Bobby Strom is a personal trainer who has worked with a host of celebrities, including Britney Spears, Ryan Reynolds and Scarlett Johansson. Here he talks to MF about training actor Joel Kinnaman for his leading role in last year’s Robocop remake.

He was lean and fit because he’d been doing a little training already. We just made him leaner, bigger, stronger and in superior condition.

I’ve been working with him since January 2013, when he had to get in shape for filming, but we’ve continued to the present day.

The Robocop suit that he had to wear was heavy, so we did a lot of core and stability work to protect his back, using a TRX, a Bosu ball, stability boards and resistance bands. We also did a lot of high-intensity interval workouts that I call ‘mash-ups’. The aim is to move hard and fast through the entire workout, and never do the same workout twice.

He really did and still does – we’re training together six days a week at the moment.