Its still 75% - normally due to a much more relaxed start your looking closer to 15sec, but with a rolling start sure, 14sec is easy.
Mind you, guys i had who were 22-23sec 200m shape, we had running 30-32sec tempo, but naturally the odd 27-28sec was popped out, which didn’t really matter so long as most were 30+.
22sec + 25% = 27.5sec. So easy really.
We never bother really timing 100’s - you can tell as a coach if somebody is going too fast with Just your eyes. Esp with Body weight exercises thrown in, that will typically drop the pace to 15-17sec per 100m. EASY. Hard workout, but EASY to recover from.
Im not coaching Sprinters for the last couple of years - but it looks like im moving town in a short while, and plane on looking for Sprinters when i do move. Currently coaching General Population for fitness, weight loss and Figure.
When i have coached sprints - normally high school (then they moved to the big city for uni) and guys were typical 10.65 - 11.20 shape after 6months, By year 11/12 that is. FAT times.