Most of the long hitters I have played with over the years have been very agile,rather than muscle bound.It is no surprise that the more successful senior players on tour are mostly slim and quite tall.
With a player with the build of Trevino who was very strong in his heyday,would find it much harder to turn(away)from the ball now in his later years.
The longest hitter that I knew,use to have to run around in the shower to get wet.