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A comparison of treadmill and arm-leg ergometry exercise testing for assessing exercise capacity in patients with peripheral arterial disease.

PURPOSE: To compare the results of treadmill exercise testing (TM) to arm-leg ergometry testing (AL) in patients with peripheral arterial disease (PAD). METHODS: Twelve men and 8 women with PAD (mean age, 62 +/- 10 years) completed a treadmill test and an arm-leg ergometer exercise test. Oxygen uptake, heart rate, rate-pressure product (x10(-3)), ratings of claudication and perceived exertion, and power were measured. RESULTS: Peak oxygen uptake, heart rate, and rate-pressure product were similar between TM and AL. Exercise duration was longer and the peak power higher on the AL than on the TM. Claudication pain > or =3/4 was the reason for test termination in all subjects during TM test and in 13 subjects during AL. Nine patients discontinued due to severe claudication on both tests, but the pain occurred later in AL than TM. CONCLUSIONS: Although peak oxygen uptake was similar between the 2 exercise tests, patients with PAD exercised longer and to a higher peak power during the AL. These data suggest that the AL test may be used to evaluate peak exercise capacity in patients with PAD. The AL may also provide an alternate method for detecting PAD and coronary heart disease.

Aged↗

Continuous laryngoscopy exercise test: a method for visualizing laryngeal dysfunction during exercise.

OBJECTIVES/HYPOTHESIS: To assess the diagnostic feasibility and patient acceptance of a new developed diagnostic test for exercise induced upper airway flow limitation. STUDY DESIGN: Clinical case control study including evaluation of contemporary ergo-spirometry and laryngoscopy continuously performed during exercise. METHODS: Twelve nonsymptomatic controls and four young females with documented dyspnea and noisy breathing during exercise were studied. All subjects exercised to exhaustion on a treadmill while attached to a fully equipped ergo-spirometry unit and a fiberoptic laryngoscope linked to a video camera and a sound recorder. RESULTS: The test situation was well tolerated. Two control subjects had a minor inspiratory synchronous medial motion of the aryepiglottic folds without limitation of laryngeal airflow. In the four symptomatic subjects, exercise induced inspiratory synchronous medial motion of the dorsal part of the aryepiglottic folds as well as vocal cord adduction and inspiratory stridor was demonstrated. CONCLUSION: The continuous laryngoscopy exercise test was easy to perform, well tolerated, and can be implemented in future diagnostic work-up programs of laryngeal dysfunction.

Adolescent↗

Influence of relative humidity and repeated exercise on exercise-induced bronchoconstriction.

The relationship between previous exercise-induced bronchoconstriction (EIB) of different magnitude and the pulmonary response to exercise 1 h later was examined in asthmatic children. After acclimatization they performed repeated, paired exercise tests in a clean-air climatic chamber at 23 degree C. The first test of each pair was carried out in 15%, 50% and 85% relative humidity (RH), respectively, to produce different degrees of EIB. All second tests were performed in 50% RH. Changes in pulmonary function were assessed by measuring PEF and FEV1. Bronchodilatation during exercise was not influenced by RH, whereas dry air increased and humid air decreased the bronchoconstrictive response to exercise. When both tests were performed in 50% RH, the second test caused significantly less EIB than did the first test. However, no differences were found between the three second test responses. This suggests that the relative refractoriness after an episode of EIB is not related to the severity of previous bronchoconstriction, but could be associated with exercise as such or other mechanisms in EIB.

Adolescent↗

Pronounced HR variability after exercise in inferior ischemia: evidence that the cardioinhibitory vagal reflex is invoked by exercise-induced inferior ischemia.

Potent cardioinhibitory vagal reflex resulting in bradycardia and hypotension has been observed under particular conditions of transmural inferior ischemia and its reperfusion, such as those observed with acute infarction. However, whether exercise-induced ischemia with ST depressions that is subendocardial and that might be recurrently experienced in daily activities can evoke this reflex remains unknown. In patients with exercise-induced ST depressions due to either inferior [right coronary artery stenosis (RCA), n = 52] or anterior ischemia [left anterior descending artery stenosis (LAD), n = 51], we evaluated post exercise vagal activity (from 0 to 6 min) by the time constant of heart rate (HR) decay and HR variability by 30-s averages of the absolute values of successive RR interval differences (DeltaRR). Exercise parameters were similar between groups. The time constant was slightly but significantly shorter in RCA than LAD patients (79 +/- 24 vs. 93 +/- 29 s, P < 0.01). More significantly, DeltaRR early after exercise (0.5-2.5 min) was approximately twofold greater in RCA than LAD patients (from +76 to +118%, P < 0.001), indicating pronounced vagal activity stimulated by inferior ischemia. Revascularization prolonged the time constant (P < 0.05) and attenuated recovery DeltaRR in RCA patients (P < 0.05, n = 10) but did not change both parameters in LAD patients (n = 12). As well as acute inferior infarction, exercise-induced inferior subendocardial ischemia, which might recurrently occur in daily activities, activates the cardioinhibitory reflex. These new findings must be taken into account in interpreting vagal activity in patients with coronary artery disease.

