DXA. Using a self-administrered questionnaire, the exercise habits during preschool (4-6 years), primary school (7-12 years), junior high school (13-15 years), high school (16-18 years), and the current habits (>18 years) were eveluated. The L-BMD, WB-BMD and WB-BMC were significantly higher in the subjects with exercise habits during both the period of <18 years and >18 years compared with those in the subjects without an exercise history during all periods (p<0.05). In a separate analysis with the data stratified by the school age, the subjects with an exercise history during primary school, junior high school, or high school had significantly higher BMD and BMC values compared with the non-exercisers (each, p<0.05). In contrast, the BMD and BMC did not differ significantly according to either the exercise history during pre-school nor the current exercise status. A multiple stepwise regression analysis revealed that the body weight, LBM, FM, age of menarche, and exercise habits during high school were significant determinants of the L-BMD, WB-BMD and WB-BMC (p<0.001). The results of the present investigation show that both the exercise history during school age and the current exercise habits affect the BMD and BMC in young adults. In particular, high school females should be encouraged to participate in the regular exercise to increase their bone health. Future studies will be needed to confirm the targeted age-group(s) for participation in sports/exercise for the improvement of bone health, including an analysis of the type and intensity of exercise/sports.

HOME BASED EXERCISE EFFECTS ON COGNITION IN THE SEMI-INDEPENDENT ELDERLY / 体力科学

This study sought to determine whether aerobic exercise training affects cognitive functioning among semi-independent (> 75 years) and independent elderly people. Seventy-six semi-independent and independent elderly subjects were divided into the following groups: semi-independent control (n = 16); semi-independent training (n = 13); independent control (n = 22); independent training (n = 25). During the 12-week intervention, subjects in both training groups performed a bench-stepping exercise at the intensity of the lactate threshold. Subjects were assessed at baseline and post-intervention using the Frontal Assessment Battery test (FAB), the Modified Mini-Mental State Exam (3MS), and a bench-stepping test of aerobic capacity. During the intervention, FAB scores improved only in the semi-independent training group (<i>p</i> = .002), while 3MS and MMSE scores improved in both the semi-independent training (<i>p</i> = .032 and <i>p</i> = .004) and independent training groups (<i>p</i> = .001 and <i>p</i> = .013). FAB and 3MS scores were higher in the semi-independent training (<i>p</i> = .001 and <i>p</i> = .002) compared with the semi-independent control group after the intervention. Finally, post-intervention scores for FAB, and 3MS in the semi-independent training group almost reached the baseline levels of the independent control and independent training groups. These results indicate that moderate intensity bench-stepping exercise training can improve cognitive and frontal lobe functioning in semi-independent elderly people, almost to the level exhibited by independent elderly people.

QUANTIFYING TIME SPENT IN MODERATE TO VIGOROUS INTENSITY PHYSICAL ACTIVITY VIA STEPPING RATE / 体力科学

The purpose of the present investigation was to examine the usefulness of the stepping rate for assessing the time spent in moderate to vigorous intensity physical activity (MVPA). In the present investigation, 11 young men wore two pedometers (LIFECORDER EX ; KZ, Walking Style ; WS) during controlled walking and jogging, as well as during free-living conditions for 3 days. In addition to the number of steps, the KZ determined the time spent in physical activity based on the intensity of the physical activity (light intensity physical activity (LPA); below 3 METs, and MVPA ; above 3 METs), and the stepping rate (≧60, ≧80, or ≧100 steps·min^-1). In contrast, the WS was defined as the physical activity for a stepping rate of 60 steps·min^-1 or more, continuously for longer than 10 min as the time spent in physical activity. Regarding the results, under continuous walking/jogging, the KZ-assessed LPA and MVPA well reflected the intensity of the physical activity. On the other hand, the WS accumulated the time spent in physical activity for longer than 90% of the actual exercise duration, regardless of the walking speed. Furthermore, the stepping rate corresponding to 3 METs was 102 steps·min^-1. Under free-living conditions, however, the KZ-detected MVPA differed significantly in comparison to the time of the physical activity as determined by the other algorithms, except for the time spent in a stepping rate of 80 or higher steps·min^-1. In conclusion, these results indicate that 100 steps·min^-1 is a useful stepping rate for the assessment of MVPA. However, under free living conditions, the stepping rate should be determined at a higher frequency than a one minute interval length in order to improve the accuracy of the MVPA assessment.

