Every player that I have ever worked with from little leaguers through pro players all know one thing:  your power comes from your legs.  After all, this is what kids are told from their first days on the t ball field.  However, while almost every player I have ever worked with can recite that to me, I find that very few players understand and/or can implement how to actually use the lower body to generate power. While there are a number of factors that go into how the lower body produces power, today I want to discuss the most talked about: hip rotation.

“Squish the Bug”

One of the first cues that young hitters get is to “squish the bug”. While I have my reasons for not liking this cue for older hitters, it highlights the importance of rotating the hips from day one on the baseball field. Players know they need to turn their hips, but why?

The way that I like to describe the lower body is as the engine of the swing.  The hips are what should start the swing and drive power.

Take a look at Justin Smoak.  Watch how once his foot hits the ground his hips start rotating first as his upper body stays closed. Once his hips can’t rotate any further, the upper body pulls around because of the hips.  



The video above shows how, in its simplest form, how the body works to generate power. The hips and shoulders “separate”. This simply means that the hips rotate towards the pitcher as much as possible and the upper body stays rotated back towards the catcher. The best hitters in the world do this to generate power and the best pitchers in the world do this to generate velocity. It is why Mookie Betts at 5’9” and weighing 175 pounds can hit 32 homeruns in a Major League season.


Why the timing of the hips is more important than turning the hips (Short Anatomy and Physiology Lesson)

For most younger hitters, or hitters who don’t generate much power, the timing of the hips and upper body is off. Watch a little League hitter and most likely, they will lead the swing with the upper body first. While these players may turn their hips fully, there is almost no contribution from the hip turn because the hips are not pulling the muscles of the upper body. Hitters who start their hip rotation before the upper body can generate a ton more power even if they don’t fully turn their hips.

The muscles in the body generate power by what is called the stretch shortening cycle. Simply put, we want to stretch a muscle just before firing it. This will produce the most amount of force possible. This is why when a basketball player goes up for a rebound they will drop down an immediately jump up instead of squatting down for 3 seconds before jumping.

This means that we want a hitter to stretch the muscles in the upper body just before they fire them. If the hips don’t go first, we won’t activate this process.

K-Vest Application

Since I have begun using the K-Vest at Elite Diamond Performance, I have been able to gather some incredibly valuable data on how much separation players create at different points in the swing, as well as the sequencing of body parts. I knew that I would find that many young hitters struggle with leading the swing with the hips but it certainly helps to have a quantifiable measure.

The first thing that I am looking for with the data is that the hips reach peak velocity and pull the upper body around. This means that the lower body should power the rotation of the upper body, which should rotate faster than the hips. If the hips rotate at 600 degrees per second, the torso should move about 1.5 x that or 900 degrees per second.  If we see a torso that rotates too slowly, their is almost always a lower body flaw that can be corrected.

The second thing that I look for is a hitter who creates separation during their first move (the beginning of upper body rotation after the launch position). Major League hitters are able to create between 25-45 degrees of separation between the hips and upper body. Here is data of an amateur hitter of mine and a pro hitter of mine. The amateur hitter’s upper body is 3 degrees ahead of his lower body. The pro player’s upper body is 31 degrees behind his lower body.

Amateur Hitter

Amateur Hitter

Pro Hitter

Pro Hitter



Below is an introductory drill to allow hitters to feel the separation of the upper and lower body, and help the hitter feel the hip rotation lead the swing.