Baseball

With far better strength and conditioning methods and equipment? With batting cages in the clubhouse that have video cameras that allow you to analyze your swing or pitching motion frame by frame? With Certified Athletic Trainers (many with Master's degrees in disciplines such as kinesiology) whose job is to keep players in top condition? With ball parks designed to favor the power hitter? (In Ruth's day, many yards had fences 450 feet or more from the plate.)

Yeah, I think he'd be pretty relevant today, as would the other greats of a century ago.