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Biomedical subjects

B H Massey

Publications and source records attributed to B H Massey.

At least 19 recordsLinked to original sources
PubMed1998

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↗
PubMed1996

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↗
PubMed1995

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↗
PubMed1992

The relative contribution of strength and physique to running and jumping performance of boys 7-11.

The purpose of this study was to determine the association of static strength with motor performance of 7 through 11 year old boys (N = 60) after accounting for differences in physique, i.e., body size, shape, and composition. Static strength measures included thigh extension, leg extension and plantar flexion measured by electronic transducer and back lift, leg lift, and right and left grips measured by spring dynamometer. Measures of body composition consisted of fat estimated from triceps, subscapsular and calf skinfolds, and fat-free body weight estimated from potassium-40 measurements. Body structure consisted of skeletal widths, and segment girths, lengths and volumes. The dependent variables were vertical jump, standing broad jump, 50-yard dash, 600-yard run and mile run. The measures of strength increased the variance accounted for from 10 to 23% over that when body size, composition and structure were used without strength. An exception was vertical jump where no increase in the variance accounted for was found with the addition of strength variables. The regression equations determined for the sample of 60 boys rendered multiple R's ranging from 0.64 (mile run) to 0.75 (50-yard dash). It was concluded that strength has a significant relation to motor performance and that its contribution can be better assessed after accounting for differences in body size, shape, and composition.

Anthropometry↗
PubMed1991

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↗
PubMed1990

Sex differences in static strength and fatigability in three different muscle groups.

Maximal voluntary static muscle force production was assessed both in strength trials and during 2-min contractions by three muscle groups (right-hand finger flexors [RHF], right-leg extensors [RLE], and both leg extensors [BLE]) in young males (n = 13) and females (n = 14). There was a significant difference (p less than .01) between males and females for RHF strength and BLE strength but no significant difference between sexes for RLE strength. During the 2-min task, impulse (force x time) declined significantly (p less than .001) and there was a significant difference (p less than .001) between muscle groups, but there was no difference between sexes. There was a significant (p less than .05) sex x time interaction for the impulse values indicating that the fatigability was greater in males than females.

Adolescent↗
PubMed1990

Cardiovascular response to sustained maximal voluntary static muscle contraction.

The cardiovascular response to maximal, voluntary, sustained 2-min static contraction by three different muscle groups (right hand finger flexors [RHF], right leg extensors [RLE], and both leg extensors [BLE]) was studied in young adult males (N = 13) and females (N = 14). Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were recorded at 30 s intervals prior to, during, and after exercise. Mean arterial blood pressure (MABP) and pulse pressure (PP) were computed from SBP and DBP. The force of muscle contraction was monitored continuously throughout the 2-min task. Data were analyzed by MANOVA. The results showed that impulse (force x time) declined significantly throughout exercise, and there were significant differences in impulse among muscle groups. SBP, DBP, PP, and MABP increased significantly throughout the 2-min contraction period, while heart rate increased initially and then leveled off. The magnitudes of the blood pressure and HR responses were related to the muscles involved: BLE greater than RLE greater than RHF. Blood pressures during rest and exercise were significantly lower for females than for males, but there was no sex effect for heart rate. These findings suggest that blood pressure increases throughout sustained static muscular contractions despite significant reductions in force production. Heart rate, on the other hand, does not increase throughout exercise under these conditions. It appears that heart rate and blood pressure responses to sustained static contraction are mediated by different mechanisms, but these mechanisms are similar for males and females.

Adolescent↗
PubMed1989

Total-body electrical conductivity (TOBEC): relationship to estimates of muscle mass, fat-free weight, and lean body mass.

A comparison of methods for estimating body composition (BC) of 12 subjects was made by using fat-free weight from total-body electrical conductivity (FFWT), muscle mass from 3-methylhistidine excretion (MM3MH) and creatinine excretion (MMCRE), fat-free weight from hydrostatic weighing (FFWBD), and lean body mass from whole-body potassium counting (LBMK). Data were analyzed for day-to-day variability and regression analyses were applied to compare the different methods of measuring BC. Mean values (+/- SEM, kg) for the estimates were 53.9 +/- 3.5 (FFWT), 26.9 +/- 2.9 (MM3MH), 25.3 +/- 2.5 (MMCRE), 53.2 +/- 3.6 (FFWBD), and 52.8 +/- 3.5 (LBMK). Regression analyses revealed that TOBEC estimates of fat-free weight had an adjusted r2 (+/- SEE, kg) of 0.95 +/- 2.2, 0.50 +/- 7.9, 0.95 +/- 1.8, and 0.88 +/- 4.0 for MM3MH, MMCRE, FFWBD, and LBMK, respectively. It was concluded that TOBEC is a potentially reliable method for estimating the muscle mass within the fat-free compartment, as well as fat-free weight and lean body mass.

