Provocative relation between soy and bone maintenance.
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Animals↗
Biomedical subjects
R A Boileau
Publications and source records attributed to R A Boileau.
Ageing, fitness and neurocognitive function.
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Aging↗
The physical activity scale for the elderly (PASE): evidence for validity.
We assessed the validity of the Physical Activity Scale for the Elderly (PASE) in a sample of sedentary adults (56 men, 134 women, mean age +/- [SD] 66.5+/-5.3 years) who volunteered to participate in a randomized controlled trial on the effect of aerobic conditioning on psychological function. Construct validity was established by correlating PASE scores with physiologic and performance characteristics: peak oxygen uptake, resting heart rate and blood pressure, percent body fat, and balance. The mean PASE scores were higher in men than in women (men = 145.8+/-78.0; women = 123.9+/-66.3, P<0.05), and in those age 55-64 years compared with those age 65 years and over (55-64 = 144.2+/-75.8; 65 and over = 118.9+/-63.9, P<0.05). PASE scores were also significantly higher in those who did not report a chronic health condition (cardiovascular disease, hypertension, cancer, or recent surgery). PASE scores were significantly associated (P<0.05) with peak oxygen uptake (r = 0.20), systolic blood pressure (r = -0.18) and balance score (r = 0.20). No significant associations of PASE score and diastolic blood pressure, resting heart rate, or percent body fat were noted. These results provide additional evidence for the validity of the PASE as a measure of physical activity suitable for use in epidemiology studies on the association of physical activity, health, and physical function in older individuals.
Aged↗
Self-reported energy intake and energy expenditure in elderly women.
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Aged↗
Age-related variability in body composition methods for assessment of percent fat and fat-free mass in men aged 20-74 years.
INTRODUCTION: Assessing body composition is important because of the association between excess body fat or obesity and the increased risk for coronary artery disease, diabetes, hyperlipidaemia and hypertension. Methodological differences among indirect body composition techniques are a source of variability that can affect estimations of fat-free mass (FEM) or percent fat, especially for different age groups. PURPOSE: This study examined the effect of age on the estimation of body composition by three methods based on the two-component model. One hundred and fifty-three men were placed into 5-year age groups from 20-24 to 70-74 years. Body composition was assessed by hydrodensitometry (underwater weighing; 40K spectroscopy (K40) and anthropometry. RESULTS: Day-to-day reliability was excellent for each method. Correlation coefficients between methods, independent of age, ranged from r= 0.71 (K40 and UWW) to r = 0.83 (UWW and anthropometry) for% fat and from r = 0.76 (K40 and anthropometry) to r = 0.90 (UWW and anthropometry) for FFM. Correlations between techniques weakened and showed greater variability as age increased. UWW produced the highest % fat and lowest FFM for the different age groups, while K40 and anthropometry yielded similar body composition values. All three methods detected age-related differences in % fat; however, only UWW determined a significant age effect in FFM. The greatest discrepancies between the methods occurred for the oldest age groups (60-74 years), but noticeable differences began occurring after the age of 40. CONCLUSIONS: Each method produced reliable data. Care should be taken when choosing any method based on the two-component model, especially when different age groups are being examined, since estimating % fat and FFM is dependent on the age-related chemical composition of an individual and the limitations of each method.
Adiposity↗
Preexercise meal composition alters plasma large neutral amino acid responses during exercise and recovery.
This study was designed to determine the effect of ingesting three preexercise meals on energy metabolism during exercise and recovery and to relate metabolic perturbations to subjective and objective measurements associated with central fatigue. Twelve subjects consumed isoenergetic meals consisting of oat, wheat, or corn cereals 90 min before cycling. A fasting trial served as the control. Blood samples and cognitive function, perceived hunger, and sleepiness measurements were obtained before and after feeding and during recovery when self-selected food intake was also measured. After meal ingestion, plasma insulin was lower for oat than for wheat or corn whereas the ratio of tryptophan to large neutral amino acids (LNAAs) for corn was less than for all others. During exercise, the tryptophan-LNAA ratio increased from preexercise values for the fasting and wheat trials, but exercise performance was unaffected. During recovery, tryptophan:LNAA increased from postexercise values in fasting trials. Also, hunger and fatigue ratings were greater in fasted subjects, but self-selected food intake measured at the end of the recovery period was not different among groups. We conclude that preexercise meal consumption affected tryptophan:LNAA before, during, and after exercise, but these changes were not sufficient to alter physical and cognitive performance.
Adult↗
Oat, wheat or corn cereal ingestion before exercise alters metabolism in humans.
This study was designed to determine metabolic and physical performance responses to ingestion of pre-exercise meals with different macronutrient and fiber profiles. Twelve physically active subjects (6 males and 6 females) were used to investigate the metabolic and physical performance consequences of consuming pre-exercise meals consisting of oat, corn, or wheat cereals. A fasting trial served as the control, and all subjects received each treatment in a Latin-square design. Blood samples were drawn before and 85 min after meal ingestion, during 90 min of cycling exercise (60% VO2peak), after a 6.4 km performance ride, and during 60 min of recovery. Expired air samples were collected to determine nutrient utilization. Resting carbohydrate oxidation rates and plasma insulin concentrations after oat ingestion were less than after wheat, and corn and wheat ingestion, respectively (P < 0.05). During exercise, the change in plasma glucose from pre-exercise was greater after consuming wheat and corn compared with oat (P < 0.05), and it was inversely related to pre-exercise plasma insulin concentration (r = -0.55, P = 0.0001). Plasma free fatty acid concentrations were inversely related to plasma lactate concentrations (r = -0.58, P = 0.0001). Free fatty acid concentrations and fat oxidation were greater in fasting trials than all others, but performance ride times did not differ among treatments. Plasma branched-chain amino acid concentrations resembled their respective meal profiles throughout exercise, the performance ride, and recovery. These results indicate that pre-exercise meal composition can influence glucose homeostasis during early exercise and plasma branched-chain amino acid concentrations over a substantial range of metabolic demands.
Adult↗
Isometric intermittent endurance of four muscle groups in men aged 20-74 yr.
Muscular endurance of upper and lower extremities may provide a more practical measure of muscle function related to normal daily activity than measures of strength, especially with the elderly. Maximal isometric intermittent endurance of the finger flexors, thumb abductors, dorsiflexors, and plantar flexors were characterized by peak force, impulse, percent total impulse, and percent force decrement in men aged 20-74 yr. Volunteers (N = 153) were placed into appropriate 5-yr age groups: 20-24, 25-29, ..., 70-74 yr. The intermittent endurance task consisted of 11 consecutive, 2-s maximal contractions, each separated by 3-s rest. Age group differences within each 2-s interval as well as differences in endurance were determined by ANOVA, and after adjusting for differences in body composition, by ANCOVA. The lower extremities had the greatest declines in absolute measures of force within each 2-s interval, and declines occurred earlier than previously reported. When values were expressed as percent change over the entire endurance task, there was generally no age group difference in force or impulse; however, there were significant muscle group differences. In conclusion, declines in absolute measures of force occurred at different ages depending on the muscle group; however, relative measures of muscular endurance were maintained for all age groups but varied by muscle group location.
Adult↗
Age-related patterns in body composition for men aged 20-79 yr.
Fat-free body mass has been reported to decline by 30% between the ages of 30 and 70 yr, whereas body weight increases until age 50 yr. This study examined the age-related patterns in body composition, specifically its two components, fat-free body mass and fat mass, in 157 men aged 20-79 yr. Total body composition was assessed by hydrodensitometry and subcutaneous fat was measured with skinfolds. Approximately 15 men were tested in each of the 12 5-yr age groups (20-24, 25-29, 30-34, ... 75-79 yr). Body density, as determined by underwater weighing, was lower successively from the youngest to oldest age groups; men below age 40 yr had significantly higher (P < 0.01) body densities than the older men. Although there was a gradual decline in fat-free body mass with increasing age, there was not a significant age group effect until age 70 yr. Fat mass gradually increased with increasing age; men above age 40 yr had significantly higher (P < 0.01) total body fat when compared to the younger men. Subcutaneous body fat was similar at the distal limb locations for each age group; however, the proximal trunk locations, especially the abdomen, demonstrated significantly (P < 0.01) higher skinfold thicknesses with increasing age. In conclusion, fat-free body mass was maintained to a later age than previously reported; thus, the age-related decline in body density could be attributed to an age-related increase in body fat.
Adipose Tissue↗
Contributions of exercise, body composition, and age to bone mineral density in premenopausal women.
