Yoga, fatigue, and regular physical activity among Japanese breast cancer survivors / 体力科学

Research highlights the importance of maintaining pre-diagnosis physical activity levels for breast cancer survivors post-treatment. However, many survivors have difficulty engaging in physical activity due to cancer-related fatigue. The aim of this study was to explore how participation in a 12-week yoga intervention impacted fatigue and physical activity. 20 individuals with breast cancer diagnosis participated in a 12-week yoga intervention. The yoga intervention included modified hatha yoga postures and consisted of 10 min. of warm-up, 45 min. of yoga postures, 10 min. of breath work, and 10 min. of supine resting pose <I>(savasana)</I>, for a total of 75 min. Assessments were administered at 3 time points: pre (T1), post (T2) yoga intervention and at a 12-week follow-up (T3). Measures included self-reported fatigue (Cancer Fatigue Scale) and physical activity (accelerometer step counts). One-way ANOVA were used to examine how fatigue scores and steps counts were changed over the course of the intervention. Total fatigue score (FS) and daily step (DS) counts at each time point were T1 (FS=21.6±8.9, DS=7709±2036), T2 (FS=14.0±8.3, DS=8429±2722), and T3 (FS=16.8±6.9, DS=8406±3389). Significant improvements in physical fatigue T1 (p<0.05, η² = 0.14) and cognitive fatigue (p<0.01, η² = 0.11) were seen at T1-T2. No significant changes were seen in psychological fatigue. 12 participants (65%) had high fatigue levels at T1, which decreased to 5 participants (27.8%) at T2. 12 participants (66.7%) increased daily steps at T2 and 8 participants (44.4%) continued to increase at T3. There were negative correlations between fatigue scores and step counts at all time points (r=-0.45~-0.55). Participation in a 12-week yoga program was associated with improved cancer-related fatigue.

The effect of press tack needles on chronic heaviness, stiffness, and lassitude of lower limbs / 全日本鍼灸学会雑誌

[Objective] The purpose of this study is to examine the effects of press tack needles (PTNs) on subjective assessment of symptoms such as heaviness, stiffness and lassitude in the lower limbs during walking, or in everyday life. Sham PTNs are used for the purpose of comparison.<BR>[Methods] The subject is a male in his seventies who has a daily routine of walking 10,000 steps; experiences heaviness, stiffness and lassitude in his lower limbs; and has spinal or internal disease. Intervention: PTNs or sham PTNs are randomly chosen and worn on the subject's body for two days. The subject fills out a questionnaire regarding subjective assessment of symptom relief in his lower limbs during the following three time periods; in advance of the use of PTN, in the evening during the use of PTN, and the following evening. PTNs are applied to a total of 10 sites around both sides of his lower limbs depending on symptomatic or tender areas. Assessment: A questionnaire, in which a Visual Analog Scale (VAS) is introduced, is filled out three times per trial, that is, thirty records from ten trials are finally kept. Differences can be seen in the result answered the following evening. The results regarding the use of PTNs and the results regarding the use of sham PTN are analyzed respectively by randomization test (R test).<BR>[Result] Significant difference was shown in the heaviness of the lower limbs for both the PTN and sham in the evening of the next day (P < 0.05). Significant difference was shown in the stiffness of the lower limbs for both the PTN and sham in the evening of the next day (P < 0.05). <BR>[Conclusion] A PTN is attached for two days when there is a feeling in the lower limbs of heaviness and stiffness, even with spinal disease, liver disease or varicose veins in the lower extremities. It is suggested that PTNs are effective in decrease of symptoms.

Psychological, Social, and Environmental Factors Associated With Utilization of Senior Centers Among Older Adults in Korea / 예방의학회지

