The development of an accreditation scheme for accredited exercise physiologists

Background: Accredited Exercise Physiologists provide exercise services for people living with chronic disease, disability or injury and are recognised in Australia as Accredited Exercise Physiologists (AEP) under a national certification system administered by Exercise and Sport Science Australia (ESSA). A major breakthrough occurred for the AEP in 2006 when the Australian Department of Health and Ageing approved the AEP to deliver clinical exercise services for people with chronic medical conditions under the taxpayer-funded national health scheme, Medicare Australia.

Aims: In light of these developments, the authors recognised the need for new accreditation criteria, and our report summarises the work that we did on behalf of the profession and ESSA in restructuring the accreditation system.

Methods and Outcomes: We first performed a background study that defined the scope of practice of the AEP and benchmarked the AEP against other allied health professions in Australia and Clinical Exercise Physiologists internationally. We then constructed a new set of accreditation criteria comprising sets of pathologyspecific knowledge and experiences, together with a set of generic standards including communication, professional behaviour and risk management. All participating Australian universities (18 out of 27 responded) and 29 practitioner experts were then invited to provide comment and input into the draft guidelines. There was strong support for the new system that was implemented nationally on 1 January 2008 and is now administered by ESSA.

Conclusions: This work has stimulated an unprecedented level of activity in the Australian university sector in developing new curricula in clinical exercise science and practice, and is intended to lead to improved standards of clinical exercise practice.

Improving the precision of the accumulated oxygen deficit using VO2-power regression points from below and above the lactate threshold

The accumulated oxygen deficit (AOD) method assumes a linear VO₂-power relationship for exercise intensities increasing from below the lactate threshold (BLT) to above the lactate threshold (ALT). Factors that were likely to effect the linearity of the VO₂-power regression and the precision of the estimated total energy demand (ETED) were investigated. These included the slow component of VO₂ kinetics (SC), a forced resting y-intercept and exercise intensities BLT and ALT. Criteria for linearity and precision included the Pearson correlation coefficient (PCC) of the VO₂-power relationship, the length of the 95% confidence interval (95% CI) of the ETED and the standard error of the predicted value (SEP), respectively. Eight trained male and one trained female triathlete completed the required cycling tests to establish the AOD when pedalling at 80 rev/min. The influence of the SC on the linear extrapolation of the ETED was reduced by measuring VO₂ after three min of exercise. Measuring VO₂ at this time provided a new linear extrapolation method consisting of ten regression points spread evenly from BLT and ALT. This method produced an ETED with increased precision compared to using regression equations developed from intensities BLT with no forced y-intercept value; (95%CI (L), 0.70±0.26 versus 1.85±1.10, P<0.01; SEP(L/Watt), 0.07±0.02 versus 0.28±0.17; P<0.01). Including a forced y-intercept value with five regression points either BLT or ALT increased the precision of estimating the total energy demand to the same level as when using 10 regression points, (5 points BLT + y-intercept versus 5 points ALT + y-intercept versus 10 points; 95%CI(l), 0.61±0.32, 0.87±0.40, 0.70±0.26; SEP(L/Watt), 0.07±0.03, 0.08±0.04, 0.07±0.02; p>0.05). The VO₂-power regression can be designed using a reduced number of regression points... ABSTRACT FROM AUTHOR

Cycling at 120 when compared to 80 rev/min increases the accumulated oxygen deficit but does not affect the precision of its calculation

The aim of the present study was to determine the influence of pedal rate on the precision and quantification of the accumulated oxygen deficit (AOD). Eight trained male triathletes completed a lactate threshold test, VO2 peak test, 10 x 3 min submaximal exercise bouts and a high-intensity exercise bout, all performed at 80 and 120 rev/min. For both pedal rates the intensities for the sub-maximal and high-intensity tests were relative to the lactate threshold and VO2 peak work rates. The VO2-power regressions were calculated using 5 intensities from above the lactate threshold combined with a y intercept value with VO2 measured after 3 min of exercise. For the 120 compared to the 80 rev/min tests, the lactate threshold work rate (255±13 versus 276±47 Watts) (p<0.01) and VO2 peak work rate (352±17 versus 382±20, Watts) (p<0.05) were lower at 120 rev/m. Conversely, the VO2 peak and the VO2 measured during the exhaustive exercise were the same for both pedal rates (p>0.05). Using linear regression modelling the slope of the VO2-power regression (0.0112 versus 0.010 L/Watt) (p<0.01), the estimated total energy demand (ETED) (5.13±0.75 versus 4.89±0.88 L/min) and the AOD (4.27±0.94 versus 3.66±1.25 L) (p<0.05) were greater at 120 rev/m. However, the 95% confidence interval for the ETED and the standard error of the predicted value were the same for both pedal rates (p>0.05). Our results demonstrate that pedal rate effects the size but not the precision of the calculated AOD and should therefore be considered when developing an AOD protocol.

