Actors have to go through a lot to portray certain roles in movies. We have seen actors who have drastically gained or lost weight just to fit in their roles. It might be crazy, but this is what acting is all about. You have to do some of the craziest things just so you can say you are the right person for the job.
There are instances when actors have to put their lives at risk just so they can fulfill their roles. Fight scenes are among the most difficult. They have to practice so they can portray the role in a believable way. They also need to ensure their personal safety and that of the people they are acting with.
It is even more complicated when the scenes have to be shot underwater or on the water. There is another element that has to be taken into consideration on top of the already difficult scenes that have to be filmed.
This is also why actors have to prepare a lot just for these movies that are to be shot on the water. Some of them have to work for hours with swimming experts so they can do well on the job.
Above ground pools are usually used for practice to ensure safety. They just can’t practice using the actual place where the movies are to be shot. They can start with pools so nothing wrong could happen.
They take it seriously
Some of the most successful actors are the ones who really take their roles seriously. It does not matter what is required of the job, they have to fulfill it. Those who have a very diva-ish attitude on set are usually not hired again for a different role. Attitude is extremely important for actors. This is why when directors have to tell them to take swimming lessons or lose weight, they have to do it right away. This is true even if they are already having a hard time.