The last point about players in their thirties appearing in more professional matches needs more clarity. It’s not that “older players are dominating the sport.” It’s that “the two best players of all time happen to be over thirty.” This is not evidence that older players have gained an edge in professional tennis.
4 of the top 10 are in their 30s. If you include players who are less than 2 months from being 30 that would make 6 of the top 10 (and #11 is also in his 30s).
There isn’t a single grand slam winner who was born after 1988. All the 7 active grand slam winners will be in their 30s in 2 months. Currently 5 of the 7 active grand slam winners are in their 30s with the remaining 2 a couple of months away.
So it’s not just Nadal and Federer skewing the statistics. Then there is also the case of someone like Wawrinka, who didn’t win a single grand slam until he turned 29 after which he won 3.
The ageing effect in tennis is not a statistical anomaly but a real thing. I do, however, agree that technology’s impact in this has been limited to better sports medicine and fitness allowing older players to compete longer. However, the same players who are winning in their old age today are playing significantly worse games than they were 5-10 years ago. In addition to technology allowing older players to compete, the ageing of the game seems to have a lot more to do with the changing demographics of people getting into the game, cult coaching techniques, which at least in the US have destroyed any chance of an American competing (US coaches due to parental pressure for their kids to win so they can get a college scholarship instead of developing a good game focus on styles of play that work for undeveloped teens, but not at the professional level), and changes in the surface and balls that have slowed the game down and eliminated the styles successful in the 90s which many kids grew up emulating.
A good follow on to this study, along the lines of tennis, would be how the introduction of polyester strings to the pro game about 20 years ago [1] impacted the game, for younger and older players - to see if similar conclusions can be reached. For myself as an older tennis player with a well developed game, I had a much harder time adjusting to this newer type of strings than many younger players. Even though the theory and what had to be done made sense, overcoming muscle memory and ingrained habits proved very difficult - of course I'm just a sample size of 1.
I wonder if we will ever really break out of being generationally bound for situations like this. I see this in social issues especially. Seems like the speed of change is rate limited by older generations dying and newer ones being born.
http://www.physics.usyd.edu.au/~cross/SPAGHETTI%20STRUNG%20R...