a hole bunch of places it allows you to move rocks
use strength
The HM04 Strength can be found in Rusturf Tunnel in Pokemon Sapphire.
after you beat the gym leader that tells you you can use the hm move go to the house right next to it and there (i hope i was of any help)
Go to Rusturf tunnel then use rock smash in either of the 2 rocks then the man(the one in the left of a rock) will talk to you and.....
First, you must go to Vanderturf Town. Now go into the cave. Go up then left. Use Rock Smash on the rocks. The man will talk to you and be impressed with your skills. He will then give you strength, and now you also have an easy path to Rusborough!
When you get to miavile in a house there is hm-Rock smash(beat Watson to use) then go to Vandturf, there will be a cave go in smash 1 boulder near the girl then the man comes accross and gives you hm-Strength
You get Strength by using Rock Smash on the rocks in Rusturf Tunnel blocking the path of the Man and Woman. When you do so the Man will automatically give you Strength. Once you get the HM Strength all you have to do is click it and select "Use" then teach it to a Pokemon that can learn it. To use it all you do is click on a boulder (with no cracks) and there ya go. You used it.
You get it from a lady in vendanturf town, and use it in front of big boulders. you need the heat badge to use it out of battle.
use rock smash on the rugged rock and the guy will give it to you when you smash one of the rocks
Head to Rusturf Tunnel which is east from Rustboro City inside use Rock Smash and talk to the karate guy he will give you the HM Strength.
break verdanttuff's rocks, i think.
unova