UV-induced DNA damage promotes resistance to the biotrophic pathogen Hyaloperonospora parasitica in Arabidopsis

Plant innate immunity to pathogenic microorganisms is activated in response to recognition of extracellular or intracellular pathogen molecules by transmembrane receptors or resistance proteins, respectively. The defense signaling pathways share components with those involved in plant responses to UV radiation, which can induce expression of plant genes important for pathogen resistance. Such intriguing links suggest that UV treatment might activate resistance to pathogens in normally susceptible host plants. Here, we demonstrate that pre-inoculative UV (254 nm) irradiation of Arabidopsis (Arabidopsis thaliana) susceptible to infection by the biotrophic oomycete Hyaloperonospora parasitica, the causative agent of downy mildew, induces dose- and time-dependent resistance to the pathogen detectable up to 7 d after UV exposure. Limiting repair of UV photoproducts by postirradiation incubation in the dark, or mutational inactivation of cyclobutane pyrimidine dimer photolyase, (6-4) photoproduct photolyase, or nucleotide excision repair increased the magnitude of UV-induced pathogen resistance. In the absence of treatment with 254-nm UV, plant nucleotide excision repair mutants also defective for cyclobutane pyrimidine dimer or (6-4) photoproduct photolyase displayed resistance to H. parasitica, partially attributable to short wavelength UV-B (280–320 nm) radiation emitted by incubator lights. These results indicate UV irradiation can initiate the development of resistance to H. parasitica in plants normally susceptible to the pathogen and point to a key role for UV-induced DNA damage. They also suggest UV treatment can circumvent the requirement for recognition of H. parasitica molecules by Arabidopsis proteins to activate an immune response.

Use of high resolution digital multi-spectral imagery to assess the distribution of disease caused by Phytophthora cinnamomi on heathland at Anglesea, Victoria

Disease caused by the soilborne plant pathogen Phytophthora cinnamomi causes long-term floristic and structural changes in native vegetation communities in Australia. Key components of the management of this disease are to know where it occurs and the rate at which it spreads. The distribution of P. cinnamomi has generally been assessed as locality points of infestation and mapping the extent of diseased vegetation in any area is difficult and costly. This study was undertaken in P. cinnamomi-infested heathland communities in southern Victoria, Australia, where the symptoms of P. cinnamomi arise as a mosaic within healthy vegetation. We investigated the potential to improve the efficiency and effectiveness of mapping and monitoring vegetation affected by P. cinnamomi using digital multi-spectral imaging. This technique was developed for the purposes of monitoring vegetation and provides a single, seamless ortho-rectified digital image over the total area of interest. It is used to spatially quantify small differences in the characteristics of vegetation. In this study, the symptoms of disease caused by P. cinnamomi infestation were related to differences in the imagery and were used to map areas of infestation. Comparison of the digital multi-spectral imaging indications with on-ground observations gave moderate accuracy between the datasets (κ = 0.49) for disease and healthy indications. This study demonstrates the ability of the technique to determine disease extent over broad areas in native vegetation and provides a non-invasive, cost effective tool for management.

Heterotrimeric G proteins facilitate arabidopsis resistance to necrotrophic pathogens and are involved in jasmonate signaling

Heterotrimeric G proteinshave been previously linked to plant defense; however a role for the Gbg dimer in defense signaling has not been described to date. Using available Arabidopsis (Arabidopsis thaliana) mutants lacking functional Ga or Gb subunits, we show that defense against the necrotrophic pathogens Alternaria brassicicola and Fusarium oxysporum is impaired in Gb-deficient mutants while Ga-deficient mutants show slightly increased resistance compared to wild-type Columbia ecotype plants. In contrast, responses to virulent (DC3000) and avirulent (JL1065) strains of Pseudomonas syringae appear to be independent of heterotrimeric G proteins. The induction of a number of defense-related genes in Gb-deficient mutants were severely reduced in response to A. brassicicola infection. In addition, Gb-deficient mutants exhibit decreased sensitivity to a number of methyl jasmonate-induced responses such as induction of the plant defensin gene PDF1.2, inhibition of root elongation, seed germination, and growth of plants in sublethal concentrations of methyl jasmonate. In all cases, the behavior of the Ga-deficient mutants is coherent with the classic heterotrimeric mechanism of action, indicating that jasmonic acid signaling is influenced by the Gbg functional subunit but not by Ga. We hypothesize that Gbg acts as a direct or indirect enhancer of the jasmonate signaling pathway in plants.

