Yesterday I was doing a super-set for abs and after last rep I got a sudden abs muscle contraction, I could not move for a few minutes. Why this happens and how to fight this?

Thank you beforehand bros.

hydration id imagine - if you werent properly hydrated then there could be a build up of salts which could cause cramp-like pains.

so this is because of not having enough water? Has this something in common regarding to calcium quantity in body?

Also you might not be stretcing properly before your workout.