The arm is the final link in the kinetic chain connecting the ground to the ball. From a seated position, someone with good arm action can throw 60 mph — that's 60% of a 100 mph fastball from the arm alone.
'Flying open' is an umbrella term for a number of different mechanical flaws, when it's supposed to only describe where the front shoulder is at footplant. Misunderstanding it is a disaster for both velocity and command.
Of all the moments in a pitcher's delivery, footplant is the most important. But without a standardized definition, analyzing mechanics is impossible.
Coaching cues like 'stay closed' or 'squish the bug' are everywhere in baseball. But when is a cue helpful, when is it harmful, and how do you know the difference?
The motion capture databases don't contain the right information. The truly elite pitchers aren't doing lab bullpens at game intensity — so what are we actually modeling?
After decades of training to throw fast — from 80mph at 12 years old to 100+ as a big leaguer — Robert Stock shares the five key lessons that helped him make velocity strides at an age when most pitchers have peaked.