Try to do the strength training after your Run. Ideally 4-6 hours after. Avoid the day before a long run. Keep you Easy Days easy and Hard Days hard – you can strength train on a speed or tempo day, but not a Long Run day.

As for weight – try to do use a weight that is heavy enough that you can do 8 reps and still have a little juice in the tank to do 2 more. If you can do 10 easily – this is too light. If your form breaks down – it too heavy.

Day 1

WARMUP:
3 sets circuit of
10/side Hip Down Side Planks
10/side Single Leg Elevated Glute Bridge
10/side Single Leg Calf Raises

MAIN:
3 set circuit
8/side Bulgarian Split Squat
8/side Staggered Leg Single Leg Deadlift
30s high plank

Day 2

WARM UP
3 set circuit
8/side Side Plank leg lifts
8/side single leg hip thrusters
8/side bent leg calf raises

MAIN
3 set circuit
8/side Single leg sit to stand
8 Hamstring Walk outs