I keep training it as part of multi-train until I hit 90 and then I roll it over 1 more time.
http://goallineblitz.com/game/player.pl?player_id=2473753 - this is a DE, but basically built like a strength based DT. Strength is currently 40% trained. He will hit 90 strength through ALG before it rolls over again. So I will stop training it after it rolls over around day 30 of this season.