Comparing methods for prescribing exercise for individuals with chronic heart failure

This study examined the accuracy of current recommended guidelines for prescribing exercise intensity using the methods of percentage of heart rate reserve (%HRR), percentage of VO₂ peak (%VO₂peak) and percentage of VO₂ reserve (%VO₂R) in a clinical population of chronic heart failure (CHF) patients. The precision of prescription of exercise intensity for 45 patients with stable CHF (39:6 M:F, 65±9 yrs (mean±SD)) was investigated. VO₂peak testing is relatively common among patients with cardiac disease, but the assessment of VO₂rest is not common practice and the accepted standard value of 3.5 mL/kg/min is assumed in the application of %VO2R (%VO₂R_3.5). In this study, VO₂rest was recorded for 3 min prior to the start of a symptom-limited exercise test on a cycle ergometer. Target exercise intensities were calculated using the VO₂ corresponding to 50 or 80 %HRR, VO₂peak and VO₂R. The VO₂ values were then converted into prescribed speeds on a treadmill in km/hr at 1 %grade using ACSM’s metabolic equation for walking. Target intensities and prescribed treadmill speeds were also calculated with the %VO₂R method using the mean VO₂rest value of participants (3.9 mL/kg/min) (%VO₂R_3.9). This was then compared to the exercise intensities and prescribed treadmill speeds using patient’s measured VO₂rest. Error in prescription correlates the difference between %VO₂R_3.5 and %VO₂R_3.9 compared to %VO₂R with measured VO₂rest. Prescription of exercise intensity through the %HRR method is imprecise for patients on medications that blunt the HR response to exercise. %VO₂R method offers a significant improvement in exercise prescription compared to %VO₂peak. However, a disparity of 10 % still exists in the %VO₂R method using the standard 3.5 mL/kg/min for VO₂rest in the %VO₂R equation. The mean measured VO₂rest in the 45 CHF patients was 11 % higher (3.9±0.8 mL/kg/min) than the standard value provided by ACSM. Applying the mean measured VO₂rest value of 3.9 mL/kg/min rather than the standard assumed value of 3.5 mL/kg/min proved to be closer to the prescribed intensity determined by the actual measured resting VO₂. These results suggest that the %HRR method should not be used to prescribe exercise intensity for CHF patients. Instead, VO₂ should be used to prescribe exercise intensity and be expressed as %VO₂R with measured variables (VO₂rest and VO₂peak).

Forearm blood flow in individuals with CHF and age-matched healthy volunteers : a study and historical review

This study examined forearm blood flow (FBF) in individuals with chronic heart failure (CHF) at rest, moderate exercise, and following limb occlusion. FBF was measured by venous occlusion plethysmography in CHF patients (n = 43) and healthy age-matched volunteers (n = 8) at rest and during exercise consisting of intermittent isometric hand squeezing at 15, 30, and 45% of maximum voluntary contraction (MVC). Peak vasodilatory capacity was also determined following the release of an occluding arm cuff. FBF was lower in CHF patients during exercise and during peak reactive hyperemia (PRH) compared to healthy volunteers, but there was no significant difference between groups at rest. Peak vasodilatory capacity was significantly higher in healthy volunteers than the CHF group ((30.6 ± 8.6 ml±100 mL^-1±min^-1 and 18.3 ± 6.9 ml±100 mL^-1±min^-1, respectively). Local blood flow stimulation in response to exercise or limb occlusion is reduced in individuals with CHF, however, there was no difference in resting flows between the two groups, suggesting vasodilatory medication may restore resting blood flow to healthy values.

A combined strength and balance exercise program to decrease falls risk in dialysis patients : a feasibility study

People suffering end-stage kidney disease receiving hemodialysis have a greater risk of falling and suffering debilitating injuries. The purpose of this study was to examine the feasibility and impact of a combined strength and balance exercise intervention on falls risk in hemodialysis patients. Twenty-four adults (mean age = 67.8 yrs) from two Australian outpatient hemodialysis clinics completed the intervention. Falls risk was measured using the Physiological Profile Assessment (PPA). There was a significant reduction in the median overall falls risk z-score from 1.67 to .52 (z = -3.11, P<.008; r = .45). Median reaction time improved from .30 to .26 sec (z = -2.86, P<.008; r = .41). A strength and balance intervention to reduce the falls risk for dialysis patients is feasible and may reduce falls risk for at risk patients.

