Two Common Mistakes Made When Performing Planks

You can’t go a day without seeing someone doing a plank in the gym. The plank is a common exercise used for training core.  Would you believe that most people are making the #1 mistake with planks?  

First of all, what is a plank?

The plank is an isometric (not moving but staying still) exercise in which the individual is in prone position (facing the ground) with arms extended in the top part of the push-up. The purpose of the plank is to recruit the abdominal muscles.   When I have clients perform planks, they are performing a “hard style” plank, a term I learned from my Russian Kettlebell Certification. What is the difference between a plank and a hard style plank? Generally speaking, a “hard style” plank is the end all plank.  All other planks are simply “wanna bees”. A “hard style” plank recruits more muscles than a traditional plank.

What muscles does a hard style plank recruit?

Strength Training Anatomy by Frederic Delavier, tells us:


Primary:  bicep brachi (biceps), latissimus dorsi (wide part of the back), rectus abdominis (the 6 pack abdominal muscles), internal and external oblique (abdominal muscles to right and left of the abdominal 6-pack)

Secondary:  Gluteus Maximus (butt), quadriceps (front part of the thigh) hamstrings (back of the thigh), trapezius (shoulder muscles between neck and shoulder and going down the center of the back), serratus anterior (connects shoulder blade to rib), rhomboids (back muscles)

Why is the plank exercise so important?  

It is teaching you how to properly contact a whole host of muscles efficiently and effectively.  The plank is one of the foundational exercises I have clients perfect before teaching them how to perform a kettlebell swing.    It excites the nervous system perfectly and in the perfect hierarchy.

Not Contacting The Core

Think of your core like an aluminum can.  The top part of your pelvis is the bottom of the aluminum can.   The bottom of the rib cage is the top part of the can. All of the muscles in your core, including abdominals and obliques, are the sides of the aluminum can.    If I tilt the aluminum can’s top and apply pressure to the can, the entire can will collapse. The result is the same if the bottom of the can is tilted. The same is true for your core.  If you are lifting something heavy, and your rib cage or pelvis are not parallel with each other, you are extremely vulnerable to injury. To prevent an injury from happening, perform planks in your workout.   The key is to perform the planks correctly with a flattened back and tightly recruited core muscles.

When you engage the core like an aluminum can, you will also contract your glues.  With the contraction, your body is forming a straight line from the shoulders to your heels.  The visual I give my clients is think of yourself as a steel i-beam, solid and strong! You should never look like is a walrus (shoulders up high, back arcs down towards the ground with the hips inches off of the ground).  


Contract your abdominals in a way that flattens your lower back.  As a result, when you flatten your back, your glutes automatically contract and your “core” feels very very rigid and solid.  When you contract your abdominal muscles, I want you to imagine a boxer being trained. The trainer repeatedly punches the boxer in the abs to ensure maximum recruitment for protection of the body.   Instead of having someone actually punching your abs, simply imagine someone jabbing you to ensure you recruit the muscles. Now, you are successfully “contracting the core”.

Not Setting The Back

When performing a plank, put yourself in the top part of a pushup, arms extended.   While in the pushup position, you want to “set your back”. In order to “set it, simply contract the latisumus dorsi (lats) muscles as well as setting your shoulder blades (retract them so the shoulder blades are flat and not winging).   By setting your shoulder blades, you are now contracting your serratus anterior. Contracting the serratus anterior is an extremely important muscle for injury prevention. (Stay tuned for a future article explain why the serratus anterior is so important).  Congratulations, you are now “setting the back”.

What can you do?

Make sure you  “set your back” and contract the muscles so your body is rigid and solid.   Use an aluminum can as inspiration for how your core should be contracting.   When you perform a plank perfectly, you are setting yourself up for success with the rest of your lift.  When you perform a plank, do you look like a steel i-beam or a walrus? The choice is yours...


Written by Steven Zahn


Steven Zahn

ACE Certified Personal Trainer

NASM Certified Personal Trainer

Pre and Post Partum Certified

Dragondoor Publications: HKC


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