Flannery of Lavaridge Town.
6th gym leader in canalave city
move rocks
In Emerald you have to beat Flannery in Lavaridge But to get Strength you have to smash the rocks in the tunnel between Rustboro and Verdanturf. Good Luck!
Proboly yes
beat the forth gym leader
You will be able to use HM04 Strength outside of battle after you defeat the 6th gym which is in Canalave City.
canalave city gym
in emerald hm05 is flash, you find it in granite cave but you have to have the knuckle badge to use it outside of battle
rock smash is hm06 and is found in mauville city but you need the dynamo badge to use it outside of battle
Press A at a large, grey boulder to gain the power to push it.
strength after the chamber
you find it in the cave by verdanturf town but you need to to beat the third gym to be able to use it outside of battle
Teach it the HM move Strength. You will also need the badge from Celadon City which will allow you to use Strength outside of battle.
its in the lost tower on route 209 u can use it in battle but u hav to defeat the 6th gym leader to use it outside of battle. hope ive helped :D