Info on the move Strength

Strength

Strength deals damage with no additional effect in battle.

When a Pokémon is holding Normalium Z and uses its Z-Power, Strength turns into Breakneck Blitz and has base power 160.

Strength is used to move large boulders in the field. Boulders can only be pushed, not pulled. It can only be used with the appropriate Gym Badge.

From Generation 5 onwards, boulders moved by Strength are often used to create shortcuts through caves and routes.

Gold Silver Crystal	A powerful physical attack.
Ruby Sapphire Emerald	Builds enormous power, then slams the foe.
FireRed LeafGreen	The foe is slugged at maximum power. Can also be used to move boulders.
Diamond Pearl Platinum HeartGold SoulSilver	The foe is slugged with a punch thrown at maximum power. It can also be used to move boulders.
Black White Black 2 White 2	The target is slugged with a punch thrown at maximum power. It can also be used to move heavy boulders.
X Y O.Ruby A.Sapphire	The target is slugged with a punch thrown at maximum power. This can also be used to move heavy boulders.
Sun Moon Ultra Sun Ultra Moon L.G. Pikachu L.G. Eevee	The target is slugged with a punch thrown at maximum power.
Sword Shield	The target is slugged with a punch thrown at maximum power.
B.Diamond S.Pearl	The target is slugged with a punch thrown at maximum power. It’s also one of the Pokétch’s hidden moves.