unbelievably i can't find any pics of deep plants for DLRVJ jumpers.. lots of dead links.
ok I lied, there's a ton on my old photobucket:
I have no idea whether or not seated calve raises contribute much to vert.. but in DLRVJ, you can get in some positions which would most definitely stress them eccentrically.. I imagine if they are stronger, they may be able to contribute "something" to overall reactive strength.
I doubt anyone knows for sure.. but it could be worth incorporating (along with standing calve raises), to make sure you aren't missing out on potential "inches". As far as standing calve raises go, they are most definitely neglected.
I'll try to find some quotes about seated calf raises in SSTM. Verkhoshansky mentions them several times, related to leaping.
pc