Four quick but effective exercises from fitness guru Josh Holland, of New York's Core Club.

1. Stationary Chair Step-Up

Plant right foot on a stable seat and step up, lifting your left knee into a slight bend. Repeat for one minute, then switch sides.

2. Bed Push-Up

Put hands in line with shoulders, slightly turned out. Bring feet together behind you. Lower chin to bed, and push up. Repeat for one minute.

3. Bed Squat

With feet hip-width apart and back straight, lower into a seated position. Jump out of it to add difficulty. Repeat for one minute.

4. Pillow Squeeze Oblique Twist

With a pillow between your knees, lie on your back, arms out, palms down. Lift legs to a right angle. Squeeze knees and lower legs to the right. Return to center, then lower left. Repeat for one minute.