Warwick L. Spinks

Effects of a long term exercise program on lower limb mobility, physiological responses, walking performance and physical activity levels in patients with peripheral arterial disease

OBJECTIVE The purpose of the study was to examine the effects of a 12-month exercise program on lower limb mobility (temporal-spatial gait parameters and gait kinematics), walking performance, peak physiological responses, and physical activity levels in individuals with symptoms of intermittent claudication due to peripheral arterial disease (PAD-IC). METHODS Participants (n = 21) with an appropriate history of PAD-IC, ankle-brachial pressure index (ABI) <0.9 in at least one leg and a positive Edinburgh claudication questionnaire response were prospectively recruited. Participants were randomly allocated to either a control PAD-IC group (CPAD-IC) (n = 11) that received standard medical therapy and a treatment PAD-IC group (TPAD-IC) (n = 10), which also took part in a 12-month supervised exercise program. A further group of participants (n = 11) free of PAD (ABI >0.9) and who were non-regular exercisers were recruited from the community to act as age and mass matched controls (CON). Lower limb mobility was determined via two-dimensional video motion analysis. A graded treadmill test was used to assess walking performance and peak physiological responses to exercise. Physical activity levels were measured via a 7-day pedometer recording. Differences between groups were analyzed via repeated measures analysis of variance (ANOVA). RESULTS The 12-month supervised exercise program had no significant effect on lower limb mobility, peak physiological responses, or physical activity levels in TPAD-IC compared with CPAD-IC participants. However, the TPAD-IC participants demonstrated significantly greater walking performance (171% improvement in pain free walking time and 120% improvement in maximal walking time compared with baseline). CONCLUSION The results of this study confirm that a 12-month supervised exercise program will result in improved walking performance, but does not have an impact on lower limb mobility, peak physiological responses, or physical activity levels of PAD-IC patients.

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.

Effects of a 6-month exercise program pilot study on walking economy, peak physiological characteristics, and walking performance in patients with peripheral arterial disease

The purpose of this study was to examine the effects of a 6-month exercise program on submaximal walking economy in individuals with peripheral arterial disease and intermittent claudication (PAD-IC). Participants (n = 16) were randomly allocated to either a control PAD-IC group (CPAD-IC, n = 6) which received standard medical therapy, or a treatment PAD-IC group (TPAD-IC; n = 10) which took part in a supervised exercise program. During a graded treadmill test, physiological responses, including oxygen consumption, were assessed to calculate walking economy during submaximal and maximal walking performance. Differences between groups at baseline and post-intervention were analyzed via Kruskal–Wallis tests. At baseline, CPAD-IC and TPAD-IC groups demonstrated similar walking performance and physiological responses. Postintervention, TPAD-IC patients demonstrated significantly lower oxygen consumption during the graded exercise test, and greater maximal walking performance compared to CPAD-IC. These preliminary results indicate that 6 months of regular exercise improves both submaximal walking economy and maximal walking performance, without significant changes in maximal walking economy. Enhanced walking economy may contribute to physiological efficiency, which in turn may improve walking performance as demonstrated by PAD-IC patients following regular exercise programs.

Lower limb movement variability in patients with peripheral arterial disease

BACKGROUND Peripheral arterial disease is a chronic obstructive disease of the arteries of the lower limb caused by atherosclerosis. The resultant decrease in blood flow can result in symptoms of pain in the lower limb on exercise known as intermittent claudication. Exercise induced pain is experienced in the calves, thigh or buttocks restricting activities of daily living and thus reducing quality of life. METHODS This study investigated lower limb movement variability in individuals with peripheral arterial disease-intermittent claudication (n=28) compared to individuals without peripheral arterial disease-intermittent claudication (control, n=25). A further aim was to examine the efficacy of various techniques used to describe single joint movement variability. All participants underwent two-dimensional angular kinematics analysis of the lower limb during normal walking. Single joint movement variability was measured using linear (spanning set and coefficient of variation) techniques. Between group differences were examined by one-way ANOVA. FINDINGS The peripheral arterial disease-intermittent claudication participants displayed significantly higher levels of lower limb movement variability in all joints when assessed using the coefficient of variation technique. There were no significant between group differences using the spanning set technique. INTERPRETATION Individuals with peripheral arterial disease-intermittent claudication have higher levels of lower limb movement variability and reduced walking speed compared to healthy age and mass matched controls. This variability may be an adaptation to the gradual onset of ischaemic pain in this population.

The influence of a long term exercise program on lower limb movement variability and walking performance in patients with peripheral arterial disease.

The purpose of this study was to examine the effects of a 12month exercise program on lower limb movement variability in patients with peripheral arterial disease (PAD). Participants (n=21) with an appropriate history of PAD and intermittent claudication (IC) volunteered for this study and were randomly allocated to either a control group (CPAD-IC) (n=11), which received normal medical therapy and a treatment group (TPAD-IC) (n=10), which received normal medical therapy treatment and a 12month supervised exercise program. All participants underwent 2D joint angular kinematic analysis during normal walking to assess lower limb movement variability and walking speed. Between-group differences were analyzed via mixed measures ANOVA. The 12month supervised exercise program made no significant impact on the lower limb movement variability or walking speed of the TPAD-IC group as determined by either intralimb joint coordination or single joint analysis techniques. Long term supervised exercise programs do not appear to influence the lower limb movement variability of PAD-IC patients.