OBJECTIVES: The purpose of the study was to examine the relationships among the psychological, social, and environmental factors influencing the utilization of senior centers among older adults in Korea. METHODS: A questionnaire survey was administered to two types of older adults who lived in Seoul, Korea: 262 older adults who used senior centers (3 places) and 156 older adults who did not use senior centers. RESULTS: Our results showed clearly that the utilization of the senior centers in Korea is affected by higher self-efficacy (odds ratio [OR], 6.08; 95% confidence interval [CI], 3.31 to 12.32), higher perceived benefits (OR, 1.71; 95% CI, 1.16 to 4.36), lower perceived barriers (OR, 6.43; 95% CI, 3.07 to 11.45), higher family support (OR, 4.21; 95% CI, 2.02 to 8.77), and higher support from friends (OR, 4.08; 95% CI, 2.38 to 7.81). The results also showed that participants whose total travel time was 15 to 29 minutes (OR, 2.84; 95% CI, 1.21 to 3.64) or less than 14 minutes (OR, 4.68; 95% CI, 3.41 to 8.41) were more likely to use a senior center than those who had to travel more than 30 minutes. CONCLUSIONS: This study showed that the utilization of senior centers in Korea is affected by psychological, social, and environmental factors, specifically by self-efficacy, perceived benefits, perceived barriers, social support, convenience of transportation, and total travel time to the senior centers. The effects of longer-term utilization of the senior centers by non-users on health-related outcomes in a large population warrant attention.

Use of Senior Center and the Health-Related Quality of Life in Korean Older Adults / 예방의학회지

OBJECTIVE: The purpose of the present study was to examine the relationship between the use of senior center and health-related quality of life in Korean older adults. METHODS: A questionnaire survey was conducted to two types of older adults who lived in Busan, Korea: 154 older adults who used a senior center and 137 older adults who did not use a senior center. The Korean version of short-form 36-item health survey was administered to assess the health-related quality of life. Demographic variables were obtained from a questionnaire. These were gender, age, family status, marital status, education, monthly income, present illness, body mass index and physical activity. RESULTS: The 8-domain scales of physical function and role-physical were significantly higher in the users of the senior center compared with the non-users (F=4.87, p=0.027 and F=7.02, p=0.009, respectively). The 8-domain scales of vitality was also significantly higher in the users of the senior center compared with the non-users (F=7.48, p=0.007). CONCLUSIONS: The present study showed that the users of the senior center have higher physical function, role-physical and vitality compared with the non-users. These findings suggest that although the results are unable to specify causal relationships using the senior center may lead to some improvement in health-related quality of life.

Laboratory practice in transfusion medicine for medical students and physicians at Okayama University Hospital / 医学教育

1) All students but 1 correctly typed the ABO blood groups, but only 33.2% of students and 63.9% of physicians properly performed cross-matching.<br>2) Most failures in cross-matching were due to the inability to detect allogeneic antibodies, but 5.2% of students and 2.9% of physicians failed to detect ABO mismatching.<br>3) Although laboratory practice is suggested to help students to solidify knowledge and comprehend principles, achieving an official goal of residency - gaining competence in performing and interpreting cross-matching independently - appeared difficult.

THE EFFECT OF COMBINED EXERCISE TRAINING ON CAROTID ARTERY STRUCTURE AND FUNCTION, AND VASCULAR ENDOTHELIAL GROWTH FACTOR (VEGF) IN OBESE OLDER WOMEN / 体力科学

The purpose of this study was to examine the influence of 12-week combined exercise program on carotid artery structure and function, and vascular endothelial growth factor (VEGF) in obese older women. All subjects were sixty years or older (66.90±4.2 years), performed the combined exercise training during 12-week consisting of aerobic exercise, band exercise, and yoga exercise for 70 minutes 3 times a week under the supervision of exercise specialist. Despite no statistically significant change in control group, percent body fat mass (3.26 %, p<.01), systolic blood pressure (6.2 mmHg, p<.05), diastolic blood pressure (5.6 mmHg, p<.001), and 10 m maximal walking time (0.56 sec, p<.05), TC (20.5 mg/dl, p<.05), and LDL-C (22.16 mg/dl, p<.05) were significantly decreased respectively after 12-week combined exercise in exercise group. In addition, sit-and-reach (3.6 cm, p<.01), oxygen uptake per weight (3.27 ml/kg/min, p<.05), VEGF (17.85 pg/dl, p<.001), and carotid artery LD (0.4 cm, p<.01), PFV (10.06 cm/sec, p<.05), EFV (6.04 cm/sec, p<.05) were significantly increased in the exercise group than in the control group. The VEGF had the significant correlation with LD (r=.389, p<.01), PFV (r=.427, p<.01), EFV (r=.264, p<.05). In conclusion, 12-week combined exercise program is effective to improve and/or physical function and body composition. And also, exercise can improve serum lipid metabolism, VEGF regulation, and carotid artery function and structure.

