Originally Posted by stoneage
I would love to see a proof of this, or at least an indication how this has been calculated.
The method of letting the racquet sweep through a high-to-low-to-high swing with a relaxed wrist in order to determine the optimum MgR/I is not a calculation -- rather, it is a method of measurement. You can easily feel the moment that the racquet applies to your hand. You don't know the magnitude of the moment, but you can perceive the direction in which it acts (either backward or forward).
If the racquet pushes back on your hand (i.e., pressing against the base knuckle of your index finger) as it comes forward through the hitting zone, then MgR/I is below the optimum (which is roughly 21.0 for an average sized male, but slightly higher for shorter players, and slightly lower for taller players). If the racquet handle pulls forward on you fingers as it comes through the hitting zone, then MgR/I is higher than your optimum.
This is the method I use to tune a racquet in a pinch, when I don't have access to a wall. A more precise way to tune MgR/I is to use the wall targeting method I described in other threads.
Also, I choose to keep the convention of including g in the formula because g can vary significantly enough between different cities around the globe to make a noticeable difference in how my racquet plays, and I travel a lot for work, and always bring a racquet with me. For example, I will at my office in Belgium next week , where g = 981. I also travel to Buenos Aires a couple of times per year, where g = 978. The difference in racquet swing dynamics affects my swing enough that I like to look up the g value when I travel and adjust accordingly.
That reminds me: I'm looking for a hitting partner in the following cities over the next 2.5 weeks: Vienna, Barcelona, Glasgow, Paris, Madrid. Any takers (I'm a 4.5-5.0)?