Aged↗

Pulmonary gas exchange during exercise in women: effects of exercise type and work increment.

Exercise-induced arterial hypoxemia (EIAH) has been reported in male athletes, particularly during fast-increment treadmill exercise protocols. Recent reports suggest a higher incidence in women. We hypothesized that 1-min incremental (fast) running (R) protocols would result in a lower arterial PO(2) (Pa(O(2))) than 5-min increment protocols (slow) or cycling exercise (C) and that women would experience greater EIAH than previously reported for men. Arterial blood gases, cardiac output, and metabolic data were obtained in 17 active women [mean maximal O(2) uptake (VO(2 max)) = 51 ml. kg(-1). min(-1)]. They were studied in random order (C or R), with a fast VO(2 max) protocol. After recovery, the women performed 5 min of exercise at 30, 60, and 90% of VO(2 max) (slow). One week later, the other exercise mode (R or C) was similarly studied. There were no significant differences in VO(2 max) between R and C. Pulmonary gas exchange was similar at rest, 30%, and 60% of VO(2 max). At 90% of VO(2 max), Pa(O(2)) was lower during R (mean +/- SE = 94 +/- 2 Torr) than during C (105 +/- 2 Torr, P < 0.0001), as was ventilation (85.2 +/- 3.8 vs. 98.2 +/- 4.4 l/min BTPS, P < 0.0001) and cardiac output (19.1 +/- 0.6 vs. 21.1 +/- 1.0 l/min, P < 0.001). Arterial PCO(2) (32.0 +/- 0.5 vs. 30.0 +/- 0.6 Torr, P < 0.001) and alveolar-arterial O(2) difference (A-aDO(2); 22 +/- 2 vs. 16 +/- 2 Torr, P < 0.0001) were greater during R. Pa(O(2)) and A-aDO(2) were similar between slow and fast. Nadir Pa(O(2)) was </=80 Torr in four women (24%) but only during fast-R. In all subjects, Pa(O(2)) at VO(2 max) was greater than the lower 95% prediction limit calculated from available data in men (n = 72 C and 38 R) for both R and C. These data suggest intrinsic differences in gas exchange between R and C, due to differences in ventilation and also efficiency of gas exchange. The Pa(O(2)) responses to R and C exercise in our 17 subjects do not differ significantly from those previously observed in men.

Adult↗

Elevated peak exercise systolic blood pressure is not associated with reduced exercise capacity in subjects with Type 2 diabetes.

Subjects with Type 2 diabetes without cardiovascular disease have a reduced exercise capacity compared with nondiabetic subjects. However, the mechanisms responsible for this phenomenon are unknown. The purpose of this study was to evaluate the impact of exercise systolic blood pressure (SBP) response on diverse exercise tolerance parameters in Type 2 diabetic subjects. Twenty-eight sedentary men with Type 2 diabetes were recruited for this study. Subjects were treated with oral hypoglycemic agents and/or diet. Evaluation of glycemic control and peak exercise capacity were performed for each subject. The subjects were divided into two groups according to the median value of peak SBP (210 mmHg) measured in each subject. We observed a 13, 13, and 16% reduction in the relative peak oxygen uptake (V(O2 peak)), absolute V(O2 peak), and peak work rate in the low- compared with the high-peak SBP group [26.95 (SD 5.35) vs. 30.96 (SD 3.61) ml.kg(-1).min(-1), 2.5 (SD 0.4) vs. 2.8 (SD 0.6) l/min, and 169 (SD 34) vs. 202 (SD 32) W; all P < 0.05]. After adjusting for age, relative V(O2 peak) was still significantly different (P < 0.05). There were similar peak respiratory exchange ratio (RER) [1.20 (SD 0.08) vs. 1.16 (SD 0.07); P = 0.24] and peak heart rate [160 (SD 20) vs. 169 (SD 15) beats/min; P = 0.18] between the low- compared with the high-SBP group. No difference in glycemic control was observed between the two groups. The results reported in this study suggest that in subjects with Type 2 diabetes without cardiovascular disease, an elevated exercise SBP is not associated with reduced exercise capacity and its modulation is probably not related to glycemic control.

