If you mean MTTs, then i play very tight at the start. There is just too many random all ins and ppl flat calling/calling raises preflop with shit so even if you hit TPTK you have to fold alot of hands coz you can't risk going out that early. There is also no way to put ppl on hands that early/with that many ppl in pots, so somebody could have flopped 2 pair on a 396 board and you would never know if they have a hand or are just raising with bottom pair and no kicker. So i normally wait for a premium hand, then play it very agressively and normally end up doubling up. Start to play alot looser as the tournament goes on.
I figure that all those guys that jump to 5k chips after 2 hands would be out of the tourament in 70% of MTTs by that stage. Not really worth the risk i don't think.
And, personally, i think the whole "rock" thing does work well in MTTs @ start. While i think a "rock" is a COMPLETE JOKE in a cash game, because you can tell almost exactly what their hand is and raise them off their blinds/pots they call, and then fold as soon as they show agression since you know they have a hand, i actually think it works well in a MTT. Reason being 1. few ppl actually pay attention to your play style in an MTT because of table shifting + random players. Now good MTT players obviously do, but good MTT players aren't going to be the ones doubling you up when you hit a hand. 2. by playing fairly loose you are just going to get alot of callers on marginal hands and then get raised all in off the pot unless you somehow flop the nuts.
I think you should play early tournament like you are the short stack in a cash game then late game open right up. I play MTTs totally different than cash games.