Doing less speed and more speed endurance will lead to decrease in 100m result.
It can be seen in Kratochvilova career from 1983. In 1982 she ran 1:56 at 800m just from her 200-400 preparation, in 1983 she improved the speed endurance element (now able to run the last 200m of the 400m in sub 25sec with one of them in 24.4 (!), and running 1:53.28 without pacemaker and only realizing with 100m to go she was on her way to the WR), as a result, her 100m went from 11.09 in 1981, 11.10 in 1982 to 11.3x (can’t remember exactly) in 1983.