[comdpa]

So what use is clubshaft lag like this (by the way I think the magnitude of the bend "observed" here is a aperture speed issue) if the shaft is bent toe up? Does anyone think this is useful in transfering power to the ball? If so how?

Golfie

Per 2-E "Notice this - the ball acquires only 70% of the Clubhead "approach" speed (so there must be speed) but 100% of the Clubhead "separation" speed (so there must be resistance to deceleration)...Prestress (Acceleration) stiffen the Clubshaft for consistent (minimum to maximum) resistance to Impact Deceleration."

By loading the shaft, you "prestress" it, making it less susceptible to deceleration during impact.

Why is that needful?

Because ball speed is dependent on two factors; Clubhead approach speed and Clubhead separation speed.

The more loaded the shaft, the more it resists deceleration because of a greater Moment of Inertia, hence increasing the second contributing factor to ball speed - separation speed.

With high approach speed and high separation speed, we will get high ball speed ceteris paribus which translates into "big" shots!

Hope that helped.