jim, oh yes, the pain! I used to run a lot, but for the last 10 odd years all I’ve done is cycle (road and mtb). However, with time limited I’ve started running again and although the heart/lungs feel good, the legs have been in shreds – heavy and tight. However, after a month or so of basically jogging on off road terrain things are much better. Interestingly, exercising at the same hrm intensities running “feels” much harder than riding.