Maximal Treadmill Research Articles

Changes in physical fitness in moderately fit adults with and without the use of exercise telemetry monitors

One of the goals of exercise prescription is the use of easily understandable physical activities to improve physical fitness. Lack of study designs investigating self-administered programs utilizing exercise telemetry monitors (ETM) compared to a no exercise telemetry monitors (NETM) guided exercise programs exist. The aim of the study was to determine whether the ETM programs improve physical fitness more than NETM programs and to measure differences between males and females. Fifty-one adults were randomly divided into either the ETM group (n = 34, age = 37.9 +/- 5.0 years, BMI = 24.6 +/- 3.0, VO(2) = 37.9 +/- 7.7 ml kg(-1) min(-1)) or the NETM group (n = 27, age = 39.6 +/- 5.5 years, BMI = 24.5 +/- 4.2, VO(2) = 40.8 +/- 6.5 ml kg(-1) min(-1)). All subjects completed a maximal incremental treadmill test to determine their submaximal and maximal running performance, oxygen uptake (VO(2)peak, VO(2-AT), VO(2-70%), km h(-1) peak, km h(-1) (AT), km h(-1) (70%)) before and after 10 weeks of an unsupervised exercise program. All exercise sessions for ETM and NETM groups were individually recorded and analyzed. Multivariate analysis of variance revealed that running performance at anaerobic threshold increased significantly in ETM vs. NETM groups (P <or= 0.03). Males in the ETM group improved significantly in all variables of VO(2), and in km h(-1) (AT) after 10 week. No significant differences in VO(2) were found for female groups. Based on the exercise records, women in the NETM group completed significantly more sessions (P <or= 0.03), specifically more moderately intense sessions (P <or= 0.02), compared to the ETM-female group. Males did not differ in total exercise sessions; however, ETM-men completed significantly more light sessions (P <or= 0.01) compared to men in NETM. Running was the activity of choice. After 10 weeks of telemetry monitor prescribed exercise program, only men, but not women, improved in physical fitness.

Longitudinal Changes in Heart Rate Recovery After Maximal Exercise in Pediatric Heart Transplant Recipients: Evidence of Autonomic Re-innervation?

Cardiac autonomic innervation modulates heart rate (HR) response during and HR recovery after exercise in normal subjects. Heart transplantation results in surgical interruption of autonomic innervation. We assessed whether HR response during exercise and HR recovery after exercise in pediatric heart transplant recipients are consistent with autonomic denervation of the heart after transplant and whether they evolve over years in a manner consistent with autonomic re-innervation. We compared HR response during and HR recovery after a maximum treadmill exercise test in 35 children (median age 13.4 years) after a median follow-up of 1 year after heart transplant with two control groups: post-operative Fontan patients (n = 31) and normal children (n = 35). We then analyzed 153 treadmill exercise tests performed serially in 45 heart transplant recipients (median 3 tests/patient) for longitudinal changes in peak HR and HR recovery after exercise. Transplant recipients had higher body mass index, higher resting HR and significantly attenuated 1- and 3-minute HR recovery after cessation of exercise compared with both control groups (p < 0.001). In transplant recipients with serial exercise tests, peak HR increased an average of 2.0 beats/min per year after transplant (p < 0.001), percent predicted peak HR increased by 1.3% per year (p < 0.001), 1-minute HR recovery increased by 1.0 beats/min per year (p < 0.001), and 3-minute HR recovery by 2.6 beats/min per year (p < 0.001). HR response to exercise and HR recovery after exercise in pediatric heart transplant recipients are consistent with autonomic denervation after transplant and suggestive of late autonomic re-innervation of these hearts.

