Fallout 2 and Fallout Tactics
Grants +3 to your Strength for the purposes of using weapons.
The Fallout 2 manual erroneously states that the Strength requirement is 1-9, instead of 1-6.
Fallout: New Vegas
It reduces the Strength requirement of all weapons by 2. It requires a Strength lower than 10.
This perk allows an Explosives or Energy Weapons focused Courier to effectively use any weapon from those categories with a Strength no higher than 6 and the appropriate skill requirements. This is most useful for players who min/max their SPECIAL attributes, as a starting Strength of 4-5 can achieve this through use of the Strength Implant, Remnants power armor and/or the Intense Training perk.