PATTERNS OF LIFESTYLE WALKING BEHAVIOR AMONG JAPANESE ADULTS AGED 30-49 / 体力科学

The purpose of this study was to explore patterns of lifestyle walking behavior among Japanese adults aged 30-49 and to identify their sociodemographic characteristics.A sample of 5,009 was collected from registrants of a social research company. The study was a cross-sectional survey using the Internet. Measured variables were walking behavior in five domains (commuting, working, shopping, exercising and other movement) and sociodemographic characteristics. Hierarchical cluster analysis was utilized to identify walking patterns.Four walking behavior clusters were identified: cluster 1 (N=1,089) walking while commuting, working and shopping; cluster 2 (N=381) walking while commuting; cluster 3 (N=1,257) walking for exercise; cluster 4 (N=1,161) walking while shopping. Cluster 1 had the highest proportion of walkers who met physical activity recommendations. Also it had a high proportion of women who were unmarried, employed, without children, or finished university or graduate school. Cluster 2 showed a high proportion of men who were married, with children, with high household income, or finished university or graduate school, and women who were married, employed, without children, with high household income, or finished university or graduate school. Cluster 3 had a high proportion of women aged 40-49. Cluster 4 showed a low proportion of men with high household income and a high proportion of women who were married, unemployed, or with children.This study indicated that walking behavior patterns in both genders was different depending on marital status, number of children, educational level and household income. In addition, the employment status of women had apparent effects on these patterns.

EFFECTS OF KNEE PAIN IMPROVEMENT PROGRAMS IN MIDDLE- AND OLDER-AGED WOMEN WITH KNEE PAIN / 体力科学

<b><i>Objective</i></b> : The present study examined the effects of the self-management print media intervention on improving quality of life.<b><i>Methods</i></b> : The study was designed as an intervention study. We conducted questionnaire research on women (JKOM, Japanese style CSQ) over 40 years old who had knee pain. After program relevance determination, self-management print media intervention and an exercise intervention were implemented. The participants were 63 women (self-management print media intervention), and 80 women (exercise intervention). We examined valiances of pain intensity and activity limitation and pain coping strategies on each intervention using Wilcoxon signed-ranks test.<b><i>Results</i></b> : Pain intensity and activity limitation improved in both interventions. On the other hand, pain coping strategies differed. In the self-management print media intervention, the scores of diverting attention, praying or hoping, increasing activity level and increasing pain behavior significantly decreased. For the exercise intervention, a significant decrease was seen in coping, self-statements, catastrophizing, increasing activity level, and increasing pain behavior.<b><i>Conclusion</i></b> : The results indicated that the self-management print media intervention had greater effect than the exercise intervention for women with knee pain. As one health assistance measure, this self-management print media intervention should become widely used.

EFFECT OF INDIVIDUAL FEEDBACK INFORMATION IN A CORRESPONDECE COURSE TYPE WALKING PROGRAM BASED ON BEHAVIORAL SCIENCE / 体力科学

The purpose of this study was to investigate the effect of individual feedback intervention (IFB) or general video intervention (GV) on promoting daily physical activity. One hundred and thirty-six community-dwelling people volunteered as subjects and participated in the 2-month walking program provided as a correspondence course. The subjects were randomly allocated to one of four groups, which consisted of either IFB or GV. Each of the groups was based on behavioral science. The stage of change in exercise, self-efficacy for exercise and daily physical activity were measured before and after intervention 4 months later during the follow-up period. There were statistically significant effects of both ‘time’ (F=3.71, p=0.026) and ‘time’בIFB’ (F=3.76, p=0.025) in self-efficacy for exercise; while there was no significant effect of interaction between ‘time’בGV’. As for daily physical activity, there was no significant effect of the interaction both of ‘time’בIFB’ and ‘time’בGV’. These results suggest the IFB of promoting self-efficacy for exercise.