ECT Generalized Seizure Drives Heart Rate Above Treadmill Stress Test Maximum

Heart rate (HR) accelerates with the electroconvulsive therapy (ECT) seizure and decelerates when it ends. The peak HR during ECT seizure has been reported to reflect clinical impact. We aimed to identify the expected range for ECT peak HR and how it varies with age and sex, as a reference in clinical use. We examined medical records for the maximum peak seizure HR over the ECT course for all ECT patients over defined periods at 2 clinical sites. Methohexital-succinylcholine anesthesia was usually used. Subject totals were 87 men and 90 women. Electroconvulsive therapy peak HR was 140 to 180 bpm and did not fall with age through 80 years, separately for men and women. A few patients lay outside this cluster and showed age-related decrease. Overall and including the extreme elderly, peak HR fell by 0.29 bpm/yr. Electroconvulsive therapy seizure peak HR less than 140 bpm points to weakness of the ECT seizure (and need to increase stimulus dose), cardiac disease, or medication effect limiting HR. Electroconvulsive therapy peak HR exceeds treadmill exercise maximum HR after 60 years and falls significantly less with age than the 0.7 to 1 bpm/yr reported for maximum HR with treadmill exercise stress. These comparisons suggest that ECT peak HR and treadmill maximum HR are limited by different aspects of physiology, and that exercise HR is limited by metabolic demand and humoral activity rather than the heart itself.

Routine functional testing after percutaneous coronary intervention: results of the Aggressive Diagnosis of Restenosis in High-Risk Patients (ADORE II) trial

Background — It is unclear whether routine or selective functional testing is optimal following percutaneous coronary intervention (PCI) in high-risk patients.Objectives — The aim of this trial was to compare exercise endurance, functional status, and quality of life (QOL) among high-risk patients randomized to either routine or selective functional testing following PCI.Methods — We randomized 84patients to either routine or selective functional testing. Patients had one or more of the following: multivessel PCI, diabetes mellitus, left ventricular ejection fraction ≤ 35%, and/or PCI of the proximal left anterior descending artery. Patients in the routine arm (n=41) underwent maximum endurance exercise treadmill testing (ETT) with nuclear perfusion imaging at 1.5 and 6months. Patients in the selective arm (n=43) only underwent functional testing for a clinical indication.All patients underwent a maximum endurance ETT at 9months. Exercise endurance, functional status, and QOL were assessed at 9months.Results — Most patients were middle-aged men (58±10years old; 87% male) who underwent PCI with stenting (94%).Among routine functional testing patients, 27.0% and 41.9% had a positive functional test at 1.5 and 6months, respectively. Exercise endurance was improved in the routine vs. selective arm at 9months (metabolic equivalents: 10.3±2.6 vs. 8.6±3.0, P=0.013).There was no difference in improvement from baseline for the Duke Activity Status Index, the Seattle Angina Questionnaire, or the SF-36. Nine-month cumulative incidences of cardiac procedures and clinical events were not significantly different.Conclusions — Routine functional testing following PCI in high-risk patients may lead to improved exercise endurance but not improved QOL.

Effect of type 2 diabetes mellitus on exercise intolerance and the physiological responses to exercise in peripheral arterial disease

There are conflicting data about the effect of type 2 diabetes mellitus on exercise tolerance in peripheral arterial disease. To elucidate this problem, we compared the tolerance and physiological responses to treadmill and cycle exercise in 31 patients with peripheral arterial disease and intermittent claudication. One group of these patients had type 2 diabetes (n = 12) and its members were matched for sex and age with a group of patients who did not have diabetes (n = 12). Since BMI and body weight were greater in the diabetic group (28.4 +/- 3.7 vs 25.2 +/- 2.4 kg/m(2); 84.0 +/- 14.6 vs 73.8 +/- 8.0 kg), we also studied a third, 'heavy' group of non-diabetic patients with claudication of similar age (n = 7; BMI = 30.9 +/- 5.3 kg/m(2); body weight = 85.2 +/- 8.2 kg). Compared with the 'light' non-diabetic group, maximum treadmill times were shorter for the diabetic and heavy non-diabetic groups (1,448 vs 845 and 915 s; ANOVA p = 0.01); maximum cycle time also tended to be shorter (ANOVA, p = 0.08) in the diabetic and heavy non-diabetic groups (median = 1,231 vs 730 and 797 s). The majority of physiological responses assessed were not different between the groups, although the time constant of oxygen uptake during submaximal treadmill and cycle exercise was significantly larger (ANOVA p < 0.05) for the diabetic group. These data demonstrate that exercise tolerance is lower in diabetic than non-diabetic patients with claudication, but that this difference is due to obesity rather than diabetes itself.

