Form: To perform a standard push up with good form, place your weight on your hands and feet, with your spine and head in alignement with your legs, and your hands just slightly wider than shoulder-width apart (palm flat on the floor). Lower your upper body to the floor, flexing the elbows, then rise back to the start position. Keep your head still, and keep your eyes looking down. Breathe in on the way down, and out on the way up, and pull the abdominal muscles tight throughout the exercise.
Notes: Push-ups which are performed with your elbows in (closer to your body) put more emphasis on the triceps. Wide arm push ups with arms at a 90 degrees angle to your body focus more on your chest. To avoid shoulder problems, it is recommended your perform push ups with your upper arms at a 45 degree angle with your torso.
Choose one of the following variations as a starting point and perform 3 sets of between 4 and 8 repetitions with periods of between 1 and 2 min of rest between each set. When you can do 3 sets of 8, move on to the next exercise in the progression.