Bobby Tewksbary On SwingTracker Metrics: Correlations and Key Numbers

PITTSBURGH – Renowned swing instructor and Diamond Kinetics Hitting Council Expert Bobby Tewksbary appeared on the “Grind Time” Podcast on Monday to discuss the future of hitter development with host Brandon Janecka.

During the show, Tewksbary discussed – at length – various Diamond Kinetics swing metrics and the implementation behind them that helps him identify how good a hitter is.

Tewks began by discussing the correlation between the SwingTracker metrics Hand Speed and Barrel Speed:

“Using Diamond Kinetics, I like to see a 1:3 ratio of Hand Speed to Bat Speed. When hitters have a 1:3 ratio … so let’s say Hand Speed would be 25 mph & Bat Speed would be 75 mph … that 1:3 ratio seems to create a lot of whip & produce good exit velocity”

Tewks then discussed the SwingTracker metric Impact Momentum and the number he sees to identify if a player truly has real power:

“Using Diamond Kinetics, if you have Impact Momentum around 26*, you’re probably a D-I caliber player. I’ve seen it get up to 32, and this is a kid who hits the ball 460 feet.”


So there you have it from one of baseball’s best hitting instructors:

  1. Make sure you have a 1:3 Hand Speed to Barrel Speed ratio
  2. And an Impact Momentum of +26 kg*m/sec


* Impact Momentum is measured in kg*m/sec, which is the standard unit of measurement relative to momentum