Why plenty of strength doesn't add pitch velocity

Plenty of pitchers have the same gut feeling: if your velocity isn't going up, you're not strong enough. So you keep adding weight to your squat and bench press, and after a winter of training the numbers have gone up a lot – but on the mound, your velocity hasn't moved. Why?

Because there's a gap between being strong and throwing hard. One study tested 13 college pitchers: their average squat 1RM was 152 kg, about 1.7 times body weight. Yet the correlation between squat 1RM and velocity was -0.01 – effectively no relationship – and the bench press was the same. You can't tell who throws hard just from the numbers on the bar.

Start with the front leg. In a study of 20 college pitchers split into two groups by velocity, the fast group threw 135 km/h and the slow group 120 km/h. At ball release, the fast group's front foot pressed into the ground with about 2.2 times body weight, the slow group 1.7 times. Only when the front leg holds firm does the forward momentum turn into the upper body whipping forward; when the front leg gives, the energy leaks out through the knee.

Next, the trunk. In a test of 24 youth pitchers, the energy transferred from the trunk into the arm correlated with velocity at 0.90 – the highest of all the measures. When this hand-off goes wrong, the shoulder pays for it: of 72 high school pitchers, 33 reached peak rotation speed in the upper body before the pelvis, and they showed about 7 degrees more shoulder external rotation and a shoulder distraction force about 9% of body weight higher.

Strength is the foundation; what you need to train is how to deliver it. So what should you train? Four things.
A front leg that brakes on landing: single-leg lateral hops – land and stick it, without the knee collapsing forward.
The back leg driving forward: lateral bounds aimed towards home plate, not jumping upward.
The trunk delivering force: step-in medicine ball forward throws and half-kneeling medicine ball side throws – rotate the hips first, then the upper body, with the arm coming through last.
Braking after the throw: face pulls and prone T and Y raises to train the muscles around the back of the shoulder.

What's your velocity right now, and has it gone up since you started strength training? Tell me in the comments.