Comparison of Cardiorespiratory Responses of Moderately Trained Men and Women Using Two Different Treadmill Protocols

In practice, the Bruce protocol is the most commonly used treadmill protocol to assess maximal oxygen consumption (V(.-)O2max). It has been suggested that a running protocol (e.g., Astrand) may elicit a comparatively higher V(.-)O2max and different cardiorespiratory responses when applied to moderately trained runners. Thus, the purpose of this study was to compare V(.-)O2max and other cardiorespiratory responses as elicited by the standard Bruce and a modified Astrand treadmill protocol in moderately trained runners. Fifteen women (age = 21 years, height = 171.5 cm, weight = 63 kg, and body fat = 18%) and 15 men (age = 26 years, height = 177 cm, weight = 72 kg, and body fat = 9%) who were moderately trained runners completed a standard Bruce and modified Astrand protocol (random order), separated by approximately 7 days. Heart rate, Borg ratings of perceived exertion, blood pressure, and pulmonary gas exchange variables were measured during the exercise tests using standard laboratory procedures. This study revealed V(.-)O2max values between the Bruce protocol (51.3 +/- 11.6 ml x kg(-1) x min(-1)) and modified Astrand (51.5 +/- 10.9 ml x kg(-1) x min(-1)) were not significantly different in either the men or the women. However, the Bruce protocol elicited significantly higher maximum treadmill time in men and maximum respiratory exchange ratio (RERmax) and maximum minute ventilation (VEmax) values in both genders. Conversely, the modified Astrand elicited a higher HRmax. These data suggest that V(.-)O2max in both moderately trained men and women runners is independent of treadmill protocol despite differences in HRmax, RERmax, and VEmax.

Changes over Four Years in Body Composition and Oxygen Uptake of Young Adult Males after University Graduation

Lifestyle changes and challenges following university graduation often present a sharp contrast to the relatively free and basically pleasant university life enjoyed by the typical college student. Adaptation to a new work environment, relocation to a new community, concerns of marriage and family, personal finances, including income and budgeting (automobile and mortgage payments, savings, etc.), and adjustment to independent living result in an unfamiliar schedule of duties, often too sedentary in nature. The aim of this study was to analyse the changes observed in young working professionals by comparing selected body composition estimates, and physiological working capacity variables at the time of university graduation and four years later. Anthropometric and functional cardio-respiratory exercise test data were collected in 26 physically active (but non-athletic) volunteer males at the time of their university graduation in 2000 and 4 years later in 2004. By the end of this four-year period body weight, body mass index (BMI), the sum of 5 skinfold thicknesses, and relative body fat content increased significantly. Both mean BMI and weight-related body fat content were within the categorized risk range at the time of the second data collection. Parallel with unfavourable changes in body composition, peak minute ventilation, aerobic power, oxygen pulse, and maximum treadmill running distance had decreased significantly during this time. We attributed the significant changes observed mainly to the dramatically changed lifestyle. The subjects could not maintain their previous level of habitual physical activity.

