What Causes the Hips to Rotate in a HL Swing?

[efastball]

OK, we're 29 posts in and we haven't seen an MLB player actually start to rotate his hips. I'm assuming the topic is the coil out, not the coil in.

Here's Granderson from toe touch to heel drop. This is when the hips begin to open with force.


This clip could be a eureka moment.

Here's Justin James

 

[Bobby Shirer]

OK, we're 29 posts in and we haven't seen an MLB player actually start to rotate his hips. I'm assuming the topic is the coil out, not the coil in.

Here we are from toe touch to heel drop. This is when the hips begin to open with force.
View attachment 14611

This clip should be a eureka moment.

Inward coil is the result of inward rotation of the femur of the trail leg in the hip socket while the movement chain is closed... the foot is in contact with the ground. Uncoil or "coil out" is the action of outwardly rotating the the femur in the hip socket with the leg in closed chain.... foot in contact with the ground.
In the first frame of your video and probably the frames immediately preceeding, you could see outward torque stress on the knee of the trail leg.

 

[Dre_007]

Left hip works back, right hip works forward, creating turn up and through the shoulders


Sent from my iPhone using Tapatalk

 

[Bobby Shirer]

View attachment 14614

Left hip works back, right hip works forward, creating turn up and through the shoulders


Sent from my iPhone using Tapatalk

How are the hips moved?

 

[efastball]

The front knee turns. This opens the hips. (front and rear) It's optimal to have momentum into the angled front foot (which changes direction).

The proof of the front knee action is when (almost all) kids swing with one foot in the air, they always turn their front knee over. This hip rotation is obviously much, much slower that the leveraged pro hitter in post #31. Even 2 legged people swinging on one leg are turning over their front 'knee'.

 

[Dre_007]

How are the hips moved?

Weight transfer coupled with the physical turn of the hips. Don’t know how else to say it.


Sent from my iPhone using Tapatalk

 

[Bobby Shirer]

Weight transfer coupled with the physical turn of the hips. Don’t know how else to say it.


Sent from my iPhone using Tapatalk

The hips are turned through the medial and lateral rotation ( inward and outward rotation) of the femurs in the hip joints and knee joint extension.

 

[efastball]

The hips are turned through the supination and pronation of the femurs in the hip joints and knee joint extension.

The knee joints do not appear to be 'extending' in post #31 Granderson. (Of course the front knee straightens/extends after hip slot, which continues/finishes the rotation)

Is the front femur effecting/causing the coil inward? Is the back femur effecting/causing the coil outward?

Good stuff.

 

[Dre_007]

The hips are turned through the supination and pronation of the femurs in the hip joints and knee joint extension.

How are the femurs supinated and pronated?


Sent from my iPhone using Tapatalk

 

[Bobby Shirer]

The core being stretched backward then forward creates torque. Along with momentum and shift creates leverage for this torque. This leverage rotates the hips. All are needed.

Momentum and shift by itself can create ‘active’ hips (unbalanced ) ( low adjustability).

Core torque by itself can create an ‘around’ swing. Among other issues.


The core being stretched both ways while the COG moves to its new ‘balanced’ position creates a powerful, adjustable, time friendly swing with minimal effort.

sequential resistance along with shift/momentum rotates the hips. ‘reactively’.

At contact, the hips and shoulders are usually aligned so there is no forward stretch. It's only a reaction after the torso realigns from the rearward rotation. The forward stretch is also the coast down that keeps the force of the bat from pulling your arms out of socket. The ball is long gone.
The rearward stretch is created in rotating the pelvis while counter rotating the shoulders resulting in torque and removal of slack in the spine allowing instantaneous power when the lead leg is extended causing the offset force on the pelvis = torque. If the pelvis isn't turned prior to application of the force of the lead leg, the counter action only resists forward movement because the force isn't offset from the center of rotation. The core muscles are contracted to realign the spine rotating the shoulders to align with the pelvis.

The knee joints do not appear to be 'extending' in post #31 Granderson. (Of course the front knee straightens/extends after hip slot, which continues/finishes the rotation)

Is the front femur effecting/causing the coil inward? Is the back femur effecting/causing the coil outward?

Good stuff.

The extension of the front knee is the dominant force in the swing. All prior linear movement is to load the lead leg and it's extension is the force that powerfully rotates the pelvis. Notice the powerful rotation really kicks in when the front leg is in contact with the ground and the extension is nearing completion.
Actually, the inward coil is the medial rotation (inward rotation) of the rear femur drawing the pelvis and the femur toward toward each other. The uncoiling is the lateral rotation of the rear femur. The lead leg rotation doesn't cause anything but a rotation of the femur in the socket because it isn't resisted by the ground... is open chain... so it moves but doesn't move anything but itself. It may create some momentum much like a pendulum.