RELEVANCE OF SOCIAL AND PHYSICAL ENVIRONMENTAL INFLUENCES TO PHYSICAL ACTIVITY PROMATION / 体力科学

<b><i>Background</i></b> A behavioral science-based approach is essential for constructing effective intervention programs to promote the shift from a sedentary to active lifestyle. Recently, the influences of social and physical environment on physical activity have been recognized as key factors for promoting physical activity. The present study attempts to identify the social and physical environmental influences associated with physical activity promotion.<b><i>Methods</i></b> We recruited volunteers from a 14,000 population of community-dwelling adults. Seventy-two adults (intervention group : n=35, control group : n=37) participated in the present study. The intervention consisted of 8 sessions for 2 months using <i>The Waseda Walking Program</i>. We assessed social support for exercise, perceived neighborhood environment for walking, stages of change in exercise behavior and physical activity outcomes at baseline and 2 months. Ffifty-seven out of 72 subjects (intervention : n=30, control : n=27) completed all of the intervention including the final questionnaire.<b><i>Results</i></b> There were significant intervention effects on physical activity outcomes, stages of change and perceived neighborhood environment. However, no significant improvement in social support was found. In addition, improvement of perceived physical environment was related to an increase in physical activity.<b><i>Conclusion</i></b> Perceived neighborhood environment for walking would be identified as a key factor to influence an effect of physical activity promotion. On the other hand, social support would be influenced to the earlier stages of change in exercise.

A COMPARISON OF CYCLISTS AND NON-CYCLISTS' THIGH MUSCLE OXYGENATION STATE DURING PEDALING / 体力科学

The purpose of this study was to compare the thigh muscle oxygenation state of competitive road cyclists and non-cyclists during varied pedaling frequency cycling. Six male college road cyclists (CY group) and five male students (NC group) performed four sets of cycling bouts, consisting of 2 minutes of warm up (60 rpm, 50 watts) followed by 5 minutes of pedaling (150 watts) using an electro-magnetic braked cycle ergometer at 40, 60, 90, and 120 rpm. Oxygenated hemoglobin and/or myoglobin (Oxy-Hb/Mb) and deoxygenated Hb/Mb (Deoxy-Hb/Mb) concentrations in the vastus lateralis were measured by near infrared spatially resolved spectroscopy. The Oxy-Hb/Mb level was significantly higher in the CY group than the NC group. But there was no significant intraction effect of the group and pedaling rate on the Oxy-Hb/Mb level. These results suggest that the changes in muscle oxygenation state according to pedaling cadence do not differ between cyclists and non-cyclists. And though the whole body work efficiency decreased according to increasing pedaling cadence, Oxy-Hb/Mb and Deoxy-Hb/Mb levels in the vastus lateralis remained unchanged up to 90 rpm. However, at 120 rpm, the Oxy-Hb/Mb level decreased remarkably and the Deoxy-Hb/Mb level increased. These results suggest that deoxygenation in the vastus lateralis at 120 rpm was higher than that for lower frequencies. And, conversely, oxygen uptake in the vastus lateralis might have increased steeply at 120 rpm. It may be that the maximum pedaling cadence that would not reduce work efficiency in the vastus lateralis is around 90 rpm.

Effects of Group-Versus Home-Based Walking Intervention on Lifestyle Activity / 体力科学

The purpose of this study was to examine the effect of class walking on lifestyle activity. The subjects were recruited from the community around the university, and volunteered to eight weeks intervention. The intervention groups were 2 different walking program groups that included a class-walking group (A : n=32) and a voluntary walking group (B : n=31) ; and the control was a blood-pressure monitor group (C : n=22) . Only A group participated in a walking class with group instruction. Physical activity was measured by pedometer counts before the start of the intervention, during the 8-week intervention and again as follow up four months afterwards. In A group, the number of pedometer counts, during the group walking activity of the 5 th and 6 th weeks, was measured in order to evaluate the number of voluntary steps on the class-walking day. Although there was no significant difference among the three groups in daily activity before the intervention, the activity of A group (12367±3290) and B group (9988±3461) was significantly increased during the intervention. Also, there were significant differences between A and B, A and C. As for A group, the number of steps due to group walking (9025±584 steps) enhanced the daily activity on the class-walking days (16191±3988 steps), but significantly attenuated the voluntary steps on the class-walking days (7166±3988 steps), which did not significantly differ from the baseline of the daily activity. The number of steps on the non-class walking days (i. e. steps other than those taken on the class-walking day ; 11719±3454 steps) was not significantly different than that of B. There was significant enhancement of daily activity 4 months after the intervention for A (11487±4057) and B (9564±2545 steps), but not for C (9070±3485 steps), compared to the baseline. There was not a significant difference between the daily activity of A and B after the intervention. These data suggest that the instruction given and the steps taken in class walking enhance daily activity during the intervention period, and that voluntary steps play a more important role in whether or not one remains active and adheres to regular exercise.

