LIMITATIONS OF THE PLANK
ALLEN HEDRICK, MA, CSCS,*D, RSCC*D, FNSCA
U
sing the plank as an exercise to train the core, both in
fitness and when training to improve athlete performance,
has become commonplace. In reviewing training programs,
we find this exercise, and its training variations (e.g., long-lever
posterior-tilt plank, the reverse side plank bridge, etc.), shows
up frequently. Despite this widespread popularity, some aspects
of this exercise cause me to question its placement in a training
program meant to assist a healthy athlete that is training to
improve athletic performance.
Before looking at the possible limitations of the exercise when
the goal of training is enhanced athletic performance, it is first
important to describe the exercise to enhance clarification.
According to the National Strength and Conditioning Association’s
“Developing the Core” book, the plank is performed in the
following manner (6):
1. Lie on your abdomen with your palms on the floor, feet
together, and spine in a neutral position
2. Lift your body up on your elbows and toes, keeping your
head, torso, and legs in a straight line
3. Contract your abdo minals and gluteals to prevent your
midsection from sticking up in the air or sagging in the middle
4. Maintain this position for the prescribed time
The primary limitations of the plank are provided in the exercise
description above. First, the exercise is performed in a prone
position with the body supported on the toes and elbows. As
explained by Gamble, biomechanical specificity includes such
things as posture and limb position (5). As a result, an exercise
performed in a standing position (e.g., medicine ball twisting
throws) will transfer more effectively to improving athlete
performance than performing an exercise in a seated or supine
position (e.g., twisting crunches). Craig and Judge agree that it
can be argued that the most effective way to enhance strength
or power for a specific sport comes from selecting exercises or
activities that have mechanical specificity to the chosen sport and
replicating those movement patterns in training (3). Because few,
if any, sports involve competing in the prone position required
when performing a plank, and because few, if any, sports involve
the prolonged isometric contractions used when performing
a plank, it can be said that the degree of specificity when
performing a plank is quite low for the vast majority of sports.
As stated, the plank exercise involves holding a prone position in
an extended isometric action. Isometric muscle actions involve the
production of force without movement of the joint or shortening/
lengthening of the muscle fibers (4).
exercise performed. The strength gained when using isometric
exercises is limited to the angle of the muscle being exercised.
Training to increase isometric strength at one specific joint angle
is not a good use of time for most athletes because most sports
require the athlete to be strong through a more complete range of
motion rather than only being strong at one specific position.
Additionally, if improving trunk stabilization is a goal of training,
performing a traditional barbell squat or front squat has been
found to be an effective exercise at achieving this goal (2).
Researchers found that squatting with a moderate external load
was an effective method to cause trunk muscle activation. The
other benefit of a squat, as compared to performing a plank, is
that it is performed in a sport-specific position (i.e., standing)
using a sport-specific movement pattern (i.e., flexion and
extension at the ankles, knees, and hips).
Another limitation of prolonged planks has to do with the concept
of progression. One of the basic principles of resistance training is
the concept of progression. For a training program to continue to
produce higher levels of performance, the intensity of the training
program must be progressively increased (1). Therefore, for
example, if I want to increase my squat one-repetition maximum I
have to increase the load on the bar gradually. The problem with
this, in relationship to the plank, is that the plank is a bodyweight
exercise; no external resistance is typically used when performing
this exercise. As a result, in terms of progression, when performing
the plank the ability to apply the concept of progression is limited
to either changing the position in which the plank is performed
(e.g., long-lever plank) or increasing the duration in which the
plank position is maintained (e.g., progressing from 30 s to 45
s and so on). While I agree that changing the position in which
the plank is performed can make the exercise more challenging,
eventually the athlete will reach a point where the exercise is
performed in the most challenging position possible and no
further progression is possible in terms of positioning.
At that point, the only other method to provide overload is to
increase the duration of the exercise. However, as we have already
established, performing an isometric contraction in a non-sportspecific position is of little value to most athletes. As a result,
increasing the length in which the plank is held simply increases
the time the athlete is performing an exercise that has limited
benefit in terms of improving performance, which is obviously
not a decision most strength and conditioning coaches would
knowingly choose to make. As a result, it makes sense that
when working with healthy athletes whose main goal is to
improve athletic performance, the plank has limited value in
most situations.
Further, isometric training produces joint angle-specific increases
in strength, meaning the increases in strength occur primarily
in the position(s) trained. Isotonic exercises (i.e., exercise that
involves both concentric and eccentric muscular contractions)
strengthen the muscle throughout the range of motion of the
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