just my 2 cents worth here:
if you live well, you age well
1) eat well (avoid toxins like alcohol)
2) sleep well (9 hours + per day)
3) train well
you lose speed if you stop doing speed....but if you do speed you have to be cautious....you can't do speed workouts like you did when you were younger. I suggest longer warmups (including the first few reps being much slower than you expect to run). Example: if I am doing 200's i am not embarrassed to start at 50 and then just gradually drop the time as my body lets me; my progression of my last workout went something like this: 44, 43, 42, 41, 39, 38, 37, 36...then i really just started the workout. i have gotten to where i do this a lot before doing anything real fast. another thing i have to accept is some days i can't break 40 (this is mostly injury/tightness related) other days i can hit 32. Don't force workouts - do what your body lets you on that day. For this reason i really don't plan workouts. I plan to run hard, but what will be determined by how my body feels.
You also have to keep those muscles loose: stretching, rolling, active release etc are very important. This helps keep your stride length and good posture while running. Simple speed drills are also good to do. I like to run in barefoot or socks and just do little strides where i try to stay off my heels. you can use those little 6 inch training hurdles to help with this. just set them about 1 meter a part and run over them. this helps with knee lift etc without even having to think about it.
I have not had any problems with recovering from hard efforts...but i think this more a function of good living (food, sleep) than anything else. Older runners who have been getting by cutting corners are the ones probably finding they just can't recovery like they used to. If anything, i find the recovery a non isssue. As i increased my mileage at age 50, i found i could recover even quicker.
i have not ventured into supershoes...so this is not a factor in my recovery....but i will say that i hate the built up shoes of today and do all my training in racing flats or spikes.
If you haven't recovered, don't do another hard effort day until you have (everyone is different) if that means you need 2 days, you take 2 days. if 4, take 4. Some will take a whole week. I can still do an occasional track workout back-to-back if they are moderately hard days or not big volume days.