Start in a side plank with left forearm on floor, elbow under shoulder, feet stacked, and hips lifted so body forms one long, straight line. Stretch right arm up to ceiling. This is your starting position. Draw the right hand down and reach it below left underarm as you curl upper body forward so shoulders are parallel to floor. Return to starting position. Repeat for 30 seconds on each side.
Leg day, arms day, chest-and-shoulders day. You already break up your regular workouts by muscle group; steal a page out of Alicia Vikander’s ab-shredding book and do the same to your core. To get ripped for Tomb Raider, Vikander broke her core workouts into three days: isometric (endurance moves, like planks); strength (sit-ups, hanging leg raises); and oblique-specific (told you so).
I try to ensure my form and posture is correct and verify the same by heading over to YouTube and clearly looking at the way every exercise is performed, taking screenshots. While I do cheat towards the end with heavy reps, I make sure I nail the first 4–5 perfectly. I also made it a point to not skip leg day. Exercising legs has incredible benefits like making you stronger on your compound lifts and releasing the maximum amount of testosterone.
Eat carbs. "There's this notion that carbs are bad and that you need crazy amounts of protein to be lean and fit," says Alcantara, who disagrees, and eats just as much carbs as protein, although the ideal ratio varies based on your goals. "Whatever you eat to get the results you want has to be sustainable, otherwise you're going to end up right back where you started with the same habits that got you there."