This may be the most important thing you read about baseball or fastpitch instruction.

Understanding the difference between rotational hitting and linear hitting is the  most important concept in advancing to the next level when you play or coach baseball or fastpitch softball.

You must understand the key differences in these techniques in order to know what to look for in choosing baseball clinics,  lessons, coaching, which team to play on, etc.

What most coaches are teaching and what the great hitters have  actually been doing for over 100 years is something completely  different.

Since a swing happens so fast, it is not obvious to most observers what  is involved in a professional baseball or softball swing.   Therefore, it was difficult to prove or disprove an "expert's"  opinion.   The advent of freeze frame video has revolutionized hitting  instruction over the past 10-20 years.   

The main differences between rotational and linear have to do with the action/timing of the arms, hands/wrists,  and the back elbow - and the swing plane (or bat plane) that results from these actions.
 

There are 3 phases to hitting a baseball or softball 

• stance 
• coil (aka stride/ weight shift/load) 
• swing forward (linear vs. rotational differences) 

 Linear vs. rotational differences are only relevant in the swing forward  (3rd) phase (after the coil/stride and after toe touch).

Some insist that a linear swing is defined by the forward movement, or weight shift,  and rotational swings include elements of linear movement.  They are misinformed.

In reality, the stride vs. no-stride debate is not related to the linear vs. rotational debate.   Some people advocate no-stride in linear hitting.  Some advocate no-stride in rotational hitting.

Linear hitters can stride, and so can rotational hitters.  Linear  hitters can lunge, and so can rotational hitters.  Linear hitters can  rotate their hips, or squish the bug, or any number of things.  But, so  can rotational hitters.
 

A pure 'linear swing' is trying to 'whip' a (rigid) bat (which can't be 'whipped')  at the end of two outstretched arms without the use of the rotating body.

The "pure" linear swing is immediately taking the knob straight to the ball,  without any hip/ back elbow "connection" (the elbow just passes by the hip),  and extending both your arms at contact, and (generally) flipping your wrists.

A "pure" linear swing is a weak double pendulum (arm extension +  bat flip) that does not greatly benefit from the torso rotation because  of the power leakage from the increased distance from the body.

If you kept your hands back with a linear swing, this would create a  triple pendulum with the added back elbow, but "pure linear" pushes the  hands in front of the elbow early. However, this generally creates late (vs early) "bat lag", so good luck  with linear.  

A linear swing generally creates a downward or diagonal swing plane(a).

The type of swing is usually predetermined the moment your hands leave your shoulder.   If they leave too soon (linear), you create a downward swing plane, take your hands to the ball,  and disconnect with your hips.

Linear usually results in bat drag (think the fence drill), and hitting  the top of the ball (thereby driving the ball into the ground).  

The "typical" rotational swing, among many other things,  is taking your back elbow/shoulder to your hip as one of your first moves,  while keeping your hands back.
 

The linear swing is mostly used in fastpitch softball, and is rarely seen in MLB.

Linear swings are frequently seen and coached (inadvertently via cues) in youth baseball.

The rotational swing is used by most (if not all) MLB hitters.  

(a)  Note that swing planes for extreme "low and in" or extreme high  pitches may not vary much for rotational/linear swing types.

Even if that's true, shouldn't your goal be to generate quicker bat speed vs. faster hand action?

The use of the entire body to generate extra leverage and the additional  pendulum action enables you to generate faster bat speed using a  rotational swing vs a linear swing.

Faster hands do not create faster bat speed.  
 

After many years stubbornly using linear, we have been advocating rotational hitting for some time now.

Chris Oleary says:
 

"Linear Hitting is what most people are taught ... and Rotational Hitting is what most major league hitters  actually do" 

We spent many years learning hitting techniques at camps and hitting lessons and via coaching during practices and games. Most of this instruction used linear hitting cues described above, such as "hands to the ball", "don't drop your shoulder", etc. So I kept stressing and reinforcing these cues to my kids.

We even attended a clinic held by fastpitch champ Lisa Fernandez where she showed us how to swing a bat next to a fence   while getting the knob to the ball.   The purpose of this was to get your hands to the ball before the bat head.  I never thought to ask her to demonstrate how far she could hit a ball using this drill.

I guess I am slow, but I always questioned whether this technique really worked  and I just thought maybe the "experts" knew better than I did.

• Why were they fouling off so many pitches? 
• Why are they not hitting it deep? 
• Why are they mostly hitting weak grounders? 
• When they swing down on the ball it goes down - not up.