The purpose of this cross-sectional study were to determine whether exercisers have greater bone mineral density (BMD) than nonexercisers, whether aerobic dancers have greater BMD than walkers, and to determine the contributions of energy expenditure, body composition, and dietary factors to spine and femur BMD. Measurements were obtained on 93 eumenorrheic women (walkers N = 28; aerobic dancers, N = 34; nonexercisers, N = 31) ages 25-41 yr; lumbar spine and proximal femur BMD, body composition, physical activity, and nutrient intakes. Mean height, weight, and body mass index and median age and calcium intakes were similar for the three groups. Mean (+/- SD) values of the spine, total femur, and femoral neck BMD, respectively, were: walkers (1.092 (+/- 0.098), 0.947 g.cm-2), dancers (1.070 (+/- 0.124), 0.990 (+/- 0.104), 0.908 (+/- 0.106) g.cm-2), and nonexercisers (1.020 (+/- 0.112), 0.887 (+/- 0.073), 0.792 (+/- 0.089) g.cm-2) multiple regression analyses indicated that exercise contributed to spine (P = 0.018), total femur (P =0.012), and femoral neck (P < 0.0001) BMD, whereas type of exercise (aerobic dance vs walking) did not (P > 0.05). Total femoral BMD was influenced by exercise (P = 0.012) and energy expenditure (P = 0.023), while vertebral BMD was influenced by age (P = 0.0067), body weight (P = 0.017), and exercise (P = 0.018). These findings suggest that walking and aerobic dance exercise may provide physically active premenopausal women with greater lumbar and femoral BMD than sedentary females.
Adult↗
Mineral and water content of the fat-free body: effects of gender, maturation, level of fatness, and age.
Variability associated with the effects of gender, level of fatness (LOF), maturation (ML), and age on the mineral (MFFB) and water (WFFB) content of the fat-free body (FFB) was investigated in 188 males and 144 females, aged 8 to 17 years. Measures of body density, bone mineral content, total body water, and skin-fold thicknesses were obtained. FFB was calculated using a multicomponent model based on body density and adjusting for variability in body water and mineral content. Subjects were classified by ML as prepubescent, pubescent, and postpubescent. Subjects were also grouped by LOF as lean, average, and obese based on percentile rankings from the age-related norms of the National Children and Youth Fitness Study. Least squares multiple regression analysis using weighted orthogonal contrasts to account for sample size differences revealed significant (p<.01) gender, ML, gender x LOF, and gender x ML effects for MFFB; however, no significant (p>.05) effects between, or within, gender were noted for WFFB. Significant ML, and nearly significant (p>.056) LOF x ML, effects were found for MFFB in the males. In contrast, only ML was significant within the female sample for MFFB. These results were upheld when age, rather than ML, was used in the analysis. The overall relative increase in MFFB across ML was greatest in the obese (17.4%, 9.3%) and least in the lean (11.3%, 6.3%) males and females, respectively. A significant increase in MFFB across ML was observed in both genders; however, the pattern and magnitude of increase is dependent upon LOF considered. Hence, consideration of gender, ML, LOF and age is essential in estimating body composition in children.
Adipose Tissue↗
The effect of test protocol instructions on the measurement of muscle function in adult women.
Consideration of the anatomy of the nervous system and events (ie., age, physical training, motor learning) that invoke changes in neural regulatory mechanisms and other bodily systems renders the impact of the type of instruction used to elicit a maximal effort in the assessment of muscle function across age, among different muscle groups, and for different parameters of muscle function tenuous. Hence, the efficacy and effect of using two types of instructions (rate vs. strength) on the assessment of the isometric functional capacity of six muscle groups were examined in women (N = 143) aged 25-74 years. The subjects were categorized by age into 10, 5-year groups. Measures of maximal force (MF), maximal rate of force increase (MR), total impulse (TI), time to MF (MFT), time to MR (MRT), and plateau time (PLT, time between 90% MF and MF) were obtained from the force-time recordings of maximal voluntary isometric contractions of the finger flexors, thumb extensors, elbow flexors and extensors, and ankle dorsiflexors and plantar flexors. Repeated measures analyses of variance indicated that instruction type influenced (p < .05) the magnitude and pattern of the force-time recordings, with the degree of difference dependent upon the muscle group and parameter of muscle function examined. Use of the rate instruction yielded greater MRs (40.9-541.0 N/sec) than the strength instruction. The strength instruction elicited greater MFs (6.4-326.7 N), longer MFTs (0.72-1.50 sec), MRTs (0.05-0.15 sec) and PLTs (0.31-0.79 sec), and greater TIs (25.1-1,079.8 N-sec) than the rate instruction.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Cortisol levels during prolonged exercise: the influence of menstrual phase and menstrual status.
