Effects of short-term and prolonged immersion on the cardiovascular responses to exercise.

The primary purpose of this investigation was to examine the effects of water immersion in 35 degrees C water, per se, and the effects of 3 h of water immersion on the physiological responses to exercise. Experiments in air were conducted after 15 min of water immersion and after 3 h of water immersion. After each condition, exercises of 20%, 40%, 60%, 80%, and 100% of the subject's maximum oxygen consumption were performed on a cycle ergometer. Oxygen consumption (VO2), cardiac output, heart rate (HR), stroke volume, and blood pressure were determined. At submaximal workloads, no significant differences in the data were observed. The VO2 at the maximal workload after 3 h of immersion (3.32 +/- 0.15 L.min-1) was significantly higher than the value after 15 min of immersion (3.03 +/- 0.20 L.min-1). Both of these values were significantly lower than the value in air (3.83 +/- 0.30 L.min-1). The peak HR's were significantly higher after 3 h of immersion (167 +/- 2 b.min-1). These observations suggest that 3 h of immersion can cause alterations in the cardiovascular responses to maximal exercise; however, submaximal responses were unaffected.

Quantitative evaluation of a home exercise program on muscle and functional capacity of patients with osteoarthritis.

Rehabilitation of patients with osteoarthritis of the knees is typically based on home exercise. These programs are believed to benefit patients and have been shown to qualitatively improve strength. The purpose of the present study was to quantify the effects of a 3-mo home exercise program on muscle function and functional capacity. The progressive program included flexibility, strength, endurance, active range of motion and functional activities. Nineteen subjects (67.4 +/- 7.5 yr) with osteoarthritis of the knees began the program, with only nine completing it. The subjects initially had significantly reduced muscle function and functional capacity. Maximal isometric strength of knee extension increased significantly at a knee flexion position of 45 degrees for hip flexion positions of 120 degrees and 60 degrees (35%); however, it failed to increase at longer muscle lengths. There were no significant improvements in hamstring strength. Maximal angular velocity improved after 3 mo of exercise (40%). Muscle endurance did not improve significantly. Although there was a slight increase in functional capacity, these data failed to demonstrate significant clinical or statistical improvement in overall function in patients after home exercise.