Adipose Tissue↗
PubMed1989

Age as a factor in the hemodynamic responses to isometric exercise.

This study was designed to determine the effect of isometric contractions of the finger flexors and leg extensor muscle groups on the cardiovascular responses of men 18-31 and 50-71 years of age. A 2X2X4 split-plot design was carried out with men representing two age groups, using two muscle groups and performing isometric contractions at four different intensities. Analysis of variance indicated significant differences for all main effects. The systolic and diastolic blood pressures were found to be (1) higher for the leg extension contractions compared to the finger flexion contractions, (2) higher for each increment in %MVC workload, and (3) higher for the older individuals. Heart rate responses were found to be (1) higher for the leg extension exercises, (2) higher with each increase in %MVC, and (3) higher for the younger subjects. Stroke volumes demonstrated (1) higher values for the young men at each workload, (2) lower values for leg extension exercises, and (3) a greater decline with longer contraction times. The older individuals had higher pressor responses than did the younger subjects, higher pressor and heart rate responses were observed with isometric leg extension exercises and increasing %MVC levels, and the older subjects had lower stroke volume responses compared to the younger subjects.

Adolescent↗
PubMed1988

Excretion of 3-methylhistidine and hydroxyproline following acute weight-training exercise.

Changes in urine excretion of 3-methylhistidine (3MH) and hydroxyproline (OHP) were investigated following a single session of weight training that produced delayed onset muscle soreness (DOMS). The subjects (n = 18) maintained meat-free diets for 6 days and collected 24-h urine volume on day 4 (PRE), day 5 (POST1), and day 6 (POST2) for analysis of 3MH, OHP, and creatinine (CRE). At the end of PRE, nine subjects (EX) performed intensive weight-training exercises. The remaining subjects (NE) served as a nonexercised group. All subjects were measured for fat free weight (FFW) and rated DOMS at the end of each urine collection period, i.e., PRE, POST1, and POST2. The results were significant DOMS ratings on POST1 and POST2 compared with PRE2 for EX only. Excretion of 3MH (x +/- SE in mumol/day) by group were, for EX, PRE 271 +/- 18, POST1 243 +/- 16, POST2 259 +/- 23; for NE, PRE 203 +/- 23, POST1 209 +/- 27, POST2 225 +/- 32. Excretion of OHP (x +/- SE in mg/day) were, for EX, PRE 30.0 +/- 5.4, POST1 32.8 +/- 6.4, POST2 29.6 +/- 6.1; for NE, PRE 22.5 +/- 5.2, POST1 21.6 +/- 6.0, POST2 22.7 +/- 6.0. Changes in urine 3MH and OHP were not statistically significant, whether analyzed in absolute terms or relative to CRE and FFW. It was concluded that the acute session of weight training which produced muscle soreness did not effect excretion of 3MH or OHP.

Adult↗
PubMed1988

Hemodynamic responses to positional change in habitually physically active and inactive older men.

This study explored hemodynamic responses to positional change in 11 habitually physically active and 11 physically inactive healthy older men (mean age 70 years). Data were collected in the supine, sitting, standing, and 70 degrees upright tilt positions over a 10-minute period (long-term response). Dependent variables were heart rate, stroke volume, cardiac output, total peripheral resistance, and blood pressure. Stroke volume, cardiac output, and total peripheral resistance were expressed per unit body surface area. The results of this study indicated that the physically active older men had significantly lower resting heart rates and significantly higher stroke volume indices in all four positions compared with the physically inactive men. The physically active men also tended to have lower total peripheral resistance indices and higher cardiac indices in all four positions, but the differences were not statistically significant. However, physically active and inactive older men reacted similarly (with respect to all hemodynamic variables except the stroke volume index) in the sitting, standing and 70 degrees upright tilt positions as compared with the supine; the stroke volume index decreased significantly more compared with that of the supine in the physically active men.

Aged↗
PubMed1988

Effect of arm training on central and peripheral circulatory function.

