I kept getting silly niggling injuries from even gentle running so I thought I see if walking very very quickly for an hour or so. Its certainly not but not so bad if it's dark and the locval kids cant throw bricks etc. ! Anyway my point being that I was pleasantly surprised that by the time I got home I really as if I'd stretched some leg bits that don't get a work out on the bike or a run. Just thought I'm mention it .... built up a bit of a sweat too, and swinging the arms seemed to loosen "tight " shoulders etc, after a stressful day.