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PubMed1985

The effects of piretanide capsules on blood pressure during ergometric and isometric work loads in patients with mild to moderate essential hypertension.

A single-blind study was carried out in 22 out-patients with mild to moderate hypertension to investigate the effects of piretanide capsules on systolic and diastolic blood pressure during standardized ergometric and isometric exercise. After a 4-week run-in period on placebo, patients received 1 capsule (6 mg) once daily for 6 weeks. If diastolic pressure was normalized (less than 95 mmHg), this dosage was continued for a further 6 weeks; patients whose blood pressure remained high after the initial 6 weeks received 1 capsule twice daily for a further 6 weeks. Significant reductions in blood pressure (9.2% for systolic, 14.6% for diastolic) were measured after 12-weeks' treatment during maximum ergometric work load exercise; during isometric exercise the reductions were 8.1% and 12.4%, respectively. The pulse-pressure product (a parameter indicating myocardial oxygen consumption), calculated for maximum ergometric exercise, was also significantly reduced by 8.8% after 12-weeks' active drug treatment. Serum levels of potassium, creatinine, urea, uric acid and cholesterol showed no clinically relevant changes during treatment. Side-effects definitely or probably associated with piretanide were observed in 13 patients. These, however, were generally mild and did not lead to interruption of piretanide treatment. Transient polyuria was reported by 5 patients during the first 2 weeks of active drug treatment; only 3 patients reported mild polyuria after 12 weeks of active drug treatment. The beneficial effect of piretanide especially on systolic blood pressure during exercise was in marked contrast effect of piretanide especially on systolic blood pressure during exercise was in marked contrast to the lack of such an effect reported during treatment with thiazide and other thiazide-like diuretics.

Adult↗

PubMed1985

The relationships of functional capacity, pain, and isometric and isokinetic torque in osteoarthrosis of the knee.

Thirty-nine patients suffering from osteoarthrosis of the knee were repeatedly measured. The relationship was studied for two groups of variables. The first group consisted of subjective assessments of functional capacity and pain and a walking test. The second group consisted of isometric knee extension torque and isokinetic knee flexion and extension torque at 30 degrees/sec, 60 degrees/sec, 120 degrees/sec and 180 degrees/sec. High correlations between each of the static and dynamic torque values were found. Multiple regression analysis showed that isometric and isokinetic torque measures are unsatisfactory predictors of functional capacity, since only 23-35% of the variation of functional capacity, pain and walking test variables was explained by the variation of torque variables. Dynamic torque measurements had very little advantage over static torque tests. It is concluded that outcome measures in studies of osteoarthrosis should be problem-oriented and include direct assessments of functional capacity, pain and walking ability.

Female↗

PubMed1985

[Comparative characteristics of the hemodynamic changes in virtually healthy persons and in ischemic heart disease patients during hand and leg isometric loading].

Comparative studies on changes of hemodynamics in manual and leg isometric loads were conducted in 30 healthy persons and 38 patients with coronary heart disease. A possibility of a leg isometric load with a maximum effort for 5 min. was shown. Intracardiac hemodynamics was estimated by echocardiography results. A possibility to reveal early stages of myocardial contractile and pumping function in patients with coronary heart disease was established. Manual dynamometry does not permit revealing early stages of heart insufficiency.

Coronary Disease↗

PubMed1984

Cardiovascular response to mental stress: dynamic and isometric exercise in hypertensive patients treated with prizidilol hydrochloride (SK&F 92657).

The cardiovascular effects of a new antihypertensive agent, prizidilol hydrochloride (SK&F 92657), have been evaluated in a group of 13 patients with mild to moderate essential hypertension, both at rest and during mental stress and isometric or dynamic exercise. After 6 weeks of therapy (200-300 mg of prizidilol b.i.d.) both systolic and diastolic blood pressure values at rest were significantly lower than those recorded before treatment and during placebo (with an average decrease of about 22/11 mm Hg in the supine position). Heart rate at rest was slightly reduced. Cardiovascular responses to dynamic exercise and mental stress were not prevented by prizidilol, but blood pressure and heart rate levels around which variation occurred were lowered to a significant extent. During isometric exercise prizidilol did not protect against a rise in diastolic blood pressure. Blood pressure and heart rate reduction both at rest and during stimulation were not related to plasma drug concentrations. Side-effects were very rare. It is concluded that prizidilol significantly reduces blood pressure both at rest and during mental stress and physical activity with only sight effects on heart rate, and with a very simple therapeutic scheme.

Adrenergic beta-Antagonists↗

PubMed1984

Myofascial pain: relief by post-isometric relaxation.

The post-isometric relaxation technique begins by placing the muscle in a stretched position. Then an isometric contraction is exerted against minimal resistance. Relaxation and then gentle stretch follow as the muscle releases. This technique was applied to tight, tender muscles that are commonly associated with musculoskeletal pain and was systematically tested on 351 muscle groups in 244 patients. The method produced immediate pain relief in 94%, lasting pain relief in 63%, as well as lasting relief of point tenderness in 23% of the sites treated. Patients who practiced autotherapy on a home program were more likely to realize lasting relief. Pain was relieved in both the muscle itself and at tender insertion points. The technique is useful in addition to, or in place of, local anesthetic injection or dry needling. These results confirm other observations that the increased tension of the affected muscles and the resulting pain and dysfunction are both relieved by restoring the full stretch length of the muscle.

Aged↗

PubMed1984

[Hemodynamic changes in patients with arterial hypertension during isometric exercise].

Forty-two patients aged 35 to 58 years with arterial hypertension were examined. The patients did not manifest any clinical signs of heart failure or coronary heart disease. All the patients were subjected to the leg form of isometric exercise test with a 100% maximal force. The blood pressure, heart rate, heart contractility and pump function were examined in the course of the test. It was demonstrated that in patients with arterial hypertension, the pressor reactions in response to the exercise were similar to those in healthy subjects but were more pronounced. In patients with stage IIA arterial hypertension, the increase of blood pressure occurred due to the inotropic reaction of the myocardium and triggering of Frank-Starling's mechanism. In patients with stage IIB arterial hypertension, the increase of blood pressure was caused by the total peripheral resistance elevation. The leg form of isometric exercise permits the detection of early signs of heart failure in patients with arterial hypertension.

Adult↗

PubMed1983

The effect of a new calcium channel blocker nicardipine on 24-hour ambulatory blood pressure and the pressor response to isometric and dynamic exercise.

We have assessed the potential antihypertensive effect of a new slow channel blocker, nicardipine, in a group of patients with essential hypertension. Fourteen patients completed a study using the 'Oxford' system for recording blood pressure during free ambulation and physiological testing. An initial 24-h recording was performed on no treatment and repeated following chronic therapy with 40 mg b.d. of nicardipine. During each recording, the patients performed isometric and dynamic exercise according to a standardized protocol. Within-patient comparisons of consecutive mean hourly systolic and diastolic blood pressures showed a reduction throughout the 24 h during nicardipine therapy. The reduction in blood pressure was also maintained at the peaks of isometric and dynamic exercise. Side-effects were encountered frequently and led to four patient withdrawals. Nicardipine appears to be effective in reducing blood pressure although the frequency of encountered side-effects may limit its usefulness as a first-line antihypertensive agent.

Adult↗

PubMed1984

Comparative analysis: effects of positive and negative lateral acceleration on isometric fatigue in the forearm.

UNLABELLED: The purpose of this investigation was to determine the difference, if any, produced by +/- Gy acceleration on forearm fatigue. The Dynamic Environment Simulator (DES) at the USAF Aerospace Medical Research Laboratory was used to create a lateral acceleration environment. The experiment was designed to measure the forearm strength, endurance, recovery from fatigue, and surface electrical activity of six subjects during +/- 2 Gy acceleration. THE RESULTS: isometric performance was degraded during -2 Gy acceleration compared to + 2 Gy acceleration. The percentage drop in center frequency of the EMG signal was determined to be unreliable as a fatigue index during lateral acceleration. When head and shoulder restraints were used during lateral maneuvers, they were a factor in pilot performance, with + 2 Gy being superior to -2 Gy. This study suggested a way of analyzing the EMG signals that may permit quantification of isometric fatigue during lateral acceleration.

Acceleration↗

PubMed1984

[Isometric load in assessing the severity of coronary insufficiency in heart surgery patients].

The test involving isometric muscular tension has been proved promising for the non-invasive quantitative evaluation of the severity of coronary insufficiency. Fifty-seven males with coronary stenosing atherosclerosis and 24 normal subjects have been studies. It has been shown that the isometric test is the method of choice in angina at rest and of a low effort as well as in labile angina, whereas tests with increasing exercise are more adequate in angina associated with moderate and hard exercise.

Adult↗

PubMed1983

Passive range of motion, not isometric exercise, amplifies acute urate synovitis.

The effects of passive range-of-motion and isometric exercises on acute monosodium urate-induced experimental arthritis in a rabbit model were assessed by serial intra-articular temperature measurements and synovial leukocyte counts. Passive range of motion significantly (p less than 0.05) increased both the intra-articular temperature and the synovial leukocyte count over the control values of the nonexercised joints. Isometric exercises across a joint with acute monosodium urate synovitis, however, did not significantly affect intra-articular temperature or synovial leukocyte count.

Acute Disease↗

PubMed1983

Simple method to determine sincerity of effort during a maximal isometric test of grip strength.

The purpose of this study was to establish a simple method to determine the legitimacy of a maximal voluntary grip contraction (MVGC). To achieve this, 36 subjects were randomly assigned to either a sincere (S) or faker group (F) and asked without investigator knowledge to execute either a MVGC or 75% MVGC on a specially designed grip dynamometer. The dynamometer was attached to a load cell with analog output obtained from a strip chart recorder at 50 mm X sec.-1. The force curves were evaluated empirically and also analyzed according to the following components: rate of force application (SLP), peak force (PK), average force divided by peak force (DEV) and peak force divided by body weight (WTRATIO). Average values for S and F subjects respectively were; SLP 2217 vs 1642 n X s-1, PK 499 vs 387 n, and DEV 0.91 vs 0.72. When all variable were transformed to z-scores, summed for each subject and categorized by sum into upper and lower 50% groups by gender, 87.5% of the females (N = 16) and 80% of the males (N = 20) were correctly classified as S or F subjects. Based upon a discriminant analysis performed by gender, DEV was found to be the only significant predictor for females with DEV, SLP and WTRATIO being significant predictors for the males. It was concluded that S and F subjects can be determined from the results of a maximal isometric grip strength test based upon a simple configuration analysis of an isometric force curve.

Adult↗

PubMed1980

Platelet release reaction in vivo in patients with ischaemic heart disease after isometric exercise and its prevention with dipyridamole.

In 20 patients with ischaemic heart disease (IHD), platelet sensitivity to ADP-aggregation, plasma von Willebrand factor (vWF) and plasma beta-thromoboglobulin (beta-TG) were measured before and after isometric exercise. Effect of dipyridamole on these determinants was studied in a crossover fashion. To assess plasma vWF level, a new simple method was employed which has the advantage of not requiring an optical aggregometer and was proved to be reproducible. No significant difference was seen in platelet sensitivity to ADP-aggregation, vWF and beta-TG among healthy controls, IHD patients on placebo and on dipyridamole at rest. After exercise, platelet sensitivity to aggregation, plasma vWF and beta-TG increased significantly in IHD patients on placebo. In healthy controls, no significant changes were seen. On dipyridamole, above changes seen in IHD patients were not seen. The results suggests that isometric exercise may induce platelet release reaction in vivo and may produce hypercoagulable state in IHD patients. These phenomena may be prevented by pretreatment with dipyridamole.

