Chris Pratt admitted the cast of 'The Tomorrow War' have suffered during the "physical" shoot.
The 41-year-old actor - who plays teacher and former Delta Force Operator Dan Forester in the upcoming sci-fi time travel movie - admitted he and his co-stars have all had their share of "bumps and bruises" on set.
He told SFX magazine: "I would say one of the biggest challenges was that this is an incredibly physical movie.
"We've taken our shares of bumps and bruises. Everyone had a day or two where they are limping or walking around with a pulled muscle or a sprained this or strained that.
"It has been really physical. But that's the kind of film it needs to be."
Pratt explained that once the characters arrive in the future, the action needed to be taken up a notch.
He added: "The minute we get dropped into the future, it's insanely intense.
"And it continues for a pretty steady clip and gets pretty gnarly at points, like meeting the White Spikes."
The movie has been made with a "combination of animatronics and animation", and Pratt revealed how the aliens have changed throughout the whole process.
He said: "It has been a very collaborative and evolutionary process getting the White Spikes to where they are right now.
"Some of the first concept artwork is actually much different than where it ended up.
"I was really excited when I first saw it, and eager to give input and very, very happy with where it's turned out. They are incredibly scary, unlike anything you've ever seen before."
And the star noted that his experience in 'Jurassic World' has set him up well for this movie.
He noted: "It's been a lot of fun. I'm seeing - we're pioneering, even - new technologies to bring forth realistic creatures.
"But this is something I'm right at home doing, and it's been fun to watch other people, some of whom have been doing it for years.
"And others are learning for the first time. It's cool to be part of that process and to be a little more seasoned in it so that I can give input."