Though Liang Yang flexed his stunt-double chops in Skyfall and X-Men: First Class, he's more than just a stand-in.

The martial arts specialist has trained scores of actors for fight scenes: He worked with Daisy Ridley for Star Wars: The Force Awakens (he even acted, playing TR8R, aka the Stormtrooper who calls Finn a ‘Traitor!’ before the two battle) and he trained Felicity Jones for Rogue One: A Star Wars Story, a prequel in the Star Wars canon, which opened on Friday.

Jones plays saboteur Jyn Erso, a soldier in the rebel Alliance who's involved in numerous fight scenes. So Yang concentrated on her coordination and strength.

He used full-impact pad drills ("This helped her crouch in many of the low fighting stances") and boosted her spatial awareness and lower-body strength in a weeks-long boot camp where she learned to perfect, among other moves, high-impact lunges and all manner of high and low kicks.

"Felicity's fitness level was good," Yang says. "But martial arts training is very different from other workouts."

Men’s Fitness spoke with Yang about how he prepped Jones and others in the Rogue One cast to hone their various martial arts skill-sets.

MF: A film like Rogue One requires a certain amount of athleticism, so did you put the cast through any specific fitness tests and then tailor your training to their fitness levels?

LY: For all cast members we do assessments to see their fitness levels and what their general movement is like. This provides an idea of how we should train them and then what particular fighting style works for their character. It depends on the scene we need to prepare for; if it’s a specific fight scene, for example, we assess their general movements whilst punching and using kick pads. We used this assessment, alongside the character's role, to choose a suitable fighting style so that training would be fluid and specifically tailored for this actor/actress alone.     

MF: What discussions did you have with Gareth [Edwards, the director] for how he wanted the action to look in the film?

LY: He wanted the martial arts in the film to have a grounded, realistic feel.

MF: Who among the cast was a natural and took easily to your training?

LY: All the cast members have a strong work ethic towards their craft, which was shown throughout their rigorous martial arts training. Everyone was committed, dedicated and put in endless effort to mastering this type of art for their given characters.

MF:  How did the martial arts training differ between Rogue One and The Force Awakens? Are there any new elements the cast had to train in?

LY: Rogue One is a standalone movie and the new characters are diverse, with each demonstrating a unique style. Felicity’s fighting style is direct whereas Chirrut Imwe’s [played by Donnie Yen] style is flamboyant. The creative team allowed us to stretch our imaginations in martial arts ideas to create fighting styles to suit each character.

As we got to understand Felicity’s character, we all decided to make her very strong, powerful and her attacking style very direct. As Donnie is a master in martial arts himself, we gathered his input in creating his flamboyant fighting style.

By contrast, in The Force Awakens the main characters’ fighting styles continued along the Jedi Knights style of lightsabers and using the Force.

MF: For Felicity, then, did you have to put her through a boot camp before the martial arts training began or were her fitness levels ready to go?

LY: Felicity exercises regularly on her own, but when we started with Felicity, we knew she had no form of martial arts training. Coordination and spatial awareness in a fight scene is vital, especially when multiple opponents are involved, and Felicity had many fight scenes where she had to perform a number of dynamic movements involving blocking, attacking, switching directions, and aiming at lower and upper parts of the body. All these high impact movements had to be timed precisely and at full speed.

We also knew Felicity needed a lot of leg and waist strength because most of the power in a fight originates from there. She had to work very hard practicing leg movements in specific martial arts stances that strengthened her legs as well as increased her flexibility. All of this enabled her to crouch in many of the low stances appropriate when fighting.

At the same time, Felicity’s character had to do a lot of big movements. These involved a lot of high impact lunges and dynamic movements, so it was important to help improve Felicity’s flexibility in order to avoid any injuries while at the same time allowing her to express herself physically through her performance.

At first, it will seem easy and simple. But after the first minute, the pain begins to kick in.

MF: So is there a sample workout that you put her and the rest of the cast through?

LY: The fitness instructor for the cast and myself collaborated, and as a martial artist, our strength training is comprised of different methods compared to a fitness trainer's methods.

For example, in leg workouts, a fitness trainer would use leg weights, squats or even jumping in terms of doing repetition to build muscle. Whereas implementing martial arts fighting stances such as Bow stance, Crouching stance, or Horse stance, the body posture, balance and coordination when moving builds all types of muscles throughout the entire lower body which includes legs and core. 

We helped the cast built arm strength when rehearsing attacking and defending weapons fight sequences. However, not only focusing exclusively on strength, as speed, control and explosive power is fundamentally important to work on a daily basis.

MF: Because much of the moves are grounded in being flexible, was there any training that sought to improve their flexibility?

LY:  Every session consisted of a warm up and warm down routine. To warm up, we did some light cardio jogging, and then a variety of leg stretches. They’d stretch their hamstring, do some bow stretches, butterfly stretches and frog stretches, as well as neck circles.   

The hips are so important to martial arts. That’s where all of the flexibility and coordination comes from. If we learned that someone had never done any martial arts training before, we knew the flexibility in their hips needed improvement for the demands required for their character role. I’d assign daily homework of the face down frog stretch—you’re kneeling down wide with your elbows on the floor parallel to your hips. Where you gradually open up your groin to as wide as possible and hold this position for at least five minutes.

At first, it will seem easy and simple. But after the first minute, the pain begins to kick in.

MF: What differed in how you approached the film training-wise?

LY: For all of the cast—not just Felicity—we focused on those three tenets of flexibility, coordination, and strength. It is important for any fighting style to work on these areas. Each day, we’d first warm up and stretch before we began coordination drills, which used full impact pad work and included punching and kicking. We also focused on allowing the actors to express their character’s aggression to connect with the scene.

Then if an actor needs help on specific techniques, we employed drills that worked on strengthening arms, legs, posture, and stance.

Once we set a base level of flexibility and strength, we felt comfortable to finally begin rehearsing the fight choreography. During the course of all of this training, though, if there were specific areas that an actor is uncomfortable with, whether because of the training or not feeling up to executing the fight scene, we would then break it down and work on that specific section with the actor until they are happy with it.