Table training and Physical training Ratio

I asked Stellan Bengtsson this question at one of his training camps last year.  He said it varied from player to player.  When he was a player he did a lot of lower body weight training (squats, etc.) but he said that other players didn't do weights but preferred running and other things.  Seems like more of a personal preference. 

If you look at the legs of the Chinese and Japanese pros they're definitely doing weights...

It must depend a lot on the type of game you play.  For players whose mainstay is the loop fitness has to be more important.  Same for off the table defenders.  But if your game is close to the table blocking/hitting with lps or anti then you can get away with being less fit.

I still don't see why young players shouldn't cross train in addition to their tt training.  How would this interfere with your muscle memory for tt?  Of course if your cross training is another racket sport then ok, not a good idea!  But shouldn't lifting weights, running, etc., be ok?

TT in the first instance is all about Brain/hand co-ordination, once that is gained to a level of competence, physical ability does come in to it, but lets get real, a 70 yr old expert, is gonna piss on a novice how ever fit he is, there is a grey area in between.

So, maybe a thread like this has come up, but I don't remember one. So I went ahead and started this one.
We all know how important training is through and through, most importantly when you start. That is, practicing and getting down repetition for your strokes, then moving into the other aspects of training, serving, serve return, linking strokes, footwork, etc. But an interesting point was brought up in Brian Pace's Textbook Table Tennis Training video and that was that there wasn't going to be any kind of physical training regimen in this video because developing the muscles etc. would mess up muscle memory and stroke development. Loosely quoted anyway. But the idea is there, beginners should not work on physical training because it actually hinders their game in development.

So how true is this? But we all know that top table tennis athletes have just as an intense, if not, a serious physical training regimen integrated with their game. So obviously there is a turning point somewhere. When do you finally turn on the lights and begin physically pushing yourself on the table along with outside of it? And if so, what's a good ratio of physical training to table training?

My take on it is, once you have your consistency down for your strokes, or at least once you've attained some form of sound technique, you should include physical training. I hadn't really thought about it much until reading about the current U.S. National Champion Michael Landers' training schedule, which included a rigorous fitness regimen including plyometrics and working with medicine balls.

So where is that line? If there is one?