Determinants of endothelial function in a cohort of patients with peripheral artery disease.

OBJECTIVES: Endothelial dysfunction assessed by brachial artery flow-mediated dilatation (FMD) has been associated with cardiovascular events. There have been relatively few studies examining FMD or other measures of endothelial function in patients with peripheral artery disease (PAD). The aim of this study was to examine determinants of FMD in a homogenous cohort of patients with PAD. METHODS: We prospectively assessed patients presenting with life style-limiting intermittent claudication to establish the presence of cardiovascular risk factors, obesity and metabolic syndrome. Fasting serum was assayed for lipids, C-reactive protein, adiponectin, leptin, resistin and osteoprotegerin (OPG). FMD was measured by high-resolution ultrasound. RESULTS: Serum concentrations of OPG were elevated in patients with obesity and metabolic syndrome. FMD was impaired in patients with obesity and metabolic syndrome and negatively correlated with serum concentrations of OPG. By multiple regression analysis, metabolic syndrome was independently associated with impaired FMD after adjustment for age, smoking, ischaemic heart disease, cerebrovascular disease and severity of PAD. CONCLUSIONS: Our findings suggest that metabolic syndrome is an important determinant of endothelial function in patients with PAD, and OPG may be a useful biomarker of this effect.

Predictors of 1000-m outrigger canoeing performance.

UNLABELLED: This study examined the relationships between body composition, peak oxygen consumption and 1000-m time trial performance of female outrigger canoeists. PROCEDURES: Female outrigger canoeists (n = 17) completed anthropometric profiling and a 1000-m outrigger ergometer time trial, during which expired air was measured continuously and analysed at 15-s intervals for determination of peak oxygen consumption. Heart rate, stroke rate and power output were also recorded at 15-s intervals. Blood lactate was measured immediately and at 3-, 5- and 7-min post-exercise. Mean power output, peak power output and progressive split times were highly correlated (r > 0.80) to 1000-m performance. Arm girths, humerus breadth, mesomorphy, peak oxygen consumption, ventilation, mean heart rate and peak lactate were moderately correlated (r > 0.50) to 1000-m performance. Stepwise multiple regression analysis verified that mean power output and to a lesser extent flexed arm girth, humerus breadth, waist girth and sitting height can predict 1000-m performance. Enhanced 1000-m performance of female outrigger canoeists appears to be achieved through a combination of greater power production and maintenance, a muscular stature and to a lesser extent, a higher aerobic capacity. These characteristics should be considered when selecting crews.

Effects of static stretching on leg power during cycling.

AIM: This study investigated the effects of warm-up involving static stretching on leg power. It was expected that the inclusion of static stretching in the warm-up would decrease leg power. METHODS: Twenty-seven healthy volunteers (16 male, 11 female) participated in the study. A prospective, repeated measures design was implemented where volunteers underwent 2 testing sessions at least 24 hours apart. One testing session involved a control warm-up (5 min submaximal cycling) followed by 4 10-s leg power tests at 5, 20, 40 and 60 min postwarm-up. For the other testing session, the subjects performed 5 min of submaximal cycling followed by 15 min of lower body static stretching and then the four leg power tests. Relative peak power, time to peak power and relative total work were measured for each leg power test. RESULTS: Peak power and total work were significantly greater after the static stretching warm-up compared to the control warm-up on all power tests. Peak power was achieved more quickly for the static stretching warm-up compared to the control warm-up on the 5 min test only. CONCLUSIONS: A warm up that includes static stretching has beneficial effects on anaerobic power events in comparison to submaximal cycling alone.

Biopsychological, affective and cognitive responses to acute physical activity.

BACKGROUND: To investigate, based on biopsychological arousal theory, the influence of physical activity intensity on biopsychological, affective and cognitive function. DESIGN: Repeated measures experiment involving one control and three treatment conditions. SETTING: Controlled laboratory environment. PARTICIPANTS: Twenty-one (of 27 volunteers) non-contraindicated females (55-65 years) recruited from general community and university populations completed the study. INTERVENTIONS: Data collection proceeded in four counterbalanced test-sessions including control (zero resistance), light (45%VO2max), moderate (60%VO2max), and high intensity (75%VO2max) cycle ergometer interventions. In all test sessions participants cycled at 25 W for 2 min (warm-up), followed by 10 min at the allocated intensity, and then 2 min at 25 W (cool-down). Blood pressure, heart rate and RPE were determined during test sessions. MEASURES: Energetic arousal (EA), tense arousal (TA), single dimension affect, and cognitive (reaction time-RT) responses were compared following physical activity. RESULTS: There was no significant difference in EA, TA, affect, or RT following zero resistance and light and moderate intensity physical activity or between light and moderate intensity physical activity. High intensity physical activity resulted in significantly lower levels of EA than light intensity physical activity, significantly higher levels of TA than zero resistance and light intensity physical activity, and significantly more negative levels of affect than either light or moderate intensity physical activity. There were no significant differences in reaction time between high intensity physical activity and any of the other intensities. CONCLUSIONS: There was partial support for the efficacy of biopsychological arousal theory in explaining the biopsychological and affective outcomes of physical activity, but no support for the influence of physical activity on cognitive function.

