Biomedical subjects

C B Cooke

Publications and source records attributed to C B Cooke.

At least 19 recordsLinked to original sources

PubMed2004

Oxygen uptake kinetics and maximal aerobic power are unaffected by inspiratory muscle training in healthy subjects where time to exhaustion is extended.

The aim of this study was to determine whether 4 weeks of inspiratory muscle training (IMT) would be accompanied by alteration in cardiopulmonary fitness as assessed through moderate intensity oxygen uptake (V(.)O(2)) kinetics and maximal aerobic power (V(.)O(2max)). Eighteen healthy males agreed to participate in the study [training group (Tra) n=10, control group (Con) n=8]. Measurements of spirometry and maximal static inspiratory mouth pressure ( PI(max)) were taken pre- and post-training in addition to: (1) an incremental test to volitional exhaustion, (2) three square-wave transitions from walking to running at a moderate intensity (80% ventilatory threshold) and (3) a maximal aerobic constant-load running test to volitional fatigue for the determination of time to exhaustion ( T(lim)). Training was performed using an inspiratory muscle trainer (Powerbreathe). There were no significant differences in spirometry either between the two groups or when comparing the post- to pre-training results within each group. Mean PI(max) increased significantly in Tra ( P<0.01) and showed a trend for improvement ( P<0.08) in Con. Post-training T(lim) was significantly extended in both Tra [232.4 (22.8) s and 242.8 (20.1) s] ( P<0.01) and Con [224.5 (19.6) and 233.5 (12.7) s] ( P<0.05). Post-training T(lim) was significantly extended in Tra compared to Con ( P<0.05). In conclusion, the most plausible explanation for the stability in V(.)O(2) kinetics and V(.)O(2max) following IMT is that it is due to insufficient whole-body stress to elicit either central or peripheral cardiopulmonary adaptation. The extension of post-training T(lim) suggests that IMT might be useful as a stratagem for producing greater volumes of endurance work at high ventilatory loads, which in turn could improve cardiopulmonary fitness.

Adaptation, Physiological↗

PubMed2003

Bone density, body composition and menstrual history of sedentary female former gymnasts, aged 20-32 years.

Few studies have examined the effects of retirement from sports involving regular, high impact and weight bearing activity on bone mass. This cross-sectional study compared total body and regional areal bone mineral density (aBMD, g/cm(2)) within female former gymnasts and women who had never participated in structured sport or exercise, and explored relations between aBMD of these former gymnasts and their duration of retirement. Eighteen sedentary female former gymnasts (GYM) and 18 sedentary controls (CON) were recruited. GYM displayed a broad range of duration of retirement (3-12 years) and a wide age range (20-32 years). GYM and CON were paired individually to match for age, body mass and stature. GYM had commenced training at least 3 years pre-menarche and had trained post-menarche for 2 or more years. They had trained continuously for 5-12 years and had retired between age 14 and 22 years. Measurements of aBMD and body composition were made using dual energy X-ray absorptiometry (DXA). Group mean values of physical and skeletal characteristics were compared using paired t-tests. Linear regression was used to explore possible relations of aBMD within GYM to duration of retirement. GYM displayed a higher aBMD than CON at all measurement sites, which ranged in magnitude from 6% for the total body ( P=0.004), to 11% for the total femur ( P=0.006). Elevations of aBMD within GYM equated to T-scores ranging from +0.8 (arms) to +1.7 (legs). There were no differences in body composition or age of menarche between groups, although 11 of 18 GYM reported a history of irregular menses. There was no significant decline of aBMD with increasing duration of retirement in GYM. The results suggested that an elevated bone mass in female former gymnasts was retained during early adulthood, in spite of a cessation of training for up to 12 years.

Adult↗

PubMed2003

Estimates of percentage body fat in young adolescents: a comparison of dual-energy X-ray absorptiometry and air displacement plethysmography.

