In a recent study competitive road cyclists experienced substantial gains in sprint and endurance... more In a recent study competitive road cyclists experienced substantial gains in sprint and endurance performance when sessions of high-intensity interval training were added to their usual training in the competitive phase of a season. The current study reports the effect of this type of training on performance of 20 distance runners randomized to an experimental or control group for 5 to 7 weeks of training. The experimental group replaced part of their usual competitive-phase training with 10 x ?30-minute sessions consisting of 3 sets of explosive single-leg jumps (20 for each leg) alternating with 3 sets of resisted treadmill sprints (5 x ?30-second efforts alternating with 30-second recovery). Before and after the training period all runners completed an incremental treadmill test for assessment of lactate threshold and maximum running speed, 2 treadmill runs to exhaustion for prediction of 800- and 1500-m times, and a 5-km outdoor time trial. Relative to the control group, the mean changes (+/-90% confidence limits) in the experimental group were: maximum running speed, 1.8% (+/- 1.1%); lactate-threshold speed, 3.5% (+/-3.4%); predicted 800-m speed, 3.6% (+/- 1.8%); predicted 1500-m speed, 3.7% (+/- 3.0%); and 5-km time-trial speed, 1.2% (+/- 1.1%). We conclude that high-intensity resistance training in the competitive phase is likely to produce beneficial gains in performance for most distance runners.
Background: Although physical activity recommendations for public health have focused on locomoti... more Background: Although physical activity recommendations for public health have focused on locomotive activity such as walking and running, it is uncertain how much these activities contribute to overall physical activity level (PAL). The purpose of the present study was to determine the contribution of locomotive activity to PAL using total step counts measured in a calorimeter study. Methods: PAL, calculated as total energy expenditure divided by basal metabolic rate, was evaluated in 11 adult men using three different conditions for 24-hour human calorimeter measurements: a low-activity day (L-day) targeted at a low active level of PAL (1.45), and a high-frequency moderate activity day (M-day) or a highfrequency vigorous activity day (V-day) targeted at an active level of PAL (1.75). These subjects were permitted only light activities except prescribed activities. In a separate group of 41 adults, free-living PAL was evaluated using doubly-labeled water (DLW). In both experiments, step counts per day were also measured using an accelerometer. Results: In the human calorimeter study, PAL and step counts were 1.42 ± 0.10 and 8,973 ± 543 steps/d (L-day), 1.82 ± 0.14 and 29,588 ± 1,126 steps/d (M-day), and 1.74 ± 0.15 and 23,755 ± 1,038 steps/d (V-day), respectively. In the DLW study, PAL and step counts were 1.73 ± 0.15 and 10,022 ± 2,605 steps/d, and there was no significant relationship between PAL and daily step counts. Conclusions: These results indicate that an enormous number of steps are needed for an active level of PAL if individuals extend physical activity-induced energy expenditure by only locomotive activity. Therefore, nonlocomotive activity such as household activity should also play a significant role in increasing PAL under free-living conditions.
Journal of Nutritional Science and Vitaminology, 2011
Several cross-sectional studies in Pima Indians and Caucasians have indicated that obese individu... more Several cross-sectional studies in Pima Indians and Caucasians have indicated that obese individuals with type 2 diabetes have a higher basal metabolic rate (BMR) than healthy, obese individuals. However, no study has investigated this comparison in Japanese subjects, who are known to be susceptible to type 2 diabetes due to genetic characteristics. Thirty obese Japanese adults with pre-type 2 diabetes (n=7) or type 2 diabetes (n=13) or without diabetes (n=10) participated in this study. BMR was measured using indirect calorimetry. The relationships between residual BMR (calculated as measured BMR minus BMR adjusted for fat-free mass, fat mass, age, and sex) and biomarkers including fasting glucose, glycosylated hemoglobin (HbA(1c)), fasting insulin, homeostasis model assessment of insulin resistance (HOMA-R), triglycerides, and free fatty acids were examined using Pearson's correlation. BMR in diabetic subjects adjusted for fat-free mass, fat mass, age, and sex was 7.1% higher than in non-diabetic subjects. BMR in diabetic subjects was also significantly (p<0.05) higher than in non-diabetic subjects. There was a significant correlation between residual BMR and fasting glucose (r=0.391, p=0.032). These results indicate that in the Japanese population, obese subjects with type 2 diabetes have higher BMR compared with obese non-diabetic subjects. The fasting glucose level may contribute to these differences.
