When Kellan Lutz first landed the role, he said that physique-wise he wanted to get really big to portray Hercules. But director Renny Harlin told him not to get any bigger as he found it very stereotypical for Hercules to be "a pile of meat", he instead instructed Lutz to "get his abs to pop out more" as he thought it would be a great effect in 3D. So Kellan Lutz adopted a special Paleo (caveman) diet for the role ensuring that no fat accumulated on his body and that his abs visibly popped throughout principal photography.
Renny Harlin said that he chose Scott Adkins for the role of King Amphitryon because of "his acting skills, his incredible physical ability and his incredible physique". He said that King Amphitryon "had to be the biggest badass the audience had ever seen and only Scott Adkins fit that bill".
Slay the Nemean Lion.
Slay the nine-headed Lernaean Hydra.
Capture the Golden Hind of Artemis.
Capture the Erymanthian Boar.
Clean the Augean stables in a single day.
Slay the Stymphalian Birds.
Capture the Cretan Bull.
Steal the Mares of Diomedes.
Obtain the girdle of Hippolyta, Queen of the Amazons.
Obtain the cattle of the monster Geryon.
Steal the apples of the Hesperides (He had the help of Atlas to pick them after Hercules had slain Ladon).
Capture and bring back Cerberus.