4 isometric exercises that'll tighten and tone

10-minute workout

Isometric crunch

Lie on your back with feet flat on floor and hands on thighs. Lift your head, then your feet. Hold position, pressing hands firmly into legs. Push your legs back into your hands with equal force. Hold for 20 seconds. Do 3 reps.

Perfect your form: Keep lower back flat on floor without arching it too much.

Dial it down: Keep head on floor.

Amp it up: Hold for an additional 10 seconds.

Rolling plank

Start in plank with forearms on floor. Place right hand under right shoulder to lift body up. Follow with left arm, so you come up into high plank position. Slowly lower body, going back to start. Repeat 10 times, switching between right and left arms each time you start.

Perfect your form: Make sure to place hand directly under shoulder.

Dial it down: Drop to knees.

Amp it up: Increase your speed and reps.

Climb the rope

Lie on your back with feet flat on floor, shoulder-width apart. Reach your hands up as high as you can while lifting head and shoulders off floor. Climb an imaginary rope for a count of 20. Do 3 reps.

Perfect your form: Reach up high rather than forward.

Dial it down: Climb up for a count of 5, release and repeat 4 more times.

Amp it up: Rock from side to side and climb down the rope as well.

Plank to side plank

Start in high plank, with shoulders stacked above wrists. Hold for 10 seconds. Rotate body into side plank, lifting top arm. Hold for 10 seconds. Repeat on opposite side. Do 3 reps.

Perfect your form: Keep hips high and body in a straight line.

Dial it down: Bring the foot of your top leg to the floor in front of you for support.

Amp it up: Increase holds to 20 to 30 seconds.