Blood Pressure↗

Effects of prior heavy exercise on VO(2) kinetics during heavy exercise are related to changes in muscle activity.

We hypothesized that the elevated primary O(2) uptake (VO(2)) amplitude during the second of two bouts of heavy cycle exercise would be accompanied by an increase in the integrated electromyogram (iEMG) measured from three leg muscles (gluteus maximus, vastus lateralis, and vastus medialis). Eight healthy men performed two 6-min bouts of heavy leg cycling (at 70% of the difference between the lactate threshold and peak VO(2)) separated by 12 min of recovery. The iEMG was measured throughout each exercise bout. The amplitude of the primary VO(2) response was increased after prior heavy leg exercise (from mean +/- SE 2.11 +/- 0.12 to 2.44 +/- 0.10 l/min, P < 0.05) with no change in the time constant of the primary response (from 21.7 +/- 2.3 to 25.2 +/- 3.3 s), and the amplitude of the VO(2) slow component was reduced (from 0.79 +/- 0.08 to 0.40 +/- 0.08 l/min, P < 0.05). The elevated primary VO(2) amplitude after leg cycling was accompanied by a 19% increase in the averaged iEMG of the three muscles in the first 2 min of exercise (491 +/- 108 vs. 604 +/- 151% increase above baseline values, P < 0.05), whereas mean power frequency was unchanged (80.1 +/- 0.9 vs. 80.6 +/- 1.0 Hz). The results of the present study indicate that the increased primary VO(2) amplitude observed during the second of two bouts of heavy exercise is related to a greater recruitment of motor units at the onset of exercise.

Adult↗

Effects of exercise during long-term support with a left ventricular assist device. Results of the experience with left ventricular assist device with exercise (EVADE) pilot trial.

BACKGROUND: Long-term implantation of a left ventricular assist device (LVAD) may be a future alternative treatment for end-stage heart failure. The objective of the present study was to determine the hemodynamic effects of supine bicycle exercise and functional capacity during upright treadmill exercise in 10 patients after LVAD implantation placed for refractory heart failure as a bridge to cardiac transplantation. METHODS AND RESULTS: With supine bicycle exercise, 46 +/- 25 days after device placement, heart and LVAD rates increased in parallel from 87 +/- 12 to 117 +/- 14 bpm and 82 +/- 18 to 107 +/- 21 bpm, respectively. Peak O2 consumption was 8.2 +/- 1.7 mL O2.kg-1.min-1. Fick Systemic blood flow rose from 5.0 +/- 1.2 to 7.8 +/- 2.5 L/min. Right atrial and pulmonary capillary wedge pressures increased from 6 +/- 4 and 5 +/- 3 mm Hg to 12 +/- 5 and 13 +/- 8 mm Hg, respectively. End-diastolic left ventricular dimension increased from 3.9 +/- 1.3 to 4.8 +/- 1.6 cm; however, right ventricular dimension decreased from 3.2 +/- 1.0 to 2.3 +/- 0.9 cm. With upright treadmill exercise, peak O2 consumption was 14.1 +/- 2.9 mL O2.kg-1.min-1. CONCLUSIONS: This study indicates that exercise during long-term LVAD support is safe and is not limited by right heart decompensation. It also justifies a larger study to examine how exercise after LVAD implantation compares with that after cardiac transplantation.

Adult↗

Exercise capacity and biochemical profile during exercise in patients with glycogen storage disease type I.

Glycogen storage disease type I (GSD-I) is an inherited disorder of carbohydrate metabolism. Hepatic glucose-6-phosphatase is deficient, leading to impaired gluconeogenesis and glycogenolysis. Patients prevent fasting hypoglycemia by frequent feeds of low glycemic index foods. Normal muscle does not contain glucose-6-phosphatase, and GSD-I is usually classified as a hepatic glycogenosis. However, clinical experience has suggested that patients have decreased cardiovascular fitness, but this had not been formally investigated. This paper reports the results of maximal treadmill cardiopulmonary exercise testing in adult patients with GSD-I. It documents a major reduction in exercise capacity in these patients and demonstrates biochemical aspects of exercise that are different from those of normal controls. All patients showed a reduction in exercise capacity, but there was a wide range of exercise tolerance. Additional work needs to address whether improved adherence to or intensification of therapy in adulthood will ameliorate exercise intolerance.

