It was strange that the article didn't talk about how one of the reasons there is so much more topspin and power in today's game is because the strings are less energetic now than they were before, meaning that players can swing a lot harder without worrying about sending the ball long.

I normally play with a racquet strung with a synthetic poly string (less stiff than Luxilon, but still pretty stiff and slippery), which allows me to absolutely whale on the ball, and in the process, generate a lot of topspin (as the racquet velocity at impact is pretty high).

A few weeks ago, while playing with a much family member, I used one of her racquets, which is strung with a much bouncier string; it was amazing how much I had to pull back on my shots to keep them from going long. Didn't hit with anywhere near as much spin or power then.

The slipperiness of the string certainly seems to have an effect on the flight of the ball, but so would the liveliness of the string. It would be interesting to see if those variables can be isolated.