A Comparison between cyclists and noncyclists of joint torque of the lower extremities during pedaling / 体力科学

The purpose of this study was to compare the effect between cyclists and noncyclists of pedal rates on ankle, knee, and hip joint torque during pedaling exercises. Six male cyclists (CY) and seven male noncyclists (NC) pedaled at 40, 60, 90 and 120 rpm with a power output of 200 W. The lower limb was modeled as three rigid segment links constrained to plane motion. Based on the Newton-Euler method, the equation for each segment was constructed and solved on a computer using pedal force, pedal, crank, and lower limb position data to calculate torque at the ankle, knee, and hip joints. The average planter flexor torque decreased with increasing pedal rates in both groups. The average knee extensor torque for CY decreased up to 90 rpm, and then leveled off at 120 rpm. These results were similar to NC. The average knee flexor torque in both groups remained steady over all pedal rates. The average hip extensor torque for CY decreased significantly up to 90 rpm where it showed the lowest value, but increased at 120 rpm. For NC, the average hip extensor torque did not decrease at 90 rpm compared with 60 rpm, and was significantly higher than CY at 120 rpm (CY : 28.1 ± 9.0 Nm, NC : 38.6 ± 6.7 Nm, p<0.05) . The average hip flexsor torque for NC at 120 rpm increased significanly from 90 rpm, and was significantly higher than CY (CY : 11.6±2.9 Nm, NC : 22.6±11.8 Nm, p<0.05) . These results suggest that it would be better for cyclists to select a pedal rate of between 90 to 110 rpm to minimize joint torque, and, as a result, reduce peripheral muscle fatigue.

Effect of frutose ingestion before and during prolonged exercise on subsequent maximal exercise performance / 体力科学

The purpose of this study was to examine the effect of fructose ingestion on maximal exercise performance capacity following prolonged steady-state exercise compared with glucose or placebo ingestion, in 7 male college students (age 23.3±0.7 yr, height 171.3±1.9 cm, weight 68.4±1.4 kg, Vo2max 3.5±0.2 L/min, mean ± SEM) . The subjects cycled constantly on an ergometer at 59± 2 % Vo2max for 100 min divided in the middle by a 5-min rest, and then performed 10 min of all-out self-paced cycling. They ingested either 8 % fructose solution (F), 8 % glucose solution (G) or artifi-cially sweetened placebo (P) before and during exercise (at 20, 40, 65, 85 mm) . Before exercise and at 50 and 100 min of exercise and 5 min after the performance ride, blood samples were collected for determination of the concentrations of blood lactate, serum glucose and serum FFA. In the G trial, the serum FFA level was significantly lower than in the P and F trials at any of the time points dur-ing and after exercise (vs. P ; p<0.01, vs. F ; p<0.05) . However, glucose ingestion maintained serum glucose at a significantly higher level during and after exercise than placebo ingestion (p< 0.01) and improved the total work output in the 10-min performance ride (G vs. P ; 135± 8 KJ vs. 128± 8 KJ, p<0.05) . Although in the F trial, the serum FFA level was elevated during exercise compared to that in the G trial and the serum glucose level was significantly higher than in the P trial (vs. P ; p<0.01), the blood lactate level after exercise was lower than in the G trial and total work output was similar to that in the P trial (123± 8 KJ, vs. G ; p<0.01) . These results indicate that fructose ingestion before and during exercise cannot improve the ability to perform high-intensity exercise late in prolonged exercise despite maintaining the serum glucose level.