Adolescent↗

Cardiopulmonary exercise testing in the evaluation of patients with ventilatory vs circulatory causes of reduced exercise tolerance.

INTRODUCTION: Cardiopulmonary exercise testing (CPX) is considered a useful procedure in the evaluation of circulatory, ventilatory, or mixed origin of reduced exercise tolerance. Our study was designed to compare CPX and a standard clinical-instrumental approach in the evaluation of patients with cardiopulmonary disorders. METHODS: Fifty-seven patients (31 male, 26 female; mean [+/- SE] age, 60 +/- 2 years) were studied. Each patient was evaluated by two different observers: one used standard clinical criteria, the other used gas exchange indexes, monitored during a maximal incremental CPX, performed on a cycle ergometer. Cardiac output (CO), at rest and at submaximal work level, was also obtained. RESULTS: In 46 patients (80.7 percent), a concordant evaluation was reached by the two observers (24 were found to have a predominant ventilatory disorder, 22 to have a circulatory disorder); among these, in subjects considered to have circulatory impairment, the maximal CO/maximal workload ratio was significantly lower than in the ventilatory group; in those with ventilatory impairment, the reduced exercise tolerance correlated with the resting spirometric values. In the remaining 11 patients (19.3 percent), CPX better defined the underlying pathophysiology of exercise limitation: in 10 of them, clinically classified as having a mixed or predominantly ventilatory disorder, a greater importance of the circulatory component was detected; 4 had evidence of pulmonary vascular impairment (high VE/VCO2 at anaerobic threshold). CONCLUSIONS: Our study confirmed the sensitivity of CPX in the evaluation of a reduced exercise tolerance in dyspneic patients with cardiopulmonary conditions; when compared with a clinical-laboratory approach, in some patients it allowed the detection of an underestimated circulatory component causing exercise limitation.

Aged↗

Abnormal movement of the arytenoid region during exercise presenting as exercise-induced asthma in an adolescent athlete.

A 16-year-old female basketball player presented with a 2 1/2-year history of exercise-induced severe dyspnea, stridor, and mild wheezing that did not respond to prophylactic treatment with beta-agonists and cromolyn. Spirometric data at rest were normal, but flow-volume loops during exercise suggested a variable extrathoracic obstruction. Laryngoscopic evaluation while the patient was riding an exercise bicycle demonstrated an abnormal motion of the arytenoid region causing obstruction of the airway during inspiration. The vocal cords moved normally. This patient demonstrates the capacity of supraglottic tissue to obstruct the airway during exercise as a cause for exercise-induced dyspnea and stridor. Patients with this disorder may be misdiagnosed as having exercise-induced asthma.

Adolescent↗

Impact of the exercise mode on exercise capacity: bicycle testing revisited.

STUDY OBJECTIVE: To test the performance of a tool designed to estimate functional capacity in order to select a bicycle ramp protocol yielding a test duration from 8 to 12 min in healthy individuals, and to assess differences in exercise responses between bicycle and treadmill tests. PARTICIPANTS AND MEASURES: Forty-one healthy and physically active volunteers (10 women; median age, 37 years; interquartile range [IQR], 29.5 to 41 years) performed an individualized ramp exercise protocol on a bicycle ergometer and a treadmill in random order. Prior to testing, the Veterans Specific Activity Questionnaire (VSAQ) combined with a modified variant of the VSAQ nomogram (metabolic equivalents [METs] derived from VSAQ and age with the modified nomogram, resulting in METs nomogram) was used to estimate exercise capacity and to select the treadmill protocol. The corresponding bicycle work capacity nomogram (in watts) was derived by the following equation: (METs nomogram - 1) x body weight/3.486. RESULTS: Using treadmill tests, all 41 participants (100%) achieved maximal exercise from 8 to 12 min, as compared to 33 participants (80%) for the bicycle tests (p = 0.003). Peak oxygen uptake (V(O2)) [bicycle: median, 49.7 mL/kg/min (IQR, 45.4 to 56.6 mL/kg/min); vs treadmill: median, 53.1 mL/kg/min (IQR, 47.3 to 57.7 mL/kg/min; p < 0.0001)] was lower using the bicycle compared to the treadmill. However, the difference in peak V(O2) values between the two exercise modes was lower (2.6 mL/kg/min; IQR, 1.1 to 4.3 mL/kg/min), corresponding to 4.6% (IQR, 2.4 to 8.5%) of the lower of both values than reported in previous studies, and seven participants (17%) even achieved a higher peak V(O2) using the bicycle. CONCLUSIONS: A modified version of the VSAQ can be effectively used to select appropriate ramp rates for exercise testing using a bicycle ergometer in healthy individuals. Differences in maximal responses are less than those previously reported, suggesting that the bicycle ergometer is an appropriate alternative to the treadmill test in healthy volunteers.

