>>34695603to add to that:
you can somewhat train the muscles and tendons just by running. But this takes them for them to build. Condition is easy to build. But not those things.
If you can, also run up hills, run with some weird terrain that forces your foot on different angles.
Inside of the club we sometimes just ran in nature, on uneven terrain just for that. Not even on high speed.
Personally, I do a lot of high intensity training on a 300 meter hill here nearby that has stairs. Man my back leg muscles grew strong as fuck to that. I could tolerate a bit more punishment on them as a result from that.
But still, 6 days, one very intense session on 12km for 1.5 hours and they are fucked.