Unit 3 – Building A Daily Assessment Process (The Research)
EMG validated design
At the initiation of our development we designed our TISO Unit after testing its reliability over 100s of tests. With technology in hand we had to decide how we would put the technology to use. When building our daily assessment process we identified a few needs we had to satisfy before further development.
The first need was to select a testing process that would globally determine a daily shoulder strength level. Due to our technology requiring an isometric contraction we turned to EMG studies to evaluate specific muscle activation through specific positioning. An EMG study looks at the electrical signals your muscles make when they are at rest and when they are being used. Results of an EMG test are given in a percent of MVIC (Maximum Voluntary Isometric Contraction). MVIC is a standardized method for measurement of muscle stimulation.
To date KineticPro only works with pitchers in baseball so when deciding to choose what muscles to look at it was clear that we had to see what muscles are used most during the throwing motion.
In most research we see the pitching motion broken down into 5 phases. As research has pointed out there is very little to no stress is received during the first phase (the Wind Up Phase). Due to the limited output during this phase we focused specifically on the Early Cocking Phase though the Deceleration Phase when evaluating EMG studies on the throwing motion. Below is what we found through each of these phases.
Early Cocking Phase
According to research on EMG analysis during the throwing motion we see the entire deltoid had peak activation when the shoulder was abducted to 90 degrees. The role of the deltoid is to hold the shoulder in this position and aid in horizontal abduction during the early cocking phase (6).
Late Cocking Phase
The trap showed high activation in the late cocking phase to help with upperward rotation. The supraspinatus, infraspinatus and teres minor began to fire late in this phase. (7)
These muscles continued to fire then decreased when the subscapularis began to fire to decelerate the shoulders external rotation. (5)
The lat and pectoralis major became most active in the late cocking phase due to the external rotation and horizontal abduction (5).
Acceleration & Deceleration Phases
Acceleration Phase
The Serratus Anterior shows its highest activation in the acceleration phase. (5)
Deceleration Phase
The follow through showed levels of activation from all of these aforementioned mentioned muscles due to the muscles working to keep the humeral head in a stable position. (5)
Based on our findings we decided to seek research based around the following muscles to include in our daily assessment…
- Pectoral Major
- Supraspinatus
- Infraspinatus
- Trap
- Subscapularis
- Teres Minor
- Latissimus Dorsi
- Deltoid
- Serratus Anterior
With musculature now selected we want to take a second and recognize the limitations of EMG. Though we have come to a conclusion on the musculature involved it is important to note we did not take EMG studies simply at face value. EMG is a piece of the puzzle that simply shows activation of the muscle. We recognize there are more influences on individual musculature and we need to acknowledge the role of independent muscle during the individual movement.
In the next unit called “Building A Daily Assessment Process (The Tests)” we will discuss the tests we selected based off of our established musculature list.