After a warmup with 3D plank to activate your core:
simple plank or bird dog plank (one arm one leg),
side plank and reverse plank(glute bridge), aim for one minute each.
see recommended routine for details and an advanced strength program.
Then do strength training:
only don't eat big so you don't get big.
do 1 or 2 sets to train almost every day,
or kick 5 sets and train 3 time a week
with 2 to 5 reps (strength range) for each set.
for legs: pistols(one leg squats) and/or weighted lunges (Elevated Reverse Lunge).
for the core: leg raises/L-sit->V-sit, back lever progressions
for arms horizontal: push-ups, body-rows (reverse rows)
for arms vertical: pike push-ups/handstand push-ups , negative pull-ups/pull-ups
Then do endurance/stamina training:
alternating between high knees(hip-flexors) and butt kicks(hamstrings) (High Knees Butt Kickers in Place for spring training www.youtube.com/watch?v=TVE_r1Af9r8) (Non Stop 1 hour High knees challenge v=l_p-wokHvzQ)
tons of reverse lunges (or walking lunges) with knee raises combo they are better than squats for running (sets of 100 to thousands) build to do them for the time of your distance (example: for 10k aim for 40min-1hour of lunges) (Runners lunge to knee drive www.youtube.com/watch?v=9KjeQxK3ii8).
jumping lunges, jumping jacks.
for more stamina you can also have days of Burpees, kettle-bell swings(for posterior chain)...
and finally you can have days to build core stamina through plank sets and then build for one [knee] plank of 40min or more.