Sit-Ups: Place your phone flat against your chest in landscape mode and hold it there with your hands.
Push-Ups: Place your phone on the floor. Bring your body or face close to the phone display or touch the display with the tip of your nose.
Squats: Hold your phone with both hands in landscape mode in front of your chest.
Pull-Ups: Put your phone upright in your pocket or hang it around your neck.