In this video are Dr Mike Israetel & Jared Feather telling that eccentric loading (slow reps) are far more important than stop/squeeze the muscle for couple seconds.
Is this true?
It does not appear that slowed or paused reps reliably produce more hypertrophy than faster reps. I believe they are wanting people to lift in a certain way they feel like produces better results. To some extent, I think we all agree that controlled tempo may aid in muscle growth, provided ROM, muscles recruited, and so on change significantly with a “fast” rep.
Still, I don’t think we would confidently say a very slow (e.g. 4 second) eccentric builds more muscle than a 1- or 2- second eccentric or that a pause is reliably better than no pause.
I think if you’re looking for data so support the claims potentially being made, you’d have to ask them.