Activities of Daily Living↗

Carbohydrate ingestion prior to exercise augments the exercise-induced activation of the pyruvate dehydrogenase complex in human skeletal muscle.

This study examined the effect of pre-exercise carbohydrate (CHO) ingestion on pyruvate dehydrogenase complex (PDC) activation, acetyl group availability and substrate level phosphorylation (glycogenolysis and phosphocreatine (PCr) hydrolysis) in human skeletal muscle during the transition from rest to steady-state exercise. Seven male subjects performed two 10 min treadmill runs at 70 % maximum oxygen uptake (VO2,max), 1 week apart. Each subject ingested 8 ml (kg body mass (BM))-1 of either a placebo solution (CON trial) or a 5.5 % CHO solution (CHO trial) 10 min before each run. Muscle biopsy samples were obtained from the vastus lateralis at rest and immediately after each trial. Muscle PDC activity was higher at the end of exercise in the CHO trial compared with the CON trial (1.78+/-0.18 and 1.27+/-0.16 mmol min(-1) (kg wet matter (WM))(-1), respectively; P 0.05) and this was accompanied by lower acetylcarnitine (7.1+/-1.2 and 9.1+/-1.1 mmol kg(-1) (dry matter (DM))(-1) in CHO and CON, respectively; P<0.05) and citrate concentrations (0.73+/-0.05 and 0.91+/-0.10 mmol (kg DM)(-1) in CHO and CON, respectively; P<0.05). No difference was observed between trials in the rates of muscle glycogen and PCr breakdown and lactate accumulation. This is the first study to demonstrate that CHO ingestion prior to exercise augments the exercise-induced activation of muscle PDC and reduces acetylcarnitine accumulation during the transition from rest to steady-state exercise. However, those changes did not affect the contribution of substrate level phosphorylation to ATP resynthesis.

Acetylcarnitine↗

Optimizing the clinical exercise test: a commentary on the exercise protocol.

The exercise test has a high yield of diagnostic, prognostic, and functional information and continues to have an integral place in cardiovascular medicine. Its two most common clinical uses are to estimate the probability of a patient having coronary disease and to estimate the likelihood of future coronary events. Although recent guidelines for exercise testing have recommended that the exercise protocol should be adjusted for each patient, this is often overlooked. This review examines the use of the exercise test and discusses which protocols are most appropriate for which patients. Appropriate attention given to exercise testing methodology, including the choice of the exercise protocol, can help to assure the maximum functional, diagnostic, and prognostic yield of information.

Clinical Protocols↗

Aging and heart failure--similar syndromes of exercise intolerance? Implications for exercise-based interventions.

A classic hallmark of chronic heart failure (CHF) is exercise intolerance; however, the extent of exercise limitation is not correlated with the degree of left ventricular dysfunction. Over the past 2 decades it has become more and more evident that peripheral factors, such as skeletal muscle dysfunction, ventilatory abnormalities, and endothelial dysfunction, contribute the greater part to the limitation of exercise capacity. The molecular and pathophysiological changes observed in these organ systems are not always specific to the underlying CHF but rather represent a common pathway that is activated in several chronic disease processes, including severe chronic obstructive pulmonary disease, cancer, and in the normal aging process. A major contributing factor for skeletal muscle catabolism (i.e. elevated cytokine expression in the skeletal muscle) can be found in both normal healthy aging and in heart failure patients. It is reasonable to assume that the overlap of aging and CHF-associated changes in the skeletal muscle partially explains the disabling consequences of the CHF syndrome among elderly patients (nearly 80% of all patients hospitalized for CHF are >65 years old). Peripheral alterations in CHF are often not adequately treated in routine clinical care since standard pharmacological therapy is still focused on the cardiac function and neurohormonal alteration. Exercise training is a guideline-oriented adjuvant therapy with well-documented beneficial effects on exercise tolerance, skeletal muscle function, endothelial function, and respiration. In this review, the effects of exercise in aging and in CHF are compared and the parallel mechanisms are explored.

