Chair dips are a convenient alternative strength exercise to regular dips. Dips target your triceps, the muscles on the back of your upper arm.

Chair Dips
Step 1
Sit on the edge of a sturdy chair, with hands next to hips.
Step 2
Slide your bottom off the edge and bend elbows to 90 degrees.
Step 3
Be sure to keep your back close to the chair, then push back up. Do 7 to 10 repetitions.

Source: Parenting