OBJECTIVE: To evaluate the accuracy of percentage body fat (%fat) estimates from air displacement plethysmography (ADP) against an increasingly recognised criterion method, dual-energy X-ray absorptiometry (DXA), in young adolescents. DESIGN: Cross-sectional evaluation. SETTING: Leeds General Infirmary, Centre for Bone and Body Composition Research, Leeds, UK. SUBJECTS: In all, 28 adolescents (12 males and 16 females), age (mean+/-s.d.) 14.9+/-0.5 y, body mass index 21.2+/-2.9 kg/m(2) and body fat (DXA) 24.2+/-10.2% were assessed. RESULTS: ADP estimates of %fat were highly correlated with those of DXA in both male and female subjects (r=0.84-0.95, all P<0.001; s.e.e.=3.42-3.89%). Mean %fat estimated by ADP using the Siri (1961) equation (ADP(Siri)) produced a nonsignificant overestimation in males (0.67%), and a nonsignificant underestimation in females (1.26%). Mean %fat estimated by ADP using the Lohman (1986) equations (ADP(Loh)) produced a nonsignificant underestimation in males (0.90%) and a significant underestimation in females (3.29%; P<0.01). Agreement between ADP and DXA methods was examined using the total error (TE) and methods of Bland and Altman (1986). Males produced a smaller TE (ADP(Siri) 3.28%; ADP(Loh) 3.49%) than females (ADP(Siri) 3.81%; ADP(Loh) 4.98%). The 95% limits of agreement were relatively similar for all %fat estimates, ranging from +/-6.57 to +/-7.58%. Residual plot analyses, of the individual differences between ADP and DXA, revealed a significant bias associated with increased %fat (DXA), only in girls (P<0.01). CONCLUSIONS: We conclude that ADP, at present, has unacceptably high limits of agreement compared to a criterion DXA measure. The ease of use, suitability for various populations and cost of ADP warrant further investigation of this method to establish biological variables that may influence the validity of body fat estimates.

Absorptiometry, Photon↗

PubMed2003

Comparison of body composition methods in overweight and obese children.

The objective of the present study was to investigate the accuracy of percent body fat (%fat) estimates from dual-energy X-ray absorptiometry, air-displacement plethysmography (ADP), and total body water (TBW) against a criterion four-compartment (4C) model in overweight and obese children. A volunteer sample of 30 children (18 male and 12 female), age of (mean +/- SD) 14.10 +/- 1.83 yr, body mass index of 31.6 +/- 5.5 kg/m, and %fat (4C model) of 41.2 +/- 8.2%, was assessed. Body density measurements were converted to %fat estimates by using the general equation of Siri (ADPSiri) (Siri WE. Techniques for Measuring Body Composition. 1961) and the age- and gender-specific constants of Lohman (ADPLoh) (Lohman TG. Exercise and Sport Sciences Reviews. 1986). TBW measurements were converted to %fat estimates by assuming that water accounts for 73% of fat-free mass (TBW73) and by utilizing the age- and gender-specific water contents of Lohman (TBWLoh). All estimates of %fat were highly correlated with those of the 4C model (r > or = 0.95, P < 0.001; SE < or = 2.14). For %fat, the total error and mean difference +/- 95% limits of agreement compared with the 4C model were 2.50, 1.8 +/- 3.5 (ADPSiri); 1.82, -0.04 +/- 3.6 (ADPLoh); 2.86, -2.0 +/- 4.1 (TBW73); 1.90, -0.3 +/- 3.8 (TBWLoh); and 2.74, 1.9 +/- 4.0 DXA (dual-energy X-ray absorptiometry), respectively. In conclusion, in overweight and obese children, ADPLoh and TBWLoh were the most accurate methods of measuring %fat compared with a 4C model. However, all methods under consideration produced similar limits of agreement.

Absorptiometry, Photon↗

PubMed2003

Differences in bone density, body composition, physical activity, and diet between child gymnasts and untrained children 7-8 years of age.

