Have you been following the thread? A lot of different ideas to answer this question have been provided.
Yes, but still haven’t got a “proper” answer, maybe I’m the one who won’t get a “proper” answer
Essentially, you have to ask yourself for what purpose are you include the heavy lifting and to what extent are you really including it? 10-20% of reps (and presumably a regular frequency @ no less than once a week, most likely twice a week) is going to amount to a great deal of your training volumes. At these frequencies and volumes, this is going to require significant recovery, which is hard to compliment with sprint training. On its own, it also does little to increase muscle mass where it is needed. Presumably, anybody that is weak enough to find strength to be significantly problematic is likely going to be lacking enough muscle in the right places (glutes, hamstrings, back, etc.).
How do you determine where extra muscle mass is needed? Are trying to increase muscle mass in a particular area? I don’t need any extra mass b/c my main event is 400m and I weight 82kg, height is 1.88m
What extra benefits are you going to see from regularly (10-20% of volume, essentially) using heavier loads versus more moderate loading? Frankly, there isn’t really going to be any if you are a sprinter/jumper and you will most likely experience significant problems in training from a recovery standpoint. You could easily do a hard 5×5 program twice a week, testing your 1rm, 3rm, or 5rm once every 3-4 weeks and you wouldn’t approach 10% of total volume >85% of 1RM, let alone >90%. That is likely far beyond what anybody would ever need (quite excessive, in fact) and it is still significantly below what Star has recommended.
I compete just during summer season, but never prepared for a full 10 month as a whole macrocycle, usually 5 month before main summer competition. This year I have a long time before summer season, so I won’t rush during my GPP. Now I can lift heavy b/c I do very minimal endurance work, very minimal sprint work so I don’t have much problems with recovery. I’ll start to introduce special endurance work just in the end of the winter b/c I noticed that for me there is no point spending more than 5 month for it, it’s sufficient time for increasing speed endurance levels before main competition. Now during my GPP sprinting at intensities near 100% is enough about once every two weeks, later I’ll do once a week b/c I don’t need quick adaptation for it as well. Believe me I worked with submaximal loads as well and it’s ok, my max strength quickly plateud, faster adapatation might have been due to interferance doing special enduranc work 3 times a week . Now I don’t have what to loose so I’ll try using heavier loads two times a week with reloading every 3-4 weeks to bring my max strength to another level. I’m doing it for a month now, I don’t feel slower or another interferance. I just want another stimulus which might help to increase my running speed. If heavy loads won’t help, so submaximal as well. Of course I introduce some explosive work as well for longer adaptation and to keep some specificity, I’ll simply replace heavy lifting during certine periods with explosive work. During spring all my strenght and speed levels wich I’ll get, simply more or less will be maintained b/c tempo/special endurance, speed endurance workouts will come into play. Simply during that time there won’t be possible to improve all qualities at once.