Comparison of physiological responses to graded exercise test performance in outrigger canoeing

Abstract The aim of this study was to establish a graded exercise test protocol for determining the peak physiological responses of female outrigger canoeists. Seventeen trained female outrigger canoeists completed two outrigger ergometer graded exercise test protocols in random order: (1) 25 W power output for 2 min increasing by 7.5 W every minute until exhaustion; and (2) 25 W power output for 2 min increasing by 15 W every 2 min to exhaustion. Heart rate and power output were recorded every 15 s. Expired air was collected continuously and sampled for analysis at 15-s intervals, while blood lactate concentration was measured immediately after and 3, 5, and 7 min after exercise. The peak physiological and performance variables examined included peak oxygen uptake ([Vdot]O2peak), minute ventilation, tidal volume, ventilatory thresholds 1 and 2, respiratory rate, respiratory exchange ratio, heart rate, blood lactate concentration, power output, performance time, and time to [Vdot]O2peak. There were no significant differences in peak physiological responses, ventilatory thresholds or performance variables between the two graded exercise test protocols. Despite no significant differences between protocols, due to the large limits of agreement evident between protocols for the peak physiological responses, it is recommended that the same protocol be used for all comparison testing to minimize intra-individual variability of results.

Identification and reliability of pacing strategies in outrigger canoeing ergometry

This study examined the pacing strategies utilised; and the performance reproducibility during repeated outrigger canoeing ergometer time trials. Trained female outrigger canoeists (N=11) completed four 1000m outrigger canoe ergometer time trials. There was a significant 1.5% improvement in 1000m time in trial four compared to trial one. A fast start strategy was adopted in 36 of the 44 trials (82%) followed by a deceleration during the mid stages. As trials progressed there was an increased adoption of negative pacing (fast finish) between the last two splits, indicating a learning effect of pacing strategy across repeated trials. These results demonstrate that although some performance improvement was evident between the first and fourth time trials, the 1000m outrigger ergometer time trial is a reliable test that may be used as a tool to assist with crew selection and performance monitoring. Further, on account of the variation in pacing strategy noted in the fourth trial, the authors recommend utilising one familiarisation session and one test session when assessing performance such that learning or training adaptations resulting from multiple trials do not impact on results.

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 a 12-month exercise program on cardiorespiratory health indicators of Vietnam War veterans resident in the tropics.

OBJECTIVE To measure the effect of a combined aerobic and resistance exercise program on key cardiovascular disease risk factors (i.e. body composition or anthropometry and cardiorespiratory function) of Australian male, Vietnam War veterans living in the tropics. DESIGN Twelve-month exercise program with assessments at commencement, 3, 6 and 12 months. SETTING North Queensland regional centre. PARTICIPANTS Australian male, Vietnam War veterans (n = 164) resident in north Queensland. MAIN OUTCOME MEASURES Measurement of heart rate, blood pressure, skinfold and girth measurements, exercise heart rate response and estimated aerobic capacity to determine whether the implementation of a simple aerobic and resistance exercise program could positively change selected cardiovascular disease risk factors in Vietnam Veterans. RESULTS Significant improvements were reported for systolic blood pressure (131.1 (SD 15.7) reduced to 122.7 (12.4) mmHg), diastolic blood pressure (82.7 (9.1) reduced to 76.3 (10.3) mmHg), resting heart rate (73 (11) reduced to 69 (11) bpm), sum of skinfolds (127.5 (40.3) reduced to 99.5 (32.1) mm), waist girth (103.2 (12.0) reduced to 100.5 (12.1) cm), hip girth (105.3 (9.6) reduced to 103.7 (10.4) cm) and aerobic capacity (2.17 (0.39) increased to 2.36 (0.34) L min(-1)). CONCLUSION Participation in a combined aerobic and resistance training program elicited significant anthropometric and cardiorespiratory benefits that might lead to a decreased risk of developing cardiovascular disease for male Vietnam War veterans resident in rural and regional areas.

Effect of shoulder angle on physiological responses during incremental peak arm crank ergometry

Abstract This study examined the effect of shoulder angle and gender on physiological and perceptual responses during incremental peak arm ergometry. Healthy adults (nine males, seven females) volunteered for the study and completed an incremental arm ergometry test on two separate occasions at two different shoulder angles (90° and 45°). Initial work rate was set at 16 W · min−1 and was increased progressively until exhaustion. Cardiorespiratory and perceptual responses were recorded at the end of each minute and compared using separate three-way (position × work rate × gender) repeated-measures analyses of variance. The systematic bias of peak responses was examined using separate two-way (position × gender) analyses of variance, while reproducibility of these parameters was explored using intraclass correlation coefficients, measurement bias/ratio, and 95% ratio limits of agreement. Despite a significantly greater peak heart rate for the 45° position, cardiorespiratory and perceptual responses were similar at peak exercise for both positions. Peak values for all variables, although similar, demonstrated similar and large inter-test variability for men and women. Reduction of the shoulder joint angle to 45° did not enhance peak work rate and peak oxygen consumption during seated upper body exercise. Due to the large inter-test variability, arm ergometry should be conducted using the same seated position.