Horizontal shoulder abduction, scap load, elbow angle are terms originally coined by Paul Nyman and which refer to the retraction of the shoulder blade (scap) prior to the arm cocking phase. Call it whatever you like, but the degree to which your scap “loads” matters. Horizontal abduction helps with layback and setting up the rest of the arm action once the lead leg blocks, decelerates and sends energy up the chain.

Studies by Stodden et al. (2005) and Takahashi et al. (2003) have demonstrated a high correlation between efficient scap load at foot plant and both angular velocity of the arm and throwing velocity.

However, the exact ranges for an efficient scap load vary from source to source. The American Sports Medicine Institute (ASMI) for example sets these bounds from 12 to 33 degrees, and while several MLB teams that we have spoken with concur, there are other sources that list ranges as high as 30-50 degrees as norms for their specific hard throwers.

Given the discrepancy, we looked at all of our mocaps with pitch velocities above 85 mph (with an average of 88 mph) and found an average scap load of 20 degrees at foot plant with 13 degrees of standard deviation. Below, you can see a plot of the data.

While setting the bounds for scap load between 10 and 30 would capture the largest number of pitchers, multiple studies have shown that a higher scap load greatly correlates with pitch velocity. So, while we use ASMI’s ranges as a baseline, we do look for an ideal range of 20 to 40 degrees. This range, we feel, will allow room for an already good pitcher to possibly add on a few miles per hour.

We need to emphasize the word “possibly” as everyone is different. Horizontal abduction that maximizes horizontal adduction velocity is what we’re after, not a maximal range of motion (ROM) just for the hell of it. The key here is identifying what ROM is ideal for each athlete. So play with it and pursue what works for you. Don’t just chase a higher number because, while more may be better, this is not always the case.

See ya’ in the gym…

Studies:

1. Relationship of Biomechanical Factors to Baseball Pitching Velocity: Within Pitcher Variation (by David F Stodden, Glenn S Fleisig, Scott P McLean, James R Andrews, March 2005)
2. Kinematic and Kinetic Comparison of Different Velocity Baseball Pitchers (Takahashi, N. Fujii, M. Ae, 2003)

By Nunzio Signore (Owner RPP Baseball) and Sophie Beier (RPP Bio-mechanist, Master’s Candidate in BioMed at Rutgers University)

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