Planks and Crunches are (almost always) a waste of time

Planks and Crunches are (almost always) a waste of time.

That was difficult to type because there is no such thing as a "bad" or a "good" exercise - it all depends on context. Therefore, I am hesitant to write that somewhat sensationalist title.

With that said, I am a big advocate of knowing your goal, and training effectively with that goal in mind. So let’s take a closer look at these two exercises, and discuss how you can more effectively train.

Planks and crunches are (almost always) a waste of time.

What are planks and crunches?

 

First, let’s accurately describe the exercises in question. They are both exercises limited by body weight, performed through a small, or no, range of motion at the lumbar spine.

In any exercise, specificity is king. The adaptations of the body are specific to the demands imposed upon it. With this in mind, an exercise is only as good or bad as the context in which it is used.

For example, squats are a great exercise to increase squat strength, but not as great at increasing your ability to jog 5 miles. Squats are less specific to that goal. That’s not to say that squats have no place in a runner’s training – just the opposite. Squats will increase the strength of the muscles of the legs, and assist in weight loss, both of which will be advantageous for running performance.

The degree to which an exercise is beneficial is dependent on two things:

  1. How does it stress the body?
  2. Is it stressing the body in a similar way to the outcome that we desire?

Which is why I want to address the reasons why planks and crunches are a waste of time for almost everyone, depending on a variety of fitness goals.

What is your fitness goal?

Aesthetics

Yes, everyone wants the shredded six pack look, and there is nothing wrong with that. Unfortunately, planks and crunches alone won’t get you there (Vispute et al., 2011). The visibility of abdominals is associated with body fat percentage, and the size of the underlying muscle. In fact, the estimated body fat percentage associated with visible abdominals may be below that which is considered healthy for normal organ function and reproductive health, especially for females (Gallagher et al., 2000).

Muscle size

There is evidence that high volume, low weight exercises can be effective in increasing the size of a muscle (Mitchell et al., 2012) – provided that the exercise is performed until muscle failure. In other words, the point at which a muscle is fatigued is such that it can no longer produce sufficient force – not to the point of "I’m kinda tired, I think I will stop here."

The growth potential for the abdominals may be limited by their anatomy: they are enclosed in a tendinous sheath, and as such, might not ‘explode’ like other muscles (think of a bodybuilder’s quads, calves, biceps, etc.).

Abdominal strength

Increasing the strength of the abdominals, or any muscle, means progressive overload. In other words, increasing the amount of force that these muscles have to contract against. Any strength exercise that you can perform fifty repetitions of is not using sufficient weight to properly stimulate strength increases in the targeted muscles.

If we extend this idea to the progressive overload principle, then crunches and planks won’t really help in this quest. Once you are able to do more than 50 crunches, you should look for an exercise that is challenges those muscles until you can only do them a couple of times, if strength is the goal. This holds true for any muscle or group of muscles, not just the abdominals.

Core stability

This is a big buzz term in the fitness industry that has no real meaning, consistent definition (Hofmann, 2013a), or correlation to performance (Hofmann, 2013b). If you are interested in increasing your ability to stabilize the lumbar spine against externally applied forces, increasing the strength of all muscles of the trunk and abdomen will assist in this goal.

Balance

Balance does not come from your core, it primarily comes from the ankle. If you don’t believe me, stand upright on one leg and watch your ankle. In fact, using your core to adjust your balance is a mistake, considering about 60% of your body weight is in the HAT (Head, Arms, and Trunk). The closest interface between your body and your base of support is your foot/ankle, and it is doing all the micro-adjusting to ensure your center of gravity remains over your base of support.

Isolation

Maybe you perform these exercises because you’d like an effective way to isolate the abdominals during training. There are many situations in which one will want to isolate a muscle, but these two exercises are not going to get it done, as they can also result in a lot of hip flexor or lumbar spine extensor recruitment depending on your posture or technique (Escamilla et al., 2006; Snarr and Esco, 2014).

Running performance

Many runners advocate that these exercises are critical for increasing running performance. But many studies (Hofmann 2013b) have demonstrated that core-focused performance tests (consisting of, you guessed it, planks and crunches) do not correlate very well to athletic performance.

“But runners have abs!”

They also have very low body fat percentage, because they are burning quite a bit of calories, especially when training at very high levels. Just because you can see one’s abdominals does not mean that they are particularly strong…and in this case, it doesn’t seem to matter anyway.

Endurance

Now we are getting warmer. Planks and crunches are two different types of endurance exercise. The principle of progressive overload applies to not just strength, but time, volume, and/or frequency of the stresses you impose on the muscle. Both of these exercises to some extent will increase the endurance of the abdominal muscles, provided the demands of the exercise (more repetitions or longer duration) are steadily increased over time. I would, however, caution anyone who believes that muscular endurance of the abdominals carries over to cardiovascular endurance (they are different)!

Weight loss

Any movement will help contribute to weight loss, but should also be combined with an active approach to improving diet.

To have fun and challenge yourself

If you or a client finds these exercises fun, challenging, and interesting, by all means they should be integrated into a workout.

Train the core like any other muscle

The muscles of the trunk (the "core") should be trained just like any other muscle in the body. So jump on a strength machine that isolates these muscles, or perform some of the traditional major barbell lifts (bench, squat, deadlift) – all of which are demanding to the core musculature. After a strength session targeting these muscles, give them adequate rest (24-72 hours), then train them again.