Strategies that enhance the acquisition of bone mass may be protective against osteoporosis. BMD was compared in 20 artistic gymnasts (10 boys; 10 girls) and 20 untrained children ages 7-8 years. Higher regional values of BMD were observed in female gymnasts than untrained girls. If retained to adulthood, this higher BMD may protect skeletal integrity in later life. Strategies that enhance the acquisition of bone mass in children may assist with the prevention of osteoporosis. This study explored the effects of regular high-impact and weight-bearing activity before the age of 7 years on total and regional bone mineral density (BMD). Twenty artistic gymnasts (10 boys and 10 girls) and 20 untrained children, 7-8 years of age, were recruited. The untrained children were matched to gymnasts by sex, height, weight, and age. Female gymnasts trained 8-10 h per week and had trained regularly for 3-4 years. Male gymnasts trained 4-6 h per week and had trained for 1-2 years. Measurements of bone mineral density were made using DXA for total body BMD (TBBMD); lumbar spine, both areal (aSBMD) and volumetric (vSBMD); total spine; pelvis; arms; and legs. Significant mean differences (8-10%) in aSBMD, vSBMD, arm BMD, and TBBMD were observed between female gymnasts and untrained girls (p < 0.05: aSBMD, vSBMD, and TBBMD body mass (BM); p < 0.01: arm BMD). A nonsignificant trend toward a higher TBBMD/BM and arm BMD was observed in male gymnasts compared with untrained boys. Trends toward a higher BMD within the pelvis, legs, and total spine were also observed in gymnasts. There were no differences in total and regional BMD between untrained boys and untrained girls. The results suggest that gymnastics training before the age of 7 years enhances the acquisition of bone mass at selected skeletal sites. The magnitude of this enhancement seems to be linked to the cumulative volume of such training. If retained during adolescence and young adulthood, a surfeit of bone acquired through high-impact and weight-bearing activity in early childhood may protect skeletal integrity in later life.

Body Composition↗

PubMed2001

Associations of leisure-time physical activity and obesity with atherogenic lipoprotein-lipid markers among non-smoking middle-aged men.

The association of both leisure-time physical activity and obesity with lipoprotein-lipids and composite atherogenic markers were examined within a cross-sectional study of middle-aged men of higher socioeconomic status. Analyses were performed on a subsample (n=629) of non-smoking, non-diabetic men (46.7+/-7.8 years) who completed a preventive medical assessment between 1992 and 1996. Mean adjusted (age, body mass index (BMI), sum of skinfolds, fasting glucose, and logarithmic alcohol consumption) levels of high-density lipoprotein-cholesterol (HDL-C) were significantly higher, and logarithmic triglycerides significantly lower, with higher physical activity index (PAI) categories (both P<0.0001). Significantly lower adjusted mean ratios of both total cholesterol to HDL-C (TC:HDL-C), and logarithmic triglycerides to HDL-C (TG:HDL-C) with higher PAI were evident following adjustment for the above covariates (P=0.005 and P<0.0001). Age-adjusted non-HDL-C (total cholesterol minus HDL-C) decreased significantly with higher PAI categories, but was not significantly lower following covariate adjustment (P=0.150). On stepwise multiple regression, logarithmic physical activity score and BMI explained 9.5-14% of the variance in the TC:HDL-C and TG:HDL-C ratios in models including age, body mass, sum of skinfolds, fasting glucose and logarithmic alcohol consumption. Age, sum of skinfolds and logarithmic alcohol consumption were significant predictors of non-HDL-C (r2=8.0%). These findings emphasise the importance of both physical activity and obesity in predicting lipoprotein-lipid risk markers.

Activities of Daily Living↗

PubMed2001

Kinematic and postural characteristics of sprint running on sloping surfaces.

The aim of this study was to identify the kinematic and postural characteristics associated with sprint running on uphill and downhill slopes of 3 degrees and on a horizontal surface. Eight male physical education students were filmed while sprinting maximally on an uphill-downhill platform under each of three conditions: (a) uphill at 3 degrees, (b) downhill at 3 degrees and (c) horizontal. Running speed, step rate, step length, step time, contact time, flight time and selected postural characteristics of the step cycle were analysed. Running speed was 9.2% faster (P < 0.05) during downhill and 3.0% slower (P < 0.05) during uphill compared with horizontal sprint running. During downhill and uphill sprint running, step length was the main contributor to the observed changes in running speed. It increased by 7.1% (P < 0.05) for downhill sprint running and was associated with significant changes in posture at touchdown and take-off. During uphill sprint running, step length decreased by 5.2% (P < 0.05), which was associated with significant changes in posture and reduced flight distance. Given the interaction between the acute changes in step length and posture when sprinting on a sloping surface, our findings suggest that such changes in posture may detract from the specificity of training on such surfaces. The chronic effects of training on such slopes on the kinematics and posture of horizontal sprint running are currently unclear.

