Pectoralis Major 75.8% MVIC / Study  11 (Decker MJ, et al.)

Musculature Accounted For-

This test is designed to assess the pectoralis major. The pectoralis major is the main muscle in use during horizontal adduction and one of the main internal rotators of the shoulder.

Safety of Testing-

The D1 pattern by definition is as follows…

• The arm moves diagonally starting from just above 90 degrees.
• The arm is slightly externally rotated and working to the opposite hip.
• During this movement the arm internally rotates. 

The activation from this pattern is due to the test creating a more direct line of pull with the muscle fibers. The starting position puts the pec into a fully lengthened position at the initiation of this test. When the muscle becomes fully lengthened it is most susceptible to injury.   

We decided due to this risk factor to bring the arm down to the same side hip. This brought the position of the pectoralis major to a shortened position. This position will allow the athlete to produce max force with the least likelihood of injury. This also allows for us to assess the same musculature consistently yielding a desired result. 

Daily Repeatability and Technology Positioning-

Where many would have an athlete lay down on a table or on the ground for this test we recognized in real time this substantially burdens our ability to capture data daily. Athlete buy-in and applicable positioning of the technology for us became a limitation when testing our approaches. For this this reason we selected the D1 positioning seen in our test list for a more simplified approach that would yield similar results. 

Supraspinatus 82% +-37 Supraspinatus 82% / Study 8  (Escamilla RF, et al.) Study 10 (Reinold, M. M, et al.)

Middle Deltoid 82% +-32 Middle Delt 82% / Study 8  (Escamilla RF, et al.) Study 10 (Reinold, M. M, et al.)

Posterior Delt 88% +-33 Posterior Delt 88% / Study 8  (Escamilla RF, et al.) Study 10 (Reinold, M. M, et al.)

Musculature Accounted For-

This test is used to assess the supraspinatus in its ability to stabilize. When the arm is abducted above the shoulder joint the supraspinatus is heavily called upon to stabilize the glenohumeral joint. This allows the deltoid to produce force. The weaker the supraspinatus is in its ability to stabilize the lower the force output we see from the deltoid. 

Safety of Testing-

When we look at horizontal abduction we need to pay attention to the length of the external rotator cuff muscles. Mainly due to their smaller size we need to look at the infraspinatus and teres minor. When the shoulder is abducted to 90 degrees, these muscles are shortened. Due to the muscles being shortened the likelihood of injury decreases. If the athlete were to start in more of a horizontally adducted position it would lengthen the muscles therefore placing these smaller muscles at higher risk for injury. 

Daily Repeatability and Technology Positioning- 

When testing the supraspinatus most would measure its strength in the first 30 degrees of abduction. This would assess the action and function of the supraspinatus in abduction at this degree of movement. Once the shoulder is abducted past 90 degrees the function of the supraspinatus changes. It becomes a stabilizer from the glenohumeral head to the scapula. We are testing the function of the supraspinatus not its action.  To ensure safety in repeatability we had athletes maintain their testing shoulder in abduction only. Additionally we recognized that being in a split stance will allow for a larger base of support that ultimately allows for maximum force production.

Middle Trap 87+- 20% MVIC / Study 8 (Escamilla RF, et al.) 

Middle Trap 69+-18% MVIC / Study 15 (Ekstrom, R. A., et al.)

Musculature Accounted For-

This test is done to assess the middle trap. When the shoulder is abducted to 90 degrees and internally rotated we see that the line of pull is with the middle trap muscle fiber. Internal rotation will also help reduce contribution of the rear deltoid by rolling the muscle more anteriorly and in a less direct line of pull. 

Safety of Testing-

When we look at horizontal abduction we need to pay attention to the length of the external rotator cuff muscles. Mainly due to their smaller size we need to look at the infraspinatus and teres minor. When the shoulder is abducted to 90 degrees, these muscles are shortened. Due to the muscles being shortened the likelihood of injury decreases. If the athlete was to start in more of a horizontally adducted position it would lengthen the muscles therefore placing these smaller muscles at higher risk for injury. 

Daily Repeatability and Technology Positioning- 

When assessing the middle trap most would have an athlete lay down on a table with their shoulder off the table. They would have an athlete adjust so that their shoulder is abducted to 90 degrees. The athlete would then move through horizontal abduction. With our testing unit we replicated this but via a standing position. 

To ensure safety we had athletes maintain their testing shoulder in abduction only. Additionally we recognized that being in a split stance will allow for a larger base of support that ultimately allows for maximum force production through this test. 

Posterior Delt 92+-49% MVIC / Study 8  (Escamilla RF, et al.) 