RELATIONSHIP BETWEEN OPEN-WATER SWIMMING PERFORMANCE AND AEROBIC CAPACITY / 体力科学

The purpose of the present investigation was to examine the relationship between the open water swimming (OW) performance and the swimming speed at 2, 3, and 4 mmol/l of blood lactate concentration (SSLA2, SSLA3, and SSLA4) or the critical swimming speed (CSS). Six male collegiate swimmers performed the 10 kilometers of OW, as well as the multi-stage graded swimming test, in order to determine the SSLA2, SSLA3, SSLA4. Furthermore, the CSS was calculated based on the personal best records for 50 to 1500 meters of free-style indoor swimming. As a result, the SSLA2, SSLA3, SSLA4, and CSS corresponded to 102±6%, 106±6%, 110±7%, and 106±5% of the average swimming speed of the OW, respectively. Thereafter, the SSLA2 did not differ significantly in comparison to the average swimming speed of the OW, whereas the SSLA3, SSLA4, and CSS differed significantly with the average swimming speed of the OW (p＜0.05). Furthermore, the average swimming speed during the OW significantly correlated with the SSLA2, SSLA3, SSLA4, and CSS, respectively (p＜0.05). These results suggest that the OW performance significantly correlated with the swimming speed at 2 to 3 mmol/l of the blood lactate concentrations and CSS. Furthermore, regarding these parameters, the SSLA2 may accurately reflect the average swimming speed of OW.

EFFECTS OF EXERCISE INTERVENTION ON BLOOD LIPID LEVELS, GLYCOMETABOLISM, ADIPOCYTOKINE LEVELS, AND CARDIAC AUTONOMIC FUNCTION IN YOUNG FEMALES WITH HIDDEN OBESITY / 体力科学

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/m², 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.

RELATIONSHIP BETWEEN DOUBLE PRODUCT BREAK POINT AND ST SEGMENT DEPRESSION ON ECG IN PATIENTS WITH ISCHEMIC HEART DISEASE PATIENTS AND ELDERLY PERSONS / 体力科学

Double product (DP, heart rate × systolic blood pressure) during an incremental exercise test has been known to start to increase steeply at a workload, i. e. double product break point (DPBP), which corresponds to the blood lactate threshold. The study was to investigate the relationship between DP transition and ST segment depression in electrocardiogram during exercise. Thirty-one patients of angina pectoris of effort and 140 elderly persons performed a continuous incremental exercise test using a stationary bicycle ergometer. During the entire test, HR and blood pressure were measured every 15 seconds and an electrocardiogram was recorded continuously. DPBP was then calculated. In ten of the 31 patients, ST level depression above -0.1 mV with a typical ischemic form in lead V 5 was observed during the test. However, workload at the DPBP was significantly lower than that of the ischemic threshold on the electrocardiogram (i. e. -0.1mV of ST depression) in relation to work load (46+/-16 vs. 78+/-20 watts), HR (96+/-13 vs. 117+/-13 bpm), SBP (160+ /-20 vs. 199+/-31 mmHg) and DP (15400+/-3400 vs. 23400+/-4900 bpm × mmHg) . In elderly persons, DPBP could be determined without the ischemic ST depression in 96% of 327 tests. This study indicated that the DPBP would be an objective index of exercise intensity with lower risk for exercise prescription in cardiac patients and elderly persons.

Comparison of Daily Energy Expenditure in Young and Older Japanese Using Pedometer with Accelerometer / 体力科学

Daily energy expenditure has been measured by the physical activity recording and/or the questionnaire method. Recently, the accelerometer or pedometer is used to measure daily energy expenditure. The purpose of this study was to examine validity of the pedometer with accelerometer and to compare the daily physical activity between young and older Japanese. To examine validity of the pedometer, 10 young subjects worn the pedometer (Lifecorder) on the waist and then performed the walking test. Energy expenditure was measured by the expired gas analysis during the test. Fourtythree young and 54 older subjects worn the Lifecorder on the waist during free-living condition for 14 days. The intensity of Lifecorder had a high correlation with the physical activity intensity (METs) (r=0.958, P<0.001) . In the free-living condition, daily energy expenditure was 2171±305 kcal in young and 1617±196kcal in older (P<0.001) . Total step in young was significantly higher than older (young: 9490±2359 steps ; older: 6071±2804 steps, P<0.001) . There was no significant difference in the duration of physical activities at the Lifecorder intensity 1 such as desk working, watching TV sitting on a sofa and driving a car. However, the duration more than the intensity 2 corresponding to 2.2 METs in young subjects was longer than that in older (P<0.001) . We concluded that in older subjects, not only amounts of daily energy expenditure but also intensities of daily living were lower compared to the young subjects.