Get Hard Core: The Exercises

Fit-Ball Side-Ups

Targets: core + obliques + balance

#1
Wedge your feet into the space where the floor meets the wall. Lie sideways, with your hip leaning on a fit ball. For week nine, start with your hands folded behind your neck, elbows out.

Fit-Ball Side-Ups

#2
Lower your upper body over the ball until you feel a slight stretch, then slowly rise up until your obliques contract.

Fit-Ball Side-Ups

#3
Do two sets of 15 reps on each side. “This move is more challenging than oblique sit-ups on the floor, says Keller. “You’re adding a balance component and taking the obliques through their full range. In week 10, hold a medicine ball (or dumbbell) overhead, progressing from three to eight pounds by week 12.

Balance Disk Tug-of-War

Targets: core + balance + arms

Find a partner, two balance disks, and a 20-foot rope. Place the disks 10 feet apart, then stand with one leg on a disk, facing your partner. Hold the rope taut between you and your opponent, and begin tugging. Topple your partner by pulling the line or creating unexpected slack. Start with 30 seconds of play on each leg. By week 12, progress to one minute per leg—with your eyes closed.

Fit-Ball Arm Explosions

Targets: core + balance + pectorals + rotator cuff

#1
Lie facing the ceiling with your shoulders on a fit ball—feet planted on the floor, knees bent at 90 degrees, and hips lifted. Your partner, standing on a bench behind you, drops a three-pound medicine ball into one of your hands, outside the line of your body. Catch the ball, then launch it as high as possible for your partner to catch.

Fit-Ball Arm Explosions

#2
Do 10 drops, then switch your catching hand and repeat. For weeks 9 and 10, use balance disks under one foot, then under both. Try the move with just one leg on the floor. “The struggle to save yourself from falling is a great way to challenge the core, says Keller.<

Bench Lateral- Weight Shift

#1
Targets: eccentric strengthening (quads) + balance + core

Standing next to a foot-high bench, drop into a high tuck position. Place one leg on the bench, then slowly shift your weight from floor leg to bench leg.

Bench Lateral- Weight Shift

#2
Gradually extend upward so you’re standing straight up, with one leg on the bench. Sink down for seven counts, shifting your weight back to the floor leg. Repeat on the opposite side, starting with one set of 10. By week 12, shoot for two sets of 10, increasing the height to a weight bench. “This move works so well for skiers because you’re training the muscle to fight against gravity, says Keller.

Lateral Drop Jumps

#1
Targets: plyometric strengthening (total leg) + agility + balance + core

Lateral Drop Jumps

#2
Drop off a low step onto your left foot, assuming a low crouch position.

Lateral Drop Jumps

#3
Immediately bound laterally to the right as high and far as you can, then step back up to the start position. Alternate legs so you’re exploding left on one drop, then right on the next, and so on.

Lateral Drop Jumps

#4
Do two to three bounds per side. To enhance the difficulty, jump further laterally and increase the height of the step. “By combining balance, agility, core, plyometrics, and strengthening, this move builds power, says Keller.

One-Legged Arm Extensions

Targets: core + balance+ deltoids

Stand on one leg on a balance disk or half foam roller. Holding dumbbells, start with hands at your chest, elbows out. Alternately extend one arm to the side, parallel to the floor, leaving the other arm at the chest. Begin with five reps on each arm with low weight (three pounds) and progress to 10 reps per side with higher weight (five pounds). “Moving one arm creates a leverage that puts you even more off balance, explains Keller. Use your core to keep yourself from falling over.