The purpose of this study was to examine the effect of endurance arm training on metabolic and circulatory function during arm and leg exercise. Thirty-eight females (aged 18 to 35 yr) participated in the study, with 19 subjects in the training group and 19 in a control group. Both a specific and general training response was observed at the conclusion of the 5-wk training period. As a result of training, during peak arm exercise, significant increases (P less than 0.05) were observed for oxygen uptake (VO2), ventilation, cardiac output, stroke volume, arterial-venous oxygen difference, cumulative work, and total performance time. During peak leg exercise following arm training, significant increases (P less than 0.05) were observed for VO2, ventilation, cardiac output, cumulative work, and total performance time. Standardized partial regression coefficients were used to examine the relative influence of the metabolic and circulatory components which define VO2. Prior to training during arm work, the arterial-venous oxygen difference accounted for the largest proportion of variance in VO2; but after training, stroke volume contributed the largest portion of variance. On the other hand, during leg exercise, stroke volume accounted for the largest portion of variation in leg VO2 both before and after arm training. The data suggest that endurance arm training as prescribed in this study elicits significant circulorespiratory function adaptations to support improved performance in both arm and leg work. Further, the findings suggest both a specific and general training effect, with the more dominant effect specific to arm work.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Physical activity and bone mineral content in women aged 30 to 85 years.

The relationship of bone mineral content and level of physical activity was investigated in 83 Caucasian females, aged 30 to 85 yr. Bone mineral content was measured by photon absorptiometry at a site one-third the distance from the distal radius to the olecranon process. Anthropometric measurements were taken and percent fat estimated. Physical activity questionnaires were independently evaluated by five physical education professionals, and subjects were assigned to low (N = 19), moderate (N = 36), or high (N = 28) activity groups. A significant difference (P less than 0.05) was seen in bone mineral content and in bone mineral content divided by bone width between the most active group of women and the two less active groups, even with age and menstrual status as co-variates. Mean values for bone mineral content divided by bone width, when adjusted for age and menstrual status, were 0.622, 0.651, and 0.679 g . cm-2 for the low, moderate, and high activity groups, respectively. No difference was found between the moderate and low activity groups. Percent fat estimates and skinfold thicknesses showed that women in the high activity category were significantly leaner (P less than 0.05), although height, weight, and skeletal widths for the groups were equivalent. The data indicate that a high level of physical activity could be a factor in reducing age-related bone loss and in preserving lean body mass in women.

Adult↗
PubMed1979

Prediction of maximal oxygen uptake in boys, ages 7-15 years.

Predictions of Vo2max (1 min-1 and ml kg-1 min-1) were obtained via multiple regression procedures from a sample of 100 boys, ages 6.7-14.8 years. Prediction equations for Vo2max (1 min-1) were obtained from the subjects' height, and the Vo2 (1 min-1) and heart rate observed during the third min of a treadmill walk (R = 0.95; CV = +/- 9.3%). A similar prediction was obtained when the subjects' age, height and weight were used (R = -0.94; CV = +/- 9.7%). Vo2max (ml kg-1 min-1) was predicted with similar accuracy (CV = +/- 8.4%) from age, and heart rate, VCO2(1 min-1), Vo2 (ml kg min-1), or from simply age, height and weight (CV = +/- 9.2%). Cross-validation of the equations with another sample of 39 boys demonstrated that the prediction equations based on laboratory data were quite stable, % errors approximately 1-2 +/- 9%. However, the equations based on age, height and weight underestimated the Vo2max slightly, both in 1 min (X = -0.091 min) and ml kg min (X = -2.2 ml kg min, P less than 0.05). The results indicate that reasonably reliable and accurate estimates of Vo2max for children may be obtained from either laboratory data, or simply from their age, height and weight.

Adolescent↗
PubMed1977

Urinary excretion of free noradrenaline and adrenaline in trained and untrained men.

Measurements of free noradrenaline and adrenaline were made in the urine of 28 men sampled after rest and exercise prior to, and following six and twelve weeks of an excercise programme. The training consisted of thirty minutes of running and walking four times per week at an intensity estimated at 75% of the age-predicted maximum heart rate. A fifteen minute standardized cycle ergometer work test was conducted on all subjects prior to the training and following six and twelve weeks of training. Noradrenaline and adrenaline excretions in the urine were measured before and after the work test.

Adult↗
PubMed1976

Cardiovascular responses of hyperactive children to methylphenidate.

Heart rate, blood pressure, and oxygen consumption were measured in 27 hyperactive children during rest, exercise, and recovery, once taking placebo and again taking methylphenidate hydrochloride. Half were measured first taking the drug and half first taking the placebo. Twenty-three matched controls were also measured twice to test for reproducibility of results. Drug and placebo ECGs were recorded on 12 of the subjects. Oxygen consumption did not change (P = .40), but heart rate (P = .001) and blood pressure (P = .003) increased significantly with methylphenidate therapy. There was a significant correlation between size of dose in milligrams per kilogram and increase in heart rate (.38, P less than .05) and blood pressure (.50, P less than .05 systolic) (.46, P less than .05 diastolic). No evidence of the development of tolerance to these drug effects was found in children who had been taking methylphenidate from two months to more than a year. No ECG changes other than tachycardia were seen.

Age Factors↗