There is general strength training and specific strength training.
General strength training should be done apart from MA training while specific strength training ( example would be specialized grip work for tiger style kung fu) should be done while doing the style.
Ideally you would like to be strong and healthy enough BEFORE BUT that isn't a must.
There is much to be said about developing strength training in conjunction with MA training.
Of course this isn't an either/or thing so it ends up being what is best for the individual, just like it was done traditionally.
Psalms 144:1
Praise be my Lord my Rock,
He trains my hands for war, my fingers for battle !