Journal of Nutritional Science and Vitaminology, 2012
ABSTRACT For energy of Dietary Reference Intakes for Japanese (DRIs-J), the concept of Estimated ... more ABSTRACT For energy of Dietary Reference Intakes for Japanese (DRIs-J), the concept of Estimated Energy Requirement (EER) is applied. The EER has been established as an index for individuals and groups. The definition of EER for individuals is "habitual energy intake in a day which is predicted to have the highest probability that energy balance (energy intake2energy expenditure, in adults) becomes zero in an individual of a given age, gender, height, body weight, and level of physical activity in good health." In contrast, the definition of EER for a group is "habitual energy intake in a day which is predicted to have the highest probability that energy balance (energy intake2energy expenditure, in adults) becomes zero in a group." The EER is calculated as follows: EER (kcal/d)5basal metabolic rate (BMR) (kcal/d)3physical activity level (PAL). Representative values for BMR per kg body weight are determined based on a number of reports for Japanese. This is called the reference value of BMR (reference BMR). Total energy expenditure measured by the doubly labeled water (DLW) method is utilized to determine PA L for each sex and age group. For adults, physical activity levels are determined based on data for Japanese adults. For children, energy deposition is added to the total energy expenditure. For pregnant and lactating women, additional values compared to EER before pregnancy for each stage of pregnancy and during lactation are calculated. Excess post-exercise oxygen consumption is not added to calculate EER in addition to energy expenditure during physical activity.
The accuracy of an anthropometric equation for estimating thigh muscle and bone area (MBA) and fa... more The accuracy of an anthropometric equation for estimating thigh muscle and bone area (MBA) and fat area (FA) was examined in two groups of Japanese male university students, an athletic group (n = 31) and a non-athletic group (n = 18). The anthropometric equation examined included the anterior thigh skinfold (SFT) and thigh circumference (CF): (CF ~ n x SFTY2/4n. Actual MBA and FA were calculated by means of a computed tomography (CT) scan. The anthropometric equation overestimated MBA and underestimated FA, although the estimated values were strongly correlated with actual values. In addition, total thigh area was also overestimated by using thigh circumference. As MBA increased, the difference between estimated and actual MBA increased. Regression analysis using estimated h4BA through an anthropometric equation was also done. The resulting equation was as follows: MBA = cl x (CF -T x SFT)'/ 4a + c2, where the value of (CFn X SFT)"/4n was the estimated MBA through the first anthropometric equation. The mean ratio of the residual to actual MBA was very small, 2.8% in the athletic group and 3.3% in the non-athletic group.
The purpose of the present study was to evaluate moderate-to-vigorous physical activity using tri... more The purpose of the present study was to evaluate moderate-to-vigorous physical activity using triaxial accelerometry in Japanese preschool children. The relationship between daily step counts as a convenient measure of physical activity and minutes of engagement in moderate-to-vigorous physical activity was also examined. Physical activity was assessed using a triaxial accelerometer (ActivTracer, GMS) and daily steps using a uniaxial accelerometer for 6 consecutive days, including weekdays and weekend days, in 157 four- to six-year-old Japanese children attending kindergarten or nursery school. Using triaxial and uniaxial accelerometers, nonlocomotive activities and step counts for young children can be evaluated, respectively. Average daily moderate-to-vigorous physical activity (physical activity ratio >or=3) and step counts were 102 (+/-32) min/day and 13,037 (+/-2,846) steps/day, respectively. A strong and significant correlation was observed between minutes of moderate-to-vigorous physical activity and step counts (r=0.832, p<0.001). The daily step counts corresponding to 60 min, 100 min, and 120 min of moderate-to-vigorous physical activity were 9,934, 12,893, and 14,373 steps/day, respectively. The correlation coefficient between minutes of higher intensity activities (physical activity ratio >or=4) and step counts was slightly lower (r=0.604, p<0.001). The daily step count corresponding to 30 min of the higher intensity activities was 14,768 steps/day. These results suggest that approximately 13,000 steps/day are required for preschool children to engage in more than 100 min of moderate-to-vigorous physical activity.