Exercise, mobility and aging.

The elderly population is growing both in size and in proportion of the total population. The costs to the community of the elderly being in poor health are also growing proportionately. The beneficial effects of exercise on various physiological and psychological parameters in the elderly have been well established. The effects of exercise on the mobility and independence of the elderly are also of primary concern, their maintenance being an important exercise goal. Impaired balance and gait are the 2 most significant risk factors for limited mobility and falls in the elderly. It is important to understand the effects of aging and exercise on these risk factors.

Dynamics of exercise induced affect.

This study investigated: (a) whether moderate intensity aerobic exercise exerted a significant affective influence during, and postexercise, (b) the nature of the affective response to exercise in relation to positive and negative affects, and affects associated with physiological distress, and (c) whether exercise induced affect was significantly influenced by exercise behaviour. Habitual exercisers (n = 15) and sedentary participants (n = 13) undertook three randomly allocated interventions; (a) exercise (EX; i.e., 20 min of cycling at 60% estimated VO2max), (b) normal workstation duties for 60 min (WRK), and (c) a 60 min sedentary lunch break (SED). Affect was measured pre, post, and 90 min postintervention, as well as every 5 min during exercise, using the Subjective Exercise Experiences Scale (SEES; McAuley & Courneya, 1994). Exercise behaviour had no significant affect on affective responses to exercise in this study (p > .05). Significant (p < .05) postintervention increases in positive affect were found for EX compared to WRK and SED indicating that exercise did produce a positive affective influence. Despite enduring postexercise (i.e., 90 min) improvements in both positive and negative affects, and affects related to fatigue, the affective response during exercise was characterised by significant (p < .05) decreases in levels of positive affect and increased levels of affects related to fatigue.

Discriminant analysis of biomechanical differences between novice, good and elite rowers.

Oar force and oar angle data resulting from a 6-min maximal rowing ergometer test undertaken by novice (n = 9), good (n = 23) and national (n = 9) level male rowers, were used to identify biomechanical performance variables which accurately discriminated between rowers of differing ability levels. The variables included two work capacity measures, mean propulsive power output per kilogram of body mass (W kg-1) and propulsive work consistency (%), and two skill variables, stroke-to-stroke consistency (%) and stroke smoothness (%). Discriminant function analysis indicated the presence of two functions, both of which clearly indicated the importance of mean propulsive power output per kilogram of body mass as a discriminating variable. Function 2 gave greater weight to stroke-to-stroke consistency and stroke smoothness than function 1; however, function 1 was the most powerful discriminator. Classification procedures were used to predict the ability level to which a rower most likely belonged and involved defining the 'distance' between each rower and each ability level centroid, with the rower being classified into the 'nearest' ability level. These procedures indicated that 100% of the elite, 73.9% of the good, 88.9% of the novice and 82.9% of all rowers were correctly classified into their respective skill levels. Stepwise discriminant analysis included the variables in the following order: mean propulsive power output per kilogram of body mass, stroke-to-stroke consistency, stroke smoothness and propulsive work consistency (P < 0.001). The results of this study indicate that biomechanical performance variables related to rowing capacity and skill may be identified and used to discriminate accurately between rowers of differing skill levels, and that, of these variables, propulsive work consistency is the least effective discriminator.

Negative pion depth-dose profile examined by means of HeLa cell-survival curves.

HeLa cells were irradiated at liquid nitrogen temperature with negative pions from Nimrod at the Rutherford Laboratory and then assayed for survival of colony-forming ability. Complete dose-response curves were obtained from repeated determinations at 14 different positions along the depth-dose profile and survival curves were fitted to the data by computer programme. A depth-damage profile was thus established in terms of the final slopes of these survival curves. This confirmed the expected RBE value of 1.84 at the ionization peak. Although a value of unity was found in the main plateau region, the "entrance" positions showed significantly higher values.