Aged↗

Exercise-induced bronchoconstriction and exercise-induced respiratory symptoms in workers exposed to tea dust.

Assuming that airborne particles and pollutants are important contributing factors in the development of exercise-induced bronchoconstriction (EIB), we performed a case-control study including 63 tea workers (36 men and 27 women, aged 36-55, duration of employment 3-30 years) and an equal number of office workers, matched by sex and age. Exercise-induced respiratory symptoms were recorded in a questionnaire. Skin prick tests, spirometry, as well as exercise and histamine challenge were carried out. Environmental measurements were performed on site during the work shifts. The prevalence of self-reported exercise-induced respiratory symptoms and EIB did not differ significantly between the exposed and control group (41.6% vs 36.8%, and 6.4% vs 4.8%, respectively). In both exposed and control workers, EIB was strongly linked to asthma (P < 0.01). In the exposed workers it was significantly associated with positive family history of asthma (P < 0.01) and positive family history of atopies (P < 0.05), whereas in the exposed smokers it was significantly related to smoking duration (P < 0.05). Bronchial reaction to exercise in the exposed smokers was significantly greater than in control smokers (P < 0.05). Self-reported exercise-induced respiratory symptoms were weakly associated with EIB, with a large proportion of false positive and a low proportion of false negative results in both groups.

Adult↗

[Changes in cardiac output during exercise in patients with hypertrophic cardiomyopathy: the study of these influences on exercise intolerance].

In order to investigate the relation between exercise intolerance and cardiac output (CO) increase during exercise in patients with hypertrophic cardiomyopathy (HCM), submaximal treadmill exercise (Sheffield protocol) with simultaneous measurement of CO and oxygen uptake (VO2) by acetylene rebreathing method were performed in twelve patients with HCM who had no demonstrable left ventricular outflow obstruction and fifteen control men. The measurements were made at rest, during exercise and recovery. 1) At rest cardiac index (CI) in patients with HCM was significantly less than in control subjects but the difference was small (HCM: 1.9 +/- 0.35 l/min/m2 vs control: 2.2 +/- 0.38, p less than 0.05), and was almost the same during light exercise (stage 1-3), but clearly increased during middle to submaximal stages (stage 4 and 5) (stage 5: 4.5 +/- 1.25 vs 8.0 +/- 1.30, p less than 0.01). 2) Heart rate was not different in both groups at rest, during exercise and recovery, which was considered to explain that the difference of CI was derived from that of stroke index (SI). 3) The change of VO2 showed the same tendency as that of CI. The difference increased considerably during the middle to submaximal stages (Stage 5: 15.3 +/- 1.42 ml/min/kg vs 25.4 +/- 4.42, p less than 0.01). 4) During recovery, CI and VO2 in patients with HCM indicated a delay of beginning to decrease toward the rest level, compared with control subjects. 5) VO2 was closely related to CI (r = 0.90, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Effects of a muscle exercise program on exercise capacity in subjects with osteoarthritis.

Maximal aerobic power and muscle function have been shown to decrease with age and to be even lower in patients with osteoarthritis (OA). This study was designed to determine if subjects with OA who underwent only a muscle exercise program had improved exercise capacity and cardiovascular fitness. A maximal graded exercise test was given before and after 3 months of exercise (isometric, isotonic, and isometric force generated as a function of time contractions, three times a week). Maximal strength and the tension-time index improved significantly. Peak aerobic power increased from 15.99 +/- 3.96 mL.kg-1.min-1 to 20.34 +/- 3.29 mL.kg-1.min-1. On average, maximal walking speed increased from 2.0 +/- 0.6 mph to 2.4 +/- 0.7mph. Exercise time increased 22%, from 9.2 +/- 2.3 minutes to 11.2 +/- 2.7 minutes. There were significant reductions in submaximal heart rate (15b.min-1) and systolic blood pressure (15mmHg) after training. It would appear that the reduction in aerobic fitness of subjects with OA is secondary to their reduced muscle function. By improving muscle function, increases in exercise capacity and aerobic fitness occurred.

Aged↗