Level 6 Valued Member
You have to go by the demands of the sport.I don't have a link but from professionalisation in the mid '90s rugby players got bigger, a lot bigger, and noticeably more muscular, but the pace of the game increased, perhaps as a consequence of fitter and stronger players, so that process started reversing and players these days are, on average, smaller than they were, say, a decade ago. But the key metric seems to have been the pace of the game. The really big guys struggle to keep up and so I would bet that as a consequence of the pace of the modern game average body fat percentage of rugby players would have declined. Sad news for big fat props!
In the last 15-20 years soccer player got beefier out of neccessity. Experts say it's because the game got faster.
Faster means higher impacts which means you need more "armour".
Look up pics of Messi and Ronaldo at the beginning of their career and now. Both packed on a good amount of muscle. That's the usual thing right now for soccer players - they start out as 16-18 years old scrawny kids and turn into underwear models by the age of 22-23.
Sure soccer comes nowhere near rugby or football when it comes to physicality, but there's still a noticeable change from the 90s to now.