LOS ANGELES—Vin Diesel didn’t want to look like a wimp.

The actor was in rehearsal for yet another fight in his seventh “Fast & Furious” movie when he started to sense his co-star and on-screen opponent, Jason Statham, was landing more blows than he was.

Mr. Diesel had an idea: Why not assign numerical values to every move—head butt, roundhouse kick, body slam—so he could calculate a total and determine if the two men were getting pummeled evenly?

In Hollywood, where sheltering the tender egos of action stars is increasingly a cost of doing business, no leading man is willing to look less macho than any other. Nowhere is that more apparent than the “Fast & Furious” franchise, where an arms race of machismo can break out between Mr. Diesel, Mr. Statham and their third beefy co-star, Dwayne Johnson.

Mr. Diesel’s points plan was eventually abandoned once everyone decided it was too complicated, according to a person present who worked with the star, but it was an example of the delicate balance that must be reached on every set the men are on. The ninth film, “Fast & Furious Presents: Hobbs & Shaw,” opens Friday.