Aerobic endurance training has been an integral component of the international recommendations for cardiac rehabilitation for more than 30 years. Notwithstanding, only in recent years have recommendations for a dynamic resistance-training program been cautiously put forward. The perceived increased risk of cardiovascular complications related to blood pressure elevations are the primary concern with resistance training in cardiac patients; recent studies however have demonstrated that this need not be a contraindication in all cardiac patients. While blood pressure certainly may rise excessively during resistance training, the actual rise depends on a variety of controllable factors including magnitude of the isometric component, the load intensity, the amount of muscle mass involved as well as the number of repetitions and/or the load duration. Intra-arterial blood pressure measurements in cardiac patients have demonstrated that that during low-intensity resistance training [40-60% maximum voluntary contraction (MVC)] with 15-20 repetitions, only modest elevations in blood pressure are revealed, similar to those seen during moderate endurance training. When properly implemented by an experienced exercise therapist, in specific patient groups an individually tailored, medically supervised dynamic resistance training program carries no inherent higher risk for the patient than aerobic endurance training. As an adjunct to endurance training, in selected patients, resistance training can increase muscle strength and endurance, as well as positively influence cardiovascular risk factors, metabolism, cardiovascular function, psychosocial well-being and quality of life. According to present data, resistance training is however not recommended for all patient groups. The appropriate training method and correct performance are highly dependent on each patient's clinical status, cardiac stress tolerance and possible comorbidities. Most studies have used middle-aged men of average normal aerobic performance capacity and with good left-ventricular (LV) function. Data are lacking for high-risk groups, women and older patients. With the current knowledge it is reasonable to include resistance training without any restraints as part of cardiac rehabilitation programs for coronary artery disease (CAD) patients with good cardiac performance capacity (i.e., revascularised and with good myocardial function). As patients with myocardial ischaemia and/or poor left ventricular function may develop wall motion disturbances and/or severe ventricular arrhythmias during resistance exercise, the following criteria are suggested for resistance training: moderate-to-good LV function, good cardiac performance capacity [>5-6 metabolic equivalents of oxygen consumption (METS)=1.4 watt/kg body weight], no symptoms of angina pectoris or ST segment depression under continued maintenance of the medical therapy. Based on available data, this article presents recommendations for risk stratification in cardiac rehabilitation programs with respect to ...

Although it is well documented that persons suffering from diabetes type 2 profit from muscular activities, just a negligible amount of patients take advantage of physical exercises. During the last decade, vibration exercise (VE) could be established as an effective measure to prevent muscular atrophy and osteoporosis with low expenditure of overall exercise-time. Unfortunately, little is known about the metabolic effects of VE. In the present study we compared VE with the influence of strength training and a control group (flexibility training) on glycemic control in type 2 diabetes patients. Forty adult non-insulin dependent patients participated in the intervention. Fasting glucose concentration, an oral glucose tolerance test (OGTT), haemoglobin A1c (HbA1c), the isometric maximal torque of quadriceps muscles, and endurance capacity were evaluated at baseline and after 12 weeks of training with three training sessions per week. The main findings are: Fasting glucose concentrations remind unchanged after training. The area under curve and maximal glucose concentration of OGTT were reduced in the vibration and strength training group. HbA1c values tended to decrease below baseline date in the vibration training group while it increased in the two other intervention groups. Theses findings suggest that vibration exercise may be an effective and low time consuming tool to enhance glycemic control in type 2 diabetes patients.

Owing to changes in cardiac output, blood volume distribution and the efficacy of the muscle pump, oxygen supply may differ during upright and supine cycle exercise. In the present study we measured, in parallel, circulatory (heart rate, stroke volume, blood pressure) and metabolic parameters (oxygen uptake, lactic acid concentration [la]) during incremental-exercise tests and at constant power levels ranging from mild to severe exercise. In supine position, cardiac output exceeded the upright values by 1.0-1.5 l.min-1 during rest, light ([la] < 2 mmol.l-1) and moderate ([la] = 2-4 mmol.l-1) exercise. At higher exercise intensities the cardiac output in an upright subject approached and eventually slightly exceeded the supine values. For both rest-exercise transitions and large-amplitude steps (delta W > or = 140 W) the cardiac output kinetics was significantly faster in upright cycling. The metabolic parameters (VO2 and [la]) showed no simple relationship to the circulatory data. In light to moderate exercise they were unaffected by body position. Only in severe exercise, when cardiac output differences became minimal, could significant influences be observed: with supine body posture, [la] started to rise earlier and maximal power (delta W = 23 W) and exercise duration (64 s) were significantly reduced. However, the maximal [la] value after exercise was identical in both positions. The present findings generally show advantages of upright cycling only for severe exercise. With lower workloads the less effective muscle pump in the supine position appears to be compensated for by the improved central circulatory conditions and local vasodilatation.