Metabolic Demands of “Junkyard” Training: Pushing and Pulling a Motor Vehicle

Junkyard training involves heavy, cumbersome implements and nontraditional movement patterns for unique training of athletes. This study assessed the metabolic demands of pushing and pulling a 1,960-kg motor vehicle (MV) 400 m in an all-out maximal effort. Six male, strength-trained athletes (29 +/- 5 years; 89 +/- 12 kg) completed 3 sessions. Sessions 1 and 2 were randomly assigned and entailed either pushing or pulling the MV. Oxygen consumption (VO(2)) and heart rate (HR) were measured continuously. Blood lactate was sampled immediately prior to and 5 minutes after sessions 1 and 2. Vertical jump was assessed immediately prior to and after sessions 1 and 2. During session 3 a treadmill VO(2)max test was conducted. No significant differences (p < 0.05) in VO(2), HR, or blood lactate occurred between pushing and pulling efforts. VO(2) and HR peaked in the first 100 m, and from 100 m on, VO(2) and HR averaged 65% and 96% of treadmill maximum values (VO(2)max = 50.3 ml x kg(-1) x min(-1); HRmax = 194 b x min(-1)). Blood lactate response from the push and pull averaged 15.6 mmol.L(-1), representing 131% of the maximal treadmill running value. Vertical jump decreased significantly pre to post in both conditions (mean = -10.1 cm, 17%). All subjects experienced dizziness and nausea. In conclusion, a 400-m MV push or pull is an exhausting training technique that requires a very high anaerobic energy output and should be considered an advanced form of training. Strength coaches must be aware of the ultra-high metabolic and neuromuscular stresses that can be imposed by this type of training and take these factors into consideration when plotting individualized training and recovery strategies.

Soleus, plantaris and gastrocnemius VEGF mRNA responses to hypoxia and exercise are preserved in aged compared with young female C57BL/6 mice

In humans, skeletal muscle capillarization and the vascular endothelial growth factor (VEGF) mRNA response to acute exercise are lower in aged compared with young. The exercise-induced increase in VEGF mRNA has been proposed to involve hypoxic regulation of VEGF and is believed to be fibre type-dependent. We hypothesized that attenuated VEGF mRNA responses to hypoxia and exercise with advanced age would be greatest in oxidative vs. glycolytic muscles. 3- and 24-month-old female C57BL/6 mice were exposed to acute hypoxia (FI O2 = 0.06) or performed a single exercise (65% of maximum treadmill running speed) bout. Capillarization and VEGF mRNA were analysed in the soleus, plantaris and gastrocnemius muscles. In each muscle, VEGF mRNA was greater in aged compared with young, while the VEGF mRNA response to acute hypoxia or acute exercise was similar between young and aged. Morphological analysis revealed that type IIA fibre percentage and type IIB capillarization in the plantaris were greater and type IIB fibre cross-sectional area (FCSA) in the gastrocnemius was smaller in aged compared with young. These findings suggest that ageing does not impair the potential for non-pathological angiogenesis in mice and that acute exercise increases VEGF mRNA in the soleus, plantaris and gastrocnemius muscles, which differ considerably in fibre type percentage.

Validation of Anaerobic Threshold Detection Based on the HR Kinetics

Since the theorization of the anaerobic threshold (AT), several direct and indirect methods have been developed for its detection. Based on the pioneer work of Sietsema (1989) about the heart rate (HR) kinetics, it has been hypothesized that a slow component on the HR kinetics, superimposing the workload requisition, would appear during supra-AT exercises which would not be true for low intensities. PURPOSE: to detect the AT based on the HR kinetics during step workload and validate it through lactacidemy measurement. METHODS: Twenty six male soccer athletes (22±5yrs; 74±7Kg; 177±7cm) completed a progressive maximum treadmill test (Bruce protocol). The HR (Polar S610, Sweden) and the pulmonary gas exchange (VO2000, Aerosport, Brazil) were monitored continuously during all tests, and lactacidemy was measured at each stage. The real AT was characterized by the onset of blood lactate accumulation and, concerning the HR kinetics, was attributed to the point where the HR could not establish steady state, characterizing the slow component. The HR kinetics was analyzed for each workload according to: (1) the coefficients of a double-exponential model (EM) extracted through non linear regression; (2) the coefficient of variation (CV) of HR during the final minute; and (3) the difference between the maximal and minimal HR (AHR) during the last minute. The AT detected by the methods described above was compared through one-way ANOVA (α= 0.05). The HR methods were compared with AT using t-paired Student's Test its reliability was expressed by Bland and Altman method. RESULTS: Volunteers achieved a maximal oxygen uptake (VO2max) averaging 56.1 1±6.35ml.kg-1.min−1, attaining the AT at 71.5±9.9% of the VO2max. All HR-based methods were able to identify the HR slow component resulting, on average, in76.9±15.1,80.6±13.2and68.6±14.9%oftheVO2maxforEM, AHR and CV respectively. Although no significant differences have been found among them, the highest correlations with the AT were attained by EM (0.67% p < 0.05) and CV (0.58%p < 0.05), and further, except for AHR, EM (p=0.44) and CV (p=0.67) were not different from the real AT. CONCLUSION: The HR-based methods were well correlated to AT, presenting acceptable reliability and validity. Besides the large applicability of a HR-based method, the HR kinetics analysis could easily be used for determining the AT.

