In Hero Zero,training is a mode that you can grow your skills with spending 3 to 10 training units.Every training lasts 5 minutes,but you can complete it with 1 donut,or to decline waiting time by 50percent with TV or batteries.They grow your skills by 5 units when you complete the required trainings,but many times they grow your skills more than 5 units,and many times over 10 (depends to your level).As all modes of the game it has heroic deeds about training,about first training and below.Also there are training trophies,who they give more training units.