The time courses of leg blood flow, systolic peak velocity, heart rate and blood pressure have been studied in nine health volunteers during dynamic exercise in upright sitting and in a tilted sitting body position. In both positions the subjects performed single and repeated foot plantarflexions against light and moderate forces corresponding to 5%-10% and 25%-30% of maximal voluntary contraction. The following measurement techniques were used: Doppler ultrasound method (blood flow parameters), FINAPRES device (arterial blood pressure) and standard ECG chest leads (heart rate). At rest the supine blood flow parameters measured in the arteria femoralis were significantly higher than in the upright sitting position. In both positions, even one single plantarflexion at the light exercise intensity caused significant increases in blood flow for almost 20s. The major part of the blood flow response to repeated contractions always occurred within the first 10s at virtually unchanged blood pressures. During this initial phase upright leg blood flow increased by factors of 2.5 (light exercise) and 3.1 (moderate exercise). The corresponding values in the tilted sitting posture were 1.7 and 1.9, respectively. The initial increases in the upright position were too large to be attributed only to the increase of the perfusion pressure caused by the withdrawal of the hydrostatic pressure on the venous side ("muscle pump"). Additional, fast decreases in local resistance have to be considered. In the supine posture effects on local resistance have to be taken into account for the early increases in blood flow since hydrostatic effects on arterio-venous pressure differences are too small. The present findings indicate that the effects of repeated contraction-relaxation cycles on the early adjustment of muscle blood flow are not sufficiently described by a "muscle pump" that induces only venous volume shifts and hydrostatic pressure changes. Additional fast effects on local resistance have to be taken into account.

BACKGROUND: It is well established that physical training enhances functionality and quality of life in patients with COPD. However, little data exist concerning the effects of the usefulness of oxygen supply during exercise training for > 3 months in patients with COPD who are normoxemic at rest and during exercise. We hypothesized that oxygen supply during training sessions enables higher training intensity and thus optimizes training results in patients with COPD. METHODS: In this blinded randomized controlled study, we carried out a 24-week training program with progressively increasing loads involving large muscle groups. In addition, we compared the influences of oxygen supplementation. Thirty-six subjects with moderate-to-severe COPD who were not dependent on long-term oxygen therapy trained under supervision for 24 weeks (3 times/week at 30 min/session). Subjects were randomized into 2 groups: oxygen supply via nasal cannula at a flow of 4 L/min and compressed air at the same flow throughout the training program. Lung function tests at rest (inspiratory vital capacity, FEV 1 , Tiffeneau index), cycle spiroergometry (peak ventilation, peak oxygen uptake, peak respiratory exchange rate, submaximal and peak lactic acid concentrations), 6-min walk tests, and quality-of-life assessments (Medical Outcomes Study 36-Item Short Form questionnaire) were conducted before and after 12 and 24 weeks. RESULTS: Independent of oxygen supplementation, statistically significant improvements occurred in quality of life, maximal tolerated load during cycling, peak oxygen uptake, and 6-min walk test after 12 weeks of training. Notably, there were no further improvements from 12 to 24 weeks despite progressively increased training loads. CONCLUSIONS: Endurance training 3 times/week resulted in significant improvements in quality of life and exercise capacity in subjects with moderate-to-severe COPD within the initial 12 weeks, followed by a stable period over the following 12 weeks with no further benefits of supplemental oxygen.

Spike recordings were obtained with preparations of group III and IV fibers from the nervus peroneus of the rat. During the recordings the muscle was stimulated by chemical substances simulating metabolic effects of static exercise: increase of [K+], enhancement of osmolality and increase of concentrations of lactic acid and inorganic phosphates. Two experimental setups were used: in series I application was performed by a perfusion of the circulatorily isolated hindleg, and in series II a single muscle of the hindleg (musculus extensor digitorum longus) was superfused by control or test solutions. Only those fiber preparations were further investigated which did not respond to pressure, tension or squeezing of the muscle. Only few fibers that were exposed to all of our stimuli responded to none of them; from the rest, about the half were selective or only preferential for one stimulus. The majority of the fibers adapted their response after 8 min while the applications still endured. A comparison of all fibers (in series II) proved that all the four stimuli elicited significant increases of activity. The greatest significant effects were found for lactic acid and potassium (in series I and II). Since the concentrations used in the test applications were characteristic for medium and heavy exercise these results support the hypothesis that metabolic muscle receptors participate in the peripheral control of circulatory and respiratory drives during static exercise.

Ten healthy male subjects performed single (< 1 s), sustained and intermittent plantarflexions (up to 40 s) of one foot in sitting exercise position. Two different absolute forces were applied, which, in terms of maximal voluntary contraction, ranged between 5%-10% and 25%-30%. Blood velocity was continuously recorded in the proximal arteria femoralis by means of the Doppler technique. Heart rate (HR) and mean blood pressure (BP) were simultaneously determined using standard ECG and the FINAPRES method. Despite the distance between the proximal arteria femoralis and the exercising muscle the Doppler data showed: effects of single contractions on the individual Doppler data, the influence of consecutive contractions, variation with exercise intensity and differences between sustained and intermittent contractions. In all exercise tests there was an immediate significant increase in blood velocity at the onset of exercise. The major part (range 52%-73%) of the response to the 40 s tests was seen during the first 6 s. It was followed by a second phase of adjustment which depended on the type of exercise and exercise intensity. The single plantarflexion provoked increases in blood velocity for about 20 s. A comparison of HR and BP tracings with the Doppler data demonstrated the importance of local mechanical factors for the perfusion of the exercising muscle. The early adjustment of muscle perfusion were not correlated to the systemic blood pressure and, therefore, appeared to be related to muscle pump effects. The subsequent flow values were influenced by passive vessel compression and changes in local vasomotor tone.(ABSTRACT TRUNCATED AT 250 WORDS)

1. The age of the subjects had no significant influence on the slopes of blood pressure increase during the different exercise modes. 2. The frequent insertion of short (3 s) periods of muscle relaxation (IM) decreased the blood pressure response more effectively than a reduction in contraction strength alone (CM). Short muscle relaxations have an immediate, mechanical effect on blood pressure and they allow a metabolic recovery which attenuates the trend of blood pressure increase.