Maintain the box would be a teaching cue for a student trying to learn the feel of staying connected on a swing on a middle middle pitch. As PN said years ago, the primary adjustments are tilt for pitch height and radius of the hand path in and out.
BM-
Let me know when you've read things.
wellphyt -
These are great pictures of Pujols demonstrating the MLB pattern. Oleary's analysis is not very good.
With regard to what you see, much of Nyman's model is good with the limitations I have mentioned. In addition, Nyman's idea of TILT is wrong and he does not understand how in vs out adjustment is made. Epstein has the best description of TILT as it relates to up/down and fast/slow adjustment. TILT is best assessed from the open view of the hitter as how much their "posture" is leaned back or toward the pitcher. Note this is how Candrea/Enquist also analyze "posture". Nyman's method is much more based on bend at waist as looked at from the pitcher's view which misses the whole point of "early batspeed" and late adjustment.
Mankin's work is best at explaining how in/out swing radius is adjusted.
A good thing about Nyman's model is describing how the swing is most easily/simply thought of as a double pendulum which is the simplest form of whip.
The key to a good whip/release is to fire the bathead (bat is second/peripheral pendulum) out with active handle torquing beginning just BEFORE the torso (torso and connected lead arm are first/central pendulum) turns with maximum momentum which is when torso turn gets to maximum "angular velocity".
The wrists are the hinge that connect the two pendula, and in the case of human hitters, this is an active connection where torquing force can be applied to the handle to control the timing of the swing which is what Mankin explains as the torque component of the swig that blends with the whip/pendulum portion which he calls CHP (circular handpath) or "flail" (2-piece whip). Mankins' model is "CHP and TORQUE".
The shoulders/scaps are used primarily to assist the arms and hands in torquing the handle which lets the upper body control the timing and synch of the torso coil and firing of the bathead together with the hands staying well back so there is quick acceleration well behind the batter which enables maximum read time of pitch location and best/latest opportunity to adjust swing for a solid collision.
So when Pujols TILTS the shoulders to boost the torquing of the bat handle that is already underway, this lets the upper body resist turning open as the hips fire at the same time. This keeps the hands back and turns the bat between them. SInce the hips are turning the body quickly in a more level plane than the steeper plane the bat turns in, the result is a quick last additional stretch/coil/load of the torso between the hips and shoulders. This type of torso load ending with a last quick adjustable stretch (adjusts timing and direction of whip) permits the quickest possible bathead acceleration which also requires a running start of the turning of the bathead so inertia from accelerating the bat does not force drag.
The body is able to coordinate all this stuff - timing and direction of torso lever, timing of bat lever - by having the hands as the single locus of control in torquing the handle.
SO this is what to look for in PUjols.
The back arm has to stay in/angle stay in back elbow for torso to reach maximum momentum/turning velocity, but at the same time the bathead is being turned between the hands to overcome inertia and provide control of developing swing plane.
Then the bathead is firing out to trigger the self feeding acceleration of the bathead as the last quick coil/stretch/cusp/x-factor stretch of the torso ends. This is when the back forearm starts to lower and the back elbow angle starts to widen.
For self feeding explanation, again, see:
best of max page 0
Then there is palmup extension of the back arm to contact with unhinging of the lead wrist for a couple of frames before contact, BUT the top hand wrist still dorsiflexed or as Williams said "unbroken".
In the extension sequence/release for longer radius swings like more outside and/or low, there will be more extension before contact, both in the back and front elbow. Once the lead wrist has started to unhinge, it is then (in sequence) OK for the angle to start widening at the lead elbow for these longer radius swings. As the swing gets even longer, it is OK for the lead forearm to supinate which is what starts the wrists rolling. This is all OK (supports quick acceleration to contact without deceleration which would ruin timing) as long as the lead upper arm stays internally rotated in the lead shoulder socket and the back arm stays palmup without getting fully straight. In this case the lead wrist does get "uncocked at contact" - extends and ADducts. In this case, it helps to think of trying to keep the palm up because lead forearm pronation will start to turn the palm over just before you run out of range of motion for extension causing deceleration.
So it's a good idea to get familiar with this extension sequence yourself and it helps to look at many videos of the same player hitting different pitches to see how it can be done.
From a backward chaining perpsective, it pays to understand this extension sequence and how it connects to/with the loading/unloading of the body (body torque as Epstein calls it with his torque drill with bat on deltoid being an excellent introduction to the feel of the MLB pattern).
BM-
I'm still holding my breath.
You got all that wellphyt? Let me know when your 11 year olds get it......
Like I said, K.I.S.S is appropriate for your students age level.
So, you can "marry" that sequence of Pujols hitting an inside pitch, and call it his best 5% and hope your students hit mostly inside pitches...