This Stat is used to calculate damage inflicted in close combat. The first Digit indicates the number of damages rolls made in one attack and the second times 100 is the posibillity of making another damage roll. Therefore, the higher the Strength value of a Hero or a ranged-weapon the higher the damage you can do (see Combat for details).
Strenght can be increased through Strength Increase. Additionaly, someRight Hand weapons (mainly two-handed weapons) have a Strength bonus in combat.