Adult↗

PubMed2001

A comparison of adolescent moderate-to-vigorous physical activity participation in relation to a sustained or accumulated criterion.

Contemporary guidelines for young people advocate both a sustained and accumulative approach to moderate-to-vigorous physical activity (MVPA) participation. In order to investigate the behavioural significance of applying these approaches, this study assessed if differences in adolescent MVPA occurred when either a sustained or accumulated criterion was adopted. Using heart rate thresholds indicative of intensity, the physical activity of 25 adolescents was assessed by monitoring heart rate over 3 days. Results indicated that differences in MVPA participation did exist when different approaches were used, in that the majority of adolescents were active with respect to an accumulated criterion yet inactive with respect to a sustained criterion. Such a disparity may be due to accumulative MVPA being more characteristic of young people's natural activity behaviour. Such findings have strong implications for practitioners seeking to counter young people's inactivity, in that the application of an accumulative approach may be more effective at initiating and establishing an habitual activity behaviour than that of a sustained approach.

Adolescent↗

PubMed2000

The oxygen consumption associated with unloaded walking and load carriage using two different backpack designs.

The purpose of this study was to assess the energy expenditure associated with load carriage using both a traditional rucksack and a new rucksack design, the AARN rucksack, which incorporates front balance pockets. Nine volunteers walked at 3 km h(-1) at various uphill and downhill gradients on a treadmill without a load and carrying a load of 25.6 kg in each of the rucksacks. The oxygen consumption associated with both of the loading conditions was significantly (P < 0.001) higher than that associated with unloaded walking at all downhill gradients tested, although there was no significant difference between the two loading conditions. During the uphill gradients the oxygen consumption associated with the AARN pack was significantly (P < 0.05) lower than that associated with the traditional pack at the 0%, 5%, 10% and 20% gradients. The mean (%) differences at these gradients, expressed in ml x kg(-1) x min(-1) were 1.18 (9%), 1.45 (8%), 1.76 (8%) and 1.88 (6%), respectively. On average for the whole protocol, the oxygen consumption associated with the AARN rucksack was 5% lower than that associated with the traditional rucksack [mean (SD) 17.28 (7.46) ml x kg(-1) x min(-1) for the AARN pack and 18.20 (7.84) ml x kg(-1) x min(-1) for the traditional pack]. The findings of the present study suggest that a load carriage system that allows the load to be distributed between the back and font of the trunk is more appropriate for carrying relatively heavy loads than a system that loads the back only.

Adult↗

PubMed2000

The effects of a children's summer camp programme on weight loss, with a 10 month follow-up.

OBJECTIVE: To assess the long-term effects of a multidisciplinary approach involving structured fun-type skill learning physical activities in the treatment of obese and overweight children. DESIGN: A longitudinal investigation incorporating repeated measurements before and after the 8 week intervention and after the 44 week follow-up period. METHODS: The camp programme (Massachusetts, USA) utilised structured fun-based skill learning physical activities, moderate dietary restriction and behaviour modification. The primary aims of the intervention were to reduce body mass and promote the maintenance of the reduction in body mass using an alternative to standard exercise prescription. SUBJECTS: One-hundred and ninety-four children (64 boys and 130 girls, aged 12.6+/-2.5y) enrolled at a summer weight loss camp, of which 102 children (38 boys and 64 girls aged 13.6+/-2.4y) returned 1 y later. MEASUREMENTS: On commencement of the programme all children were assessed for body mass and stature. At follow-up, data was available on 102 subjects for body mass and stature. RESULTS: Over the 8 week intervention significant reductions (P= 0.00) in body mass were obtained. During the 44 week follow-up significant increases (P= 0.00) were noted in body mass, body mass index (BMI) and stature, but as expected there were large variations in the responses. One year after the initial measures had been taken mean body mass and BMI were lower than at the start of the intervention, BMI significantly so (week 0, 32.9 +/- 7.4 kg/m2; week 8 29.1 +/- 6.5 kg/m2; week 52, 30.05 +/- 7.04 kg/m2); (P= 0.00). Stature increased significantly (week 0, 1.58 +/- 0.12 m; week 52, 1.64 0.11 m) (P= 0.00) during this period, demonstrating a reduction in mean body mass over a 1 y period whilst subjects continued to increase in stature. When changes in BMI are analysed with the use of standard scores, there is a non-significant increase (P=0.07) in BMI during the follow-up phase and 89% of children had a lower BMI than at week 0. CONCLUSIONS: These findings suggest that the use of a structured fun-based skill learning programme may provide an alternative method of exercise prescription to help children prolong the effects of the 8 week intervention. Further investigations will help identify the key factors that are necessary for long-term lifestyle modification.