The purpose of this study was to determine the influence of menstrual phase and menstrual status on the cortisol response during 90 minutes of treadmill running at 60% VO2max. Eight eumenhorrheic athletes were tested in the early follicular (EF) (day 3-5), late follicular (LF) (day 13-15) and mid-luteal (ML) (day 22-24) phases. Six amenorrheic athletes were tested on two separate occasions. The resting cortisol levels were similar in each menstrual phase and overall a decreasing pattern of cortisol response to exercise was observed in all menstrual phases (P greater than .05). The amenorrheic athletes had a significantly greater (P less than .01) pattern of cortisol response than was observed in eumenorrheic athletes. The net increment in cortisol levels during exercise were distinctly greater (P less than .01) in amenorrheic than eumenorrheic athletes (amenorrheic: 413.8 +/- 113.1, eumenorrheic: EF: -482.8 +/- 88.3, LF: -311.8 +/- 102.1, ML: -386.3 +/- 146.2 nmol.l-1). In conclusion the cortisol levels are independent of menstrual phase. Also a larger cortisol increment is observed in amenorrheic athletes in response to prolonged submaximal exercise. The elevated cortisol levels in amenorrheics at rest and throughout exercise provides further evidence that disturbances in the hypothalamic-pituitary-adrenal function are associated with exercise-induced amenorrhea, although the site(s) of physiological disturbance have not been identified.
Adult↗
Influence of metabolic, mechanical and physique variables on middle distance running.
The purpose of this study was to determine the variables that most limit middle distance run performance e.g. 800, 1500 and 3000 meters. A predictive research design was employed as 56 runners ran each of the three distances and were evaluated for VO2max, running mechanics, physique variables, ventilatory threshold, and anaerobic capacity and power. The data were analyzed by correlation procedures and stepwise regression analysis. The variables that most limited 1500 and 3000 meter (m) run performance were identical. Maximal oxygen uptake was the most important, but stride length and anaerobic capacity and power also contributed significantly. Run performance at 800 m was influenced by a considerably different set of variables. Peak velocity was most important, but VO2max, % fat and thigh length also contributed significantly. These data indicate that 1500 and 3000 m runners can compete favorably at either distance, while 800 m runners have a different profile and would experience difficulty competing at 1500 and 3000 meters.
Anthropometry↗
Substrate oxidation and GH responses to exercise are independent of menstrual phase and status.
The purpose of this study was to determine the extent to which growth hormone (GH) and energy substrate utilization are influenced by basal sex steroid levels during prolonged submaximal exercise across menstrual phase and status. Also the 17 beta-estradiol (E2) and progesterone responses during prolonged exercise were compared according to menstrual phase and menstrual status. Six amenorrheic (AMc) athletes and seven eumenorrheic (EUc) athletes ran at 60% VO2max for 90 min and serial blood samples were taken at rest, every 10 min throughout exercise, and 5 and 15 min post-exercise. The EUc athletes were tested in the early follicular phase (EF) (days 3-5), the late follicular phase (LF) (days 14-16) and the mid-luteal phase (ML) (days 22-25). The incremental GH response to exercise, measured by area under the curve, was consistent with previous reposts and was not altered according to menstrual phase or status (EF-37.5 +/- 11.5, LF-61.9 +/- 11.5, ML-48.1 +/- 12.8 micrograms.1-1.90 min-1). Furthermore, carbohydrate and fat utilization during exercise were not influenced by basal sex steroid levels associated with menstrual phase or status. The incremental E2 response to exercise in AMc athletes was significantly smaller than seen in EUc athletes (AMc-208.1 +/- 44.0, EF-383.0 +/- 116.4, LF-204.7 +/- 84.1, ML-45.1 +/- 18.4 pmol.1(-1).90 min-1), although the pattern of release is similar between groups. In conclusion, GH levels and substrate utilization are independent of both menstrual phase and status; hence, menstrual phase has no negative ramifications on metabolism during exercise. Amenorrhea does not result in metabolic consequences during prolonged exercise by influencing substrate utilization.
Adolescent↗
Effects of oral contraceptives on hormonal and metabolic responses during exercise.
