The plank is a body-weight static exercise in which abdominals and mid-back muscles are engaged in order to stabilize the whole body. It is an excellent exercise to strengthen the core and to improve endurance of the stabilizing muscles. The core muscles are the ones responsible for maintaining posture and body alignment, meaning that they essentially work as stabilizers. The problem is that stabilizers are generally prone to weakness; a weak core compromises balance and movement efficiency, which can lead to chronic pain and injuries in the long run.
According to the principles of functional training, muscles should be trained the same way they were naturally intended to work. This means that stabilizers are best isolated during isometric (static) exercises or small-range movements. Thus, the plank is the perfect exercise to address the core needs.
The plank can help you build a strong core by activating several major muscle groups around the body. It may also prevent or reduce low back pain associated with weak stabilizing muscles. In addition, strengthening core muscles will improve posture, balance, and the performance of activities of daily living.
Muscles Engaged
The plank activates the following muscles:
- Abdominal group
- Upper, middle and lower back muscles
- Adductor group (inner thighs)
- Gluteus medius and minimus
- Shoulder muscles
- Arm muscles
The Exercise
The plank is similar to the up phase of a push-up. However, this is a static exercise, meaning that there is no movement involved. The whole point is to hold the position as long as you can, maintaining body alignment. Start with 10-second intervals and work your way up to a whole minute.
In a full plank, the body is supported on hands and feet. The arms are extended, and the shoulders should be over the wrists. The spine should be in a neutral position (neither rounded nor arched), and the pelvis tucked in.
TIP – Don’t let your upper-body collapse in the shoulder blades. Keep the upper-back active by pulling the floor away from you.
Don’t feel discouraged if the full position seems too much for you right now. You can make it easier by holding the position in your forearms or placing your knees on the floor. As you get stronger, you can move on to more challenging variations.
Now, if you want more challenge, you can hold a tripod plank, in which one leg or arm is held up. Also challenging is to move your hands a little further in front of you. This increases the demand on the core muscles. Another option is to use an unstable surface upon which to place your hands. You can use a Bosu or a stability ball for that.
References
Bryant, C., et al, eds. ACE Advanced Health & Fitness Specialist Manual. The Ultimate Resource for Advanced Fitness Professionals. San Diego: American Council on Exercise. 2009.
Delavier, F. Women’s Strength Training Anatomy. Champaign, IL: Human Kinetics. 2003.
Delavier, F. Core Training Anatomy. Champaign, IL: Human Kinetics. 2010.
Vella, M. Anatomy for Strength and Fitness Training. New York: McGraw-Hill. 2007.