Ecophysiology of avian migration in the face of current global hazards

Long-distance migratory birds are often considered extreme athletes, possessing a range of traits that approach the physiological limits of vertebrate design. In addition, their movements must be carefully timed to ensure that they obtain resources of sufficient quantity and quality to satisfy their high-energy needs. Migratory birds may therefore be particularly vulnerable to global change processes that are projected to alter the quality and quantity of resource availability. Because long-distance flight requires high and sustained aerobic capacity, even minor decreases in vitality can have large negative consequences for migrants. In the light of this, we assess how current global change processes may affect the ability of birds to meet the physiological demands of migration, and suggest areas where avian physiologists may help to identify potential hazards. Predicting the consequences of global change scenarios on migrant species requires (i) reconciliation of empirical and theoretical studies of avian flight physiology; (ii) an understanding of the effects of food quality, toxicants and disease on migrant performance; and (iii) mechanistic models that integrate abiotic and biotic factors to predict migratory behaviour. Critically, a multi-dimensional concept of vitality would greatly facilitate evaluation of the impact of various global change processes on the population dynamics of migratory birds.

Energy metabolism and animal personality

In this paper we show how animal personality could explain some of the large inter-individual variation in resting metabolic rate (MR) and explore methodological and functional linkages between personality and energetics. Personality will introduce variability in resting MR measures because individuals consistently differ in their stress response, exploration or activity levels, all of which influence MR measurements made with respirometry and the doubly-labelled water technique. Physiologists try to exclude these behavioural influences from resting MR measurements, but animal personality research indicates that these attempts are unlikely to be successful. For example, because reactive animals “freeze” when submitted to a stress, their MR could be classified as “resting” because of immobility when in fact they are highly stressed with an elevated MR. More importantly, recent research demonstrating that behavioural responses to novel and highly artificial stimuli are correlated with both behaviour and fitness under more natural circumstances calls into question the wisdom of excluding these behavioural influences on MR measurements. The reason that intra-specific variation in resting MR are so weakly correlated with daily energy expenditure (DEE) and fitness, may be that the latter two measures fully incorporate personality while the former partially excludes its influence. Because activity, exploration, boldness and aggressiveness are energetically costly, personality and metabolism should be correlated and physiological constraints may underlie behavioural syndromes. We show how physiological ecologists can better examine behavioural linkages between personality and metabolism, as required to better understand the physiological correlates of personality and the evolutionary consequences of metabolic variability.

The impact of an exercise physiologist coordinated resistance exercise program on the physical function of people receiving hemodialysis: a stepped wedge randomised control study

Background:

Recommendations for improved data processing from expired gas analysis indirect calorimetry

There is currently no universally recommended and accepted method of data processing within the science of indirect calorimetry for either mixing chamber or breath-by-breath systems of expired gas analysis. Exercise physiologists were first surveyed to determine methods used to process oxygen consumption ([OV0312]O 2) data, and current attitudes to data processing within the science of indirect calorimetry. Breath-by-breath datasets obtained from indirect calorimetry during incremental exercise were then used to demonstrate the consequences of commonly used time, breath and digital filter post-acquisition data processing strategies. Assessment of the variability in breath-by-breath data was determined using multiple regression based on the independent variables ventilation (VE), and the expired gas fractions for oxygen and carbon dioxide, FEO 2 and FECO2, respectively. Based on the results of explanation of variance of the breath-by-breath [OV0312]O2 data, methods of processing to remove variability were proposed for time-averaged, breath-averaged and digital filter applications. Among exercise physiologists, the strategy used to remove the variability in sequential [OV0312]O2 measurements varied widely, and consisted of time averages (30 sec [38%], 60 sec [18%], 20 sec [11%], 15 sec [8%]), a moving average of five to 11 breaths (10%), and the middle five of seven breaths (7%). Most respondents indicated that they used multiple criteria to establish maximum [OV0312]O 2 ([OV0312]O2max) including: the attainment of age-predicted maximum heart rate (HRmax) [53%], respiratory exchange ratio (RER) >1.10 (49%) or RER >1.15 (27%) and a rating of perceived exertion (RPE) of >17, 18 or 19 (20%). The reasons stated for these strategies included their own beliefs (32%), what they were taught (26%), what they read in research articles (22%), tradition (13%) and the influence of their colleagues (7%). The combination of VE, FEO 2 and FECO2 removed 96-98% of [OV0312]O2 breath-by-breath variability in incremental and steady-state exercise [OV0312]O2 data sets, respectively. Correction of residual error in [OV0312]O2 datasets to 10% of the raw variability results from application of a 30-second time average, 15-breath running average, or a 0.04 Hz low cut-off digital filter. Thus, we recommend that once these data processing strategies are used, the peak or maximal value becomes the highest processed datapoint. Exercise physiologists need to agree on, and continually refine through empirical research, a consistent process for analysing data from indirect calorimetry.