A common goal of many rehab, fitness, and sports performance programs is to enhance scapular stability. The scapula provides a base of support for the shoulder during functional movements. Any deficits in the scapula’s ability to move and stabilize can result in scapular dyskinesis, winging, and poor positioning of the shoulder joint, which has been shown to correlate to shoulder injuries. This is particularly important in athletics that involve the overhead shoulder position, such as throwing.
Programs are often designed to work on strength and dynamic stability of the scapular stabilizers. These tend to focus on the muscles like the trapezius and serratus, which work together to provide protraction and upward rotation of the scapula.
One specific exercise that is commonly performed is the push up with a plus exercise. This has been shown to produce high levels of EMG activity of the serratus anterior.
A recent study from the Journal of Physical Therapy Science evaluated the EMG activity of the scapular muscles during the push up with a plus exercises with the following variations:
- Performing a full push up with a plus in the standard position on the toes in comparison to on the knees
- Performing the push up with a plus on a stable in comparison to an unstable surface
The study produced two important findings that essentially confirmed many common beliefs, but are worth discussing.
Push Ups Performed From the Knee Position Decreases Muscle Activity
This finding makes senses as the body weight load and lever arm are reduced when performing the push up on your knees instead of in the standard toe position. This study confirms this finding, showing that push ups with a plus can be regressed to on the knees or progressed to on the toes based on the specific needs of each person. There is a subsequent change in muscle activity as the position becomes more challenging.
Push Ups Performed on an Unstable Surface Produce Greater Scapular Muscle Activity
Another finding confirmed that an unstable surface does produce greater amounts of scapular activity. Exercises performed on unstable surfaces were quite popular in the past but have decreased in popularity as many people have suggested that this may not actually be a very functional activity. I think this study confirms that performing a push up on an unstable surface can be an effective exercise to enhance scapular control and stability.
No, if you are trying to gain pec strength or chest hypertrophy you would not perform a push up on an exercise ball. That is true. But if you are trying to enhance scapular control during a functional closed chain activity, such as pushing, I think using an unstable surface is beneficial.
This is really no different than a bottom up kettlebell exercise or using the landmine for a press. I’ve described the serratus slide exercise that I developed using the TRX suspension system in the past as well, just as another example.
All of these activities require you to stabilize forces in multiple planes of motion while perform a single plan movement. This is the essence of what Eric Cressey and I talk about in our Functional Stability Training series (with an Upper Body module coming soon!).
If you are trying to enhance someone’s scapular stability and possible reduce scapular dyskinesis, performing the push up with a plus exercise on an unstable surface appears to be a valuable option.