HM Strength is used to move large grey boulders.
Well its real simple you leave ectureak city go out the entrance on the right and a hiker comes up and runs into you. He hands you the HM.
u get can use it when u get the 4th or 5th badge
In Pokémon FireRed, for defeating Brock, his Badge will allow you the use of the Flash HM, Misty's Badge will allow you to use the Cut HM, Lt. Surge's Badge will allow you the use of the Fly HM, Erika's Badge will allow you the use of the Strength HM and Koga's Badge will allow you the use of the Surf HM.
You get HM strength in the lost tower, which can be found south of Solaceon Town. Talk to an old lady in the 5th floor and she'll give the HM strength. But be4 you can use it, you must have the sixth gym badge, the canalave badge. Hope this helps.
You need the rainbow badge which you get a celadon city Hm cut is needed.
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.
First you find the HM in the lost tower next to the hollow tower. then you get the badge from canlave city and your Pokemon can use strength
Gym leader #6- Byron @ Canalave City. When you defeat him, you can use HM 04 Strength outside of battle and push large boulders around.
You don't need a badge to get strength but you need a badge to use strength and that badge is the rainbowbadge and that is the 4th one in celadon city.
Articuno is in Seafoam Islands you need the HM Strength to get to it though and the HM Surf also you need the 4th and 5th badge.
Strength, which let's you move boulders around
You can use the move strength in Pokémon to move boulders. You can use strength in FireRed after getting the rainbow badge.
If u got Pokemon diamond version get the instruction booklet and go to page 34 it will tell u bout the gyms and badges. u get 5th badge in Canalave City Gym Byron Mine badge. Allows u to use hm strength , outside of battle you can unlock canalave city when obtained the hm surf.
You first have to have the HM strength and the 5th gym badge to use it. You can get the HM in Lost Tower, on Route 209. Teach it to one of your Pokemon and there you go. They HM will be on the top floor, just talk to the first old lady and she will give it to you.