Does smoking status influence the effect of physical exercise on fibrinolytic function in healthy volunteers?

Exercise has been reported to simultaneously trigger and protect against sudden death, the so-called "The Paradox of Exercise". Differences in fibrinolytic function appear to exist between chronic and acute exercise. The aim of the present study was to assess the fibrinolytic system after strenuous exercise in healthy people and explored the influence of smoking habit. 23 healthy male volunteers were studied (14 non-smokers; 9 current smokers). Citrated plasma blood samples were taken before and 30 minutes after a maximal exercise treadmill test, and levels of tissue type plasminogen activator (t-PA) antigen, plasminogen activator inhibitor (PAI-1) antigen and lipoprotein-a, Lp(a), [all ELISA] were measured as indices of fibrinolytic function. Smokers had higher body mass index and higher heart rate at baseline than non smokers (p = 0.046 and p = 0.001, respectively). At baseline, smokers showed increased plasma Lp(a) levels than non smokers (p = 0.04), with no differences in t-PA and PAI-1 antigen levels. Following the exercise treadmill test, smokers had a shorter exercise duration and lower exercise capacity than non smokers (p = 0.008 and p = 0.004, respectively). This was associated with a reduction in t-PA antigen levels in the whole study population, (p = 0.048) without differences in PAI-1 levels, with no significant differences between smokers and non smokers. Lp(a) levels were also significantly reduced (p = 0.0001). Acute exercise alters plasma tPA antigen and Lp(a) levels, but there was no significant effect of smoking status in healthy subjects.

Effects of exercise on body composition and bone mineral density during lactation

Bone mineral density (BMD) decreases during lactation, therefore, the purpose was to see if exercise could slow this loss. Women were randomized to either exercise group (EG, n=11) [weight bearing aerobic exercise (3d/wk, 45 min/d) and 3d/wk of resistance exercise (direct force on axial skeleton)] or control group (CG, n=13, no exercise). To date, 11 have completed the 16 wk study (EG n=5, CG n=6). Body composition and BMD were measured by dual x-ray absorptiometry at lumbar spine (LS), hip, and total body. Maximal strength and maximal oxygen consumption (VO2max) were determined by 1 repetition maximum and submaximal treadmill test, respectively. Significant differences in change from baseline between CG and EG were observed for LS bone mineral content (BMC) (−7.4 ± 2.4 vs −2.9 ± 1.0%, p<0.01) and LS BMD (−6.9 ± 1.9 vs −4.6 ± 1.1%, p=0.03), respectively. LS area increased by 1.8 ± 1.2% in the EG vs a decrease of −0.6 ± 2.7% in the CG (p=0.09). No significant differences in percent change were seen in total body BMD and total hip BMD. Maximal strength change increased by 23–166% for all exercises in the EG, whereas, the CG increased by 0–14%, except pushups (90%). VO2max increased in both groups (EG = 9.8 ± 7.8, CG = 6.3 ± 4.6%). Percent weight change was −5.3 ± 3.8 and −4.4 ± 4.4% for the CG and EG, respectively. EG women lost more fat mass (−2.1 ± 2.9 vs −1.5 ± 1.7 kg) and less lean body mass (−1.0 ± 1.2 vs −1.9 ± 0.8 kg), however these changes were not significant. These results suggest that resistance and aerobic exercise slow BMC loss and increase bone area of the LS resulting in less loss of BMD during lactation. Supported by NC Agricultural Research Services

