Everyone knows plank pose is a challenging position. When done strategically, it requires every muscle in your body to work together. What most people don’t realize is that plank can be stressful when inappropriately progressed for certain individuals: not giving the desired results, or worse producing wrist, low back or knee pain.
Going from quadruped to a plank requires more distance between hands and feet, making it a greater challenge, requiring more strength. If you need to modify, cut the distance in half by dropping knees to the floor. A modified plank is still a great way to strengthen the spinal flexors, shoulder, elbow, and hip muscles as they work to fight the force of gravity pulling your body to the ground.
A Higher plank, where the elbows are in extension instead of flexion is easier, but why? The technical answer: for any multi-joint exercise like plank, the overall effect of the exercise will be determined by the actual degree of challenge at each joint as it relates to their distance from the stimulant or line of force. In mechanics, this is called the moment to that joint. In laymen’s terms, the further we are from a line of force, the more effort we will have to come up with in terms of muscle contraction.
Our joints- the place where two bones come together- create motion. We will refer to them as containing the axis of motion. Since bones are connected at least at one end to another bone, they move in a circular motion. This is referred to as rotary motion. The axis is the center of the rotation around which we choose to move or not move at the joint. In plank, every joint is fighting gravity to an extent.
In order to make plank pose more challenging, we can increase the moment arm (MA) at various joints. This is a term that determines the degree of effectiveness, or influence, of a force (gravity) to produce rotation around an axis. The overall effect the of force (ie: a push or a pull) of gravity in plank is measured by the amount of torque at each joint, which is found by determining the magnitude of the force multiplied by the distance from its point of application to an axis of rotation. With a greater moment arm, muscles have to work harder to prevent motion and hold plank.
Although this concept is intricate, the moment arm is found by identifying the shortest distance from the line of force (gravity in this example) to the axis (joint). Geometrically it is always defined as the perpendicular distance from the line of force to the axis, i.e. it is ninety degrees to the line of force. We spend quite a bit of time finding moment arms at various joints in poses in our teacher training courses.
You can see here that the closer to the ground you are, you are opposing the force of gravity, (pulling down in a straight line from the ceiling to the floor) at a right angle. A lower plank will be a greater challenge because the moment arm is longer, being perpendicular to line of gravity force / longer moment arm to many of involved joints. If you’re really working on your core, try plank on your forearms!
Traditional Plank is Not For Every Student
It is very important to stay safe in this pose. There is a tendency to over-use plank pose because it can be so effective and requires little or no equipment. However, there are ways to minimize the mechanical stresses that are characteristic of the pose. Pay special attention to your hands: be sure you’re spreading your fingers apart to increase the surface area of the hand and minimize wrist stress. Your hand should come fully in contact with the mat. We bear the bulk of the load on the radial / thumb side of the hand and wrist, but be sure you’re evenly distributing your weight throughout your entire hand.
If the student cannot achieve 90 degrees of wrist extension (back of the hand moving up to the forearm) there are several modifications students can make to help them progress through plank pose over time.
Modifications to plank pose:
- Roll up mat and place hands on that so wrist doesn’t have to bend as much
- Come up on knuckles – this is neutral on your wrists but puts more pressure on hands and finger joints
- Come onto forearms – good for wrists but harder for core musculature.
Making Plank Pose More Challenging
We can change the overall effect of plank pose by adding frictional influences like pushing into the floor in various ways. You can also give intentional cues shifting the areas of the body we want to challenge. For example, shifting your weight into one leg more than the other requires the muscular system to respond the redistribution of our overall mass. This creates completely new challenges for the student. Keeping your classes novel and interesting is critical if you want to keep your students engaged over time.
Challenging plank pose progressions:
- Walk hands out in front of shoulders to further widen base of support.
- Lift one leg to increase rotational challenge
- When raising one leg, perform hip abduction to increase workload on the opposing side
- Use frictional redirects, pushing hands and feet into various ways to produce intentional challenges for various muscle groups.
By: Lauren Eirk, MS, E-RYT 500, MATRx, C-IAYT
Director of Education, Yoga I.S.® Programs