Done correctly and with enough resistance OLs will improve maximum force. Done inefficiently and (therefore) with smaller loads OLs will be of little benefit to Fmax OR RFD…
BTW Tempo IS important - performing the concentric portion of an exercise as quickly as possible maximises recruitment of the higher threshold motor units (obviously at high loads bar speed will be low)
Doc is really not that big in person, he is kind of skinny. But ya it looks like he does have some added muscle in that picture though. I think he has put on some weight since the last time I have seen him. He was 165 at the time. now he is 170 something maybe?