Markers of vascular inflammation are associated with the extent of atherosclerosis assessed as angiographic score and treadmill walking distances in patients with peripheral arterial occlusive disease

The importance of inflammation in atherosclerosis is well established in cardiovascular disease. However, limited data exist on the relationship between vascular inflammation and the severity of peripheral arterial occlusive disease (PAD). We investigated the relationship between biochemical markers of vascular inflammation and the diagnostic measures of PAD: ankle-brachial pressure index (ABI), maximum treadmill walking distance and angiographic score. In 127 patients (mean age 66 years; 64% males) with angiographically verified PAD, fasting blood samples were drawn for determination of selected soluble cell adhesion molecules, cytokines and chemokines. Tumor necrosis factor-alpha (TNFalpha), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1) and CD40 ligand (CD40L) were all significantly correlated with the angiographic score (p < 0.05 for all). After adjustment for relevant co-variates, MCP-1 and CD40L remained statistically significant (p < 0.01 for both). IL-6 was, independent of other risk factors, inversely correlated with the maximum treadmill walking distance (p < 0.01). Our cross-sectional study in PAD patients showed that the vascular inflammatory markers MCP-1, CD40L and IL-6 were significantly associated with the extent of atherosclerosis, assessed by angiographic score and maximum treadmill walking distance. These findings indicate that vascular inflammation is implicated in PAD, which might be of importance in future diagnosis and treatment of the disease.

Prothrombotic activity is associated with the anatomical as well as the functional severity of peripheral arterial occlusive disease

The importance of prothrombotic activity in cardiovascular disease has been well established. However, limited data exist on the relationship between prothrombotic activity and the severity of peripheral arterial occlusive disease (PAD). The objective of the present study was to investigate the relationship between markers of haemostasis and the diagnostic measures of PAD: ankle-brachial-index (ABI), maximum treadmill walking distance and angiographic score. In a cross-sectional study of 127 patients (mean age 66 years; 64% males) with angiographically verified PAD, fasting blood samples were drawn, and citrated plasma was obtained for determination of selected haemostatic variables: von Willebrand factor (vWF), thrombomodulin (sTM), thrombin-antithrombin complex (TAT), soluble tissue factor (sTF), tPA antigen (tPAag) and D-dimer were all significantly correlated with the angiographic score (p < 0.05 for all). D-dimer, tPAag and fibrinogen were inversely correlated with the maximum treadmill walking distance, (p < 0.0001, p < 0.04 and p < 0.05, respectively), whereas fibrinogen was the only variable correlating to ABI (r = -0.223, p < 0.05). After adjustment for relevant covariates, D-dimer and TAT remained statistically significantly associated with the angiographic score (p < 0.001), and fibrinogen was, independent of other risk factors, inversely related with both the maximum treadmill walking distance and the ABI (p < 0.01 for both). This rather large study in patients with PAD showed that plasma levels of D-dimer, TAT and fibrinogen significantly predicted the extent of atherosclerosis, evaluated by angiographic score, maximum treadmill walking distance and ABI, respectively. These findings demonstrate a prothrombotic state in PAD patients, which might be of importance in future diagnosis and treatment of the disease.