This study examined the influence of oral contraceptives (OC) on GH and PRL responses and on energy substrate utilization during prolonged submaximal exercise in moderately active women (21-30 yr). Eight women taking OC (OC) and eight women with normal menstrual cycles (C) performed a standardized treadmill test of 90 min at 50% maximal oxygen uptake. Blood samples were withdrawn from an indwelling venous catheter during a 2-h rest period, at 10-min intervals during exercise and at 3 and 15 min of recovery. Serum concentrations of glucose, GH, PRL, E2, and P4 were assayed. Carbohydrate and fat utilization were estimated from respiratory exchange ratios. Basal serum levels of GH, PRL, and glucose were not significantly different (P greater than 0.05) between OC and C. OC had significantly higher (P less than 0.05) serum GH levels than C at 10 and 20 min of exercise, but the integrated areas for GH responses were not different (P = 0.059). Serum PRL levels significantly decreased (P less than 0.05) during exercise, and PRL responses were similar for the two groups. OC exhibited significantly lower blood glucose levels (P less than 0.05) during exercise and utilized significantly lower total grams of carbohydrate (P less than 0.05) during exercise than C. In conclusion, OC use was associated with enhanced GH responses, lower glucose levels, and diminished carbohydrate utilization during prolonged exercise. These results indicated that OC users demonstrated a greater carbohydrate-sparing ability than eumenorrheic women, which may be related to the contra-insulin effects of GH. The lower blood glucose levels, however, suggest the sparing of carbohydrate may act to compensate for decreased hepatic glucose output, similar to animal data.
Adult↗
Isometric muscle force production as a function of age in healthy 20- to 74-yr-old men.
Typically, previous studies have focused on one muscle group, the finger flexors, and only one aspect of muscle function, strength, when assessing age-related muscle force production characteristics. In the present study, the maximal voluntary isometric contraction force-time curves of five muscle groups (right hand finger flexors, right thumb abductors, right forearm extensors, right leg dorsiflexors, and right leg plantar flexors) were assessed in men, ranging in age from 20 to 74 yr. One hundred fifty-three volunteers were placed into appropriate 5-yr age groups: 20-24 (N = 14), 25-29 (N = 15), 30-34 (N = 16), 35-39 (N = 13), 40-44 (N = 16), 45-49 (N = 11), 50-54 (N = 16), 55-59 (N = 12), 60-64 (N = 17), 65-69 (N = 13), and 70-74 (N = 10) years. Muscle function was characterized by a number of force-time parameters, including strength, time, rate, and impulse. The data were analyzed both with and without consideration of the influence of physique and body composition. The results indicated that there were significant age group differences in the ability to produce maximal force (strength) (P less than 0.05), to generate maximal rates of force production (P less than 0.05), and in the total forces generated (impulse) (P less than 0.05), with an overall and in the total forces generated (impulse) (P less than 0.05), with an overall decline with increasing age.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Lower thermic effect of a meal post-exercise in aerobically trained and resistance-trained subjects.
Despite the abundance of literature concerning the thermic effect of a test meal (TEM) at rest in trained and untrained subjects, there is little information available concerning the TEM post-exercise. Therefore, it was the purpose of this study to examine the metabolic response to a 763-kcal meal prior to 30 min of exercise at 50% VO2max, in aerobically trained (AT, N = 8), resistance-trained (RT, N = 8), and untrained (UT, N = 8) subjects. Mean (+/- SEM) VO2max was 60.7 +/- 2.3 ml.kg-1.min-1, 52.9 +/- 2.2 ml.kg-1.min-1 and 51.1 +/- 2.2 ml.kg-1.min-1, for the AT, RT, and UT groups, respectively. Mean (+/- SEM) percent fat was 13.7 +/- 1.2, 12.7 +/- 1.9, and 16.9 +/- 1.4 for the AT, RT, and UT groups, respectively. Post-exercise VO2 was measured by indirect calorimetry every half hour, on two nonconsecutive days (post-absorptive (PA) post-exercise and post-prandial (PP) post-exercise) for 3 h. The total TEM (post-exercise PP VO2 minus post-exercise PA VO2) was 4.86 +/- 1.62, 5.22 +/- 1.80, and 9.36 +/- 5.08 I for the AT, RT, and UT groups, respectively. The TEM post-exercise was significantly lower (P less than 0.05) for the AT and RT groups compared with the UT group. Respiratory exchange ratio (R) differed significantly only during the PA post-exercise condition, with the AT group exhibiting significantly lower (P less than 0.01) values compared with the RT and UT groups. PA post-exercise R for the RT group was not significantly different (P = 0.09) from the UT group.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