Adult↗

PubMed1982

Systolic time intervals during isometric exercise in supine position should be corrected also for arterial pressure.

In this paper we have studied the relationship between the systolic time intervals (STI) and the heart rate (HR) and systolic arterial pressure (SAP) in a group of 24 healthy subjects at three different effort levels during an isometric exercise in supine position and in basal conditions. We observed a decrease of the non corrected STI values during the exercise. Then we corrected STI using the regression equations obtained by plotting STI values versus the corresponding HR values at rest and during the exercise. We showed an increase of corrected left ventricular ejection time (LVET) during the whole exercise, and an increase of corrected total electromechanical systole (QS2c) at 50% effort level and then a return to the basal values. We also derived the multiple regression equations correlating QS2 and LVET with HR and SAP. Notwithstanding these equations show a significant positive correlation between the two STI considered and SAP only at the maximum effort, we corrected LVET and QS2 values by these equations assuming that the relationship between these parameters exists also in basal conditions and during the remaining stages of the exercise. By this correction we found a decrease of LVETc and QS2c in accordance with hemodynamic data reported by other authors. We may conclude that it seems useful to correct the STI obtained during isometric exercise in supine position both for HR and SAP.

Adult↗

PubMed1982

STI usefulness during isometric exercise in labile hypertensive patients.

Measurement of the left ventricular systolic time intervals (STI) was considered a valid method in demonstrating the presence of a state of beta-drenergic hyperstimulation. The authors used this method during isometric exercise to differentiate between a group of 16 normal subjects (N) and 16 random labile hypertensives (LH), and between the N and 16 fixed hypertensives (FH). Exercise resulted in a general shortening (p less than 0.01) of the STI, an increase (p less than 0.01) in the systolic arterial pressure (SAP), and an increase (p less than 0.01) in the heart rate (HR) in all the groups studied. The study also demonstrated that the state of blood pressure (diagnosis) alone does not significantly influence the course of the exercise test, and that the interaction diagnosis-exercise gives quantitatively different results in the three groups, to the extent that it is possible to recognize a specific polygraphic pattern for the LH. In this group there is a greater shortening of the Q--S2 and the non-corrected LVET (p less than 0.01) than for the N. The behaviour for the FH falls between the other groups, but it is not possible to distinguish clearly between this group and its neighbour on either side. We conclude that the measurement of the STI during isometric exercise could be useful in determining a diagnostic pattern for subjects who show a lability in their blood pressure.

Adult↗

PubMed1982

Cardiovascular and perceptual responses to isometric exercise.

The purpose of this study was to investigate the effects of 3 intensities of isometric handgrip contractions on selected cardiovascular parameters and perception of effort, and to determine the relationship of these cardiovascular parameters to perception of effort. Seven healthy subjects were instructed to maintain 3-minute contractions in a randomized sequence, at 15, 25, and 35% of their maximal voluntary contractions (% MVC) while heart rate, systolic blood pressure, diastolic blood pressure and perception of effort were measured at 1-minute intervals. All 4 parameters were found to significantly increase (p less than 0.05) both as a function of contraction intensity (% MVC) and time. Correlation coefficients relating perception of effort to systolic blood pressure, diastolic blood pressure, and heart rate were 0.76, 0.64, and 0.63, respectively, suggested that perception of effort was a better predictor of systolic blood pressure than of diastolic blood pressure or heart rate. A 3-step multiple regression resulted in a cumulative r value of 0.82. Recommendations were made that perception of effort be further explored for clinical use during exercise prescription as an indicator of cardiovascular stress. By using a technique of perception of effort, patients could be taught to restrict activity to within a safe range of cardiovascular variability, rather than totally refrain from all forms of isometric activity.