In a recent study competitive road cyclists experienced substantial gains in sprint and endurance... more In a recent study competitive road cyclists experienced substantial gains in sprint and endurance performance when sessions of high-intensity interval training were added to their usual training in the competitive phase of a season. The current study reports the effect of this type of training on performance of 20 distance runners randomized to an experimental or control group for 5 to 7 weeks of training. The experimental group replaced part of their usual competitive-phase training with 10 x ?30-minute sessions consisting of 3 sets of explosive single-leg jumps (20 for each leg) alternating with 3 sets of resisted treadmill sprints (5 x ?30-second efforts alternating with 30-second recovery). Before and after the training period all runners completed an incremental treadmill test for assessment of lactate threshold and maximum running speed, 2 treadmill runs to exhaustion for prediction of 800- and 1500-m times, and a 5-km outdoor time trial. Relative to the control group, the mean changes (+/-90% confidence limits) in the experimental group were: maximum running speed, 1.8% (+/- 1.1%); lactate-threshold speed, 3.5% (+/-3.4%); predicted 800-m speed, 3.6% (+/- 1.8%); predicted 1500-m speed, 3.7% (+/- 3.0%); and 5-km time-trial speed, 1.2% (+/- 1.1%). We conclude that high-intensity resistance training in the competitive phase is likely to produce beneficial gains in performance for most distance runners.
Background: Although physical activity recommendations for public health have focused on locomoti... more Background: Although physical activity recommendations for public health have focused on locomotive activity such as walking and running, it is uncertain how much these activities contribute to overall physical activity level (PAL). The purpose of the present study was to determine the contribution of locomotive activity to PAL using total step counts measured in a calorimeter study. Methods: PAL, calculated as total energy expenditure divided by basal metabolic rate, was evaluated in 11 adult men using three different conditions for 24-hour human calorimeter measurements: a low-activity day (L-day) targeted at a low active level of PAL (1.45), and a high-frequency moderate activity day (M-day) or a highfrequency vigorous activity day (V-day) targeted at an active level of PAL (1.75). These subjects were permitted only light activities except prescribed activities. In a separate group of 41 adults, free-living PAL was evaluated using doubly-labeled water (DLW). In both experiments, step counts per day were also measured using an accelerometer. Results: In the human calorimeter study, PAL and step counts were 1.42 ± 0.10 and 8,973 ± 543 steps/d (L-day), 1.82 ± 0.14 and 29,588 ± 1,126 steps/d (M-day), and 1.74 ± 0.15 and 23,755 ± 1,038 steps/d (V-day), respectively. In the DLW study, PAL and step counts were 1.73 ± 0.15 and 10,022 ± 2,605 steps/d, and there was no significant relationship between PAL and daily step counts. Conclusions: These results indicate that an enormous number of steps are needed for an active level of PAL if individuals extend physical activity-induced energy expenditure by only locomotive activity. Therefore, nonlocomotive activity such as household activity should also play a significant role in increasing PAL under free-living conditions.
Journal of Nutritional Science and Vitaminology, 2011
Several cross-sectional studies in Pima Indians and Caucasians have indicated that obese individu... more Several cross-sectional studies in Pima Indians and Caucasians have indicated that obese individuals with type 2 diabetes have a higher basal metabolic rate (BMR) than healthy, obese individuals. However, no study has investigated this comparison in Japanese subjects, who are known to be susceptible to type 2 diabetes due to genetic characteristics. Thirty obese Japanese adults with pre-type 2 diabetes (n=7) or type 2 diabetes (n=13) or without diabetes (n=10) participated in this study. BMR was measured using indirect calorimetry. The relationships between residual BMR (calculated as measured BMR minus BMR adjusted for fat-free mass, fat mass, age, and sex) and biomarkers including fasting glucose, glycosylated hemoglobin (HbA(1c)), fasting insulin, homeostasis model assessment of insulin resistance (HOMA-R), triglycerides, and free fatty acids were examined using Pearson's correlation. BMR in diabetic subjects adjusted for fat-free mass, fat mass, age, and sex was 7.1% higher than in non-diabetic subjects. BMR in diabetic subjects was also significantly (p<0.05) higher than in non-diabetic subjects. There was a significant correlation between residual BMR and fasting glucose (r=0.391, p=0.032). These results indicate that in the Japanese population, obese subjects with type 2 diabetes have higher BMR compared with obese non-diabetic subjects. The fasting glucose level may contribute to these differences.
