Theboxjumplooksamazing, butit's notjustpureverticaljumping, it's actually a complexmovethatbuildsontopof a verticaljumpbypullingyourfeetuptowardsyourhips, interestingly, about a centuryago, therewasanolympiceventcalledthestandinghighjumpanditwasprettysimilartoboxjumping.
Theproblemwiththatisthatwhenyou'redowntherewaitingtostartyourjump, you'remaking a forcethatissubmaximum, you'rejustneedingtomaketheforcethatyouneedtoholdthatdownwardpositionandtobeabletogoupward, youneedtomake a forcethatisbiggerthanthat.