Bike compared to Run

mlb929

So in my training plan for a 1/2 marathon at the end of June, I had a 4 mile run yesterday. I also biked 6 miles to school with the kids, to work, then home after work. My legs were a bit fatigued more today than what they generally are after 4 miles. I run frequently and have for the past year+, I've completed a marathon, so know my running fairly well.

My training plan says on Tue and Thurs - I can cross-train instead of run - so if I'm biking - how many miles to I go to compare to a 4 mile run? Is there an estimate of the expectation on my legs of x miles biking for x miles running?

The kids have 3 more weeks of school and if the weather is good -we'll ride most days - its 2 miles there, 2 miles to my office - and 2 miles home. So 4 miles in the Am - and 2 in the PM. Just trying to figure out if this is "cross-training" and I should skip the run?

jipper44

I haven't specifically researched it but my college track coach used to say that you have to bike 4x the amount of time you'd run to get close to the same workout...this might get you close.