For the most effective strength you should use Dharok's set because if you have the full set when you lose health you gain more strength as you lose health. Use in conjunction with rock cakes for effectivness but be sure to get healing food in case you are dying.
Guthan's set should be imployed if you do not wish to lose health as you can damage enemies and if you had activated the special effect you can gain the amount of health you hit the enemy. (Visible effect)
But you can use Verac's set if you are constantly using prayer and you can sometimes ignore the armour and prayer.
But Torag's set could be helpful because if the special is activated, you decrease the enemy's run energy by 20%.
Ahrim's set is for warrior enemies because you can damage him and reduce his strength by 10%.
Karil's should be used for anyone who has a high agility level because it
Dharok for strength, Verac for prayer, Guthan for healing, Torag for running enemies (warriors), Ahrim for magic,and Karil's for runners (mage and rangers) but you don't need use Karil or Ahrim's if you don't want to.
For more information about Barrows, clickl link to RuneScape wiki: