clock menu more-arrow no yes mobile

Filed under:

Justin Smoak and the Kinetic Chain

Justin Smoak retooled his swing this offseason. We can't know what that means for the future, until the future is the past.

new swing not pictured
new swing not pictured
Christian Petersen

Last season, from Opening Day to July 23rd, Justin Smoak had an OPS of .573. Understandably, his performance earned him a trip to Tacoma. It was only after a Mike Carp injury brought Smoak back to Seattle that he began to show improvement. From August 14th to the end of the season Justin Smoak had an OPS of .850. This should not be news to anyone. Justin Smoak was terrible before his demotion and not terrible after it. Smoak worked with AAA hitting coach Jeff Pentland during his brief trip to Tacoma. When he came back performed well. Due to the sample size (160 PAs), it's hard to tell if it was random variation or directly related to his work in AAA.

I'm mostly going to ignore Justin Smoak's 2012 September. Not because it falls into a small sample size (which it does), but because he was recalled sooner than expected due to an injury. The work he was doing on his swing was, presumably, incomplete. While the adjustments he made generated encouraging results, he continued that work into spring training this year and now we have much better look at his revamped swing.

So without further ado, lets take a look at how Justin Smoak changed his swing from before his demotion in late July to the current spring training version.

From the left (The .gifs are links that will open in a new window if you want to enlarge them):


  • 2013 Smoak has a two-handed followthrough, opposed to the one-handed followthrough from a year ago.
  • He is no longer jerking his head back after contact but following the ball through contact with the bat.
  • 2013 Smoak appears to pull his hands further back before attacking the the ball.
  • There is less wasted movement overall, specifically in his shoulders and knees.
  • His step is slightly different, he no longer pauses with his toe on the ground before setting down his heel.

From the right:


  • Last year his swing generated a lot of lateral head movement, he's cut down significantly on that.
  • Unlike his left handed swing, 2012 Smoak always followed through with two hands from the right. Although it does seem like his torso doesn't rotate as much post contact.
  • Immediately after planting his front foot, 2012 Smoak began rotating his torso. By contrast, 2013 Smoak's torso moves to the ball first before beginning to rotate. This one is harder to see at speed, I picked up on it while stepping through one frame at a time. (This may be more and adjustment to the specific pitch than an adjustment to his swing.)
  • Overall, there seems to be less superfluous movement through the swing.

We heard his swing described a number of ways "long", "loopy", or "terrible." (The last one might have been my own observation.) There is a reason why Smoak's new swing has been described as, "shorter", "more compact", and "more fluid." Intuitively, I feel these statements are true, but my feelings are not meaningful conclusions for what that means about his swing. What it actually means is his new swing is more efficient at transferring energy through from the ground through his body and into the baseball bat.

A swing is a combination of forces, both linear and rotational, working together to transfer energy from a player's body to the player's bat. The energy travels from the ground (which provides the counter force), up through the legs, into the torso, out through the arms and into the baseball bat (then hopefully the ball). This path is the kinetic chain, and it requires both proper timing and proper angles to maximize the transfer of energy.

To the eye, a proper swing will look smooth. This is because the proper transfer of energy as it flows through the chain is preserved. Energy flows seamless from one step to the next on its way to the baseball bat. His head is the key, in many of Smoak's 2012 at bats, you will see his head moving around a considerable amount. This movement siphons energy away from the kinetic energy in the chain and diminishes the total energy output in the bat. To put it simply:

Swing energy = Total energy - Energy lost to excess movement and bad timing.

Or even more simply:

Smooth is good; herky-jerky is bad.

The kinetic chain is applicable to all swing energy, from golf to tennis to baseball. Even pitchers use a kinetic chain to maximize leverage when throwing the baseball. You know when you see 2012 Smoak compared to 2013 Smoak that he made improvements, and you don't need to understand swing physics to intuitively understand it. We can conclude one thing about Justin Smoak's new swing, because he isn't moving his head as much, less kinetic energy is being siphoned away from his bat. However, we don't know whether it's been returned to the kinetic chain on its way to the bat, or if it's been removed from his swing altogether. Hope for the former, because the latter just means more warning track fly outs.

All we can do is wait and see if Justin Smoak can build on his 2012 September, and his 2013 spring training, to have a strong 2013 season. Justin Smoak is more efficiently transferring energy to the bat. The only question that remains is how often he'll transfer the kinetic energy from the bat to the baseball.

ADDITIONAL - With only four swings against Oakland last night, Justin Smoak showed us that his swing is still very much a work in progress: