Upper-Body Boot Camp: Toned Arms in 10 Minutes

Propped Push-Up

What you'll need: A 4- to 8-pound medicine ball ($15 and up, power-systems.com)

Targets: Shoulders, back, chest, triceps, and abs

• Start on all fours (knees under hips, back flat), both palms pressing into ball directly below chest, fingers pointed toward floor. Extend legs behind you and balance on toes so that you form a straight line from head to heels, with feet about 2 feet apart.
• Bend elbows to lower chest toward ball, keeping arms by sides, abs engaged and back flat. Exhale as you push back up, straightening arms.
• Do 8 reps. Rest 60 seconds; repeat.