Fifteen subjects recovering from a myocardial infarction or suffering from angina were given a maximum effort test on a bicycle ergometer and hemodynamic and angiographic investigations before and after a period of physical training. The training program consisted of three sessions of 60 to 75 min each week for two months. Maximum effort tests showed that physical capacity had increased by 17% (P less than 0.02) and that for the same amount of effort the heart rate had decreased by 13% and the blood pressure by 7% (P less than 0.01). Hemodynamic and angiographic investigations showed no significant changes after training in the left ventricular end-diastolic pressure, ventricular volume, ejection fraction, VCF, percentage of shortening and segmental contractility, in the total group, in those patients whose contractility was considerably impaired, or in those who had large dyskinetic areas or widespread akinesia. It is concluded that training had no direct influence on the myocardium, either beneficial or detrimental.