Supraspinatus  > 50%MVIC / Study 8  (Escamilla RF, et al.) 

 

Musculature Accounted For-

This test is to assess the strength of the posterior delt. With shoulders abducted to 90 and externally rotated this will allow for a best line of pull of the posterior deltoid muscle fibers. This position allows for full strength of the posterior deltoid due to supraspinatus is not as heavily asked to stabilize the shoulder. 

Safety of Testing-

When we look at horizontal abduction looking at the length of the small external rotators mainly the infraspinatus and teres minor must be looked at. When the shoulder is abducted to 90 these muscles are in a shortened position which will decrease the likelihood of injury the most. If we were to start in more of a horizontal adduction position it would put these smaller muscles at risk for injury. 

Daily Repeatability and Technology Positioning-

When testing the posterior delt many would do so with the shoulder flexed to 90 and the shoulder also in an internally rotated position. This position would put the posterior delt in the most lengthened position. Testing in this position would place the posterior delt at its highest risk of injury. We decided to keep the shoulder in abduction to 90 degrees to bring the posterior delt into a more shorted position.To ensure safety we had athletes maintain their testing shoulder in abduction only. Additionally we recognized that being in a split stance will allow for a larger base of support that ultimately allows for maximum force production through this test. 

Middle Trap 101+-32% MVIC / Study 8  (Escamilla RF, et al.)

Lower Trap 97+-16% MVIC / Study 8  (Escamilla RF, et al.)

Low Trap 95+-11% MVIC / Study 15 (Ekstrom, R. A., et al.)               

Lower Trap 97+-16% MVIC /   Study 16 (Ekstrom, R. A., et al.)

Musculature Accounted For-

This test is to assess the lower trap. The most activation of the lower trap is done with the shoulder abducted to 135 degrees and externally rotated. The lower trap muscle fiber orientation will be in the most direct line of pull of the until compared to the middle trap.The contribution of the middle trap activation happens due to the horizontal abduction movement pattern of the shoulder. 

Safety of Testing-

When we look at horizontal abduction looking at the length of the small external rotators mainly the infraspinatus and teres minor must be looked at. When the shoulder is abducted to 90 these muscles are in a shortened position which will decrease the likelihood of injury the most. If we were to start in more of a horizontal adduction position it would put these smaller muscles at risk for injury. 

Daily Repeatability and Technology Positioning- 

When assessing the lower trap most would have an athlete lay face first on a table with their shoulder off the table. The athlete would adjust to the shoulder being abducted to 135 degrees and they would horizontally abduct their shoulder. With our testing unit we replicated this position via a standing position. Additionally we recognized that being in a split stance will allow for a larger base of support that ultimately allows for maximum force production through this test. 

Subscapularis 75+-47% MVIC / Study 8  (Escamilla RF, et al.)

Ratio of ER/IR Chance of Injury /  Study 9 (Byram IR, et al.)           

Subscapularis 72.6+-19.9% MVIC / Study 13 (Jenp YN, et al.)

Musculature Accounted For-

This test assesses the strength of subscapularis in internal rotation.  With the shoulder position at 0 degrees of abduction it will force the subscapularis as a main internal rotator. This position will reduce the contribution of pectoralis major and latissimus dorsi. When the shoulder is abducted to 90 degrees the pectoralis major and latissimus dorsi moment arm are both increased which will increase their force producing capability. 

Safety of Testing-

When looking at internal rotation we decided on this position to pull the least amount of stress on the UCL and pectoralis major. With this position we can produce max internal rotation with the least amount of stress. Having the shoulder abducted and elbow flexed to 90 degrees the amount of stress on the UCL will be very high. 

Daily Repeatability and Technology Positioning- 

While most would assess the subscapularis by having an athlete lay down on their side we recognized the importance of having the athlete stand. In this position the athlete maintains flexion of the elbow to 90. This simplicity limits the error of position allowing for most repeatable results. 

Additional Information-

Byram I.R., et al conducted a longitudinal study assessing preseason shoulder strength levels of professional players for 5 years. They found that the ratio of internal and external rotation had a high correlation to injury. This is one of the reasons we included this test.

Infraspinatus  62+-13% MVIC / Study 8  (Escamilla RF, et al.)

Teres Minor 67+-37% MVIC / Study 8  (Escamilla RF, et al.)

Supraspinatus 51+-47% MVIC / Study 8  (Escamilla RF, et al.)

Infraspinatus 62% MVIC / Study 10 (Reinold, M. M, et al.)                                         

Teres Minor 67% MVIC / Study 10 (Reinold, M. M, et al.) 

