I would say the exact opposite. I think training in the Nike Frees is the way to go. They are the only thing I ever wear. You just have to introduce them slowly so the muscle can build up accordingly. I wouldnt throw them on and try doing depth jumps or bounds on the track, but line hops, skips and hops on grass would be a good place to start. Def introduce them during GPP so they have plenty of time to adapt. And start with the Free Everydays, then over time progress to the 5.0. I have yet to try the 3.0 myself so I can comment on them, but they would be the final step.