Isometric chest exercises contract your chest muscles. However, tensing your pecs won't change the muscles' length or make any joints move. Unlike other types of exercise which involve joint or muscle movement, you remain static when practicing the isometric chest press, door-fly or pushup.
Perform the isometric chest press while sitting or standing. Place your hands in a prayer position in front of your chest, keeping your elbows at 90-degree angles. Press your palms together as much as you can. Feel the contraction in your chest. Hold this position for five seconds, then rest for five to 10 seconds. Repeat the press five times and work up to holding the contraction for up to 15 seconds.
Standing in a doorway, place your hands at about chest level on each side of the frame. Pull your chest forward into the doorway. Feel the stretch across your pecs. Hold for a count of 30, and don’t move. Release gently. Rest until your upper body feels loose before you repeat the movement.
In an isometric pushup, you don’t go all the way down to the floor and return back up; instead, you hold the position partway. Begin in a standard pushup posture. Lower your body, but stop halfway to the floor. Hold the position for a count of 10. Contract the chest muscles, then release the contraction. Rise back up and repeat as desired.
You may particularly benefit from isometrics if you’re undergoing physical therapy. There are limits, however, to isometric training. You may only gain strength in isolated body parts and only at the angles of contraction performed in the exercises; and it’s unlikely isometric exercises will boost your athletic ability. In fact, your endurance may get worse. Consult your physician to make sure you can perform isometrics, especially if you have high blood pressure or heart irregularities, as isometrics often raise blood pressure due to increased tension.