Association of Muscular Strength with Incidence of Metabolic Syndrome in Men

To examine the association between muscular strength and incidence of metabolic syndrome. Participants were 3233 men (20-80 yr) initially free of metabolic syndrome who had two or more clinical examinations between 1980 and 2003, including baseline muscular strength and cardiorespiratory fitness assessment. Metabolic syndrome was defined according to NCEP-ATP III criteria. Muscular strength was quantified by combining body weight-adjusted one-repetition maximal measures for leg and bench presses. Cardiorespiratory fitness was assessed by maximal treadmill test. A total of 480 men developed metabolic syndrome during a mean follow-up period of 6.7 +/- 5.2 yr. In a Cox regression analysis adjusted for age, the hazard ratios (95% confidence intervals) of metabolic syndrome associated with the incremental categories of muscular strength were 1.00 (referent), 0.88 (0.69-1.12), 0.77 (0.60-0.98), and 0.54 (0.42-0.71), respectively (linear trend P < 0.0001). The inverse trend persisted after adjustment for smoking, alcohol intake, number of baseline metabolic syndrome risk factors, family history of diabetes, hypertension, and premature coronary disease (P = 0.004), but was attenuated (P = 0.06) when further adjusted for cardiorespiratory fitness. Compared with the lowest strength category, the highest strength category was associated with 44 and 39% lower risk (P < 0.05 each) of incident metabolic syndrome among normal weight body mass index (BMI < 25) and overweight or obese (BMI > or = 25) men, respectively. An inverse association of incident rates was also seen within stratum of age (20-39 yr, P < 0.001; 40-49 yr, P < 0.01; and 50+ yr, P < 0.05). Muscular strength was inversely associated with metabolic syndrome incidence, independent of age and body size. Potential benefits of greater muscular strength presumably through resistance exercise training should be considered in primary prevention of metabolic syndrome.

Similarity Of Maximum Ventilatory Quotients For O2 And CO2 Among Women With Lupus And Controls

Background We have previously reported functional aerobic impairment, increased cardiac output and stroke volume, and attenuated arteriovenous oxygen difference (a-vO2) in women who had mild lupus and normal hematocrit. We hypothesize that attenuated muscle oxygen extraction impairs oxidative metabolism in lupus. However, deficits in hemoglobin oxygenation could also limit the widening of a-vO2. Purpose This study was conducted to examine relationships among gas exchange and pulmonary ventilation in women with lupus. Methods Here, we compared the ventilatory equivalents for O2 (Ve/VO2) and CO2 (Ve/VCO2) among women with (n=16) and without (n=16) lupus. These quotients and corollary data were obtained at maximum treadmill exercise. Results Maximum attained Ve/VO2 was 37.38±08.46 in the women with lupus and 37.00±08.16 in the controls. Maximum attained Ve/VCO2 was 33.06±5.36 in the women with lupus and 33.19±04.64 in the controls. Ve/VO2 and Ve/VCO2 were not significantly different for the women with lupus and controls. Maximum attained VO2 (lupus =19.6±04.4 ml/kg/min vs. control = 27.4±04.7 ml/kg/min; p < 0.0001) and maximum widening of a-vO2 (lupus=10.9±02.5 ml/dl vs. control=13.3±01.8 ml/dl; p < 0.0026) were significantly lower in women with lupus than in controls. Conclusion These women with lupus had neither a history of pulmonary impairment nor symptoms of pulmonary complications and were not anemic. Neither the ratio of air ventilated to oxygen consumed nor minute ventilation normalized to expiration of CO2 appeared to be altered, at maximum exertion, in the women with lupus. Therefore, it is unlikely that impaired lung diffusion limited oxidative metabolism in these women. In the women with lupus, oxidative capacity was most likely limited by deficits in the ability of the peripheral exercising muscles to extract oxygen from the blood. Supported by NIH R03 HD39775-02

Lower Extremity Muscle Strength and Risk of Self-Reported Hip or Knee Osteoarthritis

Purpose:The purpose of this study was to investigate the gender-specific longitudinal association between quadriceps strength and self-reported, physician-diagnosed hip or knee osteoarthritis (OA).Methods:Subjects were 3081 community-dwelling adults who were free of OA, joint symptoms and injuries, completed a maximum treadmill exercise test, had isokinetic knee extension and flexion and isotonic leg press strength measurements taken at baseline and returned at least one written follow-up survey. Multivariate logistic regression was used to estimate odds ratios and 95% confidence intervals.Results:Women with moderate or high isokinetic quadriceps strength had a significantly reduced risk (55% to 64%) of hip or knee OA. A similar, nonsignificant trend was noted among men. Moderate isotonic leg press strength was protective for hip or knee osteoarthritis among men only.Conclusions:These results suggest that quadriceps weakness is an independent and modifiable risk factor for lower extremity OA, particularly among women.