Metabolic and hormonal responses to prolonged intermittent exercise / 体力科学

The purpose of this study was to compare the influence of prolonged continuous (CON) and intermittent (INT) exercises on metabolic and hormonal responses in 8 male college students (age ; 23.0±0.5 yr, weight; 67.7±1.5 kg, VO<SUB>2</SUB>max ; 2.8±0.1 L/min, mean±SE) . Both trials consisted of two 40 min cycling bouts divided by a 5-min rest period. The intensity of INT was alternated every 4 min at low intensity (25% VO<SUB>2</SUB>max) and high intensity (75% VO<SUB>2</SUB>max), whereas the intensity of CON was maintained at 50% VO<SUB>2</SUB>max. Blood samples were collected before, and after 40 and 80 min of exercise, to determine blood lactate, serum glucose, FFA, insulin, plasma adrenaline and noradre-naline. Perceived exertion (RPE) was assessed at 40 and 80 min of exercise using the Borg scale. Although the changes in the concentration of plasma noradrenaline and serum insulin from basal values were similar in INT and CON, the degree of increase in plasma adrenaline during INT was significantly smaller than that during CON (90.5±16.6 vs. 152.8±27.0 pg/ml, p<0.05, after 80 min of exercise) . There was no difference in the change in the serum glucose level between the two trials. However, serum FFA in INT was significantly smaller than that in CON after 40 min (0.28±0.06 vs. 0.10±0.04 mEq/l, p<0.05) and 80 min (0.54±0.08 vs. 0.33±0.07 mEq/l, p<0.05) of exercise. RPE did not differ between the trials. These data indicate that even if performed total work and exercise duration are the same, metabolic and hormonal responses during prolonged intermittent exercise differ from those during continuous exercise.

Effect of high-speed resistance training on muscle cross-sectional area and speed of movement / 体力科学

A conducted to determine 1) the effect of high-velocity movement in resistance training with a constant load on the velocity of movement after training and 2) the differences in the effect on muscle hypertrophy according to training velocity. Fourteen of the total subjects (male; n=10, female ; n=7) were placed in the experimental group and agreed to participate in 8 weeks of training sessions (4 times a week) . Five of the 17 subjects were in control a group before the training session. Subjects performed elbow extension and flexion exercise using 50% of one repetition maximum (% 1 RM) load. The exercise session consisted of 6 sets of 10 repetitions and 30s of rest was taken between the sets. The subjects in the experimental group trained their arms using two different protocols ; one was high-velocity movement performed as rapidly as possible (Type R), the other was low-velocity movement performed at a constant and slow velocity (Type S) . Isokinetic torque in elbow flexion was measured at angular velocities of 60, 180, 300 deg/s, respectively, during elbow flexion performed under different constant loads of 0, 30, 50% 1 RM, and the muscle cross-sectional area (CSA) of the elbow flexor was determined before and after training. It was found that Type R did not increased isokinetic torque at 300 deg/s significantly after training. However, the increase in angular velocity of elbow flexion in Type R exercise tended to be higher than in Type S exercise. The increase in CSA [Type S; 11.2%, Type R ; 14.2%] was significantly higher in Type R exercise (p<0.05) . These results suggest that high-velocity movement with a constant load in resistance training might increase the angular velocity of movement in the same mode, but might not produce a change in isokinetic strength, which involves a different mode of muscle contraction. Muscle hypertrophy would be induced to a greater extent by high-velocity movement than by low-velocity movement in resistance training with a constant load.

Effect of exercise intensity on autonomic nervous system activity during and after acute exercises / 体力科学

A study was conducted to investigate the effect of exercise intensity on the recovery of autonomic nervous activity after exercise. Ten subjects performed four kinds of 10-min cycle exercise with target heart rates of 100, 120, 140, and 160 beats/min (THR 100, THR 120, THR 140 and THR 160, respectively) following 5 min of exercise to increase the heart rate to the target level. The beat-by-beat variability of the R-R interval was recorded throughout the experiment including the 5-min pre-exercise control period and the 30-min recovery period. Spectral analysis (fast Fourier transform) was applied to every 5-min R-R interval data set before, during ( 5-10 min) and after exercise at the target heart rate. The low- (0.05-0, 15 Hz : P<SUB>1</SUB>) and high- (0, 15-1.0 Hz : P<SUB>h</SUB>) frequency areas were calculated to evaluate sympathetic (SNS) and parasympathetic (PNS) nervous activities as P<SUB>1</SUB>/P<SUB>h</SUB>and P<SUB>h</SUB>, respectively. During exercise, SNS of THR 160 was significantly higher, and PNS of THR 140 and THR 160 was significantly lower than the respective pre-exercise values (p<0.05) . Althouglt all indicators recovered to, or overshot the pre-exercise values at 20-30 min after THR 100 and THR 120, heart rate and SNS were still higher and PNS was still lower than the pre-exercise value after THR 160. These results suggest that the recovery of cardiac autonomic nervous activity is slower after high-intensity exercise than after low-intensity exercise, and that the recovery of autonomic nervous activity after acute exercise does not always corrrespond linearly on the exercise intensity.

