I've been riding outside when I can (Chicago weather) and also using a traininer. My rides are go for 45 min to 1.5 hrs depending. I'm averaging around 13-14mph during those rides. Not really excessive by any means but also not poking along either. I try to do this every other day.
The other night I went for a 1+ jog with my 12yr old daughter. I'm not a runner and never was, actually kinda hate it. Anyway during the run my lungs felt fine, probably from the biking. My quads on the other hand were throbbing! Especially in the upper area of my quads. Different area that what I would normally feel when they start burning during a bike ride.
I woke up in the am with pretty sore quads. Still went for a hour ride yesterday. My quads are still sore today.
So my question is...different muscles used running compared to biking? Obviously I'm now thinking maybe run one day and bike another. BTW I'm 44 and am clocking in at 253, although down 7 in the last month.