Adolescent↗

PubMed2000

Kinetic changes associated with load carriage using two rucksack designs.

This study assessed changes in kinetics from unloaded walking associated with load carriage using both a traditional and a new rucksack design that incorporates front balance pockets (AARN). Nine subjects walked at 3(+/-0.05) km x h(-1) over a force plate unloaded and carrying 25.6 kg in each of the rucksacks. The order of trials was randomized and speed-controlled by use of photoelectric cells and a millisecond timer. Anteroposterior and vertical ground reaction forces were analyzed using repeated measures ANCOVA (speed covariate). There was a trend for the AARN pack to elicit a shorter support time than the traditional pack, 1.025+/-0.049 versus 1.037+/-0.06 s (p = 0.056), while the unloaded condition produced the shortest support time, 1.016+/-0.04 s. Both braking and propulsive forces for the rucksacks were significantly greater than for unloaded walking. While there was no significant difference between the packs for the braking force, the AARN pack produced a significantly lower (p<0.05) propulsive force than the traditional rucksack, 0.79+/-0.2 versus 0.94+/-0.16 N x kg bodyweight(-1). Both rucksacks produced significantly greater (p<0.001) vertical force peaks than unloaded walking, the increases being proportional to the increase in system weight. These findings indicate that there may be some advantage in terms of propulsive force production for the front/back system.

Analysis of Variance↗

PubMed2000

Plasma viscosity and its biochemical predictors: associations with lifestyle factors in healthy middle-aged men.

The association of lifestyle factors and biochemical variables with plasma viscosity was examined in a sample of middle-aged males of high social status. Analyses were performed on a subsample of men that had relevant rheological and biochemical variables determined during a preventive medical assessment conducted between 1992 and 1996. Among 622 subjects (64 smokers), measures of physical activity or predicted VO2max and adiposity (sum of subcutaneous skinfolds) were the lifestyle factors significantly associated with plasma viscosity (both P < 0.001). Among the biochemical variables, serum total protein and plasma fibrinogen concentrations accounted for most of the explained variability in plasma viscosity within subjects (combined adjusted r2 = 65.5%). Logarithm-transformed triglyceride, leukocyte count and serum globulin together contributed an additional 3.0% of the variance in plasma viscosity. Serum total protein, In triglycerides and leukocyte count decreased significantly across higher quartiles of predicted VO2max (all P < 0.0001), with trends towards lower fibrinogen and globulin concentrations (P = 0.054 and P = 0.050, respectively). Higher levels of adiposity were also significantly associated with higher levels of serum total protein (P < 0.0001), globulin (P < 0.0001), fibrinogen (P < 0.01), leukocyte count (P < 0.05), and triglycerides (P < 0.0001). The association of lifestyle factors with the biochemical predictors of plasma viscosity may result directly from a pro-inflammatory state of adipose tissue origin and/or a larger plasma volume related to higher levels of cardiorespiratory fitness. Randomised controlled trials of the effects of regular physical activity of different intensities on plasma viscosity, with reference to body composition, are now required.

Adult↗

PubMed2000

Physical activity, cardiorespiratory fitness, and the primary components of blood viscosity.

PURPOSE: The relationship of both self-reported leisure time physical activity (LTPA) and predicted maximum oxygen consumption (VO2max) with plasma viscosity and hematocrit (Hct) concentration was examined within a cross-sectional sample of employed middle-aged men. METHODS: Analyses were performed on a subsample of nonsmoking men who completed a preventive medical assessment between 1992-1996. RESULTS: Among nonsmokers the mean age-adjusted levels of plasma viscosity (N = 590) and Hct concentration (N = 632) were significantly lower with higher Physical Activity Index (PAI) categories (P = 0.001 and P = 0.01, respectively). Following adjustment for conventional IHD risk factors and blood leukocyte count, a significant inverse relationship remained for Hct (P = 0.044) but not plasma viscosity. Mean age-adjusted plasma viscosity and Hct concentration also showed a significant decrease with higher quartiles of predicted VO2max (mL x kg(-1) x min(-1))(P = < 0.00005 and P = 0.0004, respectively). Following adjustment for all confounding variables mean plasma viscosity and Hct concentration remained significantly lower with higher quartiles of predicted VO2max (mL x kg(-1) x min(-1))(P = < 0.00005 and P = 0.047). CONCLUSIONS: These data confirm the inverse relationship between LTPA and/or predicted VO2max with plasma viscosity and Hct concentration within nonsmoking middle-aged men of high socioeconomic status.

