So, I've been biking to start off my plan. I've on to week four, doing ~8-10 miles/day, 4-5 days a week (basically commuting to work on my bike). At first it was mostly a cardio workout, but as my heart and lungs started to get in to shape (or at least better shape than they were in), I was able to pedal harder and started really working my legs.

Now, as I start week 4, my quads are really feeling sore all the time, specifically the tendons in front and just above my knee. I know it's just the usual aches and pains from giving yourself a real workout, but it is making it harder to push myself to get on that bike each day.

I'm not interested in pain killers (I want to be able to feel it if I do some actual damage), but I'm wondering if anyone has any tips to help tendons and ligaments heal/endure a daily workout.

I'm thinking I'll try some heat rub and maybe make some dietary adjustments to help. I've thought about just biking every other day, but I really need to make it part of my daily routine in order to stick with it. Surely the human body can handle this level of exercise.

I'm sorry if this is something you do already but are you stretching properly before and after?

After a good workout, I find doing additional stretchees later in the evening and/or the morning after to be really helpful as well.

Good luck!

The jury is still out with regard to stretching for cycling -- I understand it can be beneficial after a ride; but beforehand, it probably doesn't do anything... Don't quote me on that, it's just what I've read from several places.

Anyway, 10 miles per day for four weeks and you're getting a bit sore? Well, like you say, it's not a Herculean amount of exercise; but if you're only just starting out (or starting up again), it's enough. You need to take breaks -- not just for cycling but any exercise -- to allow the body to heal.
Take a day or two off and the worn fibres in your quads, etc. will repair -- when you get back on the bike, you'll find you'll be stronger than before.

Recovery is as important a part of training as putting in all the miles.