Edward R. Laskowski, M.D.: The squat is an exercise you can do with dumbbells to work the muscles in your thighs and buttocks. With the squat, you'll target the gluteal muscles, here, the hamstrings, here, and the quadriceps, here. Strengthening these muscles can help you improve your ability to perform daily tasks, as well as improve your performance in a variety of sports.
Nicole L. Campbell: To do a squat with dumbbells, hold a dumbbell in each hand and stand with your feet about shoulder-width apart. Let your arms hang straight below your shoulders. Tighten your abdominal muscles and slowly descend, bending through the hips, knees and ankles while keeping your spine in a balanced, stable position. Your knees should be centered over your feet and should not move ahead of your toes. Slowly return to the starting position. You'll feel tension in the muscles in your thighs and buttocks. Visualize yourself lowering your body into a chair.
When you're doing squats, keep your back in a normal arched, balanced position. Descend as low as you can, but do not bend your knees more than 90 degrees.
If you have trouble doing a standard squat, put down the weights and try a chair-assisted squat instead. Sit in a chair, then lift up out of the chair by pushing upward with your legs. Push upward with your arms on the armrest, if needed.
For most people, one set of 12 to 15 repetitions is adequate.
Remember, for best results, keep your back in a normal arched, balanced position, do not bend your knees more than 90 degrees, and keep your movements smooth and controlled.