Dear Linas Bruzas,
your questions regards many important issues (and it’s my favourite issues) that for their importance should be discussed in more deep way. Nevertheless I will try to answer you in synthetic way.
First of all, the training system of 400 m runners is quite complicate and it’s not good way that you are “training on my own” without a coach. It will be pleasure for me to suggest you a good Track&Field coach that lives in Vilnus, but I don’t know any coach in Vilnus who works with 400 m runners.
The only solution that I can suggest you is to became an expert in this matter through the reading of specific literature, but pay attention with the practical interpretation of the ideas of other persons. For example, “run slow to run faster” could be a good idea, but there could be different interpretations of what does mean “run slow”. I prefer to say “ran slow before to ran faster”. It’s one of the main principles of my Block Training System in T&F running. We are ending my new article “The block training system in endurance running” in which I describe this idea in detail.
Now, about training means. I prefer to not express a unilateral opinion about single training mean, because all depend on the whole system in which this training mean is used.
You asked me about the usefulness of Depth jumps for speed runners. I agree with Charlie Francis that this training mean is more useful for jumpers, but some volume of this means could be used also by runner if his strides pushes are not enough explosive.
How its better to incorporate the speed training in a weekly cycle when I do 3 interval session a week if to start from monday with interval session with a sunday rest?
This is really the question for your coach, because there could be different solutions: all depend on your level of aerobic capacity, legs strength, the kind of speed exercises and the kind of interval session that you use. But I know that Italian runners don’t use the glycolytic interval training more that one time per week.
Now about training means finalised to the maximal speed increasing. This exercises will be described in my article “The block training system in endurance running” together with the overload exercises that must be used before in the precedent training stage:
1. Long Build Ups, are 100-120m runs performed with a smooth increase in speed up to a point where it is kept constant by inertia while holding technical form.
2. Uphill running with an accentuated push and an active forward swinging movement of the other leg.(it could be also Uphill Bounding run and Uphill Bouncy run)
3. Fast 50 meter Bounding runs (in this exercise, I don’t suggest to put a barbell on a shoulders)
4. Short accelerations and block starts.