If you don't have access to equipment like this, keep in mind that exercises like planks and crunches will be limited to their ability to help you get to your ultimate fitness goals.

Cory Hofmann, MS
Senior Research Manager
Cybex Research Institute

References

  1. Hofmann (2013a) Are we mystified by the core? Part II
  2. Hofmann (2013b) Are we mystified by the core? Part III
  3. Snarr and Esco (2014) Electromyographical comparison of plank variations performed with and without instability devices. J Strength Cond Res 28(11): 3298-3305.
  4. Escamilla et al. (2006) EMG analysis of traditional and nontraditional abdominal exercises: implications for rehabilitation and training. Phys Ther 86(5): 656-671.
  5. Vispute et al. (2011) The effect of abdominal exercise on abdominal fat. J Strength Cond Res. 25(9):2559-64.
  6. Gallagher et al. (2000) Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index. Am J Clin Nutrition 72:694-701.
  7. Mitchell et al. (2012) Resistance exercise load does not determine training-mediated hypertrophic gains in young men. J Appl Physiol. 113(1):71-77.
Disclaimer

Cybex is a provider and manufacturer of premium commercial fitness equipment. Content featured in the Cybex Fitness Blog is meant to inspire healthy living and wellness and should not be taken as medical advice. As always, be sure to consult a physician if you are unsure of your individual exercise readiness or have a pre-existing medical condition. While these programs offer great benefits, there are many considerations that should be weighed before attempting any type of physical activity.

Comments (13) -

  • Bryan

    12/22/2015 10:12:10 AM |

    I've been telling people for years that the best "ab" exercise is a barbell squat.  Thanks for the support!

  • Caroline Jenner

    7/10/2016 4:14:43 PM |

    I don't get it...why would planks be a waste of time? People have been telling me for years that I should be doing planks to increase my core strength, but now I read this.

  • BJ Corey

    7/11/2016 4:44:38 PM |

    It's not so much that they are a waste of time all of the time, but instead that there can be better ways to strengthen your core than just doing planks. Whether it's using equipment like functional trainers (www.cybexintl.com/.../functional-trainers.aspx) or equipment designed especially for the back extension, you may find that there are better options available for a more effective core workout.

    Take a look at how to use the Eagle NX back extension here. It may be a great way for you to workout your core: blog.cybexintl.com/post/2015/01/26/the-core-is-more-than-you-think-using-the-back-extension-machine.aspx

  • Shanu

    8/19/2016 3:38:05 AM |

    Hi Cory
    I really like your article and views presented.
    A little bit off topic,  I would like to ask you a few things about reducing tummy fat. I m 31 and desperate to get my stomach flat. And I also want a fit athletic not very mascular body.
    Just the right muscles around shoulder,  chest and things and calf. To this end I am very confused as in what should be my path to this.
    How should I start and how much should I do.
    P.S I can not afford an expensive gym. So I go to the one which has basic cardio machines and few weight lifting equipment ( if I m using the terms right)  .
    Your suggestions will be really helpful for this starter .
    Wish u a nice day
    Shaanu

  • Cory H.

    8/22/2016 4:17:10 PM |

    @Shanu -  If you are concerned with fat reduction, then you must pay careful attention to your diet.  Consider consulting a nutritionist or begin to carefully monitor your caloric intake.  Good luck.

  • Mark Jones

    9/11/2016 7:53:46 AM |

    Exercises chosen should always reflect the goals desired. An analysis of a muscles function should be undertaken while choosing specific exercises and those exercises should be performed to match the targeted muscles true function for example...it is better to perform isometric exercises to improve the postural muscles if there is a possible misalignment of ones particular posture for instance internally rotating shoulders....perform isometric contractions to target the specific muscles that externally rotate the shoulders.

  • Cory H

    9/13/2016 9:36:07 AM |

    @Mark - Thanks for reading.  Agreed, exercised should be chosen with one's goals in mind.  Why are you suggesting that isometric contractions in your example would be superior to concentric/eccentric exercises for the rotator cuff?  

    Postural alignment is a function of many things, but a primary factor is the resting length of the muscle(s) surrounding the joint(s) in question.  Static and dynamic stretching are the primary ways to manage this.

  • Dave James

    12/6/2016 7:18:32 AM |

    So what are the ideal exercise programs?

  • Victoria Bellingham

    12/6/2016 8:01:12 PM |

    Okay, but is there any fitness equipment to help with core strength? I get that it's not always the best just to do core strength, but what should I be using instead?

  • Duncan Lawrence

    12/6/2016 8:43:27 PM |

    Hi Dave,

    It would be hard to say the ideal exercise programs - it all depends on your goals and capabilities. No single workout can be perfectly applied for anyone else. It is important to work with a trainer and/or a medical professional to help determine what is the ideal workout for you.

  • Dave James

    12/6/2016 8:59:56 PM |

    Thanks for the advice.  I am looking for guidance for the ideal plan.  Goal is to lose my tummy.   ;)

  • Duncan Lawrence

    12/14/2016 2:27:40 PM |

    You may want to try the Weight Loss programs in the Cybex Workout Center - just make sure to check with a medical professional and/or personal trainer to make sure the program is one that is right for you: http://www.cybexintl.com/workouts

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