I find the bicycle is the best overall for me. I can no longer run due to chronic lower back issues. I like riding outdoors but have learned that spin classes give me a more reliable and controlled workout. I also use a heart rate monitor and have learned to control it. I can get the exact workout that I want, regardles of weather or other factors, every time. I ride 3 - 4 times per week.
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Just because you don't take an interest in politics doesn't mean politics won't take an interest in you.... Pericles (430 B.C)