Adult↗

PubMed1981

Different behavior of the resistance vessels of the human calf and forearm during contralateral isometric exercise, mental stress, and abnormal respiratory movements.

Experiments were conducted in normal human volunteers to compare the response of the forearm and calf vessels to contralateral isometric exercise, mental stress, resisted breathing, coughing, and the Valsalva maneuver. Blood flows were measured by means of strain-gauge plethysmography, arterial blood pressure by auscultation, and heart rate by electrocardiography. Isometric exercise of one forearm (at one-third maximal voluntary contraction) for 90 seconds caused an increase in blood pressure and heart rate; the vascular resistance decreased in the resting forearm, and increased in the calf. The decrease in forearm resistance was greater with the subjects supine and attenuated with the subjects standing or reclining head-down. With arterial occlusion of the exercising forearm just prior to cessation of the handgrip, the blood pressure and the calf resistance remained elevated, while the heart rate returned to control. The forearm resistance increased during the occlusion period and remained elevated throughout it. Mental stress caused an increase in heart rate and blood pressure and a dilation of the forearm but not of the calf vessels; these changes were smaller in standing than in supine subjects. Resisted breathing and coughing caused an increase in heart rate and in forearm blood flow, but not in calf blood flow. The Valsalva maneuver was followed by decreases in blood flow to the upper and lower limbs. The different responses in forearm and calf vessels can be explained by a central component which triggers a vasodilator pathway (possibly cholinergic) which is distributed to forearm but not to calf vessels.

Adult↗

PubMed1981

The influence of fiber composition, recruitment order and muscle temperature on the pressor response to isometric contractions in skeletal muscle of the cat.

The blood pressure response to isometric exercise was examined in the medial gastrocnemius muscle of the cat at muscle temperatures of 28 and 38 degrees C. Contractions were sustained at tensions of between 10 and 100% of the muscle's initial strength (tetanic tension of the unfatigued muscle) with recruitment proceeding from either the fastest to the slowest or from the slowest to the fastest motor units, respectively. The results of these experiments showed that the blood pressure response throughout the duration of contractions at tensions greater than 10% of the initial strength was constant by either order of recruitment and for both muscle temperatures examined, the mean blood pressure rising linearly from an average value of 101.2 +/- 10.3 mm Hg at the onset of the contraction to 146.3 +/- 14.2 mm Hg at the point of fatigue. In contrast, during contractions at 10% of the initial strength at both muscle temperatures, the blood pressure was lower during the first 20% of the contractions when recruitment proceeded from the slowest to the fastest motor units but stayed the same throughout the remainder of the contractions. The results of these experiments indicate the importance of muscle fiber composition in determining the blood pressure response for weak isometric contractions.

Animals↗

PubMed1980

[An isometric exercise for the diagnosis of chronic obliterating arteriopathies of the lower extremities].

A non invasive method for the diagnosis of occlusive diseases of the peripheral arteries and the follow-up of therapy is proposed. The method consists in the performance of an isometric effort of the inferior limbs and the Doppler detection of the dorsalis pedis systolic pressure. 41 patients with different degrees of peripheral artery involvement have been studied and the results compared with those obtained in a control group of 12 normal subjects, equally matched for ages and sex. In the normal subjects the maximal dorsiflection of the feet for 30 seconds caused a mean increase of the heart rate of 20% and no changes of the systolic blood pressure. In the patients with peripheral artery disease the isometric effort caused, contemporary to the increase of the heart rate, a decrease of the dorsalis pedis systolic pressure, that varied from 15 to 100% according to the degree of the arterial involvement. A close correlation was found between the degree of the percent reduction of peripheral systolic pressure and the entity of the arterial involvement, as evidenced by other invasive and non-invasive methods. The method proposed appears useful for a proper diagnosis of peripheral vascular diseases in those patients who cannot undergo invasive investigations or the treadmill effort test.

Adult↗