Ask most trainers what muscles you should work to get ready for summer, and they'll steer you back toward long-term fitness. Forget the beach, they'll say. Let's work on your core. But Steve Zim, an L.A.-based trainer and author of 6 Weeks to a Hollywood Body, has an unusual expertise. His movie-star clients need beach physiques as much as overall fitness, and the secret is drop sets -- working to failure in repeating sets of lighter and lighter weight, which forces your muscles to work harder in less time. "We're all about drop sets," he says. "They won't strengthen your lower back, but if you want to look cut, they're phenomenal." Toss these exercises into your routine and you'll be photo-ready in no time.

BICEPS Hammer Curls • Drop Set* Unlike a traditional curl, hold the weights with palms facing in. Stand with weights at your sides, and slowly raise them by bending at the elbow. Try to touch the end of each dumbbell to the front of each shoulder. Return to the starting position to complete the rep. Avoid rocking at the waist, and make sure you're moving only from the elbows down.
PECTORALS Chest Presses • Drop Set* Adjust yourself so your hands are even with your chest. Press the weight slowly, making sure to keep your lower back in contact with the support pad or bench. Lower the weight to complete the rep. Proper breathing is important: Exhale while you press the weight. Inhale while lowering it.
CALVES Calf Raises • Drop Set* At a seated calf station, place only your toes and the balls of your feet on the foot bar. Raise the weight by pushing off the bar and going up on tiptoe. Slowly lower it to complete the rep. Try to max out your range of motion: Get as high up on your toes as you can in the raised half of the motion, and drop your heels as far as possible in the lowered half.
ABS & OBLIQUES Twisting V's • 3 sets of 50 alternating reps Start by lying on your back. Raise your legs and upper body roughly 30 degrees off the floor. You should be sitting on your butt, not resting on your lower back. Keeping your arms as straight as possible, twist and touch both hands to the floor on your right, then twist the other way and touch the floor on your left.