Adult↗

PubMed2000

Leisure time physical activity, cardiorespiratory fitness, and plasma fibrinogen concentrations in nonsmoking middle-aged men.

PURPOSE: The relationship of both leisure time physical activity and predicted maximum oxygen consumption (VO2max) with plasma fibrinogen concentration was examined within a cohort of employed middle-aged men. METHODS: Analyses were performed on a subsample of 635 nonsmoking men (46.7 +/- 7.7 yr) who completed a preventive medical assessment between 1992 and 1996. RESULTS: Among nonsmokers, mean age-adjusted fibrinogen concentration decreased significantly with higher physical activity index (PAL) categories and quartiles of predicted VO2max (mL x kg(-1) x min(-1)) (both P = 0.001). Mean age-adjusted plasma fibrinogen concentrations were significantly different (P < 0.05) between inactive and vigorous PAI groups and extreme quartiles of predicted VO2max (mL x kg(-1) x min(-1)). These relationships were no longer significant after adjustment for the confounding effect of other ischemic heart disease risk factors. Stepwise multiple regression analyses showed that age, sum of skinfolds, and blood leukocyte count were the strongest predictors of plasma fibrinogen concentration. CONCLUSION: These data do not confirm a significant independent association of both physical activity and predicted VO2max (mL x kg(-1) x min(-1)) with fibrinogen concentrations among nonsmoking middle-aged men of similar high social class.

Adult↗

PubMed2000

Metabolic clustering, physical activity and fitness in nonsmoking, middle-aged men.

PURPOSE: The relationship of both physical activity and predicted maximum oxygen consumption (VO2max) with the clustering of metabolic risk factors associated with the metabolic syndrome (MS) was examined within 711 employed middle-aged (46.9 +/- 7.8 yr) men. METHODS: Metabolic markers included fasting glucose, triglycerides, high-density lipoprotein cholesterol, blood pressure, and BMI, defined by highest risk quintiles or clinically relevant risk thresholds. RESULTS: The prevalence and age-adjusted odds ratios of all MS clusters were inversely graded across both higher physical activity index (PAI) and cardiorespiratory fitness (CRF) categories. The age-adjusted odds ratio for the clustering of clinically relevant metabolic markers was 0.60 (95% CI 0.22-1.22) for subjects in the occasional/light PAI, 0.32 (95% CI 0.12-0.82) for the moderate/moderately vigorous PAI, and 0.13 (95% CI 0.02-1.02) for the vigorous PAI when compared with subjects in the sedentary PAI (P < 0.05 for trend). The corresponding age-adjusted odds ratio was 0.28 (95% CI 0.14-0.57) for subjects in the moderate fitness category and 0.12 (95% CI 0.05-0.32) for the highest fitness category compared with those in the lowest fitness category (P < 0.001 for trend). Higher levels of physical activity or CRF were also associated with significantly lower age-adjusted odds ratios for the MS after exclusion of obesity in the MS definition. CONCLUSION: Overall, these cross-sectional results suggest that higher physical activity and predicted VO2max levels are associated with a decreased clustering of risk factors associated with the MS in middle-aged men of higher social class.

Adult↗

PubMed2000

Plasma viscosity, fibrinogen and the metabolic syndrome: effect of obesity and cardiorespiratory fitness.

