Since the first week of school is upon us this means one thing for the baseball program at TCU; movement screens. The last 4 days of my life have been evaluating, measuring, and deciphering movement. I recently uploaded a few videos that give some quality examples of the overhead squat, both good and poor. I'll post on those in the next couple days or so.
Today, I wanted to talk about the fist to fist test that some use, including myself, to measure shoulder mobility.
The problem with the fist to fist is that it isn't a true indicator of shoulder mobility, and more specifically, glenohumeral internal rotation. There are a number of factors that play into being able to raise the hand high on the back. A combination of elbow flexion, scap movement, and internal rotation all play a part.
Several years ago when I first began administering the fist to fist test for shoulder mobility I had an individual measured 5 cm with the right arm up, and 7 cm with the left arm up. According to Gray Cook and the FMS this is scored a 3 and shows great ROM with no imbalances to speak of. At that time I utilized this test exclusively for our shoulder ROM and didn't perform any added measurements so to speak when an athlete scored perfectly on his gross movement tests. However, this individual later ended up having an issue during the season and consequently had to be scoped following the year with a partial rotator cuff tear.
On the surface throughout this athlete's testing, and screening he didn't show any disposition to a lack of shoulder ROM. However, when he was looked at by our team shoulder specialist he had a large glenohumeral internal rotation deficit as well as a total arc deficit which we now know as a huge indicator of problems in the throwing shoulder.
At the time I couldn't quite understand how an athlete can score so well in shoulder mobility and then have such restrictions at the same time, but I soon began to dig deeper.
A study done in 2006 by Karen Ginn in the Journal of Shoulder and Elbow Surgery showed the behind the back reach test to have a low to moderate correlation with true shoulder internal rotation.
Does hand-behind-back range of motion accurately reflect shoulder internal rotation?
In an even more specific study done back in 1996, the examiners discovered that the more correlated movement occurs in the scapulothoracic area when high results are achieved with the behind the back test of shoulder mobility, and that the majority of shoulder internal rotation occurs while the arm is still in front of the body.
What these studies tell us are that the scapula, and elbow to a lesser extent accounts for more of the motion in the test than true internal rotation occurring at the shoulder.
The video above is a great example of what I'm talking about. The athlete measures well under 10 cm on both sides exhibiting no imbalances and showing great shoulder mobility . . . right? When you have the athlete remove his shirt the problem is easily identified. The movement occurs because of the scaps inability to stay stable thus allowing the athlete to get his hands so close in the screen. The actual movement isn't occurring in the shoulder. This athlete is in dire need of some scapular stabilization work here.
When we dig deeper with a goniometer and passive internal, and external rotation we find our real issues. This particular athlete is right handed pitcher with measurements as follows:
Right
External: 129 deg.
Internal: 48 deg.
Total Rotation: 177
Left
External 125 deg.
Internal 65 deg.
Total Roation: 190
We now undercover the truth of his actual glenohumeral motion. This athlete has a total rotation deficit of 13 degrees and a glenohumeral internal rotation deficit of 17 degrees. When all looks good on the fist to fist we actually find that this athlete has lost ROM in his throwing arm which is a huge indicator of shoulder injuries in throwing athlete. I actually don't even want him throwing a baseball until we recover that lost motion. It's that important. Now, had we not actually measured rotation at his shoulder we would have cleared him with flying colors because of his fist to fist test. This is where the fist to fist can and does commonly cause problems. In the past few years I have learned exponentially more about the shoulder and have come to understand why the fist to fist test leaves so much to be desired.