Training Regimen

The ordering on the card is the tell: the trample rider reads on every creature already carrying counters, and the precombat trigger is the pump that keeps feeding that pool. Together they form a static engine that widens the more you commit to it. Each combat-step counter both grows a body and switches on trample for it, so a ground stall of blockable creatures becomes a wall of damage that leaks through chump blocks. The trigger resolves before attackers are declared, so casting this in your main phase still nets a counter and a trample enabler that same turn; it does not sit dead the turn it lands, though it needs a target on the board to point at. What pays for the four-mana price is the passivity: the counter placement is a fixed trigger you cannot hold up or bluff with, and the trample clause is inert until creatures wearing counters give it something to apply to. That makes this a build-around rather than a splash: the trample text does nothing until a counters shell turns it on, and the counter distribution overlaps with the many cheaper ways green already hands out +1/+1 counters. Where it earns its slot is welding both halves into one permanent that keeps working without further input, taxing neither your mana nor your attention once it resolves.