The association between both plasma viscosity and fibrinogen concentration with clustering of metabolic risk markers was examined within a cross-sectional study of employed middle-aged men. Analyses were performed on a subsample of 629 non-smokers (46.7+/-7.8 years) without diabetes. The effect of obesity and cardiorespiratory fitness on these haemorheological parameters and their association with the metabolic syndrome was also investigated. The cohort was grouped by the number of metabolic markers present. Metabolic markers included high-density lipoprotein-cholesterol (<1.13 mmol/l), triglycerides (> or =1.805 mmol/l), glucose (> or =5.5 mmol/l) and diastolic blood pressure (> or =90 mm Hg). The age-adjusted odds ratio for hyperviscosity (> or =1.67 mPa/s) was 2.08 [95% confidence interval (CI), 1.06-4.05; P = 0.031] for the subjects with the metabolic syndrome (three or more metabolic markers) when compared with those with no metabolic abnormalities. The comparable age-adjusted odds ratio for hyperfibrinogenaemia (> or = 3.47 g/l) was non-significantly higher at 1.69 (95% CI, 0.87-3.27; P = 0.119). The mean age-adjusted plasma viscosity level and the prevalence of hyperviscosity increased significantly from 1.629 to 1.692 mPa/s (P = 0.0005) and from 21.0 to 36.0% with accumulating metabolic markers (P = 0.006). Plasma viscosity and fibrinogen concentration both increased with higher quartiles of skinfolds (P = 0.003 and P = 0.01, respectively) following adjustment for age, lipids and leucocyte count. Plasma viscosity was also significantly lower with higher levels of predicted maximum oxygen consumption (VO2max) (P = 0.0005). The odds ratio for hyperviscosity in subjects with the metabolic syndrome as compared with those with no metabolic markers was attenuated following adjustment for age, sum of skinfolds and predicted maximum oxygen consumption (VO2max) (1.44; 95% CI, 0.72-2.90; P = 0.307). These cross-sectional results suggest that plasma viscosity is associated with increased clustering of metabolic markers in middle-aged men of high socio-economic status. Obesity and poor cardiorespiratory fitness may be important in the development of haemorheological abnormalities associated with the metabolic syndrome.

Adult↗

PubMed1999

The effect of longer-term creatine supplementation on elite swimming performance after an acute creatine loading.

We investigated the effect of an acute creatine loading (25 g per day for 4 days) and longer-term creatine supplementation (5 g of creatine or 5 g of placebo per day for 2 months) on the performance of 22 elite swimmers during maximal interval sessions. After the acute creatine loading, the mean of the average interval swim times for all swimmers (n = 22) improved (44.3+/-16.5 s before vs. 43.7+/-16.3 s after supplementation; P<0.01). Three of the 22 swimmers did not respond positively to supplementation. After 2 months of longer-term creatine supplementation or placebo, neither group showed a significant change in swimming performance (38.7+/-13.5 s before vs. 38.7+/-14.1 s after for the creatine group; 48.7+/-18.0 s before vs. 48.7+/-18.1 s after for the placebo group). We conclude that, in elite swimmers, 4 days of acute creatine loading improves swimming performance significantly when assessed by maximal interval sessions. However, longer-term supplementation for 2 months (5 g of creatine per day) did not benefit significantly the creatine group compared with the placebo group.

Adult↗

PubMed1999

Primary and secondary barriers to physically active healthy lifestyles for adults with learning disabilities.

PURPOSE: Evidence shows that those with a learning disability are typically amongst the most inactive and sedentary members of the population, yet few studies have focused on the determinants of physical activity. The aim of the present study was to establish whether a group of 24 adults with mild and moderate learning disabilities receive adequate support to be able to make choices to lead a physically active lifestyle. METHOD: A descriptive study was used based on interviews with 24 adults with learning disabilities (mean age of 34 years) triangulated by day time and residential care workers. Participants volunteered from two residential homes and one social education centre (SEC) in a city in the North of England. RESULTS: The participants face a set of primary barriers that prevent them from having a choice to adopt the Department of Health's recommendations for physical activity. Identified barriers included: unclear policy guidelines in residential and day service provision together with resourcing, transport and staffing constraints; participant income and expenditure; and limited options for physically active community leisure. CONCLUSIONS: These are barriers that are widely acknowledged and understood by day and residential staff and participants in the study, but are arguably poorly understood by policy makers, health promotion agencies, commissioners and providers of learning disability services. The current lack of resources and inadequately specified responsibilities associated with community care deny many people with learning disabilities real choices to live a physically active healthy lifestyle.

Adult↗