Warwick L Spinks’s research while affiliated with James Cook University and other places

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.

In this study, we assessed the reliability of the portable Cosmed K4b^2 and the laboratory-based Powerlab 8M gas analysis systems for measuring peak physiological variables during sport-specific, upper-body exercise, to determine the error associated with repeated physiological performance tests. Ten trained female outrigger canoeists compelted two 1000-m ergometer time trials using each gas analysis system. Peak physiological responses were analysed using a two-way repeated measures analysis of variance and post hoc Tukey HSD tests. Reliability and within participant variability of peak responses were assessed using intraclass correlation coefficients (ICC) and measurement bias/ratios with 95% limits of agreement (LOA), respectively. Performance and peak physiological responses were similar across trials for each individual system, although the Powerlab 8M reported 13.6% significantly higher VCO2 and 7.4% non-significantly higher VO2 than the Cosmed K4b^2. Reliability of the Cosmed K4b^2 was high for VCO2 (0.98) and moderate for VE (0.85), whereas that for the Powerlab 8M was high for VCO2 (0.97) and tidal volume (0.94) and moderate for VO2 (0.87). Overall, the two systems report similar VO2 variability (8-9%) with the Powerlab 8M reporting higher VO2 and VCO2 values than the Cosmed K4b2. Therefore, while each system is reliable, results from each of the systems should not be used interchangeably.

The rate of nutrient intake (RNI) is a primary determinant of animal performance in grazing cattle and depends on both diet quality and instantaneous intake rate (IIR). In turn, diet quality and IIR are a function of the foraging behaviour of the animal (selectivity, bite mass and bite rate) and the characteristics of the sward. In this study we evaluated the effect of the stem density and the tensile resistance of stems on the foraging behaviour of cattle grazing tropical pasture species. The methodology involved the use of small sown microswards offered to tethered cattle. The experiment consisted of a factorial combination of five tropical grasses [Bothriochloa pertusa (Bp), Chloris barbata (Cb), Chloris gayana (Cg), Cynodon dactylon (Cd) and Heteropogon contortus (Hc)] and three stem densities (0, 400 and 800 stems m(-2)). Bp and Cd had stems of significantly lower tensile resistance (19 and 15 N respectively) (Group 1) than those of Cb, Cg and Hc (110, 211 and 167 N respectively) (Group 2). The steers avoided stems of Group 2 and thus, reduced bite area, bite mass, IIR and RNI as stem density increased. However, the animals did not avoid stems of Group 1 and there was no effect of stem density on any of the foraging behaviour variables when cattle grazed species in Group 1. These results confirm that RNI and plant part selection is closely associated with the tensile resistance of the stem.

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.

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.

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.