Supraspinatus 68% MVIC / Study 10 (Reinold, M. M, et al.)             

Infraspinatus 84+-18.3% MVIC /  Study 13 (Jenp YN, et al.)

Teres Minor 80.5+-13.1% MVIC / Study 13 (Jenp YN, et al.)

Supraspinatus 80.7+-19.1% MVIC / Study 13 (Jenp YN, et al.)

Ratio of ER/IR Chance of Injury / Study 9 (Byram IR, et al.)

Musculature Accounted For-

This test is to assess external rotators of the shoulder mainly infraspinatus and teres minor with contribution of the supraspinatus. With the shoulder 0 abduction provides these muscles to be the main force produced instead of stabilizers of the shoulder when they are away from the body. 

Safety of Testing-

This position of the shoulder allows for the most stable position of the shoulder which will in turn be the safest. 

Daily Repeatability and Technology Positioning- 

While most would assess the infraspinatus and teres minor by having an athlete lay down on their side we recognized the importance of having the athlete stand. In this position the athlete maintains flexion of the elbow to 90. This simplicity limits the error of position allowing for most repeatable results. 

Additional Information-

Byram I.R., et al conducted a longitudinal study assessing preseason shoulder strength levels of professional players for 5 years. They found that the ratio of internal and external rotation had a high correlation to injury. This is one of the reasons we included this test.

Latissimus Dorsi 64+-53% MVIC / Study 8 (Escamilla RF, et al.)

Most lat activation is at 60% of extension / Study 12 (KRONBERG, MARGARETA, et al.)

Highest lat activation at 90 degrees  at 72.44+-28.13 / Study 14  (Park, S. Y., & Yoo, W. G.)

Musculature Accounted For-

This test is to assess the lat. The lat is the man extensor of the shoulder and one of the shoulders internal rotators. The lat in research showed that the most activation was do at 45 degrees of flexion. Yet when we look at the muscle tension relationship we see the strongest the lat can be is at about 60% of extension or 110 degrees of flexion. Flexing the shoulder to 45 degrees and flexing the torso increases the length of the lat which will get close to the most ideal length tension relationship.

Safety of Testing-

When deciding on this test we know that a fully lengthened lat is when the shoulder is flexed at 180 and externally rotated. We decided to position the lat in a semi lengthened position to allow for max force to be produced with the least likelihood of injury. Keeping the shoulder in an internal rotated position will keep the insertion of the lat at the shoulder in a safe position. 

Daily Repeatability and Technology Positioning- 

When assessing the lat most would have an athlete lay on their stomach with the shoulder at 0 degrees of flexion. The athlete would then move into extension. This position puts the lat in its shortest position. We decided to have the athlete stand, flex the torso and shoulder to increase the total length of the lat to its mid range. This lengthening will increase the moment arm which will allow for a more accurate strength measurement of the lat. Additionally we recognized that being in a split stance will allow for a larger base of support that ultimately allows for maximum force production through this test. 

Serratus Anterior 96+-24% MVIC / Study 8  (Escamilla RF, et al.)

Middle Delt: 73+- 16% MVIC / Study 8  (Escamilla RF, et al.)

Anterior Delt: 69+-24% MVIC / Study 8  (Escamilla RF, et al.)

Most activity at 120 degrees in anterior delt / Study 12 (KRONBERG, MARGARETA, et al.)

Most activity at 120 degrees in mid delt / Study 12 (KRONBERG, MARGARETA, et al.)

Serratus Anterior 91+-16% MVIC / Study 15(Ekstrom, R. A., et al.)

Musculature Accounted For-

This test is to assess the serratus anterior ability to stabilize the scapular to allow for the anterior and middle delt to produce force. The serratus anterior is most active when the shoulder is flexed to 120 degrees of flexion. 

Safety of Testing-

This position is the only position being flexion of the shoulder keeps the shoulder in a safe position to produce force from. 

Daily Repeatability and Technology Positioning- 

When testing the serratus anterior most would have the athlete flex the shoulder to 90 and internally rotate the shoulder 90 degrees. The practitioner would then push back against the elbow to see a deficit in strength in the serratus anterior which could also cause a well known movement of the scapula called “scapular winging”. In our testing process we choose to have the athlete stand and flex the shoulder to 120 degrees. This would assess the athletes serreatus in its function to stabilize the scap and genrolhumral head. This would also allow for max force to be applied from the middle and anterior delt. Putting the TISO unit at 1 foot from the ground allows for a more direct line of flexion that will activate the serratus anterior.