Scap-loading occurs just before the pitchers shoulder starts to rotate. Lets break down what a scap-load is and what it does for our velocity :
The pitcher takes his elbows behind his back and pinches his shoulder blades together (as seen below in the slideshow). This action will help load the muscles around the shoulders enabling the pitcher throw 3-5mph harder. As I covered in the last article, the reason scap-loading makes us throw harder is because it helps us create more hip-to-shoulder separation. Scap-loading helps our throwing shoulder stay back longer while our front hip opens up towards home plate, creating a ton of torque. When we create hip-to-shoulder separation, our core is what pulls our arm through like a whip.
Check out some pictures of what a scap-load looks like below in the slideshow.
There is a safe way to scap-load. When a pitcher scap-loads, his elbows must below his shoulders. This is a crucial point to remember. Notice all the pitchers in the slideshow above. All of them are scap-loading the healthy way because their elbows are below their shoulders.
Take a look at Mark Prior. Notice his elbows are above his shoulders during his scap-load. This leads to a ton of stress on the UCL (elbow) and a short career.
Below you will notice that Billy Wagner fell victim to the same mechanical flaw as Mark Prior. Many relievers have a raised elbow when scap-loading. This scap-load will lead to a ton of arm injuries so this type of pitcher is best suited for short outings from the bullpen. Remember, the elbows must be relaxed and below the shoulders to properly scap-load.