ANZ Society for Vascular Surgery: Vascular 2004, Rotorua, New Zealand, September 2004: selected abstracts

Introduction: Walking programmes are recommended as part of the initial treatment for intermittent claudication (IC). However, for many patients factors such as frailty, the severe leg discomfort associated with walking and safety concerns about exercising in public areas reduce compliance to such prescription. Thus, there is a need to identify a mode of exercise that provides the same benefits as regular walking while also offering convenience and comfort for these patients. The present study aims to provide evidence for the first time of the efficacy of a supervised cycle training programme compared with a conventional walking programme for the treatment of IC. Methods: Thus far 33 patients have been randomized to: a treadmill-training group (n = 12); a cycle-training group (n = 11); or a control group (n = 10). Training groups participated in three sessions of supervised training per week for a period of 6 weeks. Control patients received no experimental intervention. Maximal incremental treadmill testing was performed at baseline and after the 6 weeks of training. Measures included pain-free (PFWT) and maximal walking time (MWT), continuous heart rate and gas-analysis recording, and ankle-brachial index assessment. Results: In the treadmill trained group MWT increased significantly from 1016.7 523.7 to 1255.2 432.2 s (P < 0.05). MWT tended to increase with cycle training (848.72 333.18 to 939.54 350.35 s, P = 0.14), and remained unchanged in the control group (1555.1 683.23 to 1534.7 689.87 s). For PFWT, there was a non-significant increase in the treadmill-training group from 414.4 262.3 to 592.9 381.9 s, while both the cycle training and control groups displayed no significant change in this time (226.7 147.1 s to 192.3 56.8 and 499.4 503.7 s to 466.0 526.1 s, respectively). Conclusions: These preliminary results might suggest that, unlike treadmill walking, cycling has no clear effect on walking performance in patients with IC. Thus the current recommendations promoting walking based programmes appear appropriate. The present study was funded by the National Heart Foundation of Australia.

Effect of Maximal Exercise on Left Ventricular Diastolic Function and Arterial Compliance in Older Hypertensives

0585 Impaired left ventricular diastolic function (LVDF) and arterial compliance (AC) are seen with aging and hypertension and can lead to impaired exercise (EX) responses. EX training improves age-related cardiac impairment and is a treatment for hypertension; however, impact of a maximal exercise session on LVDF and AC in older hypertensives and subsequent training effects are unclear. PURPOSE: To evaluate the effects of maximal EX session on LVDF and AC. METHODS: Eight older hypertensive subjects (1 M and 7 F, 68.5 ± 5.7 yrs) participated in the study. Measures of LVDF (early filling flow velocity (E), late filling flow velocity (A), E/A ratio, isovolumic relaxation time (IVRT) and deceleration time (DT)) and arterial compliance (C) in carotid and brachial arteries were assessed using a 2D echocardiography at rest before, immediately after and 24 hours after maximal treadmill EX. RESULTS: E and A flow velocities increased after the EX and returned to baseline values 24 hours after the EX (p<0.05). Similar responses in IVRT and DT were observed immediately after the EX; however, these indices remained faster 24 hours later (p<0.05). C in carotid and brachial arteries was unaltered throughout the study. CONCLUSION: In older hypertensives, impaired AC was compensated by the improved LVDF with a maximal EX session. Continued impairment of AC may lead to chronic changes in LVDF, leading to impaired compensation of LV function and EX responses. Whether chronic EX training and blood pressure lowering alter this relationship is subject to further research. Supported by A.M Anderson Award, Lawson Health Research Institute.Table

Muscle Activity, Mechanical Work and Efficiency at Ventilatory Threshold During Maximal and Sub-Maximal Treadmill Exercise

Muscle Activity, Mechanical Work and Efficiency at Ventilatory Threshold During Maximal and Sub-Maximal Treadmill Exercise