Thumb Extension Strengthening the muscles of your thumbs can help you grab and lift heavy things like cans and bottles. Put your hand flat on a table. Wrap a rubber band around your hand at the base of your finger joints. Gently move your thumb away from your fingers as far as you can. Hold for 30 to 60 seconds and release. Repeat 10 to 15 times with both hands. You can do this exercise two to three times a week, but rest your hands for 48 hours in between sessions.