At what performance levels or strength levels do the use of blocks become advantageous?
Blocks are effective when the athlete has enough strength to use them properly. (I hate to see 10 year old’s get into blocks at junior olympic meets.) Anyway, training age has a lot to do with it. Keep them doing simulated starts for feeling until they are ready.
I agree, working with even highschool aged athletes, I often wonder how many of them are ready to effectively use blocks. There defineately is a strength/power level that must be developed prior to them giving any advantage.