[BerntR]

Those terms....

I was mixing angular acceleration with radial acceleration in my last post.

Here's a pretty good description of radial and linear acceleration / tangential acceleration. Tangential acceleration is similar to linear acceleration in the sense that it works in the same direction that the subject body is moving. The only difference is that tangential acceleration changes direction all the time. This is by the way illustrated by the notation "AT" in the figure below, indicating that linear acceleration is also tangential acceleration. This was writting for alpine skiing, but it is valid for the golf swing too:

It probably comes as no surprise that acceleration plays a large role in cross country skiing. Rounding a corner, or rather trying to round a corner, while skiing down hill can often lead to disaster. On the other hand, decreasing acceleration (or deceleration) can also cause problems. Imagine a skier accelerating only to be tripped by a hidden tree root. The skier's acceleration would greatly decrease as the ski stopped on the root, and there is a possibility for injury.

One type of acceleration experienced by skiers is linear acceleration. This acceleration is simply the final velocity minus the initial velocity divided by the difference in time. Constant acceleration = (V f -Vi)/(Tf-Ti) . This means that if a skier starts from rest and 2 seconds later the skier is traveling 4 m/s, the skier is accelerating at 2 m/s 2 .

Circular acceleration is another aspect of skiing. There are two components of this acceleration, radial and tangential. Below is a circle with some of the radial and tangential acceleration vectors drawn in.

Comment from me:

This could be a golf swing - but for a split second only. Unfortunately, the direction is similar to a left handed golf swing. But my comments are right handed.

The radial acceleration will always be 90degree to where the club head is heading and the tangential force will always be in the same direction as the club head is moving. The "rope" - using a rope handling technique will always be pointing in the same direction as the sum of the two vectors Ar and At. By applying torque to the swing (something that is heavily used in a hit, and is possibly also unavoidable in parts of a "pure" swing), the "rope" will be a virtual rope, and it could easily be anchored far outside the left shoulder.

As long as there is some lag in the swing, and as long as the swing is picking up speed - the rope will be offset to origo. And this offset is lag to the primary lever. Lag doesn't have to be limited to the relation between arm and club either. It can also be related to the relation between the whole primary lever and origo.

1) Early in the downswing the ratio of tangential vs total force is relatively big. When there's a huge angle between left arm and the clubshaft, a lot of tangential force is applied to the club head. And a lot of the resistance, or weight that we feel is because the club is picking up speed.

2) Later in the downswing the ratio changes towards more radial force (force that doesn't increase speed). A lot of the resistance we feel now is from this radial force.

3) Within this frame of reference, clubhead lag is to a very large degree the ratio of tangential vs total force. With a 100% pure rope handling technique, the shaft orientation vs origo (at any time) is probably a decent indicator of this ratio.

4) Clubhead lag seems to be referring to the secondary lever most of the time. But the offset between Origo and the center of the pulling action (which could be left shoulder joint) represents lag to the primary lever assembly. You can still have lag pressure in the swing even though the clubface has caught up with your hands. Not that I recommend it though.


Original explanation continued:

Radial acceleration can be found by dividing the velocity squared by the radius. Radial acceleration = v2 /r . Radial acceleration occurs because of a change in direction of the velocity. From the formula above it is easy to see why it is harder for a skier to make a turn with a small radius than a turn with a large radius. Due to the fact that the radius is in the denominator, the smaller the radius the greater the acceleration and the larger the radius the smaller the acceleration is.

Tangential acceleration = d|v| / dt. Tangential acceleration is what causes a skier to change speed while rounding a corner. The tangential acceleration plus the radial acceleration are equal to the direction of the acceleration vector.