Annie, as was said before, endurance training is generally done at a moderate level of exertion. Intervals are done with the aim of increasing speed and strength. Keep up the indoor cycling, but look at riding a bike outdoors instead of running. I've met countless runners who took up cycling as a way to rehab running-related injuries, but never a cyclist who took up running because of cycling-related injuries.
Funny you should say that. The PT guy suggested a bike since I live so close to the trails as opposed to trying to run. That Peleton bike (and subscription) sure has my attention, but for as long as I have this gym membership I'll probably not fool with it.
The plantar tendonitis I've been fighting since January comes and goes. The most concerning thing about it, though, is no matter where on my foot it aches it ALWAYS has this "tugging" feeling at the top of my Achilles tendon. THAT is NOT a good sign. Ortho says for someone half my age it can take up to a year to heal. I'm not half my age anymore. Lol
I'm still doing the PT exercises he gave me to do to strengthen my arches and the muscles in my feet and ankles (hell, might as well since I'm doing my neck, shoulders, upper back, rotator cuffs and hand grip stuff, too ... lol). PT guy says that this is one injury that never really goes away. That you can go for months thinking you are fine and then just step just the right way and -- oops, there it is again. That has been my experience so far. Just about the time I think I've made progress with it, I will tweak it somehow and wind up starting back at square one.
Pretty soon I'm just gonna be doing a regular workout! Haha!
But anyway, I've noticed that walking more than 3-5 miles a day will aggravate it, no matter how careful I am with my gait, but I seem to be able to cycle as long as I want with no problems. I'm averaging 20-23 miles a day, 3 days on, 1 day off, rinse, repeat, with an average heart rate overall of 135-140. Doc was pretty adamant about not getting over 150 until we figure out the swelling in my throat because I've noticed that sometimes when I'm working out it tries to act up. I do think it is getting better, though. I'm not having to strain to talk nearly as hard ... and Mugsy said I sounded better Wednesday. I STILL can't yell though ...