Journal of Nutritional Science and Vitaminology, 2012
ABSTRACT For energy of Dietary Reference Intakes for Japanese (DRIs-J), the concept of Estimated ... more ABSTRACT For energy of Dietary Reference Intakes for Japanese (DRIs-J), the concept of Estimated Energy Requirement (EER) is applied. The EER has been established as an index for individuals and groups. The definition of EER for individuals is "habitual energy intake in a day which is predicted to have the highest probability that energy balance (energy intake2energy expenditure, in adults) becomes zero in an individual of a given age, gender, height, body weight, and level of physical activity in good health." In contrast, the definition of EER for a group is "habitual energy intake in a day which is predicted to have the highest probability that energy balance (energy intake2energy expenditure, in adults) becomes zero in a group." The EER is calculated as follows: EER (kcal/d)5basal metabolic rate (BMR) (kcal/d)3physical activity level (PAL). Representative values for BMR per kg body weight are determined based on a number of reports for Japanese. This is called the reference value of BMR (reference BMR). Total energy expenditure measured by the doubly labeled water (DLW) method is utilized to determine PA L for each sex and age group. For adults, physical activity levels are determined based on data for Japanese adults. For children, energy deposition is added to the total energy expenditure. For pregnant and lactating women, additional values compared to EER before pregnancy for each stage of pregnancy and during lactation are calculated. Excess post-exercise oxygen consumption is not added to calculate EER in addition to energy expenditure during physical activity.
The accuracy of an anthropometric equation for estimating thigh muscle and bone area (MBA) and fa... more The accuracy of an anthropometric equation for estimating thigh muscle and bone area (MBA) and fat area (FA) was examined in two groups of Japanese male university students, an athletic group (n = 31) and a non-athletic group (n = 18). The anthropometric equation examined included the anterior thigh skinfold (SFT) and thigh circumference (CF): (CF ~ n x SFTY2/4n. Actual MBA and FA were calculated by means of a computed tomography (CT) scan. The anthropometric equation overestimated MBA and underestimated FA, although the estimated values were strongly correlated with actual values. In addition, total thigh area was also overestimated by using thigh circumference. As MBA increased, the difference between estimated and actual MBA increased. Regression analysis using estimated h4BA through an anthropometric equation was also done. The resulting equation was as follows: MBA = cl x (CF -T x SFT)'/ 4a + c2, where the value of (CFn X SFT)"/4n was the estimated MBA through the first anthropometric equation. The mean ratio of the residual to actual MBA was very small, 2.8% in the athletic group and 3.3% in the non-athletic group.
The purpose of the present study was to evaluate moderate-to-vigorous physical activity using tri... more The purpose of the present study was to evaluate moderate-to-vigorous physical activity using triaxial accelerometry in Japanese preschool children. The relationship between daily step counts as a convenient measure of physical activity and minutes of engagement in moderate-to-vigorous physical activity was also examined. Physical activity was assessed using a triaxial accelerometer (ActivTracer, GMS) and daily steps using a uniaxial accelerometer for 6 consecutive days, including weekdays and weekend days, in 157 four- to six-year-old Japanese children attending kindergarten or nursery school. Using triaxial and uniaxial accelerometers, nonlocomotive activities and step counts for young children can be evaluated, respectively. Average daily moderate-to-vigorous physical activity (physical activity ratio >or=3) and step counts were 102 (+/-32) min/day and 13,037 (+/-2,846) steps/day, respectively. A strong and significant correlation was observed between minutes of moderate-to-vigorous physical activity and step counts (r=0.832, p<0.001). The daily step counts corresponding to 60 min, 100 min, and 120 min of moderate-to-vigorous physical activity were 9,934, 12,893, and 14,373 steps/day, respectively. The correlation coefficient between minutes of higher intensity activities (physical activity ratio >or=4) and step counts was slightly lower (r=0.604, p<0.001). The daily step count corresponding to 30 min of the higher intensity activities was 14,768 steps/day. These results suggest that approximately 13,000 steps/day are required for preschool children to engage in more than 100 min of moderate-to-vigorous physical activity.
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Papers by Shigeho Tanaka