Work intensity during pedal-stepping exercise determined using a stair simulator based on vertical velocity / 体力科学

A study was conducted to ascertain the relationship between oxygen uptake (Vo<SUB>2</SUB>) and vertical velocity using a pedal-stepping stair simulator. Ten healthy volunteers performed fbur kinds of graded exercise using a stair simulator (SS), whose pitches were set at 80, 100, and 120 beat⋅min<SUP>-1</SUP>, and also an electrically braked bicycle ergometer (BE) . Work rate on the SS was detemined on the basis of the vertical pedal velocity, in accord with the climbingvelocity for stairs. The incremental rate was set at 0.34 W⋅kg<SUP>-1</SUP> every 3 min. Heart rate and Vo<SUB>2</SUB> were measured during the final minute of every stage. Both heart rate and Vo<SUB>2</SUB> during SS were significantly lower than those on BE at the same level of work intensity. Regression equations between Vo<SUB>2</SUB> (m<I>l</I>⋅kg<SUP>-1</SUP>⋅min<SUP>-1</SUP>) and velocity (<I>v</I>: m⋅s<SUP>-1</SUP>) were as follows;<BR>pitch 80: Vo<SUB>2</SUB>=1.00×<I>v</I>+0.06<BR>pitch 100: Vo<SUB>2</SUB>=0.88×<I>v</I>+1.58<BR>pitch 120: Vo<SUB>2</SUB>=0.84×<I>v</I>+2.13<BR>These equations give a lower value of Vo<SUB>2</SUB> than the previous equation based on stair-climbingvelocity reported by the American College of Sports Medicine. Although the individual relationship between Vo<SUB>2</SUB> and heart rate was closely linear, there was a significant effect ofexercise mode and stepping pitch. These results indicate that the work intensity of pedalstepping exercise with a stair simulator is overestimated if it is calculated based on theprevious equation for stair-climbing.

Excess CO2 output independent of hyperventilation during constant-load exercise / 体力科学

Gas exchange kinetics during constant-load exercise were measured to investigate the possibility that excess CO<SUB>2</SUB> output during exercise might not be dependent on hyperventilation. Five healthy males performed twelve minutes of cycle exercise, including two minutes of 0 W pedaling, at 20, 40, 50, 60, 70, and 80% of their maximal work rate (WRmax) determined on the basis of preliminary ramp exercise of 30 W/min. Minute ventilation, O<SUB>2</SUB> uptake, and CO<SUB>2</SUB> output were measured breath-by-breath. Excess CO<SUB>2</SUB> output and CO<SUB>2</SUB> stores were calculated, assuming that the respiratory quotient (RQ) in tissue is constant during constant-load exercise and that the respiratory exchange ratio at the mouth level is equal to the RQ during the steady-state phase. Excess CO<SUB>2</SUB> output was observed at levels of WR greater than 40% WRmax after initial CO<SUB>2</SUB> storage, where VC<SUB>O2</SUB>/V<SUB>E</SUB> decreased gradually as though in parallel with the kinetics of CO<SUB>2</SUB> storage. VO<SUB>2</SUB>/V<SUB>E</SUB>, however, appeared to be constant after the initial peak. These data suggest that V<SUB>E</SUB> is closely correlated with V<SUB>O2</SUB> rather than V<SUB>CO2</SUB> during constant-load exercise, indicating that excess CO<SUB>2</SUB> output to compensate lactate production is independent of hyperventilation.

Power spectrum of heart rate fluctuations during incremental cycle exercise / 体力科学

Spectral analysis was applied to investigate whether the system for control of heart rate (HR) is influenced by exercise intensity. Five healthy males performed incremental exercise on an electrically braked cycle ergometer until exhaustion. The work rate was increased at 12 W/min following 2 min of exercise at a constant load of 20 W. HR was measured every second from R-R intervals. The power spectrum was calculated every 10 s using the FFT method for 64 consecutive data points. Power spectra during 20 W exercise showed a similar pattern to those in previous reports on resting HR perturbations, Although interindividual differences were observed for the spectrum patterns related to exercise intensity, there was a characteristic pattern revealing dissipation of the spectral power above a frequency of 0.2 Hz for all subjects. This pattern was not maintained for more than 1 min in any of the subjects, and was followed by a semirandom pattern whose magnitude varied among the subjects. These results support the hypothesis that the cardiac pacemaker is influenced by exercise intensity, presumably due to sympatho-vagal interaction with the respiratory control system.