A cross country nordic track would do the trick. I also heard that Rocky Marciano would run for about 45 minutes in the early morning would do about that much in walking in the evening. Walking isn't in addition isn't bad, you don't really have to concentrate on the task at hand and you can concentrate more on your plans, listen to music or talk on the phone. Except I'd take it easy on the legs until you know what's wrong with them.
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