Hello, fellow masters runners (54/M here, 25 miles/week on 4 days per week). I'm wondering if any of you do any truly hard, gut-busting, lung-heaving intervals like you did in your younger years. From what I've read, those days should be long behind us, but I'm not so sure about that. I think there's still a place for them, as long as we proceed cautiously.
The most "all-out" interval work I've done in the past few weeks is diagonals on a soccer pitch for 10-15 minutes (run fast from corner flag to opposite corner flag, with slow jog across the pitch, repeat). I started at 5k pace then built to mile pace toward the end of the session. It was tough, but not brutal. I think I have more in me, but all the advice I've read advises against it.
What do you fellow masters runners think? Have you had any success with truly all-out intervals (i.e. 10x400m @ mile pace with 200m jog), or did you regret it?