This is a good point. When I grew up in Chicago during the Bulls dynasty era, Michael Jordan’s trainer Tim Grover wrote a book on explosiveness training mainly through body weight type exercises and flexibility versus heavy weights, now which is finally in vogue 20 years later. Meanwhile, Phil Jackson was very into mediation, which was adopted years later by Google with mindfulness training, and now mindfulness studios are popping up everywhere. Today, information is more accessible, but it’s still probably better to learn what Federer or Lebron does versus what your local trainer is recommending.