When performed properly, a push up is an excellent exercise for toning the chest, shoulders and triceps because the exercise uses the body’s own weight to work all three muscle groups at the same time. This exercise is just as effective whether it’s performed as a knee push up or a full push up – it all depends on an individual’s strength and capabilities. However, proper form should always take precedence over repetitions: it is more important to do one rep correctly than it is to do two reps incorrectly. An improper push up can result in wrist, elbow, shoulder and neck injuries.