I know that rest days are important, but I had a question about them: I started running today, but have been cycling fairly regularly. I ran 4.2 miles this evening, and quit there, because I didn't want to overdo it my first time out. Cardio-wise I'm fine (as I ride 70-100 miles/week right now), and there is a tingling in my calves and quads from using muscles in a way I haven't before.
My question is what will the ill effects of commuting tomorrow be? It is a 10 mile ride I do regularly and since I have only gotten out once this week I was kind of planning on it. Furthermore, I plan on trying to begin a Strava challenge on saturday that will entail riding about 30 miles per day for 2 weeks. The question isn't about the Strava challenge, as 30-odd miles isn't any sort of stress on my system that really requires recovery days, but just if you would recommend against riding tomorrow after starting running, or if I shouldn't have any serious problems forgoing a rest day just this once.