The two strength workouts I go through mostly go are:
- Bodyweight 500 workout
- Plyometrics (I use the program in P90X, but there are lots of material for this out there)
When training is less intensive, i.e. during Build up, Off training and easier weeks in the sub programs I try to do 2 strength workouts every week. I tend to choose the Bodyweight 500 workout, but try to squeeze in a plyometrics workout every now and then since it’s really good for strengthening the muscles used during the kick off and landing in the running stride. That will lead to a stride that is less energy consuming.