Recently did 3x1mile (3min jog recov) on a mostly gravel loop in trainers. Split 5:15, 5:23, 5:37; went out too hard the first rep and paid the price on the atrocious last rep. 80° and somewhat windy. This was definitely difficult but not max. HS senior guy who's averaged 50mpw (a few at 55) and ran 2:08/4:43 in the 8/16 in spring TTs. 5k prediction? (Will be racing on a flat grass course)
Other workouts:
Fast finish 10 miler @ 6:35 avg pace (6:4x first 7 and 6:0x last 3)
3x2k (first/last 200m @ 35, middle 1